The International Journal of Oral & Maxillofacial Implants, 06/2023

Purpose: Alveolar ridge split (ARS) is ridge augmentation to mitigate ridge width loss that typically follows tooth extraction. This study aimed to determine the efficacy of ARS on alveolar ridge horizontal dimensional changes and the survival rates of implants placed into the same sites. Materials and Methods: An electronic and manual search was conducted for English articles published up to January 1, 2021. The PICO (problem, intervention, comparison, outcome) model for quantitative studies was established to address the following two focused questions: (1) What are the effects of the ARS technique on increasing alveolar width and implant survival?; and (2) what are the factors that influence the efficacy of the ARS technique? The outcome measures in this systematic review and meta-analysis were mean alveolar ridge gain—horizontal (buccolingual) in millimeters from baseline (initial presentation) to final assessment (minimum of 12 weeks after ARS), implant survival rate, and patient-reported complication rate. The risk of bias was evaluated using the ROBINS-I assessment tool for non-randomized interventional studies. Weighted means were calculated, and pooled effects and 95% confidence intervals (95% CI) were depicted on forest plots. Publication bias was assessed by funnel plot and Rosenthal Statistics. A sensitivity analysis was undertaken to assess the primary outcome. Results: Overall, 35 studies met the inclusion criteria and were included in the systematic review. The mean alveolar ridge gain for ARS was 3.06 mm (95% CI: 3.01 to 3.12 mm). A mean gain of 2.99 mm (95% CI: 2.93 to 3.04 mm) was found after sensitivity analysis, excluding one article with a high risk of bias. There were no significant differences in ridge width in the group with bone graft (mean difference [95% CI] of 2.97 mm [2.91 to 3.03 mm]) and in the group without bone graft (mean difference [95% CI] of 3.06 mm [2.92 to 3.20 mm]). The ARS technique demonstrated a 98.17% implant survival rate in 4,446 implants, 4,103 of which were placed at the time of ARS with a 97.72% implant survival rate, and 343 placed in a delayed approach with a 99.14% implant survival rate. The risk of bias was low in 14.2%, low to moderate in 68.5%, moderate in 11.4%, and severe/moderate in 5.7% of the included studies. Conclusions: ARS shows a high implant survival rate in narrow alveolar ridges, adequate horizontal alveolar ridge dimensional gain regardless of adding grafting material, and minimal patient-reported complications. Keywords: alveolar ridge augmentation, alveolar ridge split, dental implants, implant survival rate, narrow alveolar ridge, systematic review

Purpose: To summarize the latest scientific literature regarding the concentrations of biomarkers in saliva and peri-implant crevicular fluid (PICF) of healthy implant (HI) patients and patients with peri-implant mucositis (PIM) and peri-implantitis (PI). Materials and Methods: The literature review was performed according to PRISMA guidelines. The databases used were PubMed MEDLINE, ScienceDirect, and Cochrane Library. A combination of keywords was used, and selection criteria were applied. Selected articles were published between February 1, 2017, and February 1, 2022, written in English, conducted in humans, and examined the levels of saliva and PICF biomarkers in PI patients and compared them to HI/PIM patients. Results: A total of 16 publications were selected, involving a total of 1,117 patients with 1,346 implants. Qualitative analysis revealed 49 different biomarkers, the levels of which were compared between groups. After evaluating the most frequently studied biomarkers, significantly higher values of IL-1β, RANKL, sRANKL, IL-6, TNF-α, TNFSF12, MMP2, and MMP8 levels were observed in the PI group than in the HI group. Conclusions: Of all 49 biomarkers evaluated, IL-1β and RANKL have potentially the highest diagnostic significance in the assessment of peri-implant inflammatory conditions, as differences were observed between all three groups (HI < PIM < PI), but data from current publications were not fully sufficient to provide strong evidence. Keywords: biomarkers, dental implants, diagnosis, interleukins, peri-implantitis

Purpose: To assess the clinical performance of a two-piece zirconia implant system, with a focus on biologic complications. Materials and Methods: A total of 39 patients received 91 two-piece zirconia implants. The patients were recruited from two private clinics and were monitored for 5 to 12 years (median: 5.6 years). The primary outcomes were biologic complications, such as peri-implant infections (peri-implant mucositis and peri-implantitis), and the secondary outcome was radiographically evident marginal bone loss (MBL). Results: Three patients (7.7%) with 9 total implants (9.9%) presented with peri-implant mucositis. MBL that did not exceed the first thread was evident at 32 mesial sites (35%) and 25 distal sites (27.4%). MBL exceeding the first thread but not the third thread was evident at 6 mesial and 5 distal sites (thread pitch: 0.7 mm). Only one peri-implant pocket deepened (4 mm) and showed bleeding; however, the estimated MBL did not exceed 1.65 mm. No peri-implantitis occurred, and no implant was lost. Conclusions: This prospective study shows high survival rates and a seemingly low prevalence of biologic and prosthetic complications for this two-piece zirconia implant system over an observation period of up to 12 years. Keywords: bone resorption, dental implantation, osseointegration, peri-implantitis, two-piece zirconia implants

