The International Journal of Oral & Maxillofacial Implants, Pre-Print

Purpose: The formation of a biological seal between implant abutments and the surrounding soft tissue is a preventive strategy against peri-implantitis. The aim of this study is to test the hypothesis that surfaces of prosthetic implant abutments treated with vacuum ultraviolet (VUV) light enhance the growth and function of human gingival fibroblasts. Materials and methods: Implant abutments were treated with 172 nm VUV light for one minute. Untreated abutments were subjected as controls. Their surface properties were characterized using SEM, contact angle measurements, and chemical composition analysis. Human gingival fibroblasts were cultured on both untreated and VUV-treated abutments to evaluate cell attachment, proliferation, distribution, and collagen production. Cell detachment assays were also performed under various mechanical and chemical stimuli. Results: After VUV treatment, implant abutments demonstrated a notable transition from hydrophobic to hydrophilic wettability. Surface element analysis revealed a considerable reduction in surface carbon and increases in oxygen and titanium elements on the VUV-treated surfaces. On day 1 of culture, 3.9 times more fibroblasts attached on VUV-treated abutments than on untreated control abutments. Fibroblastic proliferation increased 1.9-3.1 times on VUV-treated abutments, along with a significant improvement in the distribution of populating cells. Collagen production on VUV-treated abutments increased by 1.5-1.7 times. While untreated abutment surfaces showed voids and limited spread of collagen deposition, dense and full coverage of collagen was observed on VUV-treated abutments, with a great contrast in the challenging axial surface zone. Cell retention against mechanical and chemical detaching stimuli was increased 11.3 and 4.3 times, respectively, by VUV treatment. Conclusion: Treatment of implant abutments with VUV light for one minute resulted in a reduction of surface carbon and a transformation of the surface from hydrophobic to hydrophilic. This led to enhanced attachment, proliferation, and retention of human gingival fibroblasts, along with nearly complete collagen coverage on implant abutments. These in vitro results indicate the promising potential of utilizing VUV photofunctionalized implant abutments to enhance soft tissue reaction and sealing mechanisms. Schlagwörter: ultraviolet light; implant abutment; gingival fibroblasts; soft tissue attachment; photofunctionalization

Objective: To explore the effect of adding an allogenic soft tissue graft at time of single implant placement using a fully digital workflow for single implant placement and restoration without making either analog or digital impressions. Materials and methods: A prospective randomized clinical study was performed enrolling thirtynine participants requiring single tooth implant randomized into (+ graft) group which received an allogenic dermal graft at the time of implant placement (n=19), or (- graft) group (n=20). A fully digital surgical and restorative protocol was implemented. Intraoral scans were taken before implant placement (T0), at time of final crown delivery (T1) and at one-year post placement (T2). Intraoral scans were aligned using Geomagic Control X 2020 software), linear and volumetric changes in buccal tissues were measured at T0, T1 and T2. Implant survival, probing depths, and complications were recorded. Participants were asked to complete an OHIP-14 survey at T0 and T2. Marginal bone levels were measured at T0 and T2 on peri-apical x-rays. Results: 39 participants completed surgery and restoration in incisor, canine, premolar and molar positions. Two early failures were recorded in central incisor positions (95% survival). Crown delivery without complication from the digital workflow (impressionless) was achieved for 36/39 of cases (92%) with implant depth control being implicated as the chief challenge. Thirtyseven participants attended the one-year follow-up visit. Both groups showed gain in buccal tissues thickness without significant differences between the two groups for both linear and volumetric measurements (P>0.05). Soft tissue grafting was associated with minimal added morbidity. The interproximal marginal bone changes recorded were -0.16mm mesial and - 0.12mm distal for the graft group and -0.01mm mesial and -0.11mm distal for the non-graft group (p=0.07 for mesial and 0.83 for distal). OHIP score was significantly reduced at T2 compared to T0 (P=0.003) for the entire cohort. Conclusions: The augmentation of alveolar mucosa on the buccal aspect of single tooth implants is associated with clinically favorable outcomes. A fully digital workflow has been validated to permit crown delivery on CAD/CAM abutments without implant impressions. Schlagwörter: Keywords: single implant, soft tissue graft, allograft, digital, marginal bone loss

Purpose: The aim of this study was to investigate whether genetic variations in cytokine genes involved in the pathogenesis of peri-implantitis, could be associated with its occurrence, an issue that remains controversial and may vary according to the population evaluated. Material and Methods: A cross-sectional analytical study was carried out on 102 Portuguese Caucasian individuals divided into two groups: 43 individuals with peri-implantitis and 59 individuals with peri-implant health. Samples from the buccal mucosa were obtained and genetic analysis was performed using the real-time polymerase chain reaction (PCR) technique for IL-1A and IL-1B and using PCR and restriction fragment length polymorphism analysis for IL-1RN. Results: The IL-1A -889 C/T polymorphism showed a higher prevalence of the less common allele (T allele) in cases of peri-implantitis than in healthy cases (27.9% vs 16.9%, respectively), but without statistical significance (p = 0.060). For the IL-1B +3954 C/T and IL-1RN (variable number of tandem repeats) polymorphisms, the analysis revealed that the allele and genotype frequencies did not differ significantly between groups. There was a significant association between a history of periodontitis and peri-implantitis (p = 0.020). Conclusions: The genetic polymorphisms evaluated had no influence on the occurrence of periimplantitis in the population studied. Further research into genetic variations in different populations is needed to elucidate the role of genetic factors in the onset and progression of periimplant disease. Schlagwörter: Keywords:dental implants, peri-implantitis, interleukin-1 receptor antagonist protein, interleukin-1, genetic polymorphisms.

Purpose: The aim of this study is to evaluate and compare patient satisfaction levels in edentulous patients treated with different configurations of implant supported prosthesis. Also, the effect of previous prosthesis experience before implant treatment on patient satisfaction was investigated. Materials and Methods: A study population of 142 patients was identified. Patients seperated into four treatment types. Group 1 comprised 43 patients treated with implant supported overdenture for mandible and conventional complete denture for maxilla while group 2 comprised 32 patients treated with implant supported overdentures for maxilla and mandible. Group 3 comprised 26 patients treated implant supported overdenture for mandible and fixed prosthesis for maxilla. Group 4 comprised 41 patients treated with implant supported maxillomandibular fixed restorations. A questionnaire consisting of specific issues about masticatory performance, pronunciation, comfort, social ability were used to evaluate treatment outcomes. Results: The patients in group 4 were significantly more satisfied regarding masticatory performance than other treatment modalities. VAS scores of Group 3 and group 4 regarding comfort and social ability were similar while scores of these two groups were significantly higher than that of group 1 and 2. The patients who used conventional removable prosthesis before implant treatment were more satisfied with their implant supported prosthesis regarding social ability.(p=.03) Conclusion: It was found that treatment design of that implant supported fixed prosthesis on maxilla and implant overdenture on mandible provided comparable level of satisfaction with maxillomandibular fixed prosthesis for edentulous patients. Implant supported fixed prosthesis for maxilla and implant supported overdenture for mandible served as a practical alternative to satisfy patients especially in patients with mandibular atrophy who would demand extensive surgeries for maxillomandibular fixed prosthesis. Satisfaction level of implant supported overdenture was not superior to conventional prosthesis for maxilla. Previous removable prosthesis experience may influence social comfort of patients.

Purpose: The current cross-sectional study aims to introduce a new method for the labiopalatal positioning and angulation of immediately placed dental implants in the anterior maxilla with relation to the type of abutment used (straight/angled abutment). Material and methods: Cone beam computed tomography scans from the database of a private practice were searched for patients who received immediate implants in anterior maxilla. After superimposition of the initial and post-operative scans, incisal/root angle (IRA), incisal/implant angle (IIA) and the difference between both angles were measured. Furthermore, assessment of whether the implant position would be lying within the safe angle or not. Age, gender, tooth/implant site and type of prosthetic abutment (straight/angled) were retrieved from patients’ records. Results: Seventy-four patients with a total of 95 immediate implants were selected for analysis. In regard to the type of abutment, 76 (80%) were straight, while 19 abutments (20%) were angled. Regardless of abutment type, 72 implants (75.8%) lay within the safe angle while 23 implants (24.2%) did not lie within the safe angle. All 19 implants with angled abutments were not lying within the safe angle. There was a statistically significant association between type of abutment, IRA, difference between IIA and IRA, gender and lying within the safe angle (P-value <0.001, OR = 19, P-value <0.001, Effect size = 0.904, P-value <0.001, Effect size = 1.209 and P-value <0.001, OR = 2.995 respectively). There was no statistically significant association between IIA, site or age and lying within the safe angle (P-value = 0.757, Effect size = 0.063, P-value = 0.200, Effect size = 0.184 and P-value = 0.387 Effect size = 0.208, respectively). There was a statistically significant association between IRA, difference between IIA and IRA and type of abutment (P-value = 0.001, Effect size = 0.762, P-value <0.001, Effect size = 1.056, respectively). Conclusions: The Safe Angle Concept can be used as a reliable planning tool to choose the correct IIP position in the anterior maxilla. Applying the safe angle concept will decrease the use of angled abutment for prosthetic correction.

Materials and Methods: Post-market, prospective, randomized, controlled, multi-center study with a primary endpoint of one year. 53 subjects were randomized to receive either immediate implant placement (test group) or delayed implant placement (control group). The mean crestal bone-level changes from implant loading to 12 months post-implant loading were measured using standardized, digital periapical radiographs. Changes in facial plate thickness measured on cone-beam computed tomography (CBCT) images, implant success and survival, implant stability, soft tissue changes, patient-centered outcomes, and adverse effects were measured to assess outcomes between the test and control treatments at 12 months post-loading. Results: 46 subjects completed the study (23 in each group). Mean bone changes from loading to the 12 month follow-up were recorded with no statistically significant difference (p=0.950) between both groups. The hypothesis was confirmed that immediate implant placement (Test) in extraction sockets is similar to delayed placement (Control). The test group was found to be similar to the control group (P=0.022) in terms of mean changes in facial plate thickness. Implant survival and success were 95.8% in the test group and 92% in the control group. Stability in the control group was superior at the time of surgery, but there was no difference between both groups at implant loading, producing a non-significant p-value of (0.563). Conclusion: This randomized, controlled, multi-center one-year study showed comparable outcomes 1-year after prosthetic loading in the immediate and delayed placement groups. Schlagwörter: Key words: prospective study, dental Implant, marginal bone level, soft tissue, complication, randomized clinical trial.

Objectives: The aim of this narrative review is to describe the emerging evidence concerning etiological factors and pathophysiological mechanisms involved in peri-implant inflammatory diseases. Material and Methods: An electronic search for articles published until November 2022 was conducted in MEDLINE by three independent reviewers to identify manuscripts reporting data on etiological factors and pathophysiological mechanisms associated with peri-implant diseases. Results: Current evidence suggests that peri-implant mucositis and peri-implantitis are inflammatory conditions linked to a microbial challenge. However, in recent years, there has been increasing evidence indicating that certain peri-implant inflammatory conditions may not be primarily related to biofilm-mediated infectious processes but rather to other biological mechanisms, such as a foreign body response. Conclusion: The current evidence, not only in the dental literature, opens new avenues for a more complex interpretation of the etiopathogenetic factors involved in peri-implant diseases. A better understanding of various factors related to the host response, including dysbiosis mechanisms associated with changes in microbiota composition, is necessary for a more precise physiopathological characterization of these diseases. Schlagwörter: Keywords: dental implant; peri-implant diseases; foreign body response; microbial biofilm; periimplant Infection.

