Risk of Bleeding during Implant Surgery in Patients Taking Antithrombotics: A Systematic Review.

The objective of this systematic review is to assess the risk of postoperative bleeding in oral surgery for implant placement in individuals taking antithrombotics (i.e., anticoagulants and/or antiplatelet agents). A literature search was performed in PubMed (MEDLINE), Web of Science, Scopus, and EMBASE databases for articles published until August 2020, with no date restriction, and manually completed. We included prospective clinical studies that provided information regarding the presence of an experimental group (i.e., implant placement), a control group (patients not under treatment with antithrombotics), and a well-established protocol for evaluating bleeding. Meta-analysis determined the risk of bleeding during the placement of implants in antithrombotic-treated patients. Of the 756 potentially eligible articles, 5 were included in the analysis with 4 ranked as high and 1 as medium quality. Antithrombotic treatment comprised the following drug classes: (1) anticoagulants: vitamin K antagonists, (2) nonvitamin K antagonist oral anticoagulants, (3) low-molecular-weight heparin, and (4) antiplatelet agents (not specified). The results suggest that the risk of bleeding is not substantially higher in antithrombotic-treated patients (odds ratio = 2.19; 95% confidence interval: 0.88-5.44, p = 0.09) compared with nontreated patients. This systematic review suggests that the absolute risk is low and there is no need to discontinue or alter the dose of the antithrombotic treatment for implant placement surgery.

Reconstruction of the edentulous mandible with fresh frozen bone grafts and implants: a 4-year report of a prospective clinical study.

Allogen bones from tissue bank are often used in dentistry although the data analyzing the long-term success in mandible are scarce. This study evaluated by computed tomography scans (CTS) the bone resorption around the implants installed on fresh frozen bone (FFB) previously grafted, after 4 years of occlusal rehabilitation. Six subjects were grafted with blocks in posterior mandible using FFB. After 6 months, 27 implants were placed and after further 4 months the prostheses were delivered. Following 4 years of the final rehabilitation procedures, another CTS was done in order to measure the resorption in periimplant bone crest at the proximal implant surfaces. It was observed a 100 % survival rate of the implants after 4 years of the fixture installation. The marginal bone resorption after 48 months was 2.82 ± 1.63 mm and no statistical significant difference was observed along the region where the implants were fixed when compared with the interimplantar space. In addition there was no significant correlation regarding the length of the implant used and the amount of marginal bone resorption. The conclusion is that grafted areas with FFB are suitable to implant installation in the posterior mandible.

Stability of implants placed simultaneously or in a delayed manner on fresh frozen onlay allografts in rabbits.

OBJECTIVES: This study evaluated the stability of implants installed simultaneously and in a delayed manner in fresh frozen onlay allografts in the tibiae of rabbits. MATERIAL AND METHODS: Analyses of the resonance frequency (ISQ) and removal torque were performed. The calvarium of three rabbits was used as donor site. Ten New Zealand female rabbits received four allografts of the same dimensions, two in each tibia. The tibiae were randomly allocated into the following two groups: Group 1, the tibiae that received implants after 84 days of healing, and Group 2, those who received the implants simultaneously with the grafts. Both groups were followed for 126 days. Proximal implants in each group were evaluated by resonance frequency (ISQ) on days 0 and 126, and the distal ones with removal torque on day 126. RESULTS: In both groups, an increase in the ISQ value of day 0-126 was observed, with a statistically significant difference (Group 1 P = 0.049 and Group 2 P = 0.021). When comparing the resonance frequency at day 0 to day 126, and the gain of stability between these days, no statistically significant difference between groups could be observed. The removal torque showed a statistically significant difference between groups 1 and 2 (P = 0.042). CONCLUSION: There was an increase in stability in groups according to the analysis of resonance frequency. Implants installed in a delayed manner in allografts showed higher shear force, according to the removal torque analysis.

Evaluation of the efficacy of the use of violet LED light in the bleaching of damaged primary incisors darkened by trauma.

BACKGROUND: The aim of this study was to evaluate efficacy of violet LED light for the bleaching treatment of primary incisors darkened by trauma. METHODS: Twenty deciduous incisors with color change were selected, divided into two groups: control - no bleaching protocol was applied, and VL- treated with violet LED. The change color analysis was taken in each tooth, by spectrophotometer. In three different time: baseline - before treatment, after 4 treatment sessions and after 8 treatment sessions. RESULTS: The color change data were analyzed using ANOVA and a post- hoc Tukey tests (α=0.05). After 4 and 8 sessions no differences were observed between the groups (p<0.05). CONCLUSIONS: Thus, it can be concluded that violet LED light was not effective in bleaching primary incisors darkened by trauma after 8 sessions.