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. Keywords: Cone-beam computed tomography, dental implant, radiology, sinus elevation, sinus graft

Purpose: To comparatively evaluate transcrestal sinus floor elevation (tSFE) and lateral sinus floor elevation (lSFE) at sites with different residual bone heights (RBHs). Materials and Methods: A re-analysis of data from a parallel-arm, randomized trial comparatively evaluating tSFE and lSFE was performed. Within each RBH interval (< 4 mm or ≥ 4 mm), tSFE and lSFE groups were compared for chair time, surgery-related costs, morbidity, and radiographic parameters (including the proportion of the implant surface in direct contact with the radiopaque area [totCON%]). Results: The intention-to-treat (ITT) population consisted of 29 and 28 patients in the tSFE and lSFE groups, respectively. Irrespective of RBH, both tSFE and lSFE lead to a median totCON% of 100%. At sites with RBH < 4 mm, pain severity was significantly higher at days 0 and 1 in the tSFE group, with no intergroup difference in the dose of analgesics. LSFE was associated with a significantly higher frequency of bruising and greater cost. At sites with RBH ≥ 4 mm, a significantly lower frequency of postoperative signs/symptoms, less chair time, and lower costs were observed in the tSFE group. Conclusions: The selection of tSFE or lSFE within the investigated RBH intervals seems to be supported by differences in chair time, costs, and morbidity between the two techniques. At sites with RBH < 4 mm, clinicians preferring tSFE should encourage the administration of analgesics according to a predefined plan in the early postoperative phase. At sites with RBH ≥ 4 mm, tSFE should be preferred to lSFE due to reduced chair time, costs, and morbidity. Keywords: alveolar process, bone resorption, maxillary sinus, bone regeneration, minimally invasive, dental implants

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. Keywords: All-on-4, atrophic maxilla, finite element analysis, stress distribution

Purpose: To assess site-related features of peri-implantitis occurring adjacent to teeth and its association with the proximal periodontal bone level. Materials and Methods: Periapical radiographs were collected from partially edentulous patients exhibiting peri-implantitis adjacent to teeth. The following variables were quantified: intrabony defect width (DW), implant marginal bone loss (MBLi), tooth marginal bone loss (MBLt), implant-tooth distance (ITd), intrabony defect angulation (DA), adjacent periodontal bone peak height (ABPh), and implant-tooth angulation (ITa). A correlation matrix using the Spearman correlation coefficient was created to explore the dependence of these variables. Univariate linear regression analysis was carried out by means of generalized estimating equations (GEE), using MBLt as dependent variable. Results: Overall, 61 patients and 84 implants were included in this study, consisting of a total of 105 implant sites facing adjacent teeth. This resulted in 515 linear and 194 angular measurements. A total of 11 different statistically significant associations were demonstrated between the different variables analyzed. Moreover, the univariate regression analysis revealed significant positive associations between MBLt and MBLi (P = .013) and between MBLt and periodontitis (PD) (P = .014). These associations were confirmed in the multivariate model. Conclusions: Teeth adjacent to untreated peri-implantitis lesions are associated with proximal loss of periodontal support. This finding is more remarkable in scenarios that display short implant-tooth distance. Keywords: peri-implantitis, peri-implant diseases, dental implant, periodontal disease, periodontitis

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. Keywords: dental implants, prefabricated fibula flap, peri-implantitis, oral rehabilitation

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. Conclusions: 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. Keywords: CBCT, implant planning, 180-degree, dental implant, ALARA, radiation, low-dose radiation, radiology

Purpose: To evaluate two pharmacologic antibiotic prophylaxis regimens and a control group of immunocompetent patients undergoing two-stage dental implant placement in a triple-blind randomized controlled clinical trial. Materials and Methods: From a group of 61 immunocompetent patients, 21 were randomly allocated into group 1 (G1) without antibiotic prophylaxis (control), 20 in group 2 (G2) with preoperative antibiotic prophylaxis (1 g amoxicillin 1 hour before the procedure), and 20 in group 3 (G3) with preoperative (1 g amoxicillin) and postoperative (500 mg every 8 hours for 5 days) antibiotic prophylaxis. Pain was assessed with the visual analog scale (VAS) and by considering the number of painkillers patients used. Infection was identified via the presence of pus and fistula. Patients were evaluated after 7, 14, 30, and 120 days. Implant failure (defined as mobility upon the application of manual torque) was evaluated after 120 days during the second surgical stage. Results: At the 7-day follow-up, pain intensity was less severe in the patients who had received antibiotics, with the G3 patients experiencing the least pain (P < .05). Infection was present in groups G1 (2 cases) and G3 (2 cases), but there was no statistically significant intergroup difference. Two implants failed, one in G1 and the other in G3. Conclusions: Based on the results of the present study, although the use of antibiotics reduced pain in the immediate postoperative period, it did not reduce infection rates and implant failure in immunocompetent patients. Keywords: clinical trial, dental implants, antibiotic prophylaxis, infections

