Pages 705-706, Language: EnglishEckert, Steven E.
DOI: 10.11607/jomi.2017.4.tar, PubMed ID (PMID): 28708904Pages 711-714, Language: EnglishEllingsen, Jan-Eirik
DOI: 10.11607/jomi.5699, PubMed ID (PMID): 28708905Pages 717-734, Language: EnglishKarl, Matthias / Albrektsson, Tomas
Purpose: A moderately rough anodized titanium implant surface (TiUnite) was introduced in 2000. This review and meta-analysis aimed to assess implant survival and marginal bone level (MBL) changes documented in the literature.
Materials and Methods: Repeated literature searches on dental implants were conducted, with the final search on October 7, 2016. The inclusion criteria were: prospective study, minimum of 20 patients, at least 12 months follow-up postloading, and TiUnite implant survival reported. Regression analysis was performed on implant survival and MBL change from implant surgery. Peri-implantitis as defined by the primary authors was reported at the patient level.
Results: One hundred six out of 32,519 publications on dental implants met the inclusion criteria. Implant survival rates at 1 year were 99.50% at the implant level and 99.12% at the patient level, and survival rates at 10 years were 95.14% at the implant level and 91.50% at the patient level. Mean MBL change at 1 year was -0.409 mm at the implant level and -0.413 mm at the patient level, and at 5 years, it was -0.886 mm at the implant level and -1.029 mm at the patient level. Nineteen studies (18%) specifically reported peri-implantitis in 64 out of 1,229 patients with a mean followup of 47.89 months, indicating a prevalence of 5.20% at the patient level.
Conclusion: Based on a metaanalysis of prospective studies, implants with the TiUnite surface provide a predictable treatment modality in a variety of indications.
Keywords: implant surface, implant survival rate, marginal bone level change, meta-analysis, moderately rough, prospective clinical study
DOI: 10.11607/jomi.5290, PubMed ID (PMID): 28231348Pages 735-740, Language: EnglishSonoda, Tetsuya / Harada, Takehiro / Yamamichi, Nobuyuki / Monje, Alberto / Wang, Hom-Lay
Purpose: Maxillary sinus augmentation via crestal approach has been advocated as an alternative approach for sinus membrane elevation. Presently, no study has examined the relationship between the amount of bone grafting material placed and the final sinus membrane elevation height. Therefore, the present study was aimed at investigating the extent of sinus membrane elevation height depending on the amount of bone grafting material inserted as well as three-dimensionally assessing the likelihood of membrane perforation during membrane elevation.
Materials and Methods: A total of 34 subjects (16 females and 18 males) with 61 crestal sinus elevation sites were recruited. The following changes in elevated sinus membrane area were recorded: vertical elevation height (VEH), buccopalatal elevation (BPE), and mesiodistal elevation (MDE). Cone beam computed tomography (CBCT) was used to measure the elevated height of the maxillary sinus floor at the initial examination, during surgery, and immediately after surgery. In addition, the VEH:BPE and VEH:MDE ratios at each site were calculated using CBCT to determine the probability of sinus membrane perforation.
Results: In average, 0.1 mL of bone graft material placed elevated VEH an average of 3.5 mm, while 0.2 mL and 0.3 mL of graft placed elevated VEH 5 mm and 6 mm, respectively. Furthermore, it was demonstrated that the VEH:BPE and VEH:MDE ratios play a determinant role on membrane integrity. As such, a ratio greater than 1.0 may jeopardize membrane integrity, while a ratio ≤ 0.8 might represent a lower risk of membrane perforation.
Conclusion: An initial 0.1 mL of bone material filling can elevate sinus membrane vertically by 3.5 mm. To avoid sinus membrane perforation, a VEH:BPE or VEH:MDE ratio of ≤ 0.8 should be obtained.
Keywords: bone replacement graft, cone-beam computed tomography, crestal approach, endosseous implants, sinus augmentation
DOI: 10.11607/jomi.5311, PubMed ID (PMID): 28708906Pages 741-750, Language: EnglishPinheiro, Lucas Rodrigues / Scarfe, William C. / de Oliveira Sales, Marcelo Augusto / Gaia, Bruno Felipe / Rodriguez Gonzalez Cortes, Arthur / Gusmão Paraiso Cavalcanti, Marcelo
Purpose: To determine the effectiveness of cone beam computed tomography (CBCT) images obtained with different kilovoltage settings compared with intraoral periapical photostimulable storage phosphor (PSP) plate images in the detection of chemically created peri-implant defects utilizing a bovine rib bone model in vitro.
Materials and Methods: After placing 80 implants in bovine ribs, peri-implant circumferential bone defects of different sizes were created with 70% perchloric acid. CBCT images (3D Accuitomo 170) were acquired at 90 and 75 kVp, and intraoral periapical images were acquired using a PSP system (Carestream KODAK, CS 7600). Using a 5-point Likert scale, two oral and maxillofacial radiologists (OMR) and two oral and maxillofacial surgeons (OMS) evaluated the likelihood of a bone defect being absent or present. The kappa statistic was used to compare observer agreement, and area under the curve values were compared using analysis of variance and the post hoc Tukey test. Significance was set at P ≤ .05.
Results: PSP reliability ranged from discordance to slight for small defects and fair to moderate for larger defects. For CBCT, OMRs had good agreement for defects using 90 kVp, and slight to fair using 75 kVp. Agreement for OMS observations was fair for 75 kVp, and varied from slight to good for 90 kVp. Small lesions were detected more effectively by CBCT than by PSP, and larger lesions were detected more effectively by CBCT at 90 kVp than by CBCT at 75 kVp or by PSP.
Conclusion: CBCT imaging at 90 kVp was associated with a significantly higher rate of detection of both small and large chemically simulated bone defects than PSP or CBCT at 75 kVp. CBCT imaging at 75 kVp proved better than PSP for the detection of small defects.
Keywords: bone, cone beam computed tomography, defect, dental implants
DOI: 10.11607/jomi.5320, PubMed ID (PMID): 28708907Pages 751-758, Language: EnglishMartin-Monge, Elena / Tresguerres, Isabel F. / Clemente, Celia / Tresguerres, Jesús A. F.
Purpose: The aim of this study was to assess the effect of local application of growth hormone on osseointegration of dental implants inserted in osteoporotic bones.
Materials and Methods: Twenty female New Zealand rabbits were used in this study. Ten were ovariectomized and fed a low-calcium diet for 6 weeks, and the others remained intact. A titanium implant was inserted into each tibia, in both groups. In half of the rabbits, 2 IU of growth hormone was placed into the ostectomy prior to the implant insertion. Two weeks after implant surgery, all animals were sacrificed. Tibiae were dissected from soft tissues, and included in methacrylate to be studied under light microscopy. Bone-to-implant contact (BIC) and bone mineral density (BMD) were measured by morphometric and densitometric analysis, respectively. Multifactorial analysis of variance (ANOVA) was used for statistical evaluation. P < .05 was considered to be significant.
Results: Ovariectomy induced less BIC and BMD in regions closer to the implant compared with the control group. Local application of growth hormone was able to increase the BIC in the ovariectomized group, with statistically significant differences with respect to the control group (P < .01). Regarding the BMD, no statistically significant differences were found.
Conclusion: Within the limitations of this experimental study, local application of 2 IU of recombinant human growth hormone at the moment of titanium implant insertion in rabbit tibiae significantly enhanced the BIC around titanium implants 15 days after the implantation in this experimental osteoporotic animal model, without affecting the BMD.