Fresh-frozen human bone allograft in vertical ridge augmentation: clinical and tomographic evaluation of bone formation and resorption.

The aim of the current study is to evaluate fresh-frozen human bone allografts (FHBAs) used in vertical ridge augmentation clinically and by computed tomography, and to analyze the resulting bone formation and graft resorption. Sixteen FHBAs were grafted in the maxillae and mandibles of 9 patients. The FHBAs, which were provided by the Musculoskeletal Tissue Bank of Marilia Hospital (Unioss), were frozen at -80°C. After 7 months, dental implants were placed and bone parameters were evaluated. Vertical bone formation was measured by computerized tomography before (T0) and at 7 months (T1) after the surgical procedure. Bone graft resorption was measured clinically from a landmark screw head using a periodontal probe. The results were analyzed by Student's t-test. Significant differences existed in the bone formation values at T0 and T1, with an average change of 4.03 ± 1.69 mm. Bone graft resorption values were 1.0 ± 0.82 mm (20%). Implants were placed with varying insertion torque values (35-45 Ncm), and achieved primary stability. This study demonstrates that FHBAs promote satisfactory vertical bone formation with a low resorption rates, good density, and primary implant stability.

The comparative analysis of homologous fresh frozen bone and autogenous bone graft, associated or not with autogenous bone marrow, in rabbit calvaria: a clinical and histomorphometric study.

The aim of this study was to evaluate the potential of fresh frozen homologous and autogenous grafts, associated or not with autogenous bone marrow, to form bone. Sixty titanium cylinders were used, and were fixed to the skulls of 30 rabbits. These cylinders were filled with (A) autogenous bone (AM) autogenous bone associated with the bone marrow (H) fresh frozen homologous bone (HM) fresh frozen homologous bone associated with the bone marrow (M) pure autogenous bone marrow and (C) blood clot. The animals were sacrificed after 02 and 03 months. After clinical evaluation, the samples were stained with hematoxylin, eosin and Mallory Trichrome dyes for optical microscopy analysis and histomorphometric analysis. Experimental groups that received mineralized materials (A, AM, H, HM) showed the best bone formation results, presenting no statistical difference between them (P > 0.05). Groups that did not receive mineralized materials (M and C) showed the worst results (P < 0.05), but the M group showed better results than the C group. Most of the autogenous and homologous bone particles were resorbed and there was a larger amount of residual particles in the homologous graft (H, HM) when compared with the autogenous graft (A, AM; P < 0.05). These findings suggest that fresh frozen homologous grafts produced similar amounts of new bone when compared with the autogenous grafts. However, the amount of residual bone particles was larger in the homogenous groups, which may indicate a slower remodeling process. The homologous fresh frozen bone seems to be a good osteoconductive material. The use of only autogenous bone marrow showed better results when compared to the bood clot. However, this research indicates that association with mineralized materials is required.

Antimicrobial photodynamic therapy using optical fiber for oral fistula resulting from mandibular osteoradionecrosis.

Osteoradionecrosis (ORN) is considered one of the most severe complications of radiotherapy (RT). Treatment modalities for ORN may vary considerably, including conservative or surgical procedures. Recently, alternative managements such as the combination of photobiomodulation therapy (PBMT) and antimicrobial photodynamic therapy (aPDT) have also yielded promising results in patients presenting ORN or delayed healing post-RT. Herein, it is reported a case of ORN manifested as an oral fistula on the mandibular alveolar mucosa in which a combination of PBMT and aPDT was used every 15 days for six weeks. A laser device with an optical fiber was introduced into the fistula for light delivery. Seven days after the first laser session, it was noted complete resolution of both edema and erythema; after six weeks, the ORN fistula was no longer present. According to the current case, the combination of PBMT and aPDT with an optical fiber to deliver the laser light seems to be a suitable alternative for restricted areas such as fistula paths.

Synergism between recombinant human bone morphogenetic protein 2/absorbable collagen sponge and bone substitutes favors vertical bone augmentation and the resorption rate of the biomaterials: Histomorphometric and 3D microcomputed tomography analysis.

