The International Journal of Oral & Maxillofacial Implants, 02/2011

Purpose: The aim of this study was to evaluate the characteristics of various titanium surfaces modified by cold plasma nitriding in terms of adhesion and proliferation of rat osteoblastlike cells. Materials and Methods: Samples of grade 2 titanium were subjected to three different surface modification processes: polishing, nitriding by plasma direct current, and nitriding by cathodic cage discharge. To evaluate the effect of the surface treatment on the cellular response, the adhesion and proliferation of osteoblastlike cells (MC3T3) were quantified and the results were analyzed by Kruskal-Wallis and Friedman statistical tests. Cellular morphology was observed by scanning electron microscopy. Results: There was more MC3T3 cell attachment on the rougher surfaces produced by cathodic cage discharge compared with polished samples (P < .05). Conclusions: Plasma nitriding improves titanium surface roughness and wettability, leading to osteoblastlike cell adhesion. Keywords: cell growth, osteoblast adhesion, plasma nitriding, titanium

Purpose: The aim of this study was to evaluate human osteoblast activity on thin hydroxyapatite (HA)-coated three-dimensional scaffolds made of titanium fiber web. Materials and Methods: A thin HA film was coated on a titanium fiber web by the molecular precursor method. Human osteoblasts were disseminated onto the uncoated and HA-coated titanium fiber web, and osteoblast activity was observed at days 3, 7, 14, and 21 of culture. Results: Proliferation activities of osteoblasts were significantly higher in the uncoated titanium fiber web. Osteoblasts in the uncoated titanium fiber web showed a typical expression pattern, but those in the HA-coated titanium fiber web showed rapid osteocalcin expression and calcification at an early stage of culture. Moreover, osteocalcin expression per osteoblast was significantly higher in the HA-coated group. Conclusion: These results suggest that HA coating with the molecular precursor method accelerated osteoblast functional activity. Keywords: functional activity, hydroxyapatite coating, molecular precursor method, osteoblast, titanium fiber web

Purpose: The aim of this study was to evaluate the effect of retightening and mechanical cycling on the maintenance of preload in the retention screws of implant-supported crowns. Materials and Methods: Five groups (n = 12 in each group) of implant-crown assemblies were created according to different abutments and veneering materials: Gold UCLA abutments cast in gold alloy veneered with ceramic (group 1) and light-curing resin (group 2), UCLA abutments cast in titanium veneered with ceramic (group 3) and light-curing resin (group 4), and zirconia abutments with ceramic veneering (group 5). The crowns were attached to implants by gold retention screws. The assemblies were submitted to mechanical cycling for a total of 1 million cycles. Removal torque measurements were performed initially and after each period of 100,000 cycles; this was followed by screw retightening with 35 Ncm of torque. Data were evaluated with analysis of variance, the paired t test, and the Student t test. Results: All groups exhibited reduced removal torque values in comparison to insertion torque initially and after all periods of mechanical cycling. Analysis of variance revealed statistically significant differences among the groups, but there were no differences among the periods of mechanical cycling or for the interaction between groups and cycling. Group 1 was the only group that did not show a difference between removal torque values of different cycling periods. The Student t test did not reveal statistically significant differences between mean removal torque values obtained before and after mechanical cycling, except for group 4. Conclusions: Torque maintenance allowed screw joint stability in the present study. Mechanical cycling associated with the retightening of abutment screws did not influence the maintenance of insertion torque. Keywords: implant, implant-supported prosthesis, torque, veneering material