Objective: The aim of the present study was to compare the histomorphometrically evaluated new bone formation (NB), the radiographically measured graft stability and the clinical implant outcome for maxillary sinus augmentation grafted with deproteinized bovine bone mineral (DBBM) with either small (Bio-Oss-S.) or large (Bio-Oss-L.) particles. Materials and Methods: By using a split-mouth study design bilateral maxillary sinus augmentation was performed in 13 patients either with Bio-Oss-S. particles (0.25-1 mm) or with Bio-Oss-L. (1-2 mm). After a healing period of 6 months bone biopsies were axially retrieved in the molar region for histologic/histomorphometric analysis of new bone formation including subsequent staged-implant placement. For determining graft stability the maxillary sinus augmentation vertical graft heights were radiographically measured immediately after sinus augmentation, at implant placement and at the 2- and 4-year post-augmentation follow ups. In addition, the clinical implant-prosthodontic outcome (survival/success/marginal bone loss) was assessed at year 1 and year 3post-loading. Results: 22 sinuses of 11 patients with split-mouth evaluation were ultimately available for data and statistical analysis. Histomorphometric analysis of the axially retrieved bone biopsies revealed new bone formation (S.:25.5Å}7.0% vs. L.:23.6Å}11.9%; p=0.640), residual graft (S.:19.6Å}9.2% vs. L.:17.5Å}6.3%; p=0.365) as well as connective tissue (S.:54.9Å}9.2% vs. L.: 58.9Å}12.5%; p=0.283) without differences between the use of small (Bio-Oss-S.) and large (Bio-Oss-L.) particles. However, there was significantly (p=0.021) higher graft-to-bone contact (BGC) for the small-particle ( 27.9Å}14.8%) than for the large-particle size (19.9Å}12.9%) representing a significantly higher osteoconductivity. Both particles showed significant (p<0.01) vertical graft height reduction over time (4 years) of about 10% with predominant graft reduction in the time-period between sinus augmentation and implant placement compared to the time-period of the follow-ups post implant placement. At the 3- year post-loading implant evaluation all implants and prostheses survived (100%) and the peri-implant marginal bone loss (S.:0.52Å}0.19 mm; L.:0.48Å}0.15 mm) as well as the periimplant health conditions (S.:87.5%, L.:81.2%) also did not differ between implants inserted with the two different xenograft particles used. Conclusions: The use of small and large bovine xenograft particles for maxillary sinus augmentation provides for comparable bone formation ensuring stable graft dimensions combined with high implant success and healthy peri-implant conditions. However, small particle size resulted in a higher bone-to-graft contact providing for higher osteoconductivity than with the larger particle size.

Purpose: The purpose of this systematic review was to assess histological and imaging outcomes related to new bone formation around implants, inserted simultaneously with sinus augmentation, comparing different types of grafts. Materials and Methods: Systematic Review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta- Analysis (PRISMA), and the Cochrane Handbook for Systematic Reviews of Interventions. LILACS/BVS, Medline/PubMed, Cochrane Library and Embase databases, including gray literature and manual investigation, were searched to identify clinical trials reporting human histological and imaging data of bone formation around implants, inserted into the maxillary sinus at the same moment of the elevation and augmentation procedure, using several materials. Study selection, risk of bias (Rob 2.0 or ROBINS I), quality of evidence (GRADE), and data collection were performed by two independent reviewers. Results: Of the 1101 potentially eligible articles, 44 were retrieved, 12 were assessed for eligibility and 5 were included in this systematic review (4 randomized and one controlled clinical trials). As a result, 130 grafted sinuses with 179 installed implants in 103 patients, aged between 24 and 79 years and followed up from 6 to 15 months, were analyzed. The heterogeneity between studies did not allow the data to be combined for meta-analyses. All graft materials proved to be viable options for the intervention. The use of BCP was related to higher bone-to-implant contact. Conclusion: All the assessed grafts are viable options for the intervention addressed. The use of some material is justified to maintain the sinus volume and allow bone formation in the apical site of implants under the sinus membrane. Longer chair time and the morbidity of the donor site should be considered when choosing autogenous bone. Synthetic biphasic materials can be selected for this intervention due to superior values of %BIC when compared to DBB. Schlagwörter: Key words: maxillary sinus augmentation, simultaneous implant, graft materials, bone neoformation, systematic review

Purpose: The purpose of this paper is to present a survival analysis of 133 consecutively placed moderately rough implants, all with a total follow up of 20 years. Materials and Methods: A total of 133 implants of the same brand placed in 46 patients at the same county clinic of Sweden have been followed up prospectively over 20 years and analyzed for survival and bone height, the latter evaluated in peri-apical radiographs. Results: A total of 7 implants failed, of which 4 failures were seen in the same patient. The reason for implant failure was associated with a combination of patient smoking and bruxing in 5 of the 7 failed cases. A 20- year survival rate of 94.7% was observed. Average marginal bone loss(mbl) at 20 years of follow up was 0.543 +-1.193 mm with 9 implants having more than 2 mm mbl . A total of 20 patients with 25 implants dropped out of the study, but if patient death as drop-out reason is ignored only 3 implants in 3 patients were unaccounted for. Conclusion: Good clinical results in the 95% survival range were observed with moderately rough implants over a 20 year follow up time.

A technique for virtually planning single implant by combining an intraoral digital scan, an opensource computer-aided design software program, bone sounding, and 2-dimensional radiographic imaging is described. The surgical implant guide is fabricated by using additive manufacturing technologies. Furthermore, the surgical implant guide positioned in the patient’s mouth is used to radiographically verify the estimated mesio-distal implant angulation before proceeding with the surgical intervention and modified, if necessary. When a cone bean computed tomography scan is not available, this technique eases implant planning procedures and minimize possible surgical complications.  Schlagwörter: Keywords: 3D printing; additive manufacturing; computer-aided design; surgical implant guide; computer-aided implant planning

Purpose: The purpose of this study was to evaluate the dimensional accuracy of implant impressions obtained using different tray types and techniques. Materials and Methods: A partially dentate maxillary Kennedy Class II model was created as a reference model through three-dimensional (3D) printing. Then, 4.3-mm diameter implant analogs were placed at the first premolar, first molar, and second molar regions. Five types of trays–metal and plastic stock trays and custom trays fabricated using liquid crystal display (LCD), fused deposition modeling (FDM), and urethane dimethacrylate (UDMA) resin–were used to create impressions. Open- and closed-tray techniques were also compared. In total, 150 impressions were obtained. The reference model and impressions were scanned using a laboratory scanner. The positional and angular deviations of implants with different tray types and techniques were evaluated using the superimposition method. Results: There was no statistically significant difference (P>0.05) between the impression accuracy with the different tray types and impression techniques. The angular deviations with plastic and UDMA trays were greater than those with metal, FDM, and LCD trays. Angular deviation at the second molar by using closed trays was greater than that using open plastic trays. The highest and lowest positional deviation were observed at the first molar implant with an open plastic tray impression (mean: 62.46 ± standard deviation: 28.54 μm) and a closed LCD tray impression (36.59 ± 29.93 μm). The greatest angular deviation was observed with an open FDM tray impression at the first premolar implant (0.067 ± 0.024°), and the lowest angular deviation was observed with a closed metal stock tray impression at the second molar implant (0.039 ± 0.025°). Statistical differences were detected using Mann–Whitney U tests for pair groups and the Kruskal– Wallis test for groups with more than three comparisons (P>0.05). Conclusion: Plastic and metal stock trays or conventional and 3D-printed custom trays can be used to obtain implant impressions for maxillary partially edentulous arches with similar dimensional accuracy. The five tray types and two techniques may be safely used to obtain impressions of partially edentulous maxillary arches with three implants. Schlagwörter: Keywords: implant, deviation, accuracy, 3D, impression

Purpose: To evaluate the feasibility of reversing a primary failure through therapeutic mechanical stimulation induced by transcutaneous application of acoustic waves (ESWT) in the peri-implant tissues. Materials and Μethods: This clinical report evaluates the outcome of a new protocol proposed to treat a primary failure (loosened oral implant); application of three cycles of ESWT, once session per week for 3 consecutive weeks, with an equivalent positive energy of 0,18 mJ/mm² (therapeutic dose: 2000 impulses/ 8Hz/ 4.0 bar). Standardized intraoral radiographs, Cone Beam Computed Tomography (CBCT), Implant Stability Quotient (ISQ) and clinical evaluations were performed. Results: It was possible to verify a progressive increase in the ISQ value after the ESWT protocol; 17 (initial), 46 (after two months) and 68 (after four months), which led to successful implant prosthetic rehabilitation (35 N/cm measured). Our evaluation at 6 years of follow-up confirms that the new bone-implant interface is preserved and ESWT as a safe non-invasive treatment. Conclusion: In the context of the new dynamic model of osseointegration, the Foreign Body Equilibrium (FBE), this represents the first report of a host-Implant equilibrium re-established after an early failure process. However, it is necessary to perform studies to determine both the medical device and the most effective therapeutic range for clinical applications of this technology in oral implantology.  Schlagwörter: ESWT, primary failure, case report, osseointegration, oral implant, osteoimmunology

Purpose: The aim of the present animal study was to examine the impact of two implant designs that promote different insertion torque values on implant stability and evaluate, histomorphometrically, the bone healing for immediate implant placement in fresh sockets. Materials and Methods: Twelve female sheep (35.0±5.0kg) and 48 conical Morse-taper dental implants divided into two groups (n = 24 per group): G1 group, where the implants present a design that can provide high insertion torque values; and G2 group, where the implants present a design that can provide low insertion torque values. Both had the same surface treatment, and dimensions (4.0 mm in diameter and 10 mm in length). The first two posterior teeth (both sides) were extracted carefully. Sequentially, there were osteotomies in the mesial socket of each molar tooth. The final implant position was 2 mm below the buccal bone crest level. On the right side, implants of the G1 were placed anteriorly, followed by implants of the G2; and, on the left side, it was the reverse. A digital torquemeter was used to measure the maximum final insertion torque value (f-IT). The initial implant stability quotient (ISQ) was measured immediately after the implant insertion (T0) and immediately after the euthanasia and removing the mandibles with the implants. The animals were euthanized (n=6 animals/ time) at 21 days (T1) and 35 days (T2). The t-test was used to compare statistical differences for each intragroup parameter analyzed. Pearson's correlation was used to analyze possible correlations: f-IT and BIC%, f-IT and ISQ, and ISQ and %BIC. Results: Regarding the insertion torque, the G1 presented higher values than the G2, with a statistically significant difference (p<0.0001). The ISQ mean values were higher in the B-L direction than those obtained for M-D for both groups. %BIC measurements showed higher values in samples from G2 than G1 at both times and in both directions. New bone, medullary spaces, and collagen matrix had statistical differences between the groups at each evaluation time. Conclusion: Using implants with a modified macrogeometry plays a significant role in implant stability and the healing process of bone tissue around the implant. It is important for clinicians to carefully consider implant macrogeometry when planning dental implant surgery to achieve optimal implant stability and successful osseointegration, mainly in cases of immediate implant placement. Schlagwörter: dental implants, macrogeometry, pre-clinical study, histomorphometry.