BACKGROUND: Recombinant human bone morphogenetic protein 2 (rhBMP-2) is an osteoinductor frequently used for bone regeneration in oral and maxillofacial surgery. There is no consensus about the ideal carrier for this growth factor. The aim of this study was to compare the bone augmentation, bone microarchitecture, and biodegradation rate of additional carriers to rhBMP-2/absorbable collagen sponge (ACS) in a vertical guided bone regeneration model. METHODS: Four titanium cylinders were fixed onto the calvaria of rabbits (n = 20) that received (n = 10) or not (n = 10) rhBMP-2/ACS in conjunction with one of the carriers: beta-tricalcium phosphate (ß-TCP), biphasic calcium phosphate (BCP), bovine bone mineral (BBM) or blood clot. The samples were analyzed by means of microcomputed tomography and histomorphology after 14 weeks. RESULTS: All the materials with rhBMP-2/ACS exhibited improvement on bone augmentation, mainly BCP (P = 0.033) and ß-TCP (P = 0.038), in the upper portion of the cylinder. Although trabecular anisotropy was improved in all the materials groups, trabecular connectivity was diminished when the biomaterials received rhBMP-2/ACS. Resorption rate of the remaining biomaterial was improved by rhBMP-2/ACS, mainly in BBM (P <0.01) and ß-TCP (P <0.01). BBM exhibited the highest osteoclast density compared with the other materials groups. CONCLUSIONS: BCP and ß-TCP biomaterials exhibited a synergic effect with rhBMP-2/ACS, acting as suitable and viable carriers for vertical bone augmentation. The addition of rhBMP-2 significantly affected the biodegradation of ß-TCP and BBM, accelerating the resorption of these materials.

Bone Formation in Grafts with Bio-Oss and Autogenous Bone at Different Proportions in Rabbit Calvaria.

BACKGROUND: The aim of this study was to assess the volumetric stability and bone formation in grafts with Bio-Oss and autogenous bone at different proportions in rabbit calvaria. Material and Methods. Ten rabbits received four titanium cylinders in their calvaria and randomly divided into the following groups: Group I: Bio-Oss (100%), Group II: Bio-Oss (75%) + autogenous bone (25%), Group III: Bio-Oss (50%) + autogenous bone (50%), and Group IV: autogenous bone (100%). After twelve weeks, the animals were euthanized, and samples were collected for clinical and histological analysis. RESULTS: Clinical analysis showed that Groups I (90.43 ± 8.99) and II (90.87 ± 7.43) had greater dimensional stability compared to Group IV (P=0.0005). Histologically, Groups I, II, and III showed areas of bone formation with particles of biomaterial remaining in close contact with the newly formed bone. However, there were no significant differences between the groups regarding the newly formed bone area. CONCLUSION: It was concluded that the use of Bio-Oss either alone or associated with the autogenous bone at a proportion of 25% showed superior dimensional stability compared to the use of autogenous bone in the proposed experimental model.

Evaluation of the effect of tumor necrosis factor-alpha gene polymorphism on the risk of peri-implantitis: a case-control study.

PURPOSE: Tumor necrosis factor-alpha (TNFalpha) is a proinflammatory cytokine, which promotes bone resorption and mediates the inflammatory response to infection. Because implant failures appear to cluster in subsets of individuals, this phenomenon may be related to gene polymorphisms. Therefore, the aim of this study was to investigate the relationship between a specific polymorphism in the TNFalpha gene (allele 2 of TNFalpha(-308)) and peri-implantitis. MATERIALS AND METHODS: This case-control study included Caucasian nonsmoking Brazilian patients with implant-supported restorations. Oral epithelial cells were taken from patients with and without peri-implantitis to evaluate the frequencies of different alleles of the TNFalpha(-308) gene by polymerase chain reaction. RESULTS: Ninety patients (49 with peri-implantitis and 41 with healthy implants) were enrolled in this study. Polymorphism in allele 2 of TNFalpha(-308) was not associated with an increased risk for peri-implantitis (P = .8171), although 14.63% of the subjects in the control group carried allele 2 and 19.39% in the peri-implantitis group carried allele 2 (chi-squared = 0.708; P = .5202). CONCLUSION: Polymorphism of the TNFalpha(-308) gene was not associated with an increased risk of peri-implantitis in the population evaluated in this study.