Keywords: BMD, bone-to-implant contact, growth hormone, implants, osteoporosis, rabbits
DOI: 10.11607/jomi.5364, PubMed ID (PMID): 28334056Pages 759-767, Language: EnglishGhasemi, Samaneh / Fotouhi, Akbar / Moslemi, Neda / Chinipardaz, Zahra / Kolahi, Jafar / Paknejad, Mojgan
Purpose: This meta-analysis and systematic review focused on the following question: Does tobacco smoking increase the risk of intra- or postoperative complications of lateral maxillary sinus floor elevation?
Materials and Methods: The following electronic databases were searched up to and including November 2015 without language restriction: CENTRAL, MEDLINE, Google Scholar, Scopus, Sirous, and Doaj. Studies were included if rates of intraor postoperative complications of sinus floor elevation in smokers and nonsmokers were recorded separately. The following complications were assessed: sinus membrane perforation, bleeding, wound dehiscence, wound infection, sinusitis, hematoma, and oroantral fistula. The Critical Appraisal Skills Programme was used to assess the risk of bias in included studies. Random-effects meta-analyses were used to assess the number of each complication in smokers and nonsmokers.
Results: Out of 929 eligible publications, 11 articles were included. Meta-analysis of the studies revealed a significantly increased risk of developing wound dehiscence after sinus floor elevation among smokers compared with nonsmokers (Risk Ratio [RR]: 7.82; 95% confidence interval [CI]: 2.38, 25.74; P = .0007). Moreover, risk of developing wound infection was greater in smokers when prospective studies were included in the meta-analysis (RR: 5.33; 95% CI: 1.34, 21.25; P = .02). However, the meta-analysis of included studies did not show significant differences between smokers and nonsmokers concerning risk of sinus membrane perforation and bleeding during sinus floor elevation (P = .46 and P = .33, respectively).
Conclusion: Considering the lack of randomized controlled trials and the small number of included studies, the results indicate that smoking seems to be associated with increased risk of wound dehiscence and infection after the sinus augmentation procedure.
Keywords: intraoperative complications, meta-analysis, oral surgical procedure, postoperative complications, sinus floor augmentation
DOI: 10.11607/jomi.5366, PubMed ID (PMID): 28212452Pages 768-773, Language: EnglishArtzi, Zvi / Anavi-Lev, Karen / Kozlovsky, Avital / Chaushu, Liat / Schwarz, Frank / Tal, Haim
Purpose: To assess the extent of osseointegration with rough-surface implants and new bone formation (NBF) within human freeze-dried bone blocks (h-FDB) grafted over rabbit calvaria.
Materials and Methods: A total of 18 rectangular h-FDB blocks were stabilized bilaterally to the calvaria of nine New Zealand rabbits by two mini titanium screws each. A total of 18 rough-surface implants (5.0 × 6.0-mm) were placed, 9 simultaneously (immediate placement [IP]) on one side and 9 at 3 months after block grafting (delayed placement [DP]) on the contralateral side. At 12 weeks after the second surgical procedure, block biopsies were harvested and processed for histologic analysis. Morphometric measurements consisted of bone-to-implant contact (BIC) and the extent of NBF from the calvarial surface and outward into the block. A paired t test was applied for statistical analysis.
Results: All h-FDB blocks were integrated, and the implants showed clinical stability. Histologically, the BIC was primarily between the apical end of the implants and the host rabbit calvaria. Bone growth between the implant threads was minimal and inconsistent among all animals. Morphometric measurements showed that the mean BIC of the IP and DP implants with the blocks was 10.50% ± 5.99% and 23.06% ± 9.58%, respectively (P < .001). NBF was observed primarily in the cancellous compartment of the block adjacent to the recipient calvarial bed. The extent of NBF into the block around the IP and DP implants was 9.95% ± 8.41% and 12.90% ± 11.07%, respectively (P = 0.2).
Conclusion: In this model, a significantly lower BIC was demonstrated when implants were placed simultaneously with h-FDB block grafting compared to those placed in a two-stage mode. However, both techniques showed limited osseointegration.
Keywords: bone-implant contact, FDB bone blocks, freeze-dried bone, graft vascularization, new bone formation, osseointegration
DOI: 10.11607/jomi.5402, PubMed ID (PMID): 28518179Pages 774-778, Language: EnglishCanullo, Luigi / Tallarico, Marco / Chu, Stephen / Peñarrocha, David / Özcan, Mutlu / Pesce, Paolo
Purpose: American and European standards recommend sterilization of customized abutments before connecting them to implants, as customized abutments are considered semi-critical medical devices. Since standardized procedures could not be identified in the literature on implantology, this survey evaluated the protocols employed at different universities worldwide to clean, disinfect, and/or sterilize customized abutments before their connection to bone-level implants.
Materials and Methods: The survey took place between October 2015 and January 2016. A single question acquiring information on how customized abutments were treated prior to connection to the implants was sent by email to researchers affiliated at 100 universities worldwide. To avoid any bias, the survey was kept rigorously anonymous. A total of 100 universities from Europe (56), USA and Canada (25), Latin America (9), South Africa (1), Asia (6), and Australia and New Zealand (3) were invited to participate in the survey.
Results: Altogether, 85 universities responded to the survey question, and 22 (25.9%) declared that no cleaning protocols were adopted. More than half of the respondents (n = 49, 57.6%) performed only one of the three procedures required by the standards (cleaning, disinfection, or sterilization). Twelve respondents (14.1%) adopted two procedures, and only two universities performed all three required procedures (2.4%).
Conclusion: This survey indicated substantial heterogeneity in treating customized abutments before connecting them to implants. This study demonstrated that the majority of the universities applied either cleaning, disinfection, or sterilization which may not meet the prevailing standards.
Keywords: customized abutments, disinfection, implant abutments, implant-abutment cleaning, oral implants, peri-implant tissues, sterilization, survey
DOI: 10.11607/jomi.5421, PubMed ID (PMID): 28708908Pages 779-791, Language: EnglishNakazawa, Masahiro / Yamada, Masahiro / Wakamura, Masato / Egusa, Hiroshi / Sakurai, Kaoru
Purpose: Titanium-doped hydroxyapatite (TiHA) nanoparticles contain titanium atoms in the hydroxyapatite lattice, which can physicochemically functionalize the titanium surface without modification of the surface topography. This study aimed to evaluate the physicochemical properties of machined or microroughened titanium surfaces coated with TiHA nanoparticles and the functions of osteoblasts cultured on them.
Materials and Methods: Titanium disks with commercially available surface topography, such as machined or sandblasted, large-grit, and acid-etched (SLA) surfaces, were coated with TiHA. The disks with original or TiHA-coated surfaces were evaluated in topography, wettability, and chemical composition. Osteoblastic cells from rat femurs were cultured on the disks and evaluated in proliferation and differentiation.
Results: TiHA coating changed from hydrophobicity to hydrophilicity on both machined and SLA surfaces. Calcium and phosphate atoms were detected all over the surface with TiHA coating regardless of the surface topography. However, the considerable change in the inherent surface topographies was not observed on both types of surfaces after TiHA coating. Osteoblastic proliferative activity at day 4 was increased by TiHA coating on both types of surfaces. TiHA coating did not enhance expressions of bone matrix-related genes such as osteocalcin, osteopontin, bone sialoprotein, alkaline phosphatase, and collagen I. However, depositions of collagen, osteocalcin, and calcium in the culture at days 7 and 20 were increased on both types of surface topographies with TiHA coating.
Conclusion: TiHA coating enhanced extracellular matrix formation on smooth and microroughened titanium surfaces by increasing osteoblastic proliferative activity without the deterioration of differentiation through hydrophilic and chemical functionalization.