Purpose: To quantify implant displacement upon axial and oblique force application and compare the effects of bone quality using an in vitro experimental setup. Materials and Methods: One hundred ninety-two implants were inserted into artificial bone block specimens using a drill guide. Ninety-six implants were placed in soft cancellous bone and loaded in 10-N increments up to 80 N in axial and oblique (30-degree angle) directions (n = 48 in each group). The other 96 implants were inserted in dense artificial bone and loaded in axial and oblique directions in the same force increments. Three-dimensional displacement data were recorded for all implants using a noncontact optical image correlation technique based on photogrammetric principles, and the absolute displacement vector was calculated. Results: There were significant differences in the absolute implant displacement in the different bone densities over all load increments. Implant displacement was significantly higher in soft cancellous bone than in dense bone. Axial and oblique loading revealed significant differences in implant displacement in the cancellous specimens, whereas oblique loading showed increased displacement (339 ± 47 µm at 80 N) compared to axial loading (266 ± 39 µm at 80 N). However, axial and oblique loading showed no significant differences over all load increments when implants were inserted in dense specimens (absolute displacement with an 80-N load: 147 ± 10 µm axial and 126 ± 17 µm oblique). Conclusions: Bone density influenced implant displacement. The loading character (axial versus oblique) significantly influenced implant displacement in soft cancellous bone block specimens only. However, the limitation of the measured displacement values to an in vitro application that did not represent the complexity of vital bone has to be considered. Keywords: implant biomechanics, implant loading, optical measurement

Purpose: Resolution of defects surrounding dental implants can be achieved through the placement of rough-surfaced implants with bone substitutes. The aim of this study was to evaluate the effect of biphasic calcium phosphates (BCP) on the healing of circumferential bone defects surrounding dental implants. Materials and Methods: The premolars were removed in four mongrel dogs, and three different types of experimental sites were created: BCP, control, and ungrafted sites. In all groups, implants were placed in the edentulous area. In the BCP group, gap defects with 2-mm diameters were surgically created around each implant and the defects were filled with BCP bone substitute. In the control group, gap defects were not made around the implants. In the sham surgery group, gap defects were prepared but were not filled with BCP bone substitute. The defects were evaluated histologically and histometrically after 8 and 16 weeks. One-way analysis of variance and the independent t test were used for statistical analysis (α = .01). Results: Histometric measurements in the groups after 8 weeks showed the smallest remaining defect depths (RDDs) in the control group (17%). The RDD in the BCP group (39%) was greater than in the control group, and the ungrafted sites group had the greatest RDD (62%). There was no difference in bone-to-implant contact among the groups. Histometric measurements at 16 weeks showed that the RDD in the ungrated sites group (57%) was greater than in both the control (12%) and the BCP (31%) groups. Conclusion: Within the limitations of this study, BCP bone substitute contributed to defect resolution and maintained space for new bone ingrowth before 8 weeks. No additional contribution to defect resolution by BCP was found after 8 weeks. Keywords: biphasic calcium phosphates, bone-to-implant contact, circumferential bone defect, implant, remaining defect depth

Purpose: The purpose of this study was twofold: (1) to estimate the level of microbial contamination found on commercial guides (CG) and in-house laboratory guides (LG) prior to use, and (2) to evaluate the antimicrobial potential of disinfectants commonly used in dentistry to decontaminate heat-sensitive surgical guides. Ethylene oxide gas was used as the positive control; sterile water served as a negative control. Materials and Methods: Evaluation of CGs and LGs for bacterial contamination occurred soon after their arrival in the laboratory. Some guides went directly into tubes of trypticase soy broth solution, vortexed and equally divided into two tubes. One tube went into an 80°C bath for 19 minutes, while the other stayed at room temperature. After plating, half of the samples underwent anaerobic incubation. All incubation was for 48 hours at 37°C. Other guides underwent water rinsing or disinfection by various methods for 5 or 15 minutes or ethylene oxide gas sterilization prior to sampling. Results: Untreated CG specimens showed modest levels of bacterial contamination, with most colonies coming from liquid specimens not exposed to 80°C. LG specimens had more bacteria from both heat-treated and non-heat-treated aliquots. Chlorhexidine gluconate, diluted bleach, and water rinsing were not able to completely eliminate microorganisms on the specimens, but no viable microorganisms were present on specimens treated with gas sterilization or 70% ethanol for 15 minutes. Conclusion: CGs and LGs, on average, had different levels of bacterial contamination prior to disinfection. Water, chlorhexidine gluconate, and diluted bleach were not totally successful in decontaminating the surgical guides, but no growth was found after 15 minutes of immersion in 70% ethanol. Preferably, surgical guides should be submerged in 70% alcohol for a minimum of 15 minutes or undergo sterilization using ethylene oxide gas. Keywords: dental implants, disinfection, surgical guides

