The International Journal of Oral & Maxillofacial Implants, 05/2008

Purpose: The purpose of this study was to histologically analyze the influence of bioactive glass and/or acellular dermal matrix on bone healing in surgically created defects in the tibiae of 64 rats (Rattus norvegicus, albinus, Wistar). Materials and Methods: A 4-mm 3 3-mm unicortical defect was created on the anterolateral surface of the tibia. Animals were divided into 4 groups: C, control; BG, the defect was filled with bioactive glass; ADM, the defect was covered with acellular dermal matrix; and BG/ADM, the defect was filled with bioactive glass and covered with acellular dermal matrix. Animals were sacrificed at 10 or 30 days postoperatively, and the specimens were removed for histologic processing. The formation of new bone in the cortical area of the defect was evaluated histomorphometrically. Results: At 10 and 30 days postoperatively, groups C (39.65% ± 5.63%/63.34% ± 5.22%) and ADM (38.12% ± 5.53/58.96% ± 7.05%) presented a larger amount of bone formation compared to the other groups (P .05). In the same periods, groups BG (13.10% ± 6.29%/29.5% ± 5.56%) and BG/ADM (20.72% ± 8.31%/24.19% ± 6.69%) exhibited statistically similar new bone formation. However, unlike the other groups, group BG/ADM did not present a significant increase in bone formation between the 2 time points. Conclusion: Based on these results, it can be concluded that all of the materials used in this study delayed bone healing in non-critical-size defects. Keywords: acellular dermis, bioactive, bioglass, bone regeneration, bone substitutes

Purpose: The purpose of this study was to modify the method of platelet-rich plasma (PRP) preparation for obtaining optimal angiogenic potential and accelerate bone healing. Also, the potential synergistic effect of a suboptimal concentration of bone morphogenic protein-2 (BMP-2) and modified PRP (mPRP) on bone healing was evaluated in vivo. Materials and Methods: The angiogenic factor-enriched PRP, which included peripheral blood mononuclear cells (mostly lymphocytes and monocytes, excluding polymorphonuclear leukocytes [PMNs], was achieved by lowering concentrations of thrombin and CaCl2, after pre-activation with shear stress using a table-top vortex machine and collagen. In vitro, endothelial cell migration activity in the mPRP group was compared to conventional PRP preparation using a modified Boyden chamber assay. In an animal study, PGA scaffold, PGA scaffold + mPRP, PGA scaffold + mPRP + rhBMP-2, and PGA scaffold + rhBMP-2 were applied to critical-sized calvarial defects in 28 nude rats. At 2 weeks, periosteal blood flow was measured using laser Doppler perfusion imaging, and bone formation was evaluated at 8 weeks by histology, dual energy x-ray absorptiometry, and micro-computed tomography. Results: mPRP induced faster migration of cord blood-derived outgrowth endothelial-like cells. In vivo, the group with mPRP with a low dose of rhBMP-2 showed significantly increased numbers of blood vessels at 2 weeks and notable synergistic effect on bone healing at 8 weeks as evaluated with histology, bone mineral density and bone mineral content, and µCT. Conclusion: The mPRP used in this study improved vascular perfusion around the defect and resulted in enhanced bone healing. Also, combining mPRP with a suboptimal dosage of rhBMP-2 improved bone formation and enhanced bone density. Keywords: angiogenic potential, athymic rat, calvarial defect, rhBMP-2