Purpose: To investigate bone regeneration among three different bone graft materials in a rat calvarum model. Materials and Methods: A total of 24 rats had two 5-mm defects placed per calvarial. Rats were divided into four groups: bovine xenograft (XG), demineralized bone matrix (DBM), mineralized bone graft (MBG), and collagen membrane control (CC). Within each group, samples were collected at two time points: 4 weeks (T4) and 8 weeks (T8). Bone regeneration was assessed by microcomputed tomography (micro-CT) imaging and was analyzed using MATLAB software. Additionally, the fixed samples were subsequently demineralized for immunohistochemistry and histomorphometry. Slides were mounted and stained with hematoxylin and eosin (H&E) stain as well as bone morphogenetic protein 2 (BMP-2) and runt-related transcription factor 2 (RUNX2) markers. The numbers of positive cells/area were calculated for each group and analyzed. Results: At 4 weeks, DBM showed low mineral density (7.7%) compared to the control (25.2%), but increased dramatically at 8 weeks (DBM, T8 = 27.6%; CC, T8 = 27.2%). Xenograft material showed an increase in mineral desnity between T4 and T8 (XG, T4 = 25.0%; XG, T8 = 32.3%). MBG remained consistent over the 8-week trial period (MBG, T4 = 30.4%; MBG, T8 = 30.4%). BMP-2 expression was present in cells adherent to all graft materials. RUNX2 expression was also observed in cells adherent to all graft materials, indicating that during the 4- to 8-week healing period, all materials supported osteogenesis. Conclusions: Compared to other materials, the DBM had high osteoinductive properties during the 4- to 8-week time period based on increased mineral content. All materials were associated with immunohistologic evidence of osteogenesis in the rat calvarial defect model. Keywords: bone regeneration, calvarial defect, immunocytochemistry, micro-CT, osteoinduction

Purpose: To investigate cytokine levels in peri-implant crevicular fluid and thus evaluate the effects of concentrated growth factor (CGF) on osseointegration. Materials and Methods: A total of 40 mandibular implants were symmetrically placed in a group of 20 systemically healthy patients enrolled in the study. In each patient, one implant wetted with liquid infiltrated from fibrin matrix was placed in the test side (Group L), and the other implant was placed in the control side without the application of any material (Group C). Peri-implant crevicular fluid was collected at 2, 4, and 12 weeks later. Marginal bone loss was measured with panoramic radiographs taken immediately after implant placement and at 12 weeks. Resonance frequency analysis (RFA) of the implants was performed intraoperatively and at 4 and 12 weeks. Results: Stability values of the implants in the CGF liquid–treated sites were higher than those of the control group at week 12 (P = .005). There was no statistically significant difference between the two groups in terms of marginal bone loss (MBL). Group L showed increased levels of tumor necrosis factor alpha (TNF-α) and receptor activator of nuclear factor kappa-B ligand (RANKL) at 2 and 4 weeks. Also, levels of osteoprotegerin (OPG) were higher in Group L at week 4 compared to Group C (P = .033). Conclusions: The increased TNF-α, RANKL, and OPG levels in this study demonstrate that CGF liquid can be used to accelerate peri-implant bone remodeling in the early phase of osseointegration. Keywords: Concentrated growth factor, peri-implant crevicular fluid, cytokine, osseointegration

Purpose: To use histomorphometric analysis to evaluate bone reconstruction in rabbit calvaria with autogenous bone, anorganic bovine bone, undecalcified human tooth bone (UdTB), and decalcified human tooth bone (dTB) grafts. Materials and Methods: Extracted human teeth were crushed, and tooth bone with and without decalcification was prepared. Bony defects were made in 10 rabbit calvaria and allocated to one of the following four groups: group 1, in which UdTB was grafted; group 2, in which dTB was grafted; group 3, in which anorganic bovine bone was grafted; group 4, in which autogenous bone was grafted. The rabbits were sacrificed at 2 or 8 weeks postoperatively, and histomorphometric comparison was performed. Results: Histologically, new bone formation was observed at the defect margin and around all graft materials. The dTB group revealed significantly greater new bone areas at 2 and 8 weeks compared to the UdTB group and the anorganic bovine bone group (P < .05). The dTB group revealed no significant difference in the new bone area at 2 weeks but revealed significantly less new bone area at 8 weeks compared to the autogenous bone group (P < .05). The dTB group also revealed significantly less graft material area compared to the anorganic bovine bone group at 8 weeks (P < .05). The autogenous bone group revealed significantly less graft material area and significantly greater bone marrow area compared to other groups at 8 weeks (P < .05). Conclusions: Grafting with dTB resulted in better bone regeneration than UdTB and anorganic bovine bone grafting at 8 weeks and addresses the potential disadvantages of autogenous bone grafting. Keywords: decalcification, particulate human tooth bone, new bone formation, histomorphometric analysis