Keywords: calcium, osseointegration, osteoblastic culture, surface topography, wettability
DOI: 10.11607/jomi.5431, PubMed ID (PMID): 28618432Pages 792-799, Language: EnglishBasaki, Kinga / Alkumru, Hasan / De Souza, Grace / Finer, Yoav
Purpose: To assess the three-dimensional (3D) accuracy and clinical acceptability of implant definitive casts fabricated using a digital impression approach and to compare the results with those of a conventional impression method in a partially edentulous condition.
Materials and Methods: A mandibular reference model was fabricated with implants in the first premolar and molar positions to simulate a patient with bilateral posterior edentulism. Ten implant-level impressions per method were made using either an intraoral scanner with scanning abutments for the digital approach or an open-tray technique and polyvinylsiloxane material for the conventional approach. 3D analysis and comparison of implant location on resultant definitive casts were performed using laser scanner and quality control software. The inter-implant distances and interimplant angulations for each implant pair were measured for the reference model and for each definitive cast (n = 20 per group); these measurements were compared to calculate the magnitude of error in 3D for each definitive cast. The influence of implant angulation on definitive cast accuracy was evaluated for both digital and conventional approaches. Statistical analysis was performed using t test (α = .05) for implant position and angulation. Clinical qualitative assessment of accuracy was done via the assessment of the passivity of a master verification stent for each implant pair, and significance was analyzed using chi-square test (α = .05).
Results: A 3D error of implant positioning was observed for the two impression techniques vs the reference model, with mean ± standard deviation (SD) error of 116 ± 94 μm and 56 ± 29 μm for the digital and conventional approaches, respectively (P = .01). In contrast, the inter-implant angulation errors were not significantly different between the two techniques (P = .83). Implant angulation did not have a significant influence on definitive cast accuracy within either technique (P = .64). The verification stent demonstrated acceptable passive fit for 11 out of 20 casts and 18 out of 20 casts for the digital and conventional methods, respectively (P = .01).
Conclusion: Definitive casts fabricated using the digital impression approach were less accurate than those fabricated from the conventional impression approach for this simulated clinical scenario. A significant number of definitive casts generated by the digital technique did not meet clinically acceptable accuracy for the fabrication of a multiple implant-supported restoration.
Keywords: dental implants, dental impression techniques, digital impression, dimensional measurement accuracy, intraoral scanner, three-dimensional imaging
DOI: 10.11607/jomi.5546, PubMed ID (PMID): 28708910Pages 801-806, Language: EnglishGallucci, German O. / Khoynezhad, Shirin / Yansane, Alfa I. / Taylor, Jacob / Buser, Daniel / Friedland, Bernard
Purpose: The purpose of this study was to examine the anatomy of the mandibular posterior region to develop an anatomical categorization for implant-prosthodontic planning.
Materials and Methods: Using cone beam computed tomography scans, 313 cross-sectional views of edentulous posterior mandibular sites were evaluated with respect to the anatomical ridge morphology. Virtual implant planning was performed, and the need for bone grafting was assessed. The level of complexity for planning implants in those positions was assessed. Sites were classified as straightforward, advanced, or complex sites based on the need for bone grafting.
Results: Five well-defined cross-sectional configurations were observed: straight (53.6%), oblique (26.2%), s-shape (7.4%), hourglass shape (1.9%), and basal bone (10.8%). There was a statistically significant association between the ridge shape and the feasibility of placing an implant with or without bone grafting; the straight and oblique ridge shapes were more likely to be associated with a favorable anatomy for implant placement.
Conclusion: The ridge shape significantly influenced the ease or difficulty of placing an implant. The s-shape, hourglass, and basal bone posterior mandibular cross-sectional shapes were associated with a higher degree of difficulty.
Keywords: dental implants, mandibular classification, posterior edentulous mandible, ridge morphology, virtual implant planning
DOI: 10.11607/jomi.5567, PubMed ID (PMID): 28708911Pages 807-813, Language: EnglishMontero, Javier / Aragón, Fernando / Blanco, Leticia A. / Guadilla, Yasmina / García-Cenador, Begona / López-Valverde, Antonio
Purpose: This study sought to quantify three biochemical mediators of inflammation (tumor necrosis factor alpha [TNF-α], superoxide anion [SOA], and myeloperoxidase [MPO]) by analyzing crestal (peri-implants) and paracrestal gingival biopsy samples obtained from an experimental study on beagle dogs treated with implants inserted immediately into fresh sockets with circumferential defects.
Materials and Methods: In 10 beagle dogs, 4 roughened titanium implants (3.8 mm wide × 8 mm high) were placed in the distal sockets of the third and fourth premolars, where a circumferential defect (5 mm wide and 5 mm deep) had been previously created by trephination. After varying follow-up periods, ranging from 80 to 190 days, the dogs were explored clinically to assess implant survival, peri-implant pocket depth, and implant stability. The levels of three biochemical mediators of inflammation (MPO, TNF-α, and SOA) were investigated using the crestal and paracrestal gingival biopsy samples with ELISA tests.
Results: It was found that 37.5% of the implants were either absent or mobile. Higher levels of the inflammatory mediators were found in the crestal samples than in the paracrestal samples. The final implant stability values were significantly correlated with the final probing depth (r = -0.83, P < .01), but neither of the clinical measures were significantly correlated with any biochemical marker. The risk of implant failure was significantly proportional to the level of MPO (odds ratio: 1.1) and TNF-α (odds ratio: 1.1) in both the crestal and paracrestal regions.
Conclusion: All the inflammatory mediators studied were higher in the crestal areas than in the paracrestal regions, but only the values of MPO and TNF-α were significant predictors of implant failure.
Keywords: dental implants, inflammation, myeloperoxidase, superoxide anion, TNF-α
DOI: 10.11607/jomi.5618, PubMed ID (PMID): 28708913Pages 815-821, Language: EnglishTakahashi, Toshihito / Gonda, Tomoya / Maeda, Yoshinobu
Purpose: This study examined the effects of attachments on strain in maxillary implant overdentures supported by two or four implants.
Materials and Methods: A maxillary edentulous model with implants inserted into anterior, premolar, and molar areas was fabricated, and three types of unsplinted attachments-ball, locator, and magnet-were set on the implants distributed under various conditions. Maxillary experimental dentures were fabricated, and two strain gauges were attached at the anterior midline on the labial and palatal sides. A vertical occlusal load of 98 N was applied and shear strain of the dentures was measured.
Results: On both sides, magnet attachments resulted in the lowest shear strain, while ball attachments resulted in the highest shear strain under most conditions. However, differences in shear strain among the three attachment types were not significant when supported by four implants, especially molar implants.
Conclusion: Shear strain of the maxillary implant overdenture was lowest when using magnet attachments. Magnet attachments mounted on four implants are recommended to prevent denture complications when using maxillary implant overdentures.
Keywords: ball attachment, implant configuration, locator attachment, magnet attachment, maxillary implant overdenture
DOI: 10.11607/jomi.5629, PubMed ID (PMID): 28708914Pages 822-829, Language: EnglishGehrke, Sergio Alexandre / Delgado-Ruiz, Rafael Arcesio / Prados Frutos, Juan Carlos / Prados-Privado, María / Dedavid, Berenice Anina / Granero Marín, Jose Manuel / Calvo Guirado, José Luiz
Purpose: This study aimed to evaluate the misfit of three different implant-abutment connections before and after cycling load.
Materials and Methods: One hundred twenty dental implants and correspondent prefabricated titanium abutments were used. Three different implant-abutment connections were evaluated: Morse taper (MT group), external hexagon (EH group), and internal hexagon (IH group). Forty implants and 40 abutments were used per group. The parameters for the mechanical evaluation were set as: 360,000 cycles, load of 150 N, and frequency of 4 Hz. Samples were sectioned in their longitudinal and transversal axes, and the misfit of the implant-abutment connection was evaluated by scanning electron microscopy analysis. One-way analyses of variance, Tukey post hoc analyses (α = .05), and t test (P < .05) were used to determine differences between groups.