The Effects of Annual Maintenance on Peri-implant Health in Patients Rehabilitated with Overdentures: A Retrospective Cohort Study.

PURPOSE: The aim of this retrospective cohort study was to assess the effects of annual maintenance over a 7-year period on the peri-implant health of patients rehabilitated with overdentures using clinical and radiographic parameters. MATERIALS AND METHODS: In order to be considered for inclusion in the study, patients had to have been rehabilitated with overdentures that had at least two implants placed in the mandible and four implants in the maxilla. Patients were divided into two groups: group 1 comprised individuals who had undergone annual maintenance over the previous 7 years, and group 2 comprised those who had not attended any dental appointment over the previous 7 years. All patients were submitted to clinical peri-implant examinations and radiographic assessments. RESULTS: Sixty-six patients received 396 implants of the external hexagon type, 132 in the mandible and 264 in the maxilla. Group 1 (44 patients with 264 implants) had a mean probing depth of 2.72 mm, while group 2 (22 patients with 132 implants) had a mean probing depth of 3.10 mm. It can be concluded that the mean of the variable probing depth is influenced by the presence of bleeding (P = .0005) and the implementation of maintenance (P = .0188), whereas plaque and local variables were not otherwise significant (P = .0605 and .0796, respectively). CONCLUSION: In this study, it was possible to observe better clinical conditions in individuals who had attended annual appointments for maintenance purposes.

A finite element analysis of two different dental implants: stress distribution in the prosthesis, abutment, implant, and supporting bone.

This study evaluates the influence of 2 commercially available dental implant systems on stress distribution in the prosthesis, abutment, implant, and supporting alveolar bone under simulated occlusal forces, employing a finite element analysis. The implants and abutments evaluated consisted of a stepped cylinder implant connected to a screw-retained, internal, hexagonal abutment (system 1) and a conical implant connected to a solid, internal, conical abutment (system 2). A porcelain-covered, silver-palladium alloy was used as a crown. In each case, a simulated, 100-N vertical load was applied to the buccal cusp. A finite element model was created based on the physical properties of each component, and the values of the von Mises stresses generated in the prosthesis, abutment, implant, and supporting alveolar bone were calculated. In the prostheses, the maximum von Mises stresses were concentrated at the points of load application in both systems, and they were greater in system 1 (148 N/mm2) than in system 2 (55 N/mm2). Stress was greater on the abutment of system 2 than of system 1 on both the buccal (342 N/mm2 x 294 N/mm2) and lingual (294 N/mm2 x 148 N/ mm2) faces. Stress in the cortical, alveolar bone crest was greater in system 1 than in system 2 (buccal: 99.5 N/mm2 x 55 N/mm2, lingual: 55 N/mm2 x 24.5 N/mm2, respectively). Within the limits of this investigation, the stepped cylinder implant connected to a screw-retained, internal hexagonal abutment produces greater stresses on the alveolar bone and prosthesis and lower stresses on the abutment complex. In contrast, the conical implant connected to a solid, internal, conical abutment furnishes lower stresses on the alveolar bone and prosthesis and greater stresses on the abutment.

Sandblasted/acid-etched vs smooth-surface implants: implant clinical reaction to experimentally induced peri-implantitis in Beagle dogs.

This study uses a sandblasted/acid-etched implant vs a smooth-surface implant to compare implant mobility and clinical reactions of peri-implant tissues to experimentally induced peri-implantitis in Beagle dogs. The right and left mandibular premolars were extracted from 5 Beagle dogs, and 2 smooth-surface (SS) implants and 2 sandblasted/acid-etched (SLA) implants were placed in each animal. After 120 days, healing abutments were connected. Fifteen days later, the prosthetic abutments were connected, the hygiene regimen was suspended, and peri-implantitis was induced by the insertion of cotton ligatures into the soft tissue around the implants. At baseline and 30, 60, and 90 days later, clinical attachment level (CAL), probing depth (PD), and mobility (MO) were measured. Probing depth increased significantly in the SLA group alone when baseline PD was compared with 30-, 60-, and 90-day evaluations (P < .05). No significant differences were noted between the 2 implant groups (P > .05). The loss in CAL was significant in both groups when the baseline value was compared with 30-, 60-, and 90-day evaluations (P < .02). Comparison between the 2 implant groups revealed a greater loss in CAL in the SLA group at the 90-day evaluation period (P = .04). A significant increase in mobility was seen in both groups when baseline values and 90-day evaluations were compared (P < .04). However, no statistically significant differences were noted between the 2 implant groups (P > .05). Experimentally induced peri-implantitis results in a greater loss of CAL in SLA implants than in SS implants in dogs; however, no differences in mobility or in PD have been noted between the 2 implant groups.