Purpose: The purpose of this study was to determine dynamic changes in bone metabolism around osseointegrated titanium implants under mechanical stress. Materials and Methods: Two titanium implants were inserted parallel to each other in the tibiae of rats and perpendicular to the bone surface with the superior aspect of the implant exposed. Eight weeks after insertion, closed coil springs with 0.5, 1.0, 2.0, and 4.0 N were applied to the exposed superior portion of the implant for 7 weeks to apply a continuous mechanical stress. Bone scintigrams were performed using a gamma camera with a modified high-resolution pinhole collimator. Images were made at 1, 4, 7, 10, 14, 21, 28, 49, and 56 days after insertion and at 3 days and at weekly intervals until 7 weeks after load application. The ratio of the metabolic activity around the implants to that around a reference site (uptake ratio) was established. The Friedman, Steel, and Tukey tests (P .05) were used to assess statistical significance. Results: In the process of osseointegration, the uptake ratio increased during the first week after implant insertion and then gradually decreased. During the initial 3 weeks the uptake ratio was significantly higher than at 1 day after insertion. In the process of load application, the uptake ratio increased with 2.0- and 4.0-N loads; it was significantly higher until 6 weeks than it had been before load application. Conclusions: Bone metabolism around the implants increases with loading and depends on the magnitude and period of the loading. Keywords: bone metabolism, bone remodeling, bone scintigraphy, mechanical stress osseointegrated titanium implant

Purpose: Atrophy of the alveolar ridge is a problem in prosthetic and esthetic treatment. In the present study, to examine effects of PGE1 on the alveolar bone after tooth extraction, PGE1 was applied to rat incisal sockets utilizing a slow drug release system using PLGA as the drug carrier. Materials and Methods: Thirty-six male Wistar rats, 10 weeks old, were divided into 3 groups. After all right mandibular incisors were extracted, the sockets were treated in the following manner. The first group was untreated (control group), the second group received a PLGA rod (PLGA group), and the third group was treated with a PLGA rod containing 0.5 mg PGE1 (PGE1 group). Six rats in each group were sacrificed at 4 weeks, and the remaining rats were sacrificed at 8 weeks. For fluorescence labeling, half of the animals were injected with calcein and tetracycline 8 days and 1 day before sacrifice, respectively. After sacrifice, the mandibles were radiologically and histologically examined. Results: In the PGE1 group, the bone volume of the alveolar ridge including the socket was significantly (P .05) greater than in the control and PLGA groups at 4 and 8 weeks. At 4 weeks in the PGE1 group, the mineral apposition rate and number of osteoclasts were higher than in the other groups, whereas these parameters were similar in all groups at 8 weeks. Conclusion: Based on this animal study, it appears that local application has the potential to preserve and/or augment the alveolar ridge after tooth extraction. Keywords: alveolar bone local administration, PLGA, prostaglandin E1, rat, tooth socket

Purpose: The aim of this study was to compare the clinical success and bone healing of implants placed in fresh extraction sockets using a flapless procedure compared to those placed with flap elevation. Materials and Methods: Twenty teeth in 20 patients were selected for this study and were scheduled for tooth extraction and immediate implant placement. Ten implants were placed with flap elevation (control group), and 10 implants were placed without flap elevation (test group). All the sites selected showed a complete bone defect at the facial wall. All the implants included in this study were 2-stage implants placed at the level of palatal/lingual bone in augmented bone. Each surgical site was protected with a collagen membrane and, subsequently, a standardized radiograph was taken to evaluate the distance between the implant shoulder and the first bone-implant contact (DIB). Six months after placement, both control and test implants underwent a second-stage surgery and a clinical examination to determine the implant stability quotient, DIB, and the distance between implant shoulder and the crestal bone at the midbuccal aspect (DIC). Results: One implant failed in the test group. Only 1 implant (test group) showed bone growth over the implant neck at the re-entry procedure. Implant stability quotient (ISQ) and DIB did not show any significant differences between the control and test group; however, a higher DIC was found in the test sites compared to the control sites. Conclusion: Data from this study showed that immediate implants with and without a mucoperiosteal flap elevation can be successfully used even in the presence of bone defects requiring augmentation procedures. It was also noted that the bone regenerated reached a higher coronal level in the group with flap elevation than in the group without flap elevation. Keywords: biomaterial, bone defect, dental implants, extraction sockets, mucoperiosteal flap