Results: At the longitudinal direction, all the groups showed the presence of microgaps before cycling load; after cycling load, microgaps were reduced in all groups (P > .05). Transversally, only the MT group showed full fitting after cycling load compared with the other groups (EH and IH) (P < .0001).
Conclusion: The application of cycling load produces an accommodation of the implant-abutment connection in internal, external, and Morse taper connections. In the longitudinal direction, the accommodation decreases and/or eliminates the gap observed initially (before load). In the horizontal direction, Morse cone implant-abutment connections experience a complete accommodation with the elimination of the gap.
Keywords: cyclic test, dental implant, implant-abutment interface, implant-supported prostheses, metallographic analysis
DOI: 10.11607/jomi.5683, PubMed ID (PMID): 28708915Pages 830-836, Language: EnglishMalloy, Kyle A. / Wadhwani, Chandur / McAllister, Bradley / Wang, Mansen / Katancik, James A.
Purpose: Assessment of crestal bone levels around implants is essential to monitor success and health. This is best accomplished with intraoral radiographs exposed at 90 degrees to the long axis of the implant, but this can be challenging to achieve clinically. Radiographic paralleling devices produce orthogonal radiographs but traditionally have required access to the implant body for each exposure. This study was conducted to determine if use of the Precision Implant X-ray Locator (PIXRL), a radiographic paralleling device that indexes the implant at the time of surgical placement, can produce orthogonal radiographs of dental implants more accurately than traditional radiologic techniques for assessing crestal bone levels.
Materials and Methods: Three dental implants were inserted in dry human skulls in supracrestal positions to simulate crestal bone loss (maxillary right first premolar [site 14], maxillary right central incisor [site 11], and mandibular left second premolar [site 35]). The implants were masked with a soft tissue moulage and restored with provisional restorations. Four dental assistants exposed six radiographs using their usual and customary technique and six using the PIXRL device for each implant. A single examiner measured crestal bone levels on the radiographs relative to the implant platform shoulder on the mesial and distal of each implant. Recorded measurements were compared to the known values. Statistical analysis was completed using a generalized linear regression model to analyze the differences, and post-hoc comparisons with pairwise adjustment were applied.
Results: The images produced using the PIXRL device were more accurate overall compared to traditional techniques and were also more consistent. The greater degree of accuracy was statistically significant for all sites with the exception of the mesial measurements of the implant at site 11.
Conclusion: This study demonstrates that the use of the PIXRL device can assist clinicians in obtaining more accurate orthogonal radiographs for assessing crestal bone height and would be a useful tool for researchers utilizing radiographic imaging of implants as a longitudinal measure of implant success and stability.
Keywords: bone height assessment, dental implants, intraoral radiographs, standardization, success criteria
DOI: 10.11607/jomi.5824, PubMed ID (PMID): 28708917Pages 838-848, Language: EnglishEsposito, Marco / Trullenque-Eriksson, Anna / Vila, Carlos Navarro / Peñarrocha, Miguel / García, Abel / Sánchez, Arturo / Muñoz-Guzón, Fernando / Martínez Martín, José Manuel
Purpose: To evaluate in dogs a newly developed intraosseous alveolar distractor (Mozo-Grau Alveolar Distractor) for vertical bone augmentation to allow placement of dental implants.
Materials and Methods: Four dogs had their posterior teeth removed, and sockets were left to heal for 20 weeks. The right and left sides of the posterior mandibles were randomly allocated, according to a split-mouth design, to receive either two distractors, distracting a 32-mm-long bone segment, or two distractors supporting one bony segment 20 mm long and one 8 mm long. Each side of the jaw was treated by a different operator. Eight days after placement, distractors were activated with one complete turn (corresponding to 0.75 mm of vertical distraction) per day for 8 days, followed by a latency period of 10 weeks. Distractors were removed, and seven dental implants of two randomly allocated designs were placed in each dog. Implants were submerged for 2 months, and the dogs were sacrificed. Outcome measures were: success of the augmentation procedure (defined as a vertical gain of at least 5 mm of bone), any complications, implant failure, bone-to-implant contact (BIC), and peri-implant marginal bone level changes.
Results: One dog was withdrawn because of a mandible fracture. Eight complications occurred, and six osseodistractors were lost, but no implant failed. Only two segments in one dog achieved a vertical bone gain of at least 5 mm. The mean radiographic vertical bone gain was 2.28 mm, whereas the mean histologic vertical bone gain was 3.16 mm. Histologically, all the implants were osseointegrated. The mean BIC for implants placed in new distracted bone was 34.78% ± 11.60% and 35.66% ± 8.84% for those placed in native bone. The mean peri-implant marginal bone level loss was 0.56 ± 0.54 mm.
Conclusion: It is possible to achieve vertical augmentation using intraosseous alveolar distractors to allow successful implantation of dental implants; however, the technique still requires surgical refinements and a dedicated training of the surgeons before being applied to humans.
Keywords: animal study, intraosseous alveolar distractor, osseodistraction, vertical augmentation
DOI: 10.11607/jomi.5889, PubMed ID (PMID): 28708918Pages 849-857, Language: EnglishNorton, Michael R.
Purpose: The purpose of this study was to evaluate the impact of low insertion torque on primary stability and the short-term clinical outcome of single-tooth implants placed into healed ridges and fresh extraction sockets.
Materials and Methods: A cohort of n = 30 implants was self-selected on the basis that their insertion torque measured ≤ 20 Ncm. The cohort was closed with the follow-up set at 1 year. Resonance frequency analysis was evaluated in both mesiodistal (MD) and buccolingual (BL) directions at the time of implant insertion and at the time of restoration. Immediate temporization was determined by the esthetic need and a minimum implant stability quotient (ISQ) reading of 55. Implants were definitively restored after approximately 3 months. Implant survival was recorded along with changes in the level of the marginal bone relative to a fixed reference point, at the 1-year follow-up.
Results: Twenty-two patients with a total of 30 implants were grouped by insertion torques of < 5 Ncm (spinners), > 5 < 10 Ncm, 10 Ncm, 15 Ncm, and 20 Ncm. One implant was excluded because follow-up data were unavailable. Of the remaining 29 implants, the mean ISQ measured 67 (MD) and 65 (BL) at surgery. The values increased to 80 (MD) and 79 (BL) after a period of 3 months. The survival rate at the end of the 1-year period was 96.7%, including the excluded implant, but 100% for the remaining 29 implants. The frequency of implants demonstrating no marginal bone loss was 71.4%, 0.1 to 0.5 mm bone loss was 21.4%, and bone loss > 0.5 mm (max = 2.82 mm) was only 7.2%. No implants were lost during the functional loading period. Data on immediate temporization revealed no significant difference in ISQ or marginal bone loss values for implants in this group.
Conclusion: Lower insertion torques yield favorable survival rates with optimal marginal bone levels compared with the accepted norm.
Keywords: dental implants, immediate loading, insertion torque, ISQ, resonance frequency analysis
DOI: 10.11607/jomi.4094, PubMed ID (PMID): 28708919Pages 858-863, Language: EnglishMendonça, Jose Alfredo / Senna, Plinio Mendes / Francischone, Carlos Eduardo / Francischone Junior, Carlos Eduardo / de Souza Picorelli Assis, Neuza Maria / Sotto-Maior, Bruno Salles
Purpose: To evaluate the influence of the collar surface topography on peri-implant marginal bone preservation.