Purpose: To evaluate levels of C-telopeptide pyridinoline crosslinks of type I collagen (ICTP), soluble receptor activator of nuclear factor-kappa B ligand (sRANKL), and osteoprotegerin (OPG) in the crevicular fluid of endosseous dental implants with the clinical diagnosis of peri-implantitis and to compare these with the crevicular fluid of clinically healthy implants. Methods: Peri-implant crevicular fluid samples were obtained from 18 root-type implants with peri-implantitis in 12 patients and 21 clinically healthy implants in 16 other patients. Modified Plaque Index, probing depths, Gingival Index, and bleeding on probing were recorded at the crevicular fluid sampling sites. ICTP, sRANKL, OPG, and albumin levels in the peri-implant crevicular fluid samples were investigated by enzyme-linked immunosorbent assay. The clinical and biochemical data were evaluated statistically using Mann-Whitney U test. Spearman correlations were used to determine relationships between the biochemical data and the clinical parameters. Results: Duration of implant loading, peri-implant crevicular fluid volume, and all clinical periodontal measurements were significantly greater in the peri-implantitis group than in the clinically healthy group. Total amounts of ICTP were significantly higher in the peri-implantitis group than in the healthy group. sRANKL concentrations, OPG total amounts, and OPG concentrations were significantly higher in the healthy group. Conclusion: The present findings suggest that local levels of ICTP and OPG reflect an increased risk of alveolar bone loss around dental implants, and their local levels may help to distinguish diseased and healthy sites. Keywords: crevicular fluid, C-telopeptide pyridinoline crosslinks of type I collagen, endosseous dental implants, osteoprotegerin, peri-implant peri-implantitis, soluble receptor activator of nuclear factor-kappa B ligand

Purpose: The aim of this article was to evaluate the effectiveness of various implant neck configurations in the preservation of marginal bone level as well as to identify the available scientific evidence. Materials and Methods: Online and hand searches of the literature published from 1976 through 2009 were conducted to identify studies dealing with modifications in the implant neck area and marginal bone loss for at least a 5-year observation period. The search terms that were used, alone or in combination, were "implant neck," "marginal bone loss," "neck design," "bone resorption," "bone remodeling," and "implant collar." Relevant studies were selected according to predetermined inclusion and exclusion criteria. Results: The initial search yielded 3,517 relevant titles and revealed eight different implant neck configurations and/or methods suggested for the preservation of marginal bone. These methods included changes in implant neck length and design, implant surface characteristics, implant diameter, and/or insertion depth; the addition of microthreads; the use of one-piece implants; and the concept of platform switching. After subsequent filtering, 20 studies were finally selected and involved the following methods: the use of microthreads (1 study); modifications in implant surface characteristics (11 studies), implant diameter (4 studies), or insertion depth (2 studies); the use of one-piece implants (3 studies); and platform switching (1 study). Because of the heterogeneity of the studies, it was not possible to analyze the data statistically. No evidence was found regarding the effectiveness of any specific modification in the implant neck area in preserving marginal bone or preventing marginal bone loss. Conclusion: The current literature provides insufficient evidence about the effectiveness of different implant neck configurations in the preservation of marginal bone. Long-term randomized controlled clinical trials are needed to elucidate the effects of such modifications. Keywords: bone remodeling, bone resorption, implant collar, implant neck, marginal bone loss, neck design