Purpose: The purpose of this study was to investigate the prosthetic complications of patients with a maxillary complete removable dental prosthesis opposing a mandibular metal-resin implant fixed complete dental prosthesis. Materials and Methods: This study is a retrospective analysis of an ongoing prospective study. Dental records from 46 patients treated with a maxillary complete removable dental prosthesis and a mandibular metal-resin implant-fixed complete dental prosthesis were reviewed for 15 different prosthetic complications. The average recall time was 7.9 years. The percentage of patients exhibiting each complication and corresponding 95% confidence intervals was calculated. Logistic regression analysis determined the effect of recall period, age, and gender on each of the following major complications: tooth fracture, complete denture relines, screw complications, and tooth replacement. The recall period was divided into 3 parts: = 2 years, 2 to 5 years, and more than 5 years. Results and Conclusion: Statistical significance was exhibited for complete denture relines, posterior tooth replacement, and screw complications. No abutment or framework fractures were recorded for any of the time intervals. The most common complications were prosthetic tooth fracture, tooth wear, maxillary hard relines, and screw complications. Patients were 1.06 times more likely to require a heat-processed hard reline with each year increase of age. After 2 to 5 years and > 5 years, patients were 3.7 times and 8.5 times more likely to require a hard reline than at = 2 years. Patients were 52.5 times more likely to need posterior tooth replacement at > 5 years than at = 2 years, and 7.7 times more likely to encounter a screw complication at > 5 years than at = 2 years. Keywords: dental implants, metal-resin, prosthetic complications, retrospective study

Purpose: The objective of the present study was to clinically and histologically evaluate the effectiveness of deproteinized bovine bone as the augmentation material in vertical ridge augmentation of the inserted implants. Materials and Methods: This retrospective study was performed on 10 vertically augmented ridges in which 24 dental implants were inserted. Deproteinized bovine bone (Bio-Oss) was used as the only augmentation material and was covered with a titanium-reinforced expanded polytetrafluoroethylene (e-PTFE) membrane (Gore-Tex). For 3 augmented areas, bone samples were retrieved for histologic and histomorphometric examination. Results: Clinical evaluations showed bone defects around the implants of 2 to 9 mm (average -5.1 mm; SD = 2.1). Bone height gain at 6 to 8 months after augmentation was 3 to 9 mm (average 5.3 mm; SD= 1.7). Differences between pre- and postaugmentation were statistically significant, for a mean value of > 4 mm (P .005). The obtained bone biopsy specimens showed significant new bone formation and remodeling of the deproteinized bovine bone material. The radiographic data and the clinical stability showed that all implants were successfully osseointegrated. The radiographic and clinical follow-up indicated that the generated bone crest levels were stable. Conclusion: This clinical study suggests that vertical ridge augmentation with an e-PTFE membrane and deproteinized bovine bone is predictable and can lead to long-term success. Keywords: barrier membranes, bovine bone matrix, vertical ridge augmentation

Purpose: To compare the efficacy of immediate functionally loaded implants placed with a flapless procedure (test group) versus implants placed after flap elevation and conventional load-free healing (control group) in partially edentulous patients. Materials and Methods: Forty patients were randomized: 20 to the flapless immediately loaded group and 20 to the conventional group. To be immediately loaded, implants had to be inserted with a minimum torque > 45 Ncm. Implants in the immediately loaded group were provided with full acrylic resin temporary restorations the same day. Implants in the conventional group were submerged (anterior region) or left unsubmerged (posterior region) and were left load-free for 3 months (mandibles) or 4 months (maxillae). Provisional restorations were replaced with definitive single metal-ceramic crowns 1 month postloading. Outcome measures were prosthesis and implant failures, biological and prosthetic complications, postoperative edema, pain, and use of analgesics. Independent sample x2 tests, Mann-Whitney tests, t tests, and paired t tests were used with a significance level of .05. Results: Fifty-two implants were placed in the flapless group and 56 in the conventionally loaded group. In the flapless group, 1 flap had to be raised to control the direction of the bur and 1 implant did not reach the planned primary stability and was treated as belonging to the conventional group. After 3 years no dropouts or failures occurred. There was no statistically significant difference for complications; however, patients in the conventional group had significantly more postoperative edema and pain and consumed more analgesics than those in the flapless group. Osstell values were significantly higher at baseline in the flapless group (P = .033). When comparing baseline data with years 1, 2, and 3 within each group, mean Osstell values of the flapless group did not increase, whereas there were statistically significant increases in the Periotest values. Conclusions: Implants can be successfully placed flapless and loaded immediately without compromising success rates; the procedure decreases treatment time and patient discomfort. Keywords: dental implants, flapless, immediate loading, partial edentulism, randomized controlled clinical trial