Materials and Methods: A total of 156 patients who received at least one cylindrical implant of regular diameter with an external-hexagon platform in the posterior region of the maxilla or mandible were recalled to the office for a retrospective evaluation. Implantation sites and implant length information were recorded, and implants were divided according to the collar surface topography: machined (M) or rough (R) surface. Each implant was assessed by digital periapical radiography, using a sensor holder for the paralleling technique. The marginal bone remodeling was determined as the distance from the implant platform to the first bone-to-implant contact, and the known implant length was used to calibrate the images in the computer software. The follow-up measurements were compared with those obtained from the radiograph taken at the time of prosthetic loading to determine the late bone remodeling. An independent t test was used to compare data.
Results: From 138 patients who attended the recall, 242 implants (M = 126; R = 116) were evaluated with a mean follow-up period of 4.6 ± 0.9 years. Similar success rates were found in both groups (M = 95.0%; R = 95.9%). Late bone remodeling in the maxilla was not influenced by the implant collar (P = .504); however, lower marginal bone loss was observed in the R group (1.20 ± 0.52 mm) compared with the M group (1.58 ± 0.73 mm) in the mandible (P = .007).
Conclusion: Although the implant collar design did not influence the success rate of dental implants, the rough collar design reduced the late marginal bone remodeling around external-hexagon implants in the mandible. The maxilla was not benefited by the rough collar design.
Keywords: bone loss, dental implants, osseointegration, surface
DOI: 10.11607/jomi.5369, PubMed ID (PMID): 28708920Pages 864-869, Language: EnglishGonzalez, Jorge / Triplett, Robert G.
Purpose: To evaluate the performance of the implant-retained zirconia complete-arch prosthesis with various opposing dentitions.
Materials and Methods: The 40 patients included in this retrospective case series study were treated with one or two implant-retained zirconia complete-arch prostheses (ZIRCAP) using the Zirkonzahn protocol. Prettau zirconia frames were created with strategic cutbacks in the structure to extend zirconia incisal coverage of the esthetic anterior sextants and complete monolithic zirconia in the molar areas; subsequent layers of porcelain were applied to nonfunctional and esthetic areas. Patients had three possible occlusal scenarios: (1) maxillary ZIRCAP and mandibular ZIRCAP, (2) maxillary ZIRCAP and mandibular natural dentition, and (3) maxillary ZIRCAP and mandibular conventional hybrid prosthesis. Complications were recorded during follow-up appointments 3, 6, and 12 months after definitive prosthesis delivery. The mean treatment observation period was 33 months.
Results: Eight prosthetic complications were noted for the 40 implant-retained zirconia complete-arch prostheses (18.18%), including six cases of minor porcelain chipping and two cases of debonding of the metal insert from the zirconia framework. Maxillary ZIRCAP opposing mandibular ZIRCAP and maxillary ZIRCAP opposing mandibular natural dentition occlusal scenarios presented the same complication ratio of 4. No complications were seen in the maxillary ZIRCAP opposing mandibular conventional hybrid prosthesis group, yet 16 complications were found as denture tooth fractures in 12 mandibular conventional hybrid prostheses (ratio of 0.75).
Conclusion: The results indicate that the implantretained zirconia complete-arch prosthesis offers acceptable performance for use as an alternative to the conventional titanium framework acrylic veneer prosthesis for complete edentulism with a lower incidence of prosthetic complications and fewer maintenance appointments. Chipping of veneering porcelain was the most common complication, but a low incidence was observed in this study. Acrylic denture teeth may represent the weakest link when restoring complete edentulism with a maxillary ZIRCAP and mandibular conventional hybrid prosthesis.
Keywords: implant-retained zirconia complete-arch prosthesis, monolithlic zirconia frame, Prettau zirconia, strategic cutback of zirconia frame
DOI: 10.11607/jomi.5396, PubMed ID (PMID): 28618434Pages 870-879, Language: EnglishPohl, Veronika / Pohl, Sebastian / Sulzbacher, Irene / Fuerhauser, Rudolf / Mailath-Pokorny, Georg / Haas, Robert
Purpose: To evaluate the use of chemically unchanged tooth material in lateral alveolar ridge augmentation or for the filling of jaw defects.
Materials and Methods: A total of 20 patients underwent either lateral augmentation of the alveolar process (11 patients) or filling of jaw defects (6 patients) with autogenous unaltered tooth material in a longitudinal 2-year study. In three patients, the jaw defect was so marked that a bone block graft had to be used for augmentation in addition to particulate dental material. In four patients, an autogenous tooth block was exclusively used; in seven, crushed tooth material was exclusively used; and in the remaining six, dystopic teeth that had been extracted were removed, crushed, and reinserted into the defect in particulate form. Fully impacted teeth served as autogenous donor teeth.
Results: After a healing time of 3 to 6 months, 28 implants could be placed (10 immediate implants, 18 delayed implants). At 6, 12, and 24 months postrestoration, peri-implant bone loss as assessed by x-ray was 0 mm, 0.4 mm, and 0.6 mm, respectively. Peri-implant probing depth was 1 mm after 1 year and 2 mm after 2 years. Bleeding on probing was not seen in any of the implants after 2 years.
Conclusion: Autogenous tooth material appears to be suitable for the restoration of lateral and intraosseous defects of the alveolar ridge with both complete blocks and in particulate form. However, additional long-term studies with higher case numbers will be required for substantiating these results.
Keywords: alveolar ridge reconstruction, autogenous bone graft, autogenous tooth, bone substitutes, implants
DOI: 10.11607/jomi.5454, PubMed ID (PMID): 28334058Pages 880-892, Language: EnglishJokstad, Asbjørn / Gussgard, Anne M. / Fava, Joseph / Lin, Mark / Shokati, Babak / Somogyi-Ganss, Eszter / Winnett, Brenton / Zahran, Mohammed
Purpose: The aim of this noninterventional, retrospective study was to benchmark the outcomes of patients with partial fixed prostheses supported by implants treated at the University of Toronto at least 10 years earlier. A study protocol for assessing outcomes on like patients developed at the University of Bern, Switzerland, was followed.
Materials and Methods: All patients who had received at least one implant before 2002 were considered eligible to be included in the study (n = 298). The treatment histories were recorded from the patient chart of the participants, or from the participants' dentists by consent. Calibrated clinicians examined the study participants clinically and radiologically and recorded peri-implant mucosal status and observable technical and mechanical failures. Past adverse events were identified in the patient charts. Independent assessors measured bone levels on digitized radiographs. Statistical analysis included descriptive statistics at implants, teeth, and study participant levels, respectively.
Results: Of the 298 eligible patients, 121 attended a clinical examination (41%), while 12 declined (4%). The 121 study participants had received 321 implants between 1983 and 2001. The implants showed a success rate of 88.9% and a survival rate of 94% after an average of 17.5 years (SD 5.2, range 10 to 28 years). Approximately 5% of the surviving implants showed signs, or were associated with a prior history, of peri-implantitis. The distance from the implant shoulder to the first bone contact varied from -3 mm to 7 mm (mean = 1.52 mm [SD 1.57], median = 2.2 mm). Approximately half of the study participants had experienced at least one defect of their superstructure, representing a 52% "success rate," while the survival rate was 70%. The majority were very satisfied or satisfied with the treatment (102/121).
Conclusion: A high proportion (94%) of conventional machined Brånemark System implants placed between 1983 and 2001 remained in function after an average of 17.5 years. The original superstructures predominantly fabricated as prefabricated acrylic teeth and acrylic resin reinforced with a cast palladium-silver alloy core were still in place for 70% of the participants, and 48% of the superstructures had never undergone any form of repairs.