Purpose: The aim of this systematic review and meta-analysis is to analyze the risk of dental implant failure for patients who had a history of anti-depressant use. Materials and methods: An electronic search was performed up to June 2023 in three databases, including PubMed/MEDLINE, Web of Science and Cochrane Central Register of Controlled Trials with data on comparison of implant failure rate for patients with and without the use of antidepressants were included. Meta-analyses for the risk ratio of implant failure rate at the patient level and implant level were performed. Results: Eleven clinical studies were selected for inclusion in this review. The meta-analyses showed a risk ratio of 2.44 (95% confidence interval= 1.75 to 3.39, p< 0.0001) and 2.44 (95% CI= 1.73 to 3.46, p< 0.0001) for the implant failure at the patient level and implant level, respectively. The comparisons presented a low heterogeneity for the patient-level analysis and a moderate heterogeneity for the implant-level analysis among the pooled studies. Subgroup analyses also revealed that patients who received only selective serotonin reuptake inhibitors (SSRIs) or SSRIs with other type of anti-depressants had a higher risk of implant failure than those who were not on any anti-depressants. Conclusions: The current review demonstrates the use of anti-depressants, such as SSRIs, may increase the risk of dental implant failure at both patient level and implant level. Although limited evidence suggests that a certain type of SSRI (sertraline) may have more influence on implant failure than other SSRIs, future studies are needed to warrant this finding. Schlagwörter: dental implants, antidepressive agents, selective serotonin reuptake inhibitors, systematic review

Objective: This systematic review aimed to compare the influence of immediate and non-immediate loading protocols on overdentures retained by reduced-diameter implants(≦3.5mm). Methods: Electronic databases, including MEDLINE (via PubMed), Embase and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials (RCTs) comparing clinical outcomes of immediately and nonimmediately loaded reduced-diameter implants supported overdentures. The risk of bias within and across the studies and the certainty of evidence were assessed by RoB 2.0 and GRADE, respectively. Sensitivity analysis was performed by eliminating studies at high risk of bias, and repeating the data synthesis employing the randomeffect model. Subgroup analyses were conducted based on the implant diameter and the length of follow-up. Results: Six RCTs with 255 patients were included in this systematic review. The meta-analyses found similar implant survival rates between immediate and nonimmediate loaded implants in mini implant (RR=0.98; 95% CI=0.95, 1.01; p=0.12) and narrow implant subgroups (RR=0.99, 95% CI=0.94, 1.03, p =0.56), as well as in short-term (RR=0.98, 95% CI=0.97, 1.00, p =0.11) and long-term (RR=0.97, 95% CI=0.93, 1.01, p =0.09) follow-up subgroups. Additionally, marginal bone loss (MBL) showed no statistically significant difference between the loading protocols in the subgroup of long-term follow-up (MD=0.03; 95%CI=-0.16, 0.23; p=0.74). Three RCTs investigating peri-implant parameters found relatively higher modified plaque index and probing depth in reduced-diameter implant under immediate loading. Conclusion: Compared with non-immediate loading, the immediately loading protocol can achieve comparable survival rates and MBL in reduced-diameter implant retained overdentures. Schlagwörter: reduced-diameter implant, immediate loading, conventional loading, loading protocol, implant-retained overdenture

Objectives: To investigate the influence of a single infrapositioned ankylosed tooth or implant supported restoration, in smile attractiveness. Material and methods: A series of 48 digital modified images, simulating a varying degree of infraposition(from 0.25 to 2.0 mm, with a step of 0.25 mm), was created for each one of the maxillary anterior tooth, by altering the full-portrait image of a smiling male adult, in medium and high smile lines. For the model with the high smile line, also a series of 24 digital modified images simulating infraposition of a single anterior tooth with a restored incisal edge was created. Smile attractiveness for each one of the images was evaluated from 160 participants (80 dentists and 80 laypersons), implementing a visual analog scale. Results: For the images with the high smile line, an infraposition ≥ 0.25mm in central incisor’s region and ≥ 0.5mm in the region of the lateral incisor or the canine, had a negative effect on the perceived smile attractiveness both for the dentists and the laypersons. Regarding the medium smile line, an infraposition ≥ 0.5mm in central and lateral incisor’s region, had a negative effect on the perceived smile attractiveness for both groups of observers. In the area of the canine, infraposition ≥ 0.5mm for the dentists and ≥ 0.75mm for the laypersons, had a negative impact on the smile attractiveness. Conclusions: Even a minor infraposition of a single maxillary anterior ankylosed tooth or implant supported restoration, can reduce the perceived attractiveness of the face. Infraposition in canine’s area can be better tolerated in a medium, compared to a high smile line. In patients with a high smile line prosthetic intervention in order to restore the incisal edge of an infrapositioned tooth, without to harmonize the gingival contour, can be beneficial for the lateral incisor, ineffective for the central incisor and unfavorable for the canine. Schlagwörter: implant submersion, infraocclusion, ankylosed tooth, craniofacial growth, smile esthetics

Single implants are a predictable treatment, and immediate loading can be an option with acceptable survival rates. Clinical and patient-centered outcomes comparing immediate and delayed protocol of single implants are unclear. The purpose of this study was to assess complications, satisfaction, and quality of life of patients rehabilitated with delayed and immediate loading single crowns. An electronic search was conducted in PubMed/MEDLINE, Scopus, Web of Science, Cochrane Library, and Embase databases up to February 2023. Only prospective studies, randomized and non-randomized clinical trials comparing immediate and delayed loading were included. For the quantitative analysis, dichotomous and continuous variables were evaluated with a 95% confidence interval. A total of 20 studies were evaluated. No statistically significant difference between protocols was observed: satisfaction (I²: 0%; P = 0.42), quality of life (I²: 0 %; P = 0.05), biological complications (I²: 9%; P = 0.17) mechanical complications (I²: 58%; P = 0.84), and survival rate (I²: 0%; P = 0.38). Subgroup analysis showed significant differences only for marginal  bone loss when immediate implants were placed in the mandible (IÇ: 15%; P = 0.01) and posterior zone (I²: 0%; P = 0.001). Complications and patient-centered outcomes for immediate single-implant crowns were comparable to delayed loading. Scientific evidence showed no significant difference between loading protocols for survival rates. Although several factors could interfere with the complication events, implant failures, and marginal bone loss, the subgroup analysis evidenced that only immediate implants placed in the posterior mandible zone had higher statistically significant mean marginal bone loss. Schlagwörter: immediate dental implant loading, implant-supported dental prosthesis, patient satisfaction, quality of life, survival rate

Purpose: This study aimed to identify the technical complications associated with maxillary complete-arch implant-supported fixed prostheses (ISFPs) and to evaluate the survival rates of both implants and prostheses. Additionally, we sought to analyze the impact of the presence of cantilevers, the type of prosthetic abutment, and the number of implants on the occurrence of complications. Materials and Methods: Data were obtained from standardized clinical assessments carried out in a single appointment by two calibrated professionals using information from dental records. Results: The sample consisted of 64 patients rehabilitated with ISFPs classified as hybrid prostheses (metal-resin). The survival rate for implants was 98.6% after 1 to 12 years (5.2 years ± 36.6 months) and was 100% for the prostheses after a follow-up  period of 12 to 144 months (mean 48.1 ± 33.94 months). The most frequent complications were occlusal wear (82.8% of patients) and loosening of prosthetic screws (16.6%) and abutments (8.1%). Screw loosening frequency was significantly greater in 30-degree abutments compared with straight abutments (P=0.008), but no significant difference was found between 17-degree and 30-degree abutments. Prostheses with a higher occurrence of screw loosening had a greater average CL/AP spread ratios (0.9 􀀀 0.5). In addition, abutments installed on distal implants were more likely to loosen (P<0.001). The absence of mutually protected occlusion did not significantly influence the loosening of screws and prosthetic abutments. Conclusions: Implantsupported fixed maxillary complete-arch rehabilitations have high survival rates but are subject to technical complications. Schlagwörter: dental implants, maxillary edentulism, mechanical outcomes, screw loosening, follow-up

Purpose: Determining the esthetic success of single-tooth implant restorations (STIR) requires an objective tool such as one devised by Belser et al., 2009 - pink esthetic scores and white esthetic scores (PES/WES). This study aimed to utilized PES/WES to establish threshold scores based on (1) detectability and (2) acceptability of a STIR by lay person perception, (3) to study the difference in the ability of laypeople and dentists in detecting the presence of STIR, and (4) to study the pink and white deficiencies in relation to the detectability of the presence of STIR. Materials and Methods: A total of 38 calibrated photographs of STIR in the anterior region were scored with PES/WES by 3 prosthodontists. Next, 100 laypeople and 60 dentists were instructed to identify the STIR among the anterior teeth and provide reasoning behind the identification (based on pink and white esthetic criteria). The acceptance of the STIR was recorded. Receiver Operating Characteristics (ROC) analysis was utilized to determine the threshold scores. Results: At the PES/WES score of 17, 71% of laypeople could not correctly identify the STIR, and at the  PES/WES score of 12, 80% of laypeople accepted the implant. Out of 3,800 occasions, laypeople correctly identified the STIR 1,770 (46.58%) of those occasions. Among the correctly identified STIR, 751 (42.43%) of those occasions were identified with pink deficiencies and 1019 (57.57%) of those occasions were with white deficiencies. Out of 2,280 occasions, dentists correctly identified STIR 1869 (81.98%) of those occasions. Conclusions: The PES/WES score of 12 indicates the clinically acceptable threshold, while the score of 17 indicates the detectable threshold for an exceptional esthetic outcome. Laypeople tend to accept the implant despite its detectability. For both laypeople and dentists, root convexity/soft tissue color and texture are the most focused criteria of PES/WES, followed by overall white deficiencies that remain influential. Compared to laypeople, dentists tend to have a higher ability to detect STIR. Schlagwörter: pink esthetic scores, white esthetic scores, single-tooth implant restorations, implant esthetic

Purpose: To explore the contribution of paired-related homeobox 1-positive cells to the implant-induced osseointegration process in adult alveolar bone and the potential underlying mechanisms. Materials and Methods: Cre recombinase-induced lineage tracing and cell ablation were conducted in a murine dental implant model. Scratch and transwell assays were used to assess MC3T3-E1 cell migration after paired-related homeobox 1 overexpression. Single-cell RNA sequencing were applied to identify potential genes involved in pairedrelated homeobox 1-positive cells-driven osteogenesis. Results: Paired-related homeobox 1- positive cells were observed to accumulate in the peri-implant area in a time-dependent manner. The number of these cells were found to reach its maximum on day 14. Osseointegration in mice were noticeably impaired after ablation of paired-related homeobox 1-positive cells. Further, it was discovered that paired-related homeobox 1 promotes MC3T3- E1 cell migration, a process which is indispensable for sound healing of peri-implant tissue.  Finally, Semaphorin 3C was detected exclusively and abundantly expressed by paired-related homeobox 1-positive cells. Knockdown of semaphorin 3C in paired-related homeobox 1- positive cells significantly weakened their osteogenic potential. Conclusion: Our data suggest that paired-related homeobox 1-positive cells contribute to the osseointegration process under stress stimulation and semaphorin 3C may play a critical role in paired-related homeobox 1- positive cell-driven osteogenesis. Paired-related homeobox 1 could significantly promote MC3T3-E1 cell migration. Schlagwörter: paired-related homeobox 1-positive cells, osseointegration, alveolar bone, semaphorin 3C

Background: After tooth extraction, a physiological shrinkage of the alveolar ridge occurs. Applying a buccal overbuilding some months before tooth extraction may create a stiffer hard tissue that might protect the alveolar crest from resorption. Hence, the aim of this experiment was to evaluate the dimensional changes in the alveolar crest after buccal overbuilding performed before tooth extraction. Materials and Methods: At the test sites, an alveolar crest overbuilding was performed on the buccal aspect of the distal root of the third premolar using xenograft covered with a collagen membrane. No treatment was applied at the control sites. After 3 months, the distal roots of both third premolars were extracted and implants were immediately installed into the alveolus allowing a non-submerged healing. After 3 months, biopsies were collected. Results: At the histological analyses, no statistically significant differences in hard tissue dimensions were found. The buccal bone plate at the test sites presented a tendency of higher resorption compared to the control sites. However, if the contribution of the residues of biomaterial was considered, a higher volumetric gain was registered at the test than at the control sites. Conclusions: The buccal overbuilding performed before tooth extraction did not contribute to the preservation of the alveolar crest dimensions after extraction. This could be due to failure to incorporate the graft into the newly formed bone.