Purpose: The aim of this study was to report the long-term results of a 2-stage sinus lift procedure with autologous bone graft and Astra Tech Tioblast ST implants (Astra Tech, Mölndal, Sweden). Materials and Methods: Sinus lift procedures were carried out in 36 patients, 25 unilateral and 11 bilateral. Bone grafts were obtained from the iliac crest, mandibular angle, or chin region. Healing time for bone grafts varied between 4 and 5 months. Implants were allowed to heal for 6 months. The patients were followed in a standardized clinical and radiographic method for up to 5 years. Patients with partial dentition in the maxilla and limited bone volume below the sinus cavity (6 to 7 mm) were consecutively included in the study. Smoking was a contraindication to inclusion in the study unless patients who smoked quit smoking for at least 6 months prior to surgery. Results: All patients have been successfully restored with fixed complete dentures. There was no implant loss. Radiographic examination showed minor changes in bone graft height (1 to 1.5 mm) over 5 years and moderate bone remodeling (1 to 2 mm over 5 years). Signs of sinus infection appeared in 8 patients. In 4 patients, partial loss of bone graft material occurred. Conclusion: Two-stage sinus lift procedure with autologous bone graft material in combination with Astra Tech Tioblast ST implants has a predictable outcome. The method is reliable and useful for patients with severe resorption of the posterior maxilla. Keywords: bone-implant interaction, bone regeneration, clinical research, sinus floor elevation, surgical techniques

Purpose: To study the stability and the peri-implant alveolar bone response of immediately loaded micro-implants. Materials and Methods: Micro-implants were implanted into the mandibles of male beagle dogs, immediately loaded in the test group (200-g horizontal force) and unloaded in the control group. The healing bone was then labeled with polyfluorochrome at intervals over 10 weeks. Radio-graphs were taken at the beginning and end of the study. Seventy-three days after implantation, the dogs were euthanized, and the dissected mandibles were prepared for examination. The tissue specimens were evaluated by light microscopy, fluorescent microscopy, polarized light microscopy, scanning electron microscopy, and energy dispersive x-ray spectroscope. Results: The teeth anchored by the micro-implants moved normally, while the micro-implants remained basically stable. All the microscopy results showed that osseointegrated interfaces were formed between the micro-implants and the alveolar bone. Fluorochrome labels demonstrated that lamellar bone had appeared at 6 weeks after implantation, and was formed more extensively after another 3 weeks. Conclusion: This in vivo study found that the stability and osseointegration of immediately loaded micro-implants were not impaired. Micro-implants inserted in dense cortical alveolar bone in the mandibles of beagle dogs may be loaded immediately in a dog model to achieve satisfactory orthodontic anchorage. Keywords: bone-implant interface, immediate loading, micro-implant, osseointegration, stability