Purpose: To analyze the process of early oral osseointegration of titanium (Ti) implants in diabetic 129/Sv mice through microCT and histologic and immunohistochemical analysis. Materials and Methods: A group of 30 male 129/Sv mice was equally subdivided into two groups: (1) nondiabetic (ND), in which mice did not undergo systemic alterations and received a standard diet, and (2) diabetic (D), in which mice were provided a high-fat diet from the age of 6 weeks until the conclusion of the study and received two intraperitoneal (IP) injections of streptozotocin (STZ) at a concentration of 100 mg/Kg each. Each mouse underwent extraction of a maxillary first molar, and customized Ti screws (0.50 mm diameter, 1.5 mm length) were placed in the residual alveolar sockets of the palatal roots. At 7 and 21 days after implant placement, the animals were euthanized for maxilla and pancreas collection. Maxillae containing Ti implants were analyzed with microCT, histology, and immunohistochemistry for cells that were positive for F4/80, CD146, runt-related transcription factor 2 (Runx2), and proliferating cell nuclear antigen (PCNA). Pancreata were histologically analyzed. Quantitative data were statistically analyzed with a significance level at 5% (P < .05). Results: ND mice presented successful healing and osseointegration, with a significantly higher fraction of bone volume compared to D mice, both at the alveolar sockets (53.39 ± 5.93 and 46.08 ± 3.18, respectively) and at the implant sites (68.88 ± 7.07 and 44.40 ± 6.98, respectively) 21 days after implant placement. Histologic evaluation revealed that the ND mice showed a significant decrease in inflammatory infiltrate and a significant increase in newly formed bone matrix at 21 days, whereas peri-implant sites in the D mice were predominantly encapsulated by fibrous tissue and chronic inflammatory infiltrate. Immunohistochemical characterization revealed higher Runx2 osteoblast differentiation and higher cell proliferation activity in the ND mice at 7 days, while higher amounts of macrophages were present in D mice at 7 and 21 days. Interestingly, no differences were found in CD146-positive cells when comparing ND and D mice. Conclusions: This study evaluated the effects of immediate dental implant placement in 129/Sv diabetic mice by using specific healing markers to identify changes in cellular events involved in early oral osseointegration. This approach may serve as tool to evaluate new materials and surface coatings to improve osseointegration in diabetic patients. Keywords: hyperglycemia, mouse, osseointegration, inflammation, bone

Purpose: To compare the 3D accuracy of three scanning strategies and conventional impressions using an edentulous model with six implants. Materials and Methods: An edentulous maxillary master model was fabricated with six equigingival internal connection implants at 0 degrees of angulation. Ten conventional open-tray splinted implant-level impressions were made and poured in stone. A master model and conventional casts were digitized with a reference scanner. Digital impressions were made by calibrated clinicians with a TRIOS 3 intraoral scanner ([IOS] 3Shape) according to three scanning strategies: DIG1 (occlusal-palatal-lingual), DIG2 (S-type motion from buccal to palatal), and DIG3 (scanning two half arches and connecting them at the midline). Each technique was repeated 10 times on the master model. Deviations from the STL datasets (N = 40) were compared to those of the reference master model using the Hexagon Metrology software system PC-DMIS CAD++. Linear distortions (dX, dY, dZ), global linear distortion (dR), and angular distortions (Absdθx, Absdθy) were calculated. Kruskal-Wallis test and mixed linear and logistic regression models were used to compare the original and binary distortion measures between the techniques. Results: The mean dR ranged from 91 μm (conventional method) to 183 μm (DIG1). The mean angular distortion ranged from 0.20 degrees (Absdθx for DIG2) to 0.69 degrees (Absdθy for DIG3). No scan pattern resulted in a more accurate reproduction in any of the measured parameters than the conventional impression method. There were significant differences between the methods for all distortion measures. Conclusions: No group reproduced the 3D position of the six-implant master model below the thresholds for both global linear and angular distortions. All the digital strategies tested were less accurate than the conventional open-tray splinted implant-level impression technique. Keywords: scan pattern, edentulous arch, implant-level impression, distortion, digital, three-dimensional