Purpose: This study aimed to assess the accuracy and precision of prosthetically-driven implant placement achieved through static computer-aided implant surgery. The primary objective was to analyze the linear and angular deviations of dental implants in patients treated at a university dental clinic. Various types of surgical techniques and templates were utilized to optimize implant positioning. Materials and Methods: A total of fiftythree dental implants were included in this study. The implants were positioned using either tooth-supported templates or tooth-tissue-supported templates with fixation pins. Two distinct guided surgery approaches were used, these being pilot drill guided and fully guided. Three-dimensional (3D) data from the implant planning phase was superimposed with the 3D data from the final implant positions using the ‘Treatment Evaluation’ tool within CoDiagnostix. implant planning software (Straumann AG). This enabled the automatic calculation of deviations in implant placement accuracy. Results: Average angular deviation observed was 3.90 degrees. For linear deviations, the mean 3D deviation at the most coronal point of the implants was 1.04 mm, while at the implant apex it was 1.56 mm. Conclusion: This research demonstrates the feasibility of a digital workflow for guided implant surgery, offering a promising treatment option. Nonetheless, it is important to note that deviations do occur, with the apical region of the implant being the most affected area. Care should be taken, particularly in cases of limited bone availability.

Purpose: The purpose of this study was to examine the mechanical influence of edentulous mandibular morphology on peri-implant bone in implant prosthetics by finite element analysis. Materials and Methods: Computed tomographic data from 25 patients with edentulous mandibles were selected and the radius of mandibular curvature and the height of the mandible at the midline were measured in order to clarify the morphological characteristics of the mandible. From the measurement, two patients with the smallest and largest radii of the mandible were selected. Two types of three-dimensional finite element models consisting of the edentulous mandible (small and large radius), superstructure (a cantilever bridge), implants, and abutments were created. Four implants were inserted between the right and left mental foramina. The upper surface of the mandibular condyle was constrained, and a vertical load of 100 N was applied on the occlusal surface of the right first molar. Three-dimensional finite element analysis of each model was performed to examine the mechanical influence of the edentulous mandibular morphology on the peri-implant bone. Results: Measurement of mandibular morphology in CT images indicated that the lower the mandibular height was, the larger was the radius of the anterior mandibular curvature. Finite element analysis revealed that a higher equivalent stress was generated in the peri-implant bone of the model with a larger radius of curvature than that of the model with a smaller radius of curvature. The highest equivalent stress in the mandible was generated in the distal margin of the peri-implant bone posterior to the loaded side of the large radius of curvature model. Conclusions: The mandibular morphology had a mechanical influence on the peri-implant bone.

Purpose: Maxillary sinus floor augmentation is a safe and predictable technique used to increase bone volume under sinus cavity for implant placement in atrophic posterior maxilla before implant placement. Despite conflicting results concerning the new bone formation rates with or without a barrier membrane, the benefits of using a collagen membrane to cover the lateral bone window has been demonstrated, in order to prevent bone substitute particles dislodgement that may occur from the sinus cavity through the sinus antrostomy towards the oral mucosa, and to significantly reduce the postoperative swelling and pain reactions. The purpose of this case series is to present a sling suture technique used to stabilize the collagen membrane against the lateral bone window so as to improve the bone substitute stability inside the sinus cavity. Materials and Methods: Maxillary sinus floor augmentation with lateral approach using sling suture technique to maintain the collagen membrane against the lateral bone window was performed in 17 patients (8 women/ 9 men, mean age: 58.2 years). Postoperative cone-beam computed tomography (CBCT) images up to 6-month follow-up were performed to control the bone graft stability at the level of the lateral antrostomy. The clinical postoperative pain and swelling were assessed through a Visual Analogue Scale (VAS) questionnaire from level 1 (low), level 5 (acceptable), to level 10 (high) at one week postoperative. Results: No bone substitute displacement was observed for all clinical cases on the CBCT images at 6-month postoperative. The pain and swelling level observed at one-week post operative were significantly low (respectively 1.6±1.0/2.1± 0.9). Conclusions: Within the limits of this case series, the use of sling suture technique to maintain the barrier membrane at the level of the lateral bone window in case of maxillary sinus floor augmentation with lateral approach surgery revealed to be a predictable protocol to prevent bone substitute displacement outside the sinus cavity.

Purpose: Marginal bone resorption (MBR) around oral implants may sometimes be a selflimiting condition due to balancing immunological reactions against the utilized materials, rather than a progressive bacterial infection. Contrary to previous assumptions from ligature induced experimental peri-implantitis studies, our recent 8-week experiment showed that marginal ligatures per se trigger an inflammatory immune response, resulting in bone resorption around implants in absence of a plaque. The present study aims to investigate whether this inflammatory/immunological reaction attenuates or progresses toward implant failure after a longer healing time, 12 weeks. Materials and Methods: Sterile silk ligatures were placed around the top of titanium (Ti) implants and compressed against the femoral cortical bone plate of 6 rabbits. A non-ligated implant was used as control. After 12 weeks of submerged healing, ground sections of implants and surrounding tissues were investigated with light microscopy. The marginal soft tissues were also analyzed using selected qPCR markers. Results: Histologically, the ligatures were outlined by immune cells, including multinucleated giant cells (MNGC), with adjacent fibrous encapsulation and resorbed peripheral bone that contrasted from the osseointegrated non-ligated control implants. The difference in expression of qPCR markers was not significant, but >2-fold upregulation of markers CD11b, IL1b, ARG1, NCF1, CD4 and >2-fold downregulation of CD8 indicated a mild, focal inflammatory/immune response against the ligatures compared to controls, with upregulation of M1 and M2 macrophages, neutrophils and helper T-cells and downregulation of killer T cells. Further, the bone formation markers OC and ALPL were >2 fold down regulated, consistent with the lack of osseointegration of the ligatures, compared to control implants. Conclusions: Marginal silk ligatures per se trigger an inflammatory/immune response and aseptic bone resorption around oral implants. Compared to our previous 8-week study, the inflammatory reaction against the silk appears to attenuate with time, with only a mild persisting inflammation that may block osseointegration and instead maintains a fibrous tissue encapsulation type reaction. This may explain why traditional ligature experiments have required regular exchange of ligatures in order for the bone resorption to progress.

Purpose: Laser-created titanium surface topographies enhance soft tissue attachment and implant stability. However, knowledge about the underlying mechanisms governing the tissue-level reaction is lacking. The objective of this study was to examine the behavior and function of human gingival fibroblasts growing on healing abutments with or without laser-textured topography. Materials and methods: Human primary gingival connective tissue fibroblasts were cultured on healing abutments with machined or laser-textured (Laser-Lok, BioHorizons) surfaces. Cellular and molecular responses were evaluated by cell density assay (WST-1), fluorescence microscopy, qRT-PCR, and detachment test. Results: The machined surface showed mono-directional traces and scratches from milling, whereas the laser-textured surface showed a distinct morphology consisting of mono-directional meso-scale channels (15 μm pitch) and woven, oblique micro-ridges formed within the channel. There were no differences in initial fibroblast attachment, subsequent fibroblast proliferation, nor collagen production between the machined and laser-textured surfaces. Fibroblasts growing on laser-textured surface spread mono-directionally along the meso-channels, while cells growing on machined surfaces spread randomly. Fibroblasts on laser-textured surfaces were 1.8-times more resistant to detachment than those on machined surfaces. An adhesive glycoprotein (fibronectin) and trans-membrane adhesion linker gene (integrin beta-1) were upregulated on laser-textured surfaces. Conclusions: The increased fibroblast retention, uniform growth, increased transcription of cell adhesion proteins compellingly explain the enhanced tissue-level response to laser-created, hybrid textured titanium surfaces. These results provide a cellular and molecular rationale for the tissue reaction to this unique surface and support its extended use from implant fixtures and healing abutments to diverse prosthetic components where enhanced soft tissue responses would be desirable. Schlagwörter: Laser-Lok, microchannels, abutments, implant, soft tissue attachment, laser-textured

Purpose: This retrospective clinical follow-up study assesses double-crown retained implanttooth- supported removable partial dentures (DCR-ITSRPDs) survival, evaluates abutment survival and identifies first aftercare measures. Materials and Methods: The influence of various factors on the survival of the DCR-ITSRPDs and the abutments were observed in this retrospective clinical follow-up study using Kaplan-Meier estimate. In addition, the first occurred aftercare measure per prosthesis was evaluated. Results: 47 DCR-ITSRPDs were investigated (mean observation: 4.3 ± 3.8 years; max. 14.3 years) out of which three (6.4%) had to be replaced. The 5- and 10- year survival probability for DCR-ITSRPDs was 100% and 75%. A total of 297 abutments (120 natural teeth and 177 dental implants) were observed, of which 22 (7.4%; 6 teeth and 16 implants) failed. The 5- and 10-year survival probability for teeth was 90.2% and for dental implants 90.4% and 76.3%. Conclusion: DCR-ITSRPDs are a successful and durable treatment option for patients with substantially reduced residual dentitions. Both, prostheses and abutments show good survival times after 5- and 10-years in function. The patient associated factors tested showed no influence on the survival of DCR-ITSRPs and abutments. Peri implant infection was the decisive factor for abutment loss, therefore, regular dental prophylaxis and examinations are of major importance. Schlagwörter: removable dental prosthesis, double crown, dental implants, tooth-implant supported, survival

Purpose: To evaluate the influence of immediate loading on osseointegration and bone density of implants installed in a healed alveolar bone crest and supporting single crowns. Materials and Methods: Two solid titanium transmucosal mini-screws were inserted in the distal regions of the mandible in 14 patients. One mini-implant was immediately functionally loaded, whereas the other was left unloaded. After two months of healing, biopsies were retrieved and new bone, old bone, and total bone (new and old bone) were assessed. Results: Histological examination was performed on biopsies This peer-reviewed, accepted manuscript will undergo final editing and production prior to print publication. from 12 patients (n=12). New bone-to-implant contact percentage (BIC%) was 40.3 ± 16.8 % and 55.1 ± 19.1 % (p=0.043) at the unloaded and loaded sites, respectively, while the total BIC% was 44.9 ± 17.0 % and 59.5 ± 18.8 %, respectively (p=0.034). The new bone density was 45.9 ± 11.6 % and 45.9 ± 16.7 % in the unloaded and loaded implants, respectively (p=0.622). Conclusions: Immediate loading positively affected bone apposition on the implant surface, while no effect on bone density was observed after 2 months of healing. Schlagwörter: immediate dental implant loading, implant supported prosthesis, clinical trial, osseointegration, biopsy