Keywords: dental implantation, dental implants, edentulous jaw, endosseous, implant placement, implant-supported dental prostheses, stomatognathic system
DOI: 10.11607/jomi.5484, PubMed ID (PMID): 28296982Pages 893-896, Language: EnglishDawood, Anew / Kalavresos, Nicholas
This article details the significant complications associated with treatment of a patient who underwent maxillary reconstruction based entirely on zygomatic implants. The use of zygomatic implants is becoming increasingly widespread, and treatment has been shown to be predictable and generally free of surgical complications. However, extending from the maxillary alveolus, alongside or through the maxillary antrum, toward the zygoma or orbital rim, these long implants have the potential to create a range of complications that may be more serious than those encountered with conventional dental implants. In the case presented, complications included implant failure, prominence of the implant apices, recurrent loosening of the implant prosthesis, and, most significantly, extraoral infection associated with the apex of one implant. The authors describe the complications and remedial surgical treatment for this patient.
Keywords: cone-beam computed tomography, extraoral complications, implant apicoectomy, zygomatic implants
DOI: 10.11607/jomi.5519, PubMed ID (PMID): 28708921Pages 897-903, Language: EnglishAlzoubi, Fawaz / Bedrossian, Edmond / Wong, Allen / Farrell, Douglas / Park, Chan / Indresano, Thomas
Purpose: To assess outcomes of treating completely edentulous patients with a fixed implant-supported profile prosthesis utilizing a graftless approach for the maxilla and for the mandible, with emphasis on clinically related outcomes, specifically implant and prosthesis survival.
Materials and Methods: This was a retrospective study with the following inclusion criteria: completely edentulous patients rehabilitated with a fixed implant-supported profile denture utilizing a graftless approach. Patients fulfilling the inclusion criteria were asked to participate in the study during their follow-up visits, and hence a consecutive sampling strategy was used. Data regarding implant and prosthesis cumulative survival rates (CSRs) were gathered and calculated.
Results: Thirty-four patients were identified with a total of 220 implants placed. An overall CSR of 98.2% was recorded with an observation of up to 10 years. For tilted, axial, and zygomatic implants, CSRs of 96.9%, 98.0%, and 100%, respectively, were observed for up to 10 years. For provisional prostheses, CSRs of 92.3% at 1 year, and 84.6% at 2 years were observed.
Conclusion: The results suggest that treating completely edentulous patients with a fixed profile prosthesis utilizing a graftless approach in the maxilla and the mandible can be a reliable treatment option.
Keywords: All-On-4, fixed prosthesis, graftless, immediate loading, tilted implants, zygoma implants
DOI: 10.11607/jomi.5578, PubMed ID (PMID): 28708922Pages 904-911, Language: EnglishTestori, Tiziano / Galli, Fabio / Fumagalli, Luca / Capelli, Matteo / Zuffetti, Francesco / Deflorian, Matteo / Parenti, Andrea / Del Fabbro, Massimo
Purpose: To analyze the long-term outcome of fixed prostheses supported by six implants, two of which were tilted, placed in the maxilla and immediately loaded more than 10 years earlier.
Materials and Methods: A retrospective review of implants placed between May 29, 2003 and February 12, 2005 and used to support immediately loaded fixed dental prostheses in the maxilla was conducted. The features of failed implants were analyzed. In the most recent follow-up visits, survival of individual implants and prostheses was verified, and modified Plaque Index as well as modified Sulcular Bleeding Index were assessed. Patients also filled out a questionnaire requiring graded responses from 0 (poor) to 10 (excellent) that was designed to assess their quality of life.
Results: A total of 162 implants were placed between May 29, 2003 and February 12, 2005 to support immediately loaded maxillary fixed prostheses of 27 totally edentulous patients (19 female, 8 male). Three patients (1 male, 2 female) dropped out, so 144 implants were followed up. Seven of the 144 original implants failed, corresponding to a survival rate of 95.1% over 10 years. All the failures occurred within 2 years after surgery. Patients' responses to the questionnaire produced an average score of 8.4 to 8.8, showing a relevant degree of satisfaction.
Conclusion: Based upon this study of 27 patients who received immediately loaded maxillary full-arch fixed implant-supported prostheses supported by two tilted and four axial implants, it appears that this is a reliable procedure with a high long-term survival rate and a high level of patient satisfaction.
Keywords: immediate loading, maxilla, tilted implants, 10-year follow-up
DOI: 10.11607/jomi.5712, PubMed ID (PMID): 28708923Pages 912-918, Language: EnglishBovaira, Maite / Herrero Babiloni, Alberto / Jovaní, María / Peñarrocha-Diago, Miguel / González-Lemonnier, Sandra / Peñarrocha-Oltra, David
Purpose: The aims of this study were to evaluate the relationship of age, sex, and type and duration of the surgery with preoperative anxiety in patients undergoing dental implant surgeries under intravenous conscious sedation, and to assess preoperative anxiety association with the postoperative satisfaction of both the patient and surgeon.
Materials and Methods: This prospective study included 180 patients receiving dental implant surgeries under intravenous conscious sedation by means of midazolam, fentanyl, and propofol. Preoperative anxiety (Corah Dental Anxiety Scale), number of implants, duration of surgery, surgeon satisfaction (evaluated as three categories: patient too awake and nervous, adequate sedation, or patient too asleep), and patient satisfaction (classified as five levels: agreeable, neither agreeable nor disagreeable, slightly uncomfortable, unpleasant, traumatic) were recorded.
Results: All 180 patients completed the study, and 72.2% of them experienced moderate or high levels of anxiety. The mean Corah scale score was 9.2 ± 3.5. Anxiety was significantly higher among men but showed no relation to age. A significant relationship was found between patient anxiety and the number of implants: those patients who received eight or more implants, with a duration of surgery longer than 60 minutes, had lower anxiety. Surgeon satisfaction was adequate in 90% of the cases. Patients evaluated the procedure as agreeable in 34.4% of cases, neither agreeable nor disagreeable in 26.7%, slightly uncomfortable in 29.4%, unpleasant in 7.8%, and traumatic in 1.7%. High anxiety levels were related with poor patient satisfaction but not with surgeon satisfaction.
Conclusion: Preoperative anxiety was moderate or high in two-thirds of patients undergoing dental implant surgeries, having a negative influence on patient satisfaction, but not affecting surgeon satisfaction. Additionally, the intravenous conscious sedation technique was considered a satisfactory technique by the surgeon to control anxiety.
Keywords: conscious sedation, dental anxiety, dental implants, intravenous anesthesia, satisfaction
DOI: 10.11607/jomi.5859, PubMed ID (PMID): 28708924Pages 919-926, Language: EnglishLago, Laura / da Silva, Luis / Gude, Francisco / Rilo, Benito
Purpose: The aim of this prospective study was to evaluate radiographic levels of peri-implant bone crest as well as soft tissue response, papilla height, and buccal mucosa recession, in bone-level implants restored with platform switching after 1-year and 5-year follow-ups.
Materials and Methods: This prospective study called for the placement of 59 implants to obtain a target of 90% power. To compensate for possible dropouts, the sample size was adjusted to 67 implants. To assess marginal bone level changes, periapical radiographs were taken at baseline, 1 year, and 5 years after the definitive restorations. Peri-implant soft tissue modifications were evaluated by performing a photographic sequence at 15 days, 1 year, and 5 years after implant restoration. Parameters measured were: (1) distance from the tip of the papilla to the contact point and (2) apicocoronal crown length.