Piezoelectric osteotomy is based on ultrasonic vibration of an osteotomic device that permits precise cutting of bone structures without cutting adjacent soft tissues. To date, however, there have been no studies of the outcome and complications of alveolar distraction for piezoelectric osteotomy versus conventional osteotomy. The present study evaluated piezoelectric versus conventional osteotomy in alveolar distraction. Materials and Methods: A retrospective study was performed on all patients of the auothors who requested dental implants and who after preliminary evaluation were judged to require alveolar distraction osteogenesis for rehabilitation of edentulous mandibular regions. The distraction was performed using the same distraction system in all cases, but with the osteotomy performed either by conventional techniques using rotary instruments and chisels (conventional osteotomy group, n = 11), or by piezoelectric osteotomy using the Piezosurgery system (Mectron Medical Technology; Carasco, Genoa, Italy; n = 6). The 17 distractions were compared with respect to patient age, patient sex, intra- and postoperative complications, degree of surgical difficulty, postdistraction morphology of the alveolar ridge, and rehabilitation success rate. Results: Both surgical difficulty (as measured by the number of surgical instruments required) and the incidence of intraoperative complications were significantly lower in the piezoelectric osteotomy group than in the conventional osteotomy group. However, postdistraction morphology of the alveolar ridge (as determined at implant placement) was worse in the piezoelectric osteotomy group than in the conventional osteotomy group (P = .072). The overall rehabilitation success rate was 100% in the conventional osteotomy group versus only 66.7% (4 of 6 cases) in the piezoelectric osteotomy group. Conclusions: The use of piezoelectric osteotomy in alveolar distraction appears to simplify surgery and reduce the incidence of intraoperative complications. However, results also suggest that piezoelectric osteotomy increases the risk of postoperative and postdistraction complications and reduces the overall rehabilitation success rate. Keywords: bone surgery, distraction osteogenesis, piezoelectric surgery

Objectives: The objective of this study was to assess to what extent the outcome of immediate implantation and provisionalization for replacing single maxillary teeth in the esthetic zone is favorable and predictable from biologic and esthetic points of view. Material and Methods: An electronic search (MEDLINE and Cochrane Oral Health Group Specialized Trials Register) and a manual search were performed to detect studies concerning maxillary single-tooth replacements by means of dental implants immediately placed into fresh extraction sockets and provisionalized within the first 24 hours. Only full-text reports on clinical studies published in English up to June 2006 were included. Case reports and reviews on the topic of interest were excluded. Results: Eleven studies were selected. Based on a qualitative data analysis, implant survival and even management of papilla levels seem predictable following immediate implantation and provisionalization. However, maintaining the midfacial gingival margin may be more problematic, since postextraction bone remodeling and therefore marginal gingival changes will occur irrespective of the timing of the placement of an implant. The long-term impact of this remodeling is currently unclear and needs to be elucidated in future research. Conclusion: The clinician is recommended to be reserved when considering immediate implant placement and provisionalization for replacing single maxillary teeth in the anterior zone. At the very least, a number of guidelines and prerequisites need to be taken into consideration. Keywords: immediate implantation, immediate loading, maxilla, single-tooth dental implants

Objectives: The aim of this study was to determine whether a diagnosis of osteoporosis affected the survival rate of osseointegrated dental implants. Other variables that were studied were age, arch location of the implant, and smoking status on the effect of dental implant survival. Materials and Methods: A retrospective chart review was completed on all women who were 50 years of age or older at the time of dental implant placement at the Mayo Clinic between October 1, 1983, and December 31, 2004. Osteoporotic status was defined on the basis of bone mineral density (BMD) score utilizing World Health Organization criteria. Univariate analyses were performed to evaluate the following independent variables' effect on implant survival: BMD T-score, age, osteoporosis status, arch location of the implant, and smoking status at the time of implant placement. Results: A total of 3,224 implants in 746 female patients 50 years of age or older at the time of implant placement were evaluated. BMD scores within 3 years of implant placement were available for 646 implants (192 patients). In this group, 37 implant failures were noted. The 5-year implant survival rate was 93.8% in the group of patients with BMD scores. In this group of 192 patients, there were 94 (49%) who were not diagnosed with osteopenia or osteoporosis, 57 (29.7%) with a diagnosis of osteopenia, and 41 (21.4%) with a diagnosis of osteoporosis. Patients with a diagnosis of osteoporosis or osteopenia were not significantly more likely to develop implant failure compared to those without such a diagnosis (HR = 1.14, 95% CI = 0.50 to 0.60, P = .76 and HR = 0.98, 95% CI = 0.40 to 2.42, P = .97, respectively). Arch location and BMD score did not have a statistically significant effect on implant survival rates. The only tested variable to demonstrate a significant effect was smoking. Implants in patients who were smokers during the time of implant placement were 2.6 times more likely to fail compared to implants placed in patients who did not smoke (HR = 2.6, 95% CI = 1.20 to 5.63; P = .016). Conclusions: Based upon the data derived from this retrospective study of 192 women at least 50 years of age at the time of implant placement, the following observations were made: (1) a diagnosis of osteoporosis and osteopenia did not contribute to increased risk of implant failure and (2) implants placed in patients who were smokers at the time of implant placement were 2.6 times more likely to fail than implants placed in nonsmokers. Based on these data, a diagnosis of osteoporosis or osteopenia is not a contraindication to dental implant therapy. Keywords: dental implants, implant survival, osteoporosis