Purpose: This in-vitro study aims to investigate whether the wettability of two zirconia implant disk surfaces is affected by glycine and erythritol air-polishing, using saline, bovine serum albumin, bovine thrombin, and bovine artificial blood as the testing mediums. Materials and Methods: Zirconia disks were provided by two implant companies: SDS. (Swiss Dental Solutions, Plymouth, MA, USA) (n=6) and Patent. (Zircon Medical AG, Altendorf, Switzerland) (n=6). Surface parameters (Sa, Sz, Sdr, Ssk, Sku, and Spd) were measured to determine their initial surface roughness. Air-polishing was completed using glycine or erythritol powders using the AIRFLOW. PERIO device (Manufactured by Electro Medical Systems (EMS)). The wettability of the disk surfaces was evaluated by the contact angle analysis applied on treated and untreated disks using four wetting solutions, saline, bovine serum albumin (BSA), bovine thrombin, and bovine artificial blood. In total, 720 contact angle measurements were completed with n=30 per group. Statistical analysis was performed using the one-way analysis of variance and post-hoc Tukey HSD test. Results: The results indicate SDS. has a greater wettability than Patent. before and after air-polishing. The wettability of surfaces treated with glycine was hydrophobic in some cases. Erythritol increased the surface wettability of zirconia disks compared to glycine. BSA and bovine artificial blood had lower contact angles than saline and bovine thrombin for both untreated disks. Conclusions: The initial wettability of zirconia disks differs between manufacturers, and air-polishing with erythritol powder increases the wettability of zirconia implant disks for saline, bovine serum, bovine thrombin, and bovine artificial blood. Schlagwörter: contact angle, erythritol, glycine, wettability, zirconia

Background: Simvastatin (SMV), a lipid lowering drug, can modulate the process of bone regeneration at the molecular and cellular levels. Its effect on the osseointegration of implants has been studied extensively on animals with assuring results with limited research on human subjects. Aim: To estimate the effect of simvastatin gel in the osseointegration of dental implants using bone scintigraphy, Materials and Methods: 20 participants with missing mandibular first molars and D2 type bone were assigned equally to Group A receiving 1.2% simvastatin and Group B receiving Placebo gels during the placement of implants. The participants were subjected to bone scintigraphy to determine the osteoblastic activity at baseline, 30th day and 90th day after implant placement. Results: Group A revealed a significant increase in osteoblastic activity between baseline, day 30 and 90 (P<.05) with a higher mean of 100.06±21.644% on day 30. Group B revealed a significant increase in osteoblastic activity only between baseline and day 30, and baseline and day 90 (P<.05) whereas there was no difference between day 30 and 90 (P>.05) with a higher mean of 79.20±18.255% on day 30. Bivariate analysis at different time periods revealed a significant difference between groups A and B on day 30. Conclusion: Implants placed with 1.2% simvastatin gel showed enhanced osteoblastic activity on the fourth week of implant placement, indicating faster rate of osseointegration at an early stage. Schlagwörter: Simvastatin, Osseointegration, Osteoblastic activity

Purpose: To investigate the effect of lateral sinus floor elevation (LSFE) on sinus membrane (SM) thickness and sinus health in mucosa thickness less and more than 5 mm. Materials and Methods: LSFE was performed in a prospective controlled clinical trial on two groups with less than and more than 5 mm (group A & B) SM thickness and followed for 6 months. Using preoperative and 6-month postoperative CBCT and clinical evaluation, SM thickness changes (primary outcome variable), sinus health, augmented bone height, and length (augmentation adequacy), membrane–related variables, and operation time were measured. Results: Forty unilateral sinus augmentations (A:20, B:20) with simultaneous installation of 52 fixtures were performed on 40 subjects (72.5% males, mean age of 48.8±7.6). The mean preoperative and 6- month SM thicknesses in group A and group B were 1.4±0.9 and 1.3±0.6 mm, and 6.8±1.0 and 3.4±1.7 mm, respectively. The mean postoperative SM thickness significantly decreased (P<0.001) only in group B. The mean SM thickness changes also revealed a noticeable difference between the two groups (P<0.001). Augmentation adequacy and membrane perforation rate were similar in both groups. Clinical and radiographic rhinosinusitis was not detected in any of the patients. Bleeding during separation and resistance to elevation in group B were significantly higher than in group A (P=0.003, P=0.001). Surgical time in group B (12.08 ± 8.26 minutes) was longer than in group A (8.64 ± 3.70 minutes), without reaching a significant level (P=0.097). Conclusions: LSFE in thickened mucosa (≤10 mm) and thinner mucosa (≤5 mm) does not cause abnormal changes in the sinus membrane and sinus health. LSFE in thickened mucosa results in adequate sinus augmentation. Thickened SM also shows a significant thickness reduction. The thickened membrane does not appear to be a contraindication to SFE. Schlagwörter: Sinus floor elevation, Schneiderian membrane, sinus membrane, mucosal thickness, ostium patency

Purpose: Despite the high clinical accuracy of dynamic navigation, inherent sources of error exist. The purpose of this study was to improve the accuracy of dynamic navigated surgical procedures in the edentulous maxilla by identifying the optimal configuration of intra-oral points that results in the lowest possible registration error for direct clinical implementation. Materials and Methods: Six different 4-area configurations were tested by 3 operators against positive and negative controls (8-areas and 3-areas, respectively) using a skull model. The two dynamic navigation systems (X-Guide® and NaviDent®) and the two registration methods (bone surface tracing and fiducial markers) produced four registration groups. The accuracy of the registration was checked at the frontal process of the zygoma. Intra- and inter- operator reliability for each registration group were reported. Multiple comparisons were conducted to find the best configuration with the minimum registration error. Results: Ranking revealed one configuration in the tracing groups (Conf.3) and two configurations in the fiducial groups (Conf.3 and Conf.5) that had the best accuracy. When the inferior surfaces of the zygomatic buttress were excluded, fiducial registration produced better accuracy with both systems (p 0.006 and <0.0001). However, tracing 1 cm areas at these surfaces bilaterally resulted in similar registration accuracy as placing fiducial markers there (p 0.430 and 0.237). NaviDent® performed generally better (p 0.049, 0.001 and 0.002) albeit having a wider margin of uncertainty in the obtained values. Changing the distribution of the 4 tracing areas or fiducial markers had a less pronounced effect with X-Guide® than with the NaviDent® system. Conclusion: For edentulous maxillary surgeries, 4 fiducial markers placed according to configuration 3 or 5 result in the lowest registration error. Where implants are being placed bilaterally, an additional 2 sites may reduce the error further. For bilateral zygomatic implant placement, it is optimal to place 2 fiducials on the inferior surfaces of the maxillary tuberosities, other 2 on their buccal surfaces, and 2 on the anterior labial surface of the alveolar bone. Utilising the inferior zygomatic buttress is recommended over the inferior maxillary tuberosities in other types of maxillary surgeries. Schlagwörter: Dynamic Navigation, Fiducial, Implants, Maxilla, Registration, Tracing

Purpose: To investigate the esthetic outcomes based on the color differences in zirconia of varying thickness, resin cement color, and types of titanium implant surface treatments. Materials and Methods: Twenty-eight HTMZ specimens were arranged into four groups based on zirconia thickness: 1.0, 1.5, 2.0, and 2.5 mm (n=7). Each group was tested using two resin cement colors (n=7) (clear and opaque) in combination with six surface-treated titanium groups (n=7): untreated titanium (UT), anodization (AN), 50-μm alumina airborne-particle abrasion followed by AN (SBAN), AN followed by 50-μm alumina airborne-particle abrasion (ANSB), 95% hydrofluoric acid followed by AN (HFAN), and AN followed by 95% hydrofluoric acid (ANHF) for the 48 experimental groups, and using composite resin (n=7) (A2D) for the four control groups. All the specimens were measured using a spectrophotometer and subsequently compared with composite resin (control) with the corresponding zirconia thickness to establish the color differences. A color difference of <2.7 was considered clinically acceptable. The data obtained were statistically analyzed using the analysis of variance and post hoc test (p=0.05). Results: Zirconia thickness, resin cement color, and type of titanium implant surface treatment significantly affected the observed color differences (p<0.05). When using 2.5-mm HTMZ with clear resin cement on AN, UT, SBAN, HFAN, and ANSB, the mean color differences obtained were below the clinically acceptable values. However, when using 2.5-mm HTMZ with clear resin cement on AN, UT, and SBAN, the 95% confidence intervals of color differences obtained were below the clinically acceptable values. Conclusions: HTMZ with a minimum thickness of 2.5 mm and clear resin cement on AN, UT, and SBAN groups potentially result in acceptable color matching with 95% confidence intervals. Schlagwörter: anodize, cement, ceramic, color, spectrophotometer, zirconia

Purpose: The objective of this systematic review is to assess the impact of implant placemen at different periods on the aesthetic and clinical outcomes, in the aesthetic zone. Material and Methods: Literature screening was conducted in PubMed, ScienceDirect and Cochrane library databases. Relevant articles were chosen according to selection criteria and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data was collected from studies published from 2017-2022 in English. Results: Nine articles were included, where a total of 495 implants were placed, from which 250 were immediate, 109 early, and 136 delayed. Immediate implants showed no statistical difference in Pink Esthetic Score (PES) contrasted to delayed implants. Immediate implants showed significantly higher PES in comparison to early implants (MD= -0.76 with 95% CI= -1.50 to -0.02; P=0.04). The probing depth (PD) was considerably greater in the immediate implants when compared to delayed (MD= -0.62 with 95% CI= -1.05 to -0.18; P=0.005), and the plaque index (PI) was statistically greater in early implants compared to immediate implants (MD= 0.15 with 95% CI= 0.11 to 0.19; P<0.00001). All other soft tissue outcomes showed equal results. The marginal bone level (MBL) loss was statistically higher in early implants compared to immediate implants (MD= 0.09 with 95% CI= 0.02 to 0.16; P=0.02). Conclusions: immediate implants had significantly superior PES, marginal bone loss, and plaque index results when compared to early implants. The probing depth was significantly higher in the immediate group compared to the delayed group. All other outcomes showed no significant difference between the three implant groups. It is important to highlight the limitations of this review such as the small number of studies included and the few reports on aesthetic indices. Schlagwörter: dental implant; endosseous dental implant therapy; dental implantation, endosseous; esthetics, dental.

Natural Coral Particles (NCPs) are a suitable scaffold material for Guided Bone Regeneration (GBR) procedures; it combines the placement of a bone substitute supporting a barrier membrane. Due to increasing sea pollution and the declarations of endangered coral species (KYOTO 1997), they are no longer suitable for the medical industry. Novel domestic corals have been grown under controlled conditions to produce cultivated coral graft (CCG) material. This study aimed to evaluate a new CCG in an in vivo experimental GBR procedure. The calvarias of 8 rabbits were surgically exposed, and circular defects 8 mm in diameter were prepared. One defect was filled with CCG particles (experimental group); the contralateral defect (control group) was spontaneously filled by blood clot. The defects were covered with a collagen membrane. Animals were euthanized after 8 weeks. Histological observations of the defects showed similar bone growth patterns in both experimental and control osteotomies. In the experimental defects, no traces of coral particles were observed. Histometric analysis showed denser bone in the pristine zone (65-66%) than in the peripheral zone for both the control (50%) and experimental defects (31%) (P= NS). The new bone percentage was reduced from the peripheral zone toward the middle and the center of the defect (31%, 32% and 27%, respectively) as the distance from the peripheral pristine bone borders increased. The existing data support the complete degradation of CCG as space-maintaining scaffold for GBR procedures. Schlagwörter: coral, graft, animal study, GBR, bone, rabbit

Background: The preclinical study presented here compared crestal bone loss between titanium implants with a conventional etched surface (SLA type) and others coated with chitosan, after 12 weeks of immediate implantation in the mandible of a canine model. Material and Methods: Forty-eight implants (24 experimental and 24 control) of Ti-Al16-V4 with an internally connected tapered screw design were randomly inserted into six maxillary canines, four per hemiarch. The experimental implants were coated with Chitosan by immersion and sterilization with ethylene oxide. Primary stability was measured using the Osstell® device. No grafting materials were used, and three-dimensional micro-CT measurements included crestal bone volume (CBV) and bone volume change in crestal area (∆CBV), which were considered outcome measures. Parallelized periapical radiographs were also taken at the time of implant placement and after 12 weeks to assess changes in crestal bone levels. Results: In terms of volumetric changes, it was observed, that the experimental group showed better results than the control group (p=0.049 and p=0.303, respectively). Regarding the implantation sites, no significant differences were found between the experimental implants and the control group, only the implants placed at P4 level in the experimental group obtained the best result (p=0.041). The linear data obtained from the periapical radiographs indicated greater bone loss in the control group compared to the experimental group (3.2±0.45 and 2.75±0.55 mm, respectively). Conclusions: Despite the better results obtained for the chitosan-coated surface group, further preclinical studies would be necessary to confirm our results.