Purpose: To systematically review clinical studies on prosthodontic complication rates of implant fixed dental prostheses in edentulous patients after an observation period of at least 5 years. Materials and Methods: A literature search was conducted using different electronic databases. Specific terms were used for the database search, which spanned the years 1990 to 2008. The search was augmented by using the option of "related articles" as well as by hand searching of references and relevant journals. Relevant studies were selected according to predetermined inclusion and exclusion criteria. Agreement between reviewers was determined by using Cohen kappa coefficients. Results: The initial database search yielded 8,216 relevant titles. Following the filtering process, 19 studies were finally selected. No study directly compared the incidence of prosthodontic complications of complete implant-supported metal-ceramic versus metal-acrylic resin fixed prostheses in the completely edentulous patient. Studies of metal-ceramic prostheses were scarce and short term. Conclusion: Metal-acrylic resin complete implant fixed prostheses presented with various prosthodontic complications after long-term function. The most frequent complications were veneer fracture and material wear. Keywords: edentulous arch, implant fixed prosthesis, meta-analysis, prosthodontic complications, screw, veneer

Purpose: This study was conducted to evaluate the influence of fluoride-treated, titanium dioxide grit-blasted implant surfaces on marginal bone levels through radiography at 3 years after functional loading and to determine whether a correlation exists between primary stability and marginal bone levels of implants. Materials and Methods: Edentulous patients who sought two-implant-retained mandibular overdentures and were available for follow-up were included. Each patient received two implants in the mandible; one implant received fluoride treatment and the other did not. To determine primary stability of the dental implants, resonance frequency analysis was performed at the time of implant placement. Panoramic radiographs were obtained preoperatively, at the time of overdenture connection, and at 6-month and 1- , 2-, and 3-year follow-up examinations. Results: Fifty-two edentulous patients with a mean age of 58 years (range, 40 to 70 years) were enrolled. All implants survived the observation period. No statistically significant differences were observed in the marginal bone levels of implants with and without fluoride treatment at 6 months and 1, 2, and 3 years (P > .05). No significant relationship was found between marginal bone levels and the recorded resonance frequency analysis values of the implants. Conclusions: Fluoride treatment of titanium dioxide grit-blasted implants was not effective in preventing marginal bone loss, and primary stability did not affect marginal bone loss around implants placed in anterior mandibles. Keywords: dental implant surface, fluoride treatment, grit blasting, marginal bone loss, resonance frequency analysis, titanium dioxide grit blasting

Purpose: To assess the esthetic and functional outcome, as well as the volume maintenance, of autogenous block grafts placed in anterior sextants of thin periodontal biotype subjects over a long-term period. Materials and Methods: Fifteen consecutive patients were followed up yearly for an average of 40 months after autogenous block grafting. Preoperative and postoperative cone beam computed tomographic scans were analyzed to evaluate bone volume maintenance around the implants placed in the grafted sites. Clinical parameters (mucosal recession and implant transparency through the soft tissue) were assessed at prosthesis delivery and follow-up to evaluate the esthetic outcome. Digital photographs were used to confirm clinical outcomes. Results: The average augmentation per site was 2.2 times the initial buccolingual (BL) width, and 97% of the augmented width was maintained after 3.3 years. The difference between preaugmentation and postaugmentation BL width, 3.3 versus 7.4 mm, was statistically significant (P < .0001; CI 95%: 3.4 to 4.9 mm). There was a lack of implant transparency or mucosal recession around the implants in all 15 patients after an average of 40 months. Conclusions: Autogenous block grafting seems to be a predictable treatment modality to reconstruct alveolar ridge defects in the long term. A thin periodontal biotype did not seem to affect the volume of transplanted bone for the population studied. Keywords: alveolar ridge augmentation, bone graft, bone regeneration, bone transplant, endosseous implants, volumetric computed tomography