Purpose: In this retrospective study, the long-term survival and success rates of implants with 2 different surfaces placed in extremely atrophic maxillae augmented with Le Fort I osteotomy and interpositional bone grafts were assessed. Materials and Methods: In 12 consecutive patients (7 female, 5 male; average age, 55 years; age range, 47 to 63 years), the resorbed maxilla was reconstructed using Le Fort I osteotomy in combination with interpositional iliac bone grafts. After 5 to 6 months, machined or titanium plasma-sprayed implants were inserted. The patients were followed clinically and radiographically for 6 to 12 years (mean 102 ± 24.42 months) after prosthetic loading. Implant outcome in terms of survival and success using Albrektsson's criteria was analyzed. Results: In all cases, the bone-grafting procedures allowed implant placement. Of the 104 implants placed (53 machined and 51 titanium plasma-sprayed), 11 failed, resulting in an overall cumulative survival rate of 89.4%. When the success rate was calculated using the defined criteria, the cumulative success rate was 67.3%. The respective survival and success rates were 86.8% and 66.0% for the machined implants and 92.2% and 68.7% for the titanium plasma-sprayed implants. The mean marginal bone resorption was 2.91 ± 0.77 mm (range, 0.6 to 4.9 mm) around machined implants and 2.72 ± 0.84 mm (range, 0.7 to 5.3 mm) around titanium plasma-sprayed implants. No significant differences in survival, success rate, or marginal bone resorption were found between the 2 implant groups. Conclusions: Le Fort I osteotomy combined with bone grafts and delayed implant placement gave predictable long-term results. There was a distinct relationship between implant survival and the long-term success rate. The implant surface had no significant effect on the survival, success rate, or marginal bone resorption. Keywords: alveolar bone augmentation, atrophic maxilla, autogenous bone graft, dental implants, follow-up study, Le Fort I osteotomy

Purpose: This study compares the prevalence and the length of mental loops, which were measured with panoramic radiographs and spiral computerized tomographs (SCT). Materials and Methods: Seventy-three panoramic radiographs and 73 SCTs were taken for preoperative planning of implant placement in the interforaminal region of the anterior mandible. The bone quality of both mental regions in each patient was determined by 1 experienced calibrated clinician, and the cross-sectional images of the SCTs were evaluted for bone quality according to the Lekholm and Zarb classification. Panoramic radiographs and cross-sectional SCT images were examined carefully by the same calibrated clinician to determine the presence and to measure the length of the mental loop in each patient. The relationship between these radiographs was also examined and correlated with bone quality. Paired samples t test and Pearson's correlations were used to examine the agreement between 2 radiographic methods at each bone quality. A 5% level of significance was chosen. Results: The prevalence of the mental loop in panoramic radiographs and spiral CT images was 28% and 34%, respectively. The mental loop was identified more frequently in spiral CT images regardless of bone quality. The demonstration of the mental loop between radiographic methods was more pronounced in poor bone quality. The mean length of the mental loop in panoramic radiographs was 3.71 ± 1.35 mm and 3.00 ± 1.41 mm in SCT. Measurements for panoramic radiographs were higher than those for spiral CT images. There was a correlation of r = 0.66 (P = .01) between the 2 radiographic methods, indicating agreement. Conclusions: SCT demonstrated a higher prevalence of mental loops than panoramic radiographs. SCT can be more useful to visualize and measure the mental loop in low bone qualities. Panoramic radiographs significantly overestimate (P = .02 in type 3, P = .01 in type 4) mental loop length, which were measured in spiral CT images in poor bone quality, but there is a close correspondence between these 2 radiographs in higher quality bone. Keywords: anterior loop, mental nerve, panoramic radiography, preoperative implant planning, spiral computerized tomography