Results: A one-way analysis of variance (ANOVA rank test) was used to compare quantitative data among the three time points studied. Mean marginal bone level changes were as follows: -0.06 ± 0.32 mm from baseline to 1 year, -0.23 ± 0.38 mm from 1 to 5 years, and -0.28 ± 0.45 mm from baseline to 5 years. In bone-level outcomes, no statistically significant differences were found between baseline and 1 year, while the mean differences between 1 and 5 years and baseline and 5 years showed statistically significant differences. In the soft tissue analysis, the distance from the tip of the papilla to the contact point showed the following values: baseline, 2.08 mm; 1 year, 1.54 mm; 5 years, 1.31 mm. No statistically significant differences were found between baseline and 1 year, whereas statistically significant differences between 1 and 5 years and baseline and 5 years were found. Apicocoronal crown length measurements showed the following values: baseline, 9.44 mm; 1 year, 9.28 mm; 5 years, 9.81 mm. No significant differences were found between times studied.
Conclusion: This prospective clinical study of 67 bone-level implants restored according to the platform-switching concept reported that radiographic levels of peri-implant bone crest were statistically significant between 1 and 5 years and baseline and 5 years. For the soft tissue response, the greatest reduction in the distance from the papilla to the contact point from 1 to 5 years and baseline to 5 years was observed. No significant differences were shown in the buccal margin.
Keywords: bone level, follow-up, platform switching, soft tissues
DOI: 10.11607/jomi.3732, PubMed ID (PMID): 28708925Pages 927-934, Language: EnglishCorreia, Francisco / Gouveia, Sónia / Felino, António Campos / Costa, Ana Lemos / Almeida, Ricardo Faria
Purpose: To evaluate the differences between the survival rates of implants placed in patients with no history of periodontal disease (NP) and in patients with a history of chronic periodontal disease (CP).
Materials and Methods: A retrospective cohort study was conducted in which all consenting patients treated with dental implants in a private clinic in Oporto, Portugal, from November 2, 2002 through February 11, 2011 were included. All patients were treated consecutively by the same experimental operator. This study aimed to analyze how the primary outcomes (presence of disease, time of placement, and time of loading) and the secondary outcomes (severity-generalized periodontitis, brand, implant length, prosthesis type, prosthesis metal-ceramic extension) influence the survival rate of dental implants. The survival analysis was performed through the Kaplan-Meier method, and the equality of survival distributions for all groups was tested with the log-rank test with a significance level of .05 for all comparisons.
Results: The sample consisted of 202 patients (47% NP and 53% CP) and 689 implants (31% NP and 69% CP). The survival rate in the NP and CP groups showed no statistically significant differences (95.8% versus 93.1%; P ≥ .05). Implants were lost before loading in 54.9% of the cases. The majority of the implants were lost in the first year and stabilized after the second year. Survival rates in the NP and CP patients showed no statistically significant differences when comparing the following factors: subclassification of the disease, implant brands, implant length (short/ standard), type of prosthesis, extension of the prosthesis metal-ceramic, and time of placement and loading (P ≥ .05).
Conclusion: This work disclosed no statistically significant differences in terms of survival rates when compared with the control group. Placing implants in patients with a history of periodontal disease appears to be viable and safe.
Keywords: cohort studies, dental implants, periodontal diseases, survival rate
Online OnlyDOI: 10.11607/jomi.2017.4.gomi, PubMed ID (PMID): 28708903Pages Gi-G200, Language: EnglishLaney, William R.
Online OnlyDOI: 10.11607/jomi.5472, PubMed ID (PMID): 28708909Pages e191-e198, Language: EnglishVerri, Fellippo Ramos / Santiago jr., Joel Ferreira / Almeida, Daniel Augusto Faria / de Souza Batista, Victor Eduardo / Araujo Lemos, Cleidiel Aparecido / Mello, Caroline Cantieri / Pellizzer, Eduardo Piza
Purpose: The aim of this study was to use three-dimensional finite element analysis to analyze the stress distribution transferred by single implant-supported prostheses placed in the anterior maxilla using different connections (external hexagon, internal hexagon, or Morse taper), inclinations of the load (0, 30, or 60 degrees), and surgical techniques for placement (monocortical/conventional, bicortical, or bicortical with nasal floor elevation).
Materials and Methods: Nine models representing a bone block of this region were simulated by computer-aided design software (InVesalius, Rhinoceros, SolidWorks). Each model received one implant, which supported a cemented metalloceramic crown. Using FEMAP software, finite elements were discretized while simulating a 178-N load at 0, 30, and 60 degrees relative to the long axis of the implant. The problem was solved in NEi Nastran software, and postprocessing was performed in FEMAP. Von Mises stress and maximum principal stress maps were made.
Results: The von Mises stress analysis revealed that stress increased with increasing inclination of the load, from 0 to 30 to 60 degrees. Morse taper implants showed less stress concentration around the cervical and apical areas of the implant. The bicortical technique, associated or not with nasal floor elevation, contributed to decreasing the stress concentration in the apical area of the implant. Maximum principal stress analysis showed that the increase in inclination was proportional to the increase in stress on the bone tissue in the cervical area. Lower stress concentrations in the cortical bone were obtained with Morse taper implants and the bicortical technique compared with other connections and surgical techniques, respectively.
Conclusion: Increasing the inclination of the applied force relative to the long axis of the implant tended to overload the peri-implant bone tissue and the internal structure of the implants. The Morse taper connection and bicortical techniques seemed to be more favorable than other connections or techniques, respectively, for restoring the anterior maxilla.
Keywords: dental implant, finite element analysis, mechanical stress
Online OnlyDOI: 10.11607/jomi.5611, PubMed ID (PMID): 28708912Pages e199-e206, Language: EnglishToniollo, Marcelo Bighetti / Macedo, Ana Paula / Pupim, Denise / Zaparolli, Danilo / da Gloria Chiarello de Mattos, Maria
Purpose: The aim of this study was to compare the bone stress generated by rehabilitation using regular and short-length Morse taper implants (11 and 5 mm, respectively) in the same context and allied with splinted (SP) and nonsplinted (NSP) prostheses in the posterior area of the mandible using finite element analysis.
Materials and Methods: Three-dimensional geometric models using regular implants (∅4 × 11 mm) and short implants (∅4 × 5 mm) were simulated with a left posterior mandible that had the first premolar tooth and all teeth posterior to that premolar removed. The four experimental groups were as follows: Group 1 NSP (two regular implants and one short implant rehabilitated with nonsplinted prostheses), Group 1 SP (two regular implants and one short implant rehabilitated with splinted prostheses), Group 2 NSP (one regular implant and two short implants rehabilitated with nonsplinted prostheses), and Group 2 SP (one regular implant and two short implants rehabilitated with splinted prostheses). Oblique forces were simulated in molars (365 N) and premolars (200 N). Qualitative and quantitative analyses of the minimum principal stress in bone were performed using the ANSYS Workbench software, version 10.0.
Results: The splinted prostheses decreased the stress to the surrounding bone of short implants. Moreover, they also decreased the stress on the surrounding bone adjacent to the tooth. However, the splinted prostheses generated higher stress in the coverage of the surrounding bone for regular intermediate implants and prominently in the bone at the implant cervical region, at the edge crest, compared with the individualized groups.
Conclusion: The benefits in the use of splinted prostheses are notable for the preservation of the bone surrounding the short implants and tooth; however, it is necessary to evaluate each clinical situation because, in this context, the regular implants are at higher stress than the individualized implants.
Keywords: ceramics, dental implantation, dental prosthesis implant-supported, finite element analysis
Online OnlyDOI: 10.11607/jomi.5686, PubMed ID (PMID): 28708916Pages e207-e212, Language: EnglishHadrowicz, Piotr / Hadrowicz, Joanna / Kozakiewicz, Marcin / Gesing, Adam
Purpose: The aim of this prospective study was to evaluate parathyroid hormone serum level as a potential single factor of bone metabolism around dental implants.