Effect of systemic intermittent administration of human parathyroid hormone (rhPTH[1-34]) on the resistance to reverse torque in rabbit tibiae.

The aim of this study was to evaluate the effect of intermittent administration of human parathyroid hormone [rhPTH (1-34)] on the removal torque of implants placed in rabbit tibiae. Twenty male New Zealand rabbits were submitted to implant surgery. Each animal received one machined screw-type implant (3.75 mm diameter x 8 mm length) in the proximal metaphysis of the right tibia. The rabbits were then divided into 2 groups: the test group (n = 10) received 6 microg/kg of rhPTH (1-34) subcutaneously in the dorsal region 3 days a week, and the control group (n = 10) received placebo. Removal torque was performed at 28 and 56 days after implant placement for both groups. The mean removal torque values at 28 days were 37.0 +/- 4.36 Ncm and 47.4 +/- 6.77 Ncm for control and test groups respectively (P < .05). At 56 days the reverse torque was 45.8 +/- 3.96 Ncm for the control group and 55.8 +/- 2.86 Ncm for the test group, indicating that the removal torque was significantly higher in the test groups (P < .05). These results demonstrated that intermittent treatment with rhPTH (1-34) enhanced the removal torque of implants in rabbit tibiae.

Bone autografts & allografts placed simultaneously with dental implants in rabbits.

OBJECTIVE: This study compared stability, removal torque, bone implant contact (BIC) and area (BA) of implants installed simultaneously with onlay autografts or allografts in rabbits' tibias. MATERIAL AND METHODS: Total of 18 rabbits were used in this study. Fresh frozen allografts were obtained from six animals at T(-6). Two implants with autogenous grafts (Group 1) or allografts (Group 2) were simultaneously inserted into both sides of the tibiae in a vertical periimplant defect model at T0. The resonance frequency (ISQ) was measured in implant proximal epiphysis on the day of installation of T0 and T18 (18 weeks post-surgery). At T18 the removal torque was assessed at the distal implants, the implants' proximal epiphysis and surrounding bone were harvested to perform histomorphometric analysis. The BIC and BA within the limits of the implants threads were evaluated. RESULTS: The ISQ revealed a statistically significant difference between T0 and T18 in each group (p = 0.024, p = 0.003). The removal torque indicates that there was no significant difference between the two groups (p = 0.47). No significant differences were observed between the groups regarding both BIC (p = 0.3713) and the BA (p = 0.3883). CONCLUSION: Both grafts and implants demonstrated the same stability, torque removal and the BIC and BA.

Periodontal clinical evaluation before and after surgically assisted rapid maxillary expansion.

INTRODUCTION: The surgically assisted rapid maxillary expansion is a procedure that reduces the resistance of the sutures correcting the posterior crossbite in adults. OBJECTIVE: The aim of this study was to evaluate the periodontal status of 17 adults submitted to this procedure. METHODS: The clinical attachment level (CAL), gingival recession, attached gingiva and bleeding were evaluated in maxillary first premolars and molars, central and lateral incisors of right and left sides before surgery, 5 days and 6 months after. Means, standard deviation, medians, minimum and maximum values were compared among the evaluations using the Friedman and McNemar tests. RESULTS: There was a statistically significant increase in CAL in the right central incisor, right and left premolars and right and left molars. There was a statistically significant increase in gingival recession in the right and left premolars and molars. The amount of attached gingiva significantly decreased in right premolars and right and left molars. There was increase in bleeding in most of the teeth. CONCLUSION: Results indicated that the surgically assisted rapid maxillary expansion might cause alterations in periodontal tissue.

Growth Dynamic of Allogeneic and Autogenous Bone Grafts in a Vertical Model.