Purpose: To compare the efficacy of 2 common materials in sinus augmentation surgery and to assess their contribution when enriched with autogenous bone. Materials and Methods: The prospective human study was performed in 48 sinus grafting operations using b-tricalcium phosphate or deproteinized bovine bone (pure or mixed with 10% to 20% autogenous bone) or autogenous bone. Biopsy specimens were taken after 9 months. Statistical evaluation was done with a 2-sample t test (P .05). Results: When autogenous bone was used, 49.2% ± 3.1% of new bone was found, which is significantly higher than in all the other groups. A higher proportion (34.2% ± 13.1%) of the new vital bone was found in the deproteinized bovine bone group, in comparison with the b-tricalcium phosphate group (21.4% ± 8.1%) and the b-tricalcium phosphate composite graft group (24.0% ± 6.6%; P .05). No significant differences between single-component grafts and corresponding composite grafts were established. Conclusions: Sinus augmentation with the aforementioned augmentation materials is a well-accepted procedure. However, autogenous bone alone was the best material. More new bone was found using deproteinized bovine bone than b-tricalcium phosphate. The addition of 10% to 20% autogenous bone to the bone substitute did not significantly influence the new bone formation. Keywords: autogenous bone graft, b-tricalcium phosphate, composite graft, deproteinized bovine bone, histomorphometry, sinus augmentation

Implant dentistry has developed predictable treatment outcomes. Nevertheless, there are multiple reasons for implant failure. This case report documents a previously unreported type of implant failure that occurred 1 month after crown cementation. The implant failure is believed to be associated with retained excess subgingival cement. Keywords: cement, complication, dental implant, implant loss

This is a review of the literature on osteogenesis imperfecta and a case report of an edentulous patient with osteogenesis imperfecta rehabilitated with implant-supported fixed prostheses in the maxilla and mandible. Quality and quantity of the bone is of paramount importance for establishment of osseointegration. In osteogenesis imperfecta bone is osteoporotic. There are few reported cases in the literature of implant placement and subsequent rehabilitation of patients with osteogenesis imperfecta. To our knowledge, this is the first reporting of successful short-term follow-up of an edentulous osteogenesis imperfecta patient with implant-supported fixed prostheses. Keywords: dental implants, dentinogenesis imperfecta, edentulous, osteogenesis

The objective of this report is to present a device to achieve equal platform height in the vertical axis to allow the spherical abutments to work correctly in mandibular overdentures retained with 2 implants. The device is fabricated over plastic castable abutments, with a plate perpendicular to the implant platforms and located at the top of the platform height. Once implants are inserted, the device is screwed to an implant and allows evaluation of the height of the platforms. Keywords: edentulous arch, overdenture, surgical template

Benign paroxysmal positional vertigo (BPPV) is a relatively rare condition characterized by onset of rotation dizziness triggered by head movements or change in posture. BPPV etiology includes head injury, infection, vascular disorders, surgical trauma, and idiopathic events. This report presents a case of protracted BPPV following osteotome sinus floor elevation and simultaneous implant placement. A 49-year-old female suffered intense vertigo and nausea immediately after implant placement using an osteotome sinus floor elevation procedure, especially when changing head position while sitting upright. Despite antivertigo medications, the condition did not improve. Following referral to a neurotologist, BPPV contralateral to the operation site was diagnosed 14 days after the osteotome sinus floor elevation procedure. The Epley's maneuver was then applied and, gradually, symptoms of BPPV disappeared 3 months after the implant surgery. No recurrence of BPPV was observed during further 3-month follow-up. Prevention and management of osteotome sinus floor elevation-related BPPV are reviewed in this report. Keywords: benign paroxysmal positional vertigo, canalith repositioning procedure, dental implantation, osteotome sinus floor elevation