Purpose: to measure the surface temperature distribution after CO2-laser heating of titanium dental implants using different power settings, application intervals and irradiation times. Materials and methods: 10 tissue-level-type titanium implants (Camlog Screw-line Promote Plus 4.3mm x 11mm) were embedded (Epofix, Struers ApS, Copenhagen, Denmark) and irradiated with a carbon-dioxide-laser (Denta II, Lutronic Corporation, Fremont, USA) with a wavelength of 10.6µm and at power levels of 4watts (group 1), 6watts (group 2), 8watts (group 3) and 10watts (group 4). A continuous beam mode (setting I) and non-continuous beam modes with 5second (setting II) and 10second (setting III) pause intervals were used. For each setting, a total irradiation time of 50seconds was used and repeated 10 times. The temperature was measured using external thermocouples (Testo SE & Co. KGaA, Lenzkirch, Germany) in contact with the implant surface at implant shoulder, middle and apex. A linear regression model was used to analyse the data (p = 0.05). Results:  Setting I demonstrated the most rapid increase in implant surface temperature in all three test sites as well as the greatest total temperature at 50 seconds of irradiation time. The greater the pause interval (settings II and III) during the 50 seconds of irradiation, the lower the rate of temperature increase as well as the total temperature in all three test sites and with all power levels. The average temperature difference between the apex and shoulder site was significant for test setting III for all groups, but not for any groups in settings I and II. Conclusion: Heating the internal aspect of a dental implant with a CO2-laser produces different temperature distribution profiles depending on the laser power level and the application interval. Laser-beam irradiation leads to a temperature gradient which is greatest at the implant apex and smallest at the implant shoulder. 

Background: The clinical use of bioactive substances, such as growth factors, have significantly increased, however, potential regenerative effects derived from the addition of different growth factors to bone substitutes on maxillary sinus floor augmentation (MSA) procedures is still controversial. This systematic review (SR) aimed at answering the following question: “Do recombinant, purified and concentrated growth factors enhance the regenerative potential of particulate bone graft substitutes in maxillary sinus floor augmentation?”. Methods: Human studies comparing histomorphometric data of the outcomes of interest new bone formation, residual graft material, and fibrous tissue ratio following MSA procedures employing particulate bone grafts/substitutes in combination or not with growth factors were retrieved from PubMed/MEDLINE, Web of Science, Cochrane and Scopus online databases and complemented with a hand search. Controlled studies published in English up to December 2022 and reporting on histomorphometric data expressed as percent volume of the outcomes of interest were considered. Risk of bias was assessed, and a meta-analysis (MA) was performed to investigate the effects of supplementary growth factors on new bone formation, remaining graft particles and fibrous tissue ratio. Results: Data of 613 samples from 477 patients reported in 22 publications were included. MA showed PRP or PRF resulted in 49% more new bone formation than in areas in control groups (P=0.004), and those areas supplemented with growth factors presented 57% less residual graft particles after healing (P<0.0001). A significant (P=0.03) 1.85-fold increase in connective tissue formation was noted in areas treated with rhBMP after healing. Conclusion: The MA provided evidence that selective supplementary growth factors may enhance new bone formation and accelerate particulate graft turnover, while rhBMP may significantly increase connective tissue formation in MSA procedures in humans. 

Background: Platelet-rich fibrin (PRF) is used to prepare "sticky bone" by combining it with bone-graft material. The present study investigated the ability of different bone grafts to absorb growth factors from the PRF and release them over time. Methods: Human blood was collected from 10 healthy volunteers for liquid PRF preparation. Bovine bone, allograft (mineralized and demineralized), and synthetic bone were each mixed with the PRF to prepare a sticky bone. All sticky bone samples were incubated for up to 4 days and the absorption and release pattern kinetics of two selective growth factors within the PRF (Platelet-Derived Growth Factor and bone morphogenetic protein 2) were quantified with immunofluorescence staining and ELISA. Results: All the tested bone graft materials adsorbed the examined growth factors from the PRF. β-TCP showed the highest adsorption levels, followed by the xenograft, and the allografts showed the lowest adsorption levels. Furthermore, PDGF showed a fast release pattern from the grafts, whereas BMP2 was released at a later stage. Similar to the adsorption pattern, the β-TCP and xenograft were better able to sustain the release of the PRF growth factors from the graft than the allografts. Conclusions: The adsorption of PDGF and BMP2 differ between graft materials, with superior results for βTCP, followed by xenograft and lastly the allograft materials. 

Purpose: This prospective study evaluated the marginal bone level and periodontal parameters 6 years after placement of a convergent transmucosal neck implant. Materials and Methods: In total, 71 implants were placed in 60 patients. Of these, 52 implants were placed with a flapless technique and with the convergent neck exposed for 1.0 mm (early and delayed placement), while 19 implants were placed immediately after extraction (immediate placement). At least 3 months after insertion, customised abutments were applied and provisional resin crowns were cemented, while being careful to prevent any tissue compression. After 3 weeks, definitive metal-ceramic crowns were designed with the finishing line at the soft tissue level and free from any compression. The implant survival rate at 6 years, marginal bone level changes (MBL, mm), and Pink Esthetic Score (PES) were evaluated. Gingival phenotype was determined before the implant surgeries (thin/thick). A three-level hierarchical model was examined with a random intercept and random slope on follow-up time at the patient level, and a random intercept at the implant level. Results: In all, 57 patients with 67 implants reached the 6 year point; 3 (5.0%) dropped out. The implant survival rate was 100%. ΔMBL T0-T24 was 0.58 mm (95% CI 0.48, 0.68), while ΔMBL T24-T72 was 0.33 mm (95% CI 0.19, 0.47). PES improved steadily from 6 to 48 months (+0.96; 95% CI 0.71, 1.20), with overall stability at 72 months. No correlation between MBL and PES was observed. A significant association was found between the gingival phenotype and less MBL variation. Greater implant diameter offered more MBL stability after 3 years, but lower PES values. Conclusion: The use of convergent transmucosal neck implants placed with a flapless transmucosal approach with the crown margin positioned at the gingival level preserved marginal bone and guided gingival morphology for up to 72 months. The gingival phenotype was the parameter that most affected the soft and hard tissues. In the long term, implant placement timing was not related to MBL. 

Purpose: The objective of this systematic review is to assess the impact of implant placemen at different periods on the aesthetic and clinical outcomes, in the aesthetic zone. Material and Methods: Literature screening was conducted in PubMed, ScienceDirect and Cochrane library databases. Relevant articles were chosen according to selection criteria and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data was collected from studies published from 2017-2022 in English. Results: Nine articles were included, where a total of 495 implants were placed, from which 250 were immediate, 109 early, and 136 delayed. Immediate implants showed no statistical difference in Pink Esthetic Score (PES) contrasted to delayed implants. Immediate implants showed significantly higher PES in comparison to early implants (MD= -0.76 with 95% CI= -1.50 to -0.02; P=0.04). The probing depth (PD) was considerably greater in the immediate implants when compared to delayed (MD= -0.62 with 95% CI= -1.05 to -0.18; P=0.005), and the plaque index (PI) was statistically greater in early implants compared to immediate implants (MD= 0.15 with 95% CI= 0.11 to 0.19; P<0.00001). All other soft tissue outcomes showed equal results. The marginal bone level (MBL) loss was statistically higher in early implants compared to immediate implants (MD= 0.09 with 95% CI= 0.02 to 0.16; P=0.02). Conclusion: immediate implants had significantly superior PES, marginal bone loss, and plaque index results when compared to early implants. The probing depth was significantly higher in the immediate group compared to the delayed group. All other outcomes showed no significant difference between the three implant groups. It is important to highlight the limitations of this review such as the small number of studies included and the few reports on aesthetic indices. 

Aim: This report stems from a homogeneous patient cohort from two similarly designed prospective controlled studies in the same center on surgical reconstructive treatment of peri-implantitis. The aim of this re-analysis study was exploring prognostic factors associated with surgical outcomes. Materials and methods: Individual patient data of both studies were gathered. The initial study employed a submerged healing approach via primary wound closure with implant supra-structure removal and complete coverage of grafted sites. The second study employed a non-submerged healing protocol in which healing abutments were kept in place and the implant was not fully submerged. Both studies measured all outcomes at similar timepoints throughout 1 year, to include clinical and radiographic defect fill (DF and RDF), reduction of pocket depth (PDR) and bleeding on probing (BOP). Multi-level regression was used for statistical assessment of outcomes, relative to the impact of site-/local-, surgical- and patient-related variables. Results: Overall, 59 implants (30 in submerged and 29 in the non-submerged group) were treated. A statistically significant higher DF (on average 0.9 mm higher), RDF (1.7 mm) and PDR (1.3 mm) were observed when a submerged reconstructive approach was performed, whereas BOP reduction was similar. After controlling for treatment (submerged/non-submerged), there were no other significant associations with patient- (age, gender, smoking, prior periodontitis etc.), or implant-related (previous prosthesis type, arch, KTW, etc.) factors. Conclusion: Within its limitations, we conclude that a submerged reconstructive approach for surgical management of peri-implantitis leads to significantly enhanced clinical and radiographic outcomes when compared to a non-submerged approach. 

Purpose: Dental implant manufacturers recommend healing abutments (HA) be used for single-patient use; however, reuse on multiple patients following decontamination and sterilization is common. This study aims to evaluate four decontamination strategies utilizing enzymatic agents, available in most clinical settings, to determine the level to which biomaterial can be removed in a group of previously used HA (uHA). Secondly, to determine the degree to which the decontaminated HA are capable of inducing an inflammatory response in-vitro compared to new, never used HA. Materials and Methods: Fifty HA were collected following 2-4 weeks of intraoral use and distributed randomly into 5 test groups (Group A-E; n = 10/group). Group A: Enzymatic cleaner foam + Autoclave; Group B: Ultrasonic bath with enzymatic cleaner + Autoclave; Group C: Prophy jet + Enzymatic cleaner foam + Autoclave; Group D: Prophy jet + ultrasonic bath with enzymatic cleaner + Autoclave; Group E: Prophy jet + Autoclave. Ten new, sterile HA served as controls (Group “Control”). Residual protein concentration was determined by a Micro BCA protein assay while HA from each group were stained with Phloxine B and macroscopically examined for the presence of debris. To examine the inflammatory potential, human primary macrophages were exposed to HA and supernatant levels of 9 cytokines/chemokines profiles were analyzed using a multiplex bead assay. Results: All test groups presented with differences in the degree of visual decontamination compared to Controls, with Groups D and E displaying the most effective surface debris removaland reduced protein concentration. Of the detoxification strategies, Groups D and E removed the greatest biomaterial while least effective was Group A. However, compared to Controls, multiplex assays revealed high levels of inflammatory cytokine secretion up to 5 days from all Test Groups (A-E) irrespective of the decontamination method used. Conclusion: Our study found that compared to new, never used HA, decontamination of uHA utilizing enzymatic cleaners failed to reestablish inert HA surfaces and prevent an inflammatory immune response in-vitro. Clinicians should not reuse HA even after attempts to decontaminate and sterilize HA surfaces.