Materials and Methods: Parathyroid hormone levels were measured before implantation. Intraoral digital radiographs were taken in standardized conditions in all cases: immediately after implantation, immediately after functional loading, and 3, 6, 9, 12, 18, and 24 months after functional loading. The next phase was to align all radiographs geometrically. Two regions of interest were marked in the bone image: one in the implant neck region and another in the periapical region. Next, the entropy of the microarchitecture of the bone image was calculated, and an analysis of simple regression was performed.
Results: The prospective study included 107 patients of both sexes in the age range of 17 to 67 years (mean ± SD: 45.53 ± 12.1 years). A significant relationship was observed between higher levels of parathyroid hormone (but still in the normal range) and the decrease of textural entropy in the alveolar ridge bone at 3, 6, 12, and 18 months after functional loading. However, in the periods immediately after implantation, immediately after functional loading, and 9 and 24 months after functional loading, the relationship was not statistically significant.
Conclusion: Assessment of the parathyroid hormone serum level can be considered a useful method to predict bone condition around a dental implant, but not as a single factor.
Keywords: dental implants, entropy, parathyroid hormone
Online OnlyDOI: 10.11607/jomi.5536, PubMed ID (PMID): 28618433Pages e213-e220, Language: EnglishKuchler, Ulrike / Rudelstorfer, Claudia M. / Barth, Barbara / Tepper, Gabor / Lidinsky, Dominika / Heimel, Patrick / Watzek, Georg / Gruber, Reinhard
Purpose: Recombinant human bone morphogenetic protein 2 (rhBMP-2) together with an absorbable collagen carrier (ACS) was approved for augmentation of the maxillary sinus prior to implant placement. The original registration trial was based on a lateral window approach. Clinical outcomes of crestal sinus augmentation with rhBMP-2 have not been reported so far.
Materials and Methods: An uncontrolled pilot trial in which seven patients with a residual maxillary height below 5 mm were enrolled to receive crestal sinus augmentation with rhBMP-2/ACS was conducted. Elevation of the sinus mucosa was performed by gel pressure. Primary endpoints were the gain in augmentation height and volume measured by computed tomography after 6 months. Evaluation of bone quality at the time of implant placement was based on histology. Secondary endpoints were the clinical and radiologic evaluation of the implants and patient satisfaction by visual analog scale (VAS) at the 2-year follow-up.
Results: Median gain in augmentation height was 7.2 mm (range 0.0 to 17.5 mm). Five patients gained at least 5 mm of bone height. Two patients with a perforation of the sinus mucosa failed to respond to rhBMP-2/ACS and underwent lateral window augmentation. The median gain in augmentation volume of the five patients was 781.3 mm3 (range 426.9 to 1,242.8 mm3). Biopsy specimens showed a cancellous network consisting of primary plexiform bone with little secondary lamellar bone. After 2 years, implants were in function with no signs of inflammation or peri-implant bone loss. Patients were satisfied with the esthetic outcomes and chewing function.
Conclusion: This pilot clinical trial supports the original concept that rhBMP-2/ACS supports bone formation, also in crestal sinus augmentation, and emphasizes the relevance of the integrity of the sinus mucosa to predict the bone gain.
Keywords: dental implants, osteoinductivity, rhBMP-2, sinus augmentation
Online OnlyDOI: 10.11607/jomi.5652, PubMed ID (PMID): 28708926Pages e221-e230, Language: EnglishFujioka-Kobayashi, Masako / Schaler, Benoit / Shirakata, Yoshinori / Nakamura, Toshiaki / Noguchi, Kazuyuki / Zhang, Yufeng / Miron, Richard J.
Purpose: To investigate the bone-inducing properties of two types of collagen membranes in combination with recombinant human bone morphogenetic protein (rhBMP)-2 and rhBMP-9 on osteoblast behavior.
Materials and Methods: Porcine pericardium collagen membranes (PPCM) and porcine dermis-derived collagen membranes (PDCM) were coated with either rhBMP-2 or rhBMP-9. The adsorption and release abilities were first investigated via enzyme-linked immunosorbent assay up to 10 days. Moreover, murine bone stromal ST2 cell adhesion, proliferation, and osteoblast differentiation were assessed by MTS assay; real-time polymerase chain reaction for genes encoding runt-related transcription factor 2 (Runx2); alkaline phosphatase (ALP); and osteocalcin, ALP assay, and alizarin red staining.
Results: Both rhBMP-2 and rhBMP-9 adsorbed to collagen membranes and were gradually released over time up to 10 days. PPCM showed significantly less cell attachment, whereas PDCM demonstrated comparable cell attachment with the control tissue culture plastic at 8 hours. While both rhBMPs were shown not to affect cell proliferation, collagen membranes combined with rhBMP-9 significantly increased ALP activity at 7 days and ALP mRNA levels at either 3 or 14 days compared with the control tissue culture plastic. Furthermore, rhBMP-9 increased osteocalcin mRNA levels and alizarin red staining at 14 days compared with the control tissue culture plastic.
Conclusion: The results from this study suggest that both porcine-derived collagen membranes combined with rhBMP-9 accelerated the osteopromotive potential of ST2 cells. Interestingly, rhBMP-9 demonstrated additional osteogenic differentiation compared with rhBMP-2 and may serve as a suitable growth factor for future clinical use.
Keywords: bone regeneration, BMP-2, BMP-9, collagen membrane, guided bone regeneration, porcine collagen membrane
Online OnlyDOI: 10.11607/jomi.4957, PubMed ID (PMID): 28518185Pages e231-e240, Language: EnglishNakata, Hidemi / Yamamoto, Maiko / Okada, Emi / Nagayama, Tomoko / Miyasaka, Munemitsu / Kasugai, Shohei / Kuroda, Shinji
Purpose: Among potential cell-based therapies, adipose-derived stem cells (ASCs) have been proposed as a promising source of stem cells for tissue regeneration. Although many recent clinical trials have investigated the use of adipose tissue or ASCs in transplantation, analysis of the microstructures of outgrowing macrosized spheroids (macrospheroids) or three-dimensional coculture of ASC spheroids and monocyte/macrophage lineages has not been performed. The aim of this study was to analyze the microstructures of murine-derived ASC macrospheroids and the growth and osteogenic potential of these macrospheroids in a three-dimensional environment and after calcification induction by coculture with monocytes.
Materials and Methods: The histologic structures of murine-derived ASC macrospheroids and the expression of marker genes for multipotency within these macrospheroids were analyzed by hematoxylin and eosin staining and in situ hybridization. ASC macrospheroid microstructures were observed by transmission electron microscopy, and cell proliferation in the spheroids was analyzed. Additionally, the growth and osteogenic potential of these macrospheroids were assessed in two-dimensional and three-dimensional environments and after calcification induction by coculture with monocytes.
Results: The expression of Oct3/4, Nanog, and Sox2 was detected even in the deep zone of spheroids, although higher expression was observed at the surface. Cell proliferation was detected within the spheroid centers. Observation of spheroid microstructure revealed extracellular matrix production within the spheroid architecture. Transplantation of a spheroid on the hydroxyapatite disc resulted in three-dimensional cell growth, filling the disc. Coculture of the spheroids with monocytes led to the formation of many osteoclast-like, multinucleated cells, and calcification was observed after 3 weeks of coculture.
Conclusion: ASC spheroids exhibited high capacity for dynamic three-dimensional growth and osteogenic differentiation. Furthermore, ASC spheroids promoted monocyte differentiation into osteoclast-like cells, which may enhance the osteogenic potential of ASC spheroids.
Keywords: adipose-derived stem cells, coculture, macrospheroid, monocyte, three-dimensional culture