Several techniques have been proposed for vertical bone regeneration, and many of them use bone autogenous and allogeneic grafts. The purpose of this study was to compare demineralised freeze-dried bone allografts (DFDBA), fresh-frozen (FF) allografts, autogenous bone grafts to find differences between volumetric and histological quantity of bone formation and vertical bone growth dynamic. A vertical tissue regeneration bone model was performed in rabbit calvarias under general anaesthesia. Four hollow cylinders of pure titanium were screwed onto external cortical bone calvarias in eight rabbits. Each one of the cylinders was randomly filled with one intervention: DFDBA, FF, autogenous bone, or left to be filled with blood clot (BC) as control. Allogeneic grafts were obtained from a ninth animal following international standardised protocols for the harvesting, processing, and cryopreservation of allografts. Autogenous graft was obtained from the host femur scraping before adapting hollow cylinders. Animals were euthanized at 13 weeks. Vertical volume was calculated after probe device measurements of the new formed tissue inside the cylinders and after titanium cylinders were removed. Histomorphometry and fluorochrome staining were used to analyse quantity and dynamic of bone formation, respectively. Results showed that DFDBA and fresh-frozen bone improved the velocity and the quantity of bone deposition in distant portions of the basal plane of grafting. Remaining material in allograft groups was more intense than in autogenous group. Both allografts can be indicated as reliable alternatives for volume gain and vertical bone augmentation.

Vertical Bone Augmentation Using Deproteinized Bovine Bone Mineral, Absorbable Collagen Sponge, and Recombinant Human Bone Morphogenetic Protein-2: An In Vivo Study in Rabbits.

PURPOSE: The objective of this investigation was to assess vertical bone augmentation using deproteinized bovine bone mineral (DBBM) infused or not with recombinant human bone morphogenetic protein (rhBMP-2) in rabbit tibiae. MATERIALS AND METHODS: A total of 18 female rabbits (New Zealand) received two blocks of DBBM in each tibia. The DBBM blocks were randomly assigned into four experimental groups: DBBM (only the bone graft); DBBM associated with absorbable collagen sponge (ACS); DBBM plus rhBMP-2 (1.5 mg/mL); and DBBM infused with rhBMP-2 (1.5 mg/mL) in an ACS carrier. Animals were sacrificed after 12 weeks, and the tibiae containing the DBBM blocks were dissected and analyzed radiographically (microcomputed tomography [micro-CT]), histologically, and immunohistochemically. RESULTS: Micro-CT analysis showed a considerable increase in bone volume (BV) and BV/tissue volume in the rhBMP-2/ACS group compared with all the others. Trabeculae thickness also increased in the rhBMP-2/ACS group compared with the DBBM/ACS group. Trabecular number, separation, and bone mineral density were not different among groups. Histomorphometric evaluation showed increased newly formed bone in the rhBMP-2/ACS group compared with the DBBM and DBBM/ACS groups. The amount of residual bone graft was statistically higher in the rhBMP-2 groups compared with the DBBM/ACS group. Immunohistochemical analysis showed that the vascular endothelial growth factor (VEGF) expression was more intense in the rhBMP-2/ACS group compared with the DBBM/ACS group. The immunopositivity for type 1 collagen tended to be higher in the two groups with rhBMP-2. CONCLUSION: Collectively, the results of this study suggest that the addition of rhBMP-2 in an ACS carrier placed on top of the DBBM graft enhanced bone formation in this animal model.

Peri-implant bone loss around posterior mandible dental implants placed after distraction osteogenesis: preliminary findings.

BACKGROUND: The present study evaluates implant survival and peri-implant bone loss around posterior mandible dental implants placed at sites of distraction osteogenesis. METHODS: On removal of the distraction devices, 34 dental implants were inserted into 14 posterior mandible sites in 10 healthy, non-smoking female patients. Prosthetic treatment was performed 4 months after implant placement using fixed implant prostheses. After 6 to 16.5 months, periapical radiographs were taken and evaluated for peri-implant bone loss and radiolucency. The distance between the implant margin and the first visible bone-implant contact was measured on the mesial and distal aspects of the implants using imaging software. Radiographic dimensional distortion was corrected as a function of the known true dimension of the implant. RESULTS: Of the 34 implants placed, two (5.9%) failed to integrate at reentry surgery. Both were replaced and restored during the course of the study so that a total of 34 implants was followed for 12.1 +/- 3.8 months post-restoration and 16.1 +/- 3.8 months post-insertion. Mean loss of marginal bone height was 2.6 +/- 1.0 mm. During the follow-up period, radiolucent lines along the implant surface were absent. CONCLUSIONS: The mean peri-implant bone loss in areas of alveolar bone distraction was 1.9 mm/year. A high implant survival rate was observed.