Purpose: The primary aim of this study is to evaluate the correspondence between an Artificial Intelligence driven new tool prediction and the clinician’s evaluation in the immediate loading suitability of curves recorded during implant insertion in an in vitro test. The secondary aim is to analyse peak insertion torque (pIT) and variable torque work (VTW) values of the implants used for the in vitro study. Material and methods: The study was performed on artificial bone blocks of solid rigid polyurethane without cortical layer with four different densities. Five types of implants with different macrogeometries were used. A total of 140 implants (7 implants of each type in the four polyurethane blocks) were inserted. Immediately after implant placement the insertion curves were classified by the operator as suitable or non-suitable for immediate loading. In a second moment the same curves were analyzed by the new AIT that classified them as belonging to YES or NO class. For each implant pIT and VTW were also recorded. Results: The correspondence between surgeon and AIT evaluation was 99,3% with only one false-negative reported by the algorithm analysis. The sensitivity resulted 98.95%, the specificity 100%, positive predictive value 100% and negative predictive value 97.8%. Mean pIT of the whole sample was 34.19 + 19.43 Ncm while mean VTW was 2266.89 + 1993.73 Ncm. Statistically significant differences were found between implant systems in the whole sample and when divided by polyurethane block density. Conclusions: AIT showed a high level of accuracy in the prediction of immediate loading suitability of insertion curves examined. All the implants used in the in vitro test were able to reach good levels of primary stability, excluding when inserted in the less dense polyurethane block. Clinical studies conducted in larger samples and with more surgeons involved are necessary to confirm these results.

Introduction: Different surgical procedures have been proposed to achieve successful horizontal ridge reconstruction of the anterior maxilla, most of these procedures require complex surgical stages with morbidity and are time-consuming. Aim: The purpose of this study is to evaluate the efficacy of using a customized xenograft shell with a 1:1 mixture of particulates xenograft and autogenous bone for the reconstruction of horizontally deficient anterior maxillary alveolar ridges. Methods: Cone beam computed tomography (CBCT) images of the atrophic maxilla of eight patients were acquired and generated into 3D models. The data were transferred to a 3D printer and solid models were fabricated. During the surgery, the xenograft blocks were manually sliced and customized on the 3D printed models and fixed then the gap was augmented with a 1:1 xenograft autograft mixture. Results: Clinical assessment showed no adverse effects. However, one patient exhibited wound dehiscence. The mean difference between the preoperative and the six months postoperative showed a net average bone gain by 4.06 mm at 2 mm from the crest and 4.34 mm at 5 mm from the crest, which was statistically significant. On the other hand, a statistically significant graft resorption by 1.41 mm and 2.19 mm at 2 and 5 mm from the crest was found when the mean difference between the immediate and the six months postoperative was calculated. Conclusions: Within the limitations of the study, the use of xenograft shells as a barrier for maxillary alveolar ridge reconstruction is predictable technique however, further investigations regarding the required time for graft consolidation is required. 

Dental implants are an established treatment options for varying edentulous conditions and has grown in popularity since the 1990’s. This increased clinical application has evidenced a parallel increase in dental implant related research. The objective of this paper was to perform a comprehensive bibliometric analysis of five dental implantology journals from 1991-2023. Materials and Methods: We performed a search in the ISI Web of Science database between 1991 and 2023 in 5 journals with a focus on dental implantology: Clinical Oral Implant Research, Clinical Implant Dentistry and Related Research, Implant Dentistry, International Journal of Oral and Maxillofacial Implants, and International Journal of Oral Implantology. Results marked as correction, retraction notices, retracted articles, meeting abstract, withdrawn publications were removed from the analysis. The time period analyzed was divided into 4 decades: 1991-2000, 2001-2010, 2011-2020, 2021-2023. Additionally, the top 100 cited papers were also exported separately. Authors and countries with most publications were tabulated from the Web of Science database. VOS Viewer software was used to create network maps of keywords and title word occurrences for each of the time periods. Histcite software was used to analyze number of publications and citation counts. Results: Network maps of keywords and title word occurrences suggested an early focus on osseointegration and titanium implants between 1991-2000. Publications between 2001-2010 saw a focus on in-vivo studies, implant surface and peri-implantitis. Publications post 2011 saw a focus on bone regeneration, complications and zygomatic implants. USA ranked highest in total number of publications in all time periods analyzed. Conclusions: Within the limitations of the study, we reported a comprehensive bibliometric analysis from 1990-2023. We identified trends in keywords and titles of dental implant publications in these journals which mirrored the trends seen in clinical practice. 

Purpose: Dental implants are a common method for the treatment of tooth loss, and its accuracy directly affects forward efficacy and stability. This study compared the accuracy of different modalities of dental implant placement (dynamic navigation [DN], fully guided [FG] static navigation, partially guided [PG] static navigation, and free handed [FH]) through a network meta-analysis. Materials and Methods: This study followed the Preferred Reporting Items for Meta-Analyses (PRISMA) guidelines and conducted an electronic literature search (Inception-Oct 2, 2022). The comparison of implant accuracy in all the included randomized controlled trials (RCTs) conformed to at least one of the following: deviation at the crown of the implant, deviation at the apical portion of the implant, or angular deviation of the implant. Results: Twenty-six articles were included for the qualitative analysis (17 RCTs; 3 prospective studies; 6 retrospective studies), and 17 RCTs of which were included for network meta-analysis. The data included in this study had high consistency, and the funnel plot showed that the articles had low publication bias. Compared with FH, FG and DN had higher accuracy in coronal deviation (P<0.05), and FG, DN, and PG had higher accuracy in apical deviation and angular deviation (P<0.05). According to the SUCRA value, FG had the highest accuracy in coronal deviation, while DN had the highest accuracy in apical deviation and angular deviation. Conclusions: According to the results of this literature review, the accuracy of DN, FG, and PG were higher than those of FH. DN showed the highest accuracy in terms of apical deviation and angular deviation. FG had the best control over the coronal deviation. There was no statistical difference between DN and FG in terms of accuracy. Given the limitations of the current study, further validation is required in the future. 

Purpose: The purpose of the study is to investigate the screw loosening and fracture resistance of different hybrid abutment crown restorations after thermomechanical aging. Materials and Methods: Restorations were produced from zirconia, lithium disilicate, and hybrid ceramics with CAD-CAM system (n=10). Restorations and titanium bases (Tibases) were cemented and the abutment screws were torqued to 30 Ncm. They were retorqued after 10 minutes, and removal torque values (RTV) were measured. When 250000 and 500000 cycles of thermomechanical aging were completed, the RTVs were measured again and removal torque loss (RTL) ratios were calculated. The specimens were subjected to fracture resistance test after 750000 cycles of thermomechanical aging. The load at failure was recorded as the fracture resistance (N). The results were statistically analyzed (α=0.05).  Results: Aging was effective on the RTVs and RTL ratios (P<0.001). The highest RTV was observed before aging; however, the RTVs significantly decreased and RTL ratios significantly increased after aging (P<0.05). The fracture resistance values significantly differed among the ceramic materials. All lithium disilicate and hybrid ceramic specimens showed restoration fracture, while most of the zirconia specimens were displayed Tibase related failure. Conclusion: Hybrid abutment crowns made of zirconia, lithium disilicate, and hybrid ceramics can withstand the average occlusal forces in the molar region; however ceramic type may affect the failure type. Retightening of the abutment screws after 10 minutes after first tightening and annually may be beneficial to prevent the adverse effects of screw loosening on the integrity of implant-abutment connection. 

Purpose: The structural and compositional similarities between dentin and alveolar bone formed the basis for utilizing dentin for bone regeneration. Various authors recommended using treated mineralized, partially demineralized, and demineralized dentin grafts over xenografts because of their comparable clinical and radiographic results and lower costs. Therefore, the current study aimed at comparing the effect of untreated mineralized dentin grafts (UMDG) versus xenografts in vertical and horizontal augmentation around dental implants that were immediately placed in the mandibular anterior region. Materials and methods: A total of 56 patients who required immediate dental implant placement in the lower anterior region were randomly allocated to group I (study), where ground dentin was washed with normal saline and placed around the dental implants, and to group II (control), where xenograft was used. The primary implant stability was measured at the time of implant placement. Secondary stability, plaque index (PI), bleeding index (BI), probing depth (PD), and keratinized mucosa width (KMW) were assessed at baseline (time of definitive abutment and temporary crown placement) and then at 3, 6, and 12 months. Pain and the number of analgesics consumed were assessed daily during the first postoperative week. Marginal bone loss (MBL) and radiodensity were assessed radiographically. Results: There were no significant differences between both groups in terms of postoperative pain, the number of analgesic tablets consumed, peri-implant mucositis, or peri-implantitis. Both groups showed comparable results for the PI, BI, and BD. Moreover, there was no statistical difference between both groups with regard to primary implant stability and secondary stability at baseline and 12 months. Group I showed significantly lower secondary stability after loading at 3 and 6 months and significantly greater bone loss and lower bone density before exposure. KMW and MBL after exposure were significantly higher in group I at all time points. Conclusion: Although UMDG showed similar clinical results as xenografts, including primary and secondary implant stability, they had higher resorption rates than xenografts. Therefore, treatment of the dentin graft is required. Thus, the authors do not recommend using untreated mineralized dentin grafts.

Purpose: To quantify the clinical accuracy of a robotically assisted implant guidance system in partially edentulous patients without the use of postoperative cone-beam radiography. Materials and Methods: A total of 10 implants (7 patients) were placed in partially edentulous patients utilizing robotically assisted implant guidance system. Following the implant placement a intraoral scan was performed to register the implant position after attaching a scan body. The virtual plan and the postoperative intraoral scan with the scan bodies were exported as STL files, superimposed and discrepancies were analyzed using Geomagic Control X software. Positional deviations were measured between the midpoint of the platform and apex of the planned and achieved implant positions. Results: Seven of the 10 samples in this study were defined as fully robotically dynamically guided, while 3 were partially robotically guided. For the fully robotic dynamically guided group the mean deviation at the midpoint of the restorative platform of the implant, the apex of the implant, the top of the scanbody, and the mean angular deviation were 1.31mm (SD0.46mm), 1.58mm (SD0.61mm), 1.11mm (SD0.57mm), and 2.34 degrees (SD1.71º), respectively. While for the partially robotic dynamically guided cases it was 1.31mm (SD0.49mm), 1.45mm (SD0.3mm), 1.74mm (SD0.47mm), and 3.75 degrees (SD2.53º). Eight out of the 10 implants (irrespective of full or partial guidance) showed a buccal displacement. Conclusion: Robotic surgery offers a level of accuracy similar to fully guided implant placement, without the need for a physical template, and allowing for changes in the surgical plan at any time. The analytical  method described in this study is an effective and radiation free quality control tool that  can be used in implant dentistry as well as in other areas of dental research dentistry. 