Purpose: This study evaluated the biologic response to titanium mesh and autogenous particulate bone grafts for the reconstruction of segmental mandibular defects in a dog model. Materials and Methods: Unilateral 40-mm critical-sized continuity defects of the mandible were made in five beagle dogs. Titanium mesh was shaped and fixed with titanium screws in the defects. Autogenous bone was harvested from the ablated mandible and iliac crest (the ratio of cortical bone:cancellous bone was 3:1) and used to fill the mesh. Two implants were placed into each bone graft. The animals were sacrificed after 6 months. Radiographs, histologic sections, scanning electron microscopy, and energy dispersive spectroscopy were performed to evaluate bone formation and osseointegration of the implants in the reconstructed mandibles. Results: The outline of the reconstructed mandible was satisfactory, and no bone resorption was observed in the defect area. All implants showed excellent osseointegration of the grafted bone. Furthermore, the density of bone formed around the implants was higher than that seen in control samples (intact, ungrafted dog hemimandibles). Conclusions: Shaped titanium mesh with autogenous particulate bone graft is a predictable method for restoring critical-sized continuity defects of the mandible. Simultaneous implant placement is feasible and the structure of bone formed near implants may be optimal. Keywords: bone graft, immediate implant placement, mandibular reconstruction, titanium mesh

Purpose: To assess the prevalence of radiographic signs of maxillary sinus pathology in patients undergoing dental implant treatment and to compare the efficacy of panoramic radiography, computed tomography (CT), and three-dimensional (3D) CT with Implametric software in the diagnosis of sinus pathology. Materials and Methods: Thirty patients were selected at random from those being treatment-planned to receive implant-supported restorations in the maxilla and who had a panoramic radiograph, a conventional CT scan in acetate, and a 3D CT scan in digital format. The radiographic maxillary sinus findings were categorized as: (1) no sign of pathology, (2) mucosal thickening, (3) mucous cyst, or (4) occupation of the entire sinus. Results: Seventeen women and 13 men were included, with a mean age of 50.9 years. There was a 38.3% prevalence of radiographic abnormalities (23.3% mucosal thickenings, 10% mucous cysts, and 5% occupation of the entire sinus). Of the 23 sinuses that displayed radiographic signs of pathology, only 1 (4.3%) was correctly diagnosed by the panoramic radiograph. Conclusions: The most common radiographic maxillary sinus finding was mucosal thickening, followed by mucous cysts and occupation of the whole sinus. Conventional CT can be considered a reliable method for the diagnosis of maxillary sinus pathology. Keywords: antral pseudocyst, maxillary sinus, mucocele, panoramic radiograph, sinus elevation

Purpose: To investigate the influence of implant geometry on primary stability and on peri-implant bone loss in an in vitro model using the Periotest and Osstell devices. Materials and Methods: Screw-type implants of various diameters and lengths were inserted into bovine bone blocks of different densities, and the primary insertion stability was recorded. To study the influence of implant geometry on implant stability with different levels of peri-implant bone loss, implants were inserted into acrylic resin blocks to mimic osseointegration, and different amounts of the peri-implant acrylic resin were removed. Measurements with both devices at each millimeter step yielded the threshold for the least detectable attachment loss. Results: The predominant factors influencing implant stability were bone quality and attachment loss. Implant type and length exerted some influence on implant stability values, while variations in implant diameter produced only minor alterations in the measurements. In simulations of peri-implant attachment loss, implant stability decreased more dramatically for the shorter and narrower implants. The inclusion of more variables in the analyses resulted in less focused measurements. Conclusions: The results of this study clearly show that the outcome of implant stability assessment depends on environmental factors such as bone quality and implant geometry. While the authors do not recommend the use of the Periotest or Osstell devices for a comparison of the stability of two individual implants, both should be useful to monitor the state of an individual implant over time. Keywords: bone loss, damping capacity assessment, implant geometry, implant stability, peri-implantitis, resonance frequency analysis

Purpose: The present study