Purpose. The purpose of this study is to compare the factors of taper, length, angle and number of vertical axial walls that affect the retentive strength of a cemented crown on a partially customizedhybrid abutment in the esthetic zone. Materials and Method. A total of 35 metal copings were used in this study divided into one group with 30 copings cemented to their corresponding 8° tapered abutment with lengths from 3 to 8 mm with 1 mm increments. The remaining five consisted of a standardized metal coping matching a hexagonal abutment with 3 mm vertical axial walls and the sequential removal of 1, 2, and 3 contiguous vertical axial walls. Dislodgment tests were performed for all copings in both groups. Maximum retentive forces were measured in kgF with a conversion factor of 9.807 N to 1 kgF.  Results. At each tapered abutment length, the retentive strength increased proportionally and was significantly different from 31.67 ± SD 4.10 kgF to 67.68 ± SD 11.22 kgF, respectively [F (5,24) =20.46, p < 0.001]. An unmodified hexagonal abutment demonstrated the highest retentive strength of 70.15 ± SD 12.97 kgF. Sequential removal of 1, 2, and 3 contiguous vertical axial walls of the hexagonal abutment was 59.89 ± SD 10.06 kgF, 57.01 ± SD 9.62 kgF, and 55.99 ± SD 9.35 kgF, respectively with no significant difference (p > 0.05) in retentive strength. Conclusion. A partially customized abutment with vertical axial walls on one side and a profile reduction on the opposite side can provide comparable retention of cemented copings at 1/3 the length and 1/6 the surface area of an 8 mm high abutment with an 8° taper.

Purpose:  The aim of this study was to investigate the effects of membrane stabilization by suturing the sinus membrane and dental implant insertion on endo-sinus bone formation in lateral sinus lifting performed without grafting. Materials and Methods: Maxillary sinus lift surgery using the lateral approach was performed bilaterally in 30 New Zealand white rabbits. The maxillary sinus areas were divided into control and test groups. In the control group, a titanium screw was placed after sinus membrane elevation, while in the test group, the sinus membrane was sutured to the lateral walls and a titanium screw was placed in the center of the alveolar crest. The animals were sacrificed at 4 and 8 weeks. Samples were collected, and micro-computed tomography (micro-CT) analysis was performed. The volume of newly formed bone, percentage of osseointegration, sinus volume, residual bone height, and protrusion length of the implants were measured using micro-CT analysis. Results: The sinus volume, volume of newly formed bone, and percentage of osseointegration in the test group were significantly higher than those in the control group at 4 weeks (p = 0.01, p = 0.04, p = 0.02, respectively) While the volume of newly formed bone was 17.1 ± 3.08 mm3 in the control group, it was 26.9 ± 14.26 mm3 in the test group at 4 weeks. The volume of newly formed bone was significantly decreased from 26.9 ± 14.26 mm3 to 17 ± 3.66 mm3 at 8 weeks (p = 0.02). No significant difference in residual bone height was found at 4 and 8 weeks (p = 0.07). No significant difference in implant protrusion length was found between the control and test groups (p = 0.18). Protrusion length and new bone formation in the sinus showed a negative relationship (p = 0.01). Conclusion: Suturing the sinus membrane to the lateral sinus wall is an effective approach for increasing osseointegration, bone volume, and sinus volume in the short-term. A slow-absorbing suture material can be used to maintain sinus and bone volumes in the long-term.

Purpose: The aims of the study were to evaluate the clinical performance and the complications of combined tooth-implant supported 3 unit fixed partial dentures in the posterior mandible. Materials and methods: 78 partially edentulous patients in the posterior mandible were recruited for the study (n=26/group). Group 1 served as the control group and received 2 dental implants for supporting 3 unit fixed partial dentures (FPD). Groups 2 and 3 were the experimental groups where an implant was combined with a tooth. As stated by the dental implant company, standard implants (8 mm or longer) were included in Group 2, while short implants (shorter than 8 mm) were included in Group 3. Periapical radiographs were taken for evaluation of marginal bone resorption (CBL). Modified plaque index (MPI), bleeding index (BI) and sulcus depth of abutment teeth was recorded at the time of FPD insertion, 6 months after FPD insertion and annually. Abutment tooth intrusions, cementation failures of the restorations, porcelain chipping/delamination, framework fracture, abutment screw loosening, abutment and abutment screw fracture, implant fracture were also recorded as complications. Results: Statistically significant different was observed between group 1 (.06 .17) and group 2 (.18 .32) and group 1 and group 3 (.17 .30) in terms of MPI (p≤0.05). No difference was observed between group 2 (.11 .34) and group 3(.14 .36) and group 1(.04 .22) and group 2 in terms of BI. There was statistically significant difference in terms of CBL between group 1 (.259 .05 mm) and group 3 (.11 .03 mm), and group 2 (.03 .03 mm) and group 3 (p≤0.05).The mean abutment tooth sulcus depth was 1.11 .31 mm for group 2 and 1.20 .46 mm for group 3. Conclusion: Within the limitations of the current study, it was concluded that combined tooth-implant supported prostheses (CTISP) is a predictable treatment choice in posterior mandible. When CTISP is planned, it is more predictable to use short dental implant rather than a standard-length dental implant. 

Purpose: To examine the stresses caused by different All-on-4 surgical techniques—conventional, a combination of monocortical and bicortical, bicortical, and nasal floor elevation—on the implant and the surrounding bone using 3D finite element analysis (FEA). Materials and Methods: A 3D bone model of the  atrophic maxilla was created based on CT imaging of the fully edentulous adult patient. All implants used in the models were 4 mm in diameter, and the length was 13 mm in the anterior and 15 mm in the posterior. Implants were applied to four different atrophic maxillary models with the All-on-4 technique: anterior and posterior monocortical implants in the first model, anterior monocortical and posterior bicortical in the second model, anterior and posterior bicortical in the third model, and anterior and posterior bicortical with nasal floor elevation in the fourth model. Eight linear analyses were performed by applying force from both vertical and 45-degree oblique directions to the four models prepared in our study. Results: When the cortical and cancellous bone around the anterior implants was examined, it was observed that the oblique and vertical loading conditions and the stresses around the implant were similar in all models. When the posterior implants were examined, model 1 (ie, anterior and posterior monocortical implants) showed the greatest oblique compression, vertical compression, and vertical tension forces. According to the Von Mises stress (VMS) analysis results for anterior and posterior implants, higher values were observed in model 1 compared to models 3 and 4 under oblique and vertical forces. It was observed that bicortical placement of the implants reduced the stresses on the bone and implant-abutment system but had no significant effect on the stress on the bar. Conclusions: According to the results of our study, in the All-on-4 technique, bicortical placement of the implants reduced the stresses on the bone and implant when the anatomical limitations allowed. In addition, nasal floor elevation can be applied in the atrophic maxilla in appropriate indications. 

Purpose: To assess the peri-implant and flap parameters of the prefabricated microvascular fibula flap and determine the dental implant survival rate. Materials and Methods: This retrospective study investigated a cohort of subjects who received prefabricated microvascular fibula flaps at two highly specialized tumor reconstruction centers. The subjects had all suffered atrophy or a large segmental defect of the jaws due to tumor resection or injury. Two independent surgeons determined the dental implant survival rate and assessed the peri-implant parameters and flap parameters during clinical follow-up. Results: In total, 41 subjects were treated with a prefabricated fibula flap between 1999 and 2012. Of these, 17 subjects (10 male, 7 female) with a total of 62 dental implants were examined. The other 24 subjects were unavailable for assessment and had to be excluded. Ten of the 62 dental implants (16.1%) had to be removed due to peri-implantitis before the follow-up assessment. Follow-up assessments were performed at intervals ranging from 2 to 12 years (mean: 7.2 years) after fibula flap transplantation. The dental implant survival rate was found to be 83.9%. A total of 208 dental surfaces were assessed. Overall, 96% of all surfaces had a pocket depth (PD) of ≤ 4 mm and 4% had a pocket depth of > 5 mm. An attachment level (AL) of 3 mm was measured in 48.5% of implants and ≥ 5 mm was measured in 15.9% of implants. Dental implants with a PD > 4 mm showed a significantly higher plaque index (PI) (75%; P = .0057), papillary bleeding index (PBI) (62.5%; P = .0094), and radiologic bone loss (P = .0014) compared to dental implants with a PD ≤ 4 mm. Conclusions: Reconstructive surgery using microvascular fibula flaps represents an alternative tool for oral rehabilitation in subjects suffering from a large segmental defect in the maxillary or mandibular bone compared to the conventional method. However, it appears that the different ossification processes that develop the fibula and the jawbones affect dental implant survival. 

Purpose: To compare the standard 360-degree CBCT acquisition protocol to the low dose 180-degree CBCT protocol for implant planning. Materials and methods: Two groups of patients, each consisting of 35 patients, were included in the study. The first group was imaged with the conventional 360-degree CBCT protocol, and the second group was imaged with the low dose 180-degree CBCT protocol. The primary outcome of this study was the number of scans that needed to be repeated due to poor image quality. In addition, six secondary parameters were evaluated quantitatively and qualitatively. Results: The results showed that there was no need to repeat any of the CBCT scans that were obtained in either group, which showed that 360-degree and 180-degree protocols had comparable image quality. As for the secondary parameters, the results showed that the evaluators were able to evaluate the six chosen parameters in a comparable manner. Conclusion: The 180-degree low dose CBCT scan is a viable option for dental implant treatment planning in the posterior mandible as it provides comparable and adequate information regarding accuracy of measurements, identification of critical structures, evaluation of bone quality, and any pathology. Schlagwörter: CBCT, implant planning, 180-degree, dental implant, ALARA, radiation, low-dose radiation, radiology

Purpose: To examine the changes of dentoalveolar structures and pathologies in the maxillary sinus before and after dental implant surgery alone or with direct vs indirect sinus lifting using CBCT images of the maxillary posterior region. Materials and Methods: Preoperative and postoperative CBCT images of 50 sinus sites and the alveolar bone around 83 implants in 28 patients were evaluated. Maxillary sinus pathologies were classified as mucosal thickening (MT), mucus retention cyst (MRC), polyp, and sinusitis before and after surgery. The changes after surgery were determined to be no change, reduction in pathology, or increase in pathology. Comparisons of pathology changes among the treatment groups were evaluated statistically with chi-square test, McNemar test, and Mann-Whitney U test. Results: Of the 50 sinuses evaluated for the presence of sinus pathology, 24 of 50 did not change postoperatively, the pathology increased in 10 sinuses, and the pathology decreased in 16. When the maxillary sinus regions were evaluated after indirect sinus lifting, direct sinus lifting, and in patients who had only implant surgery, there was no statistically significant difference between pathology distribution in terms of the procedure applied to the sinus (P > .05). However, in the maxillary sinuses with a pathology before implant placement were evaluated postoperatively, a statistically significant difference was found in favor of the presence of a change in pathology (ie, improvement or a decrease; P < .05). The maxillary sinuses without pathology before implant placement showed a statistically significant difference for no change; ie, continuation of the healthy state (P < .05). Conclusion: This study showed that surgical procedures could have a direct effect on the sinus membrane and maxillary sinus. Both the implant procedure and surgical approach may have an effect on maxillary sinus pathology, as well as an increase or decrease of the pathology. Hence, further studies with a longer-term follow-up should be performed to better understand the correlation between implant surgery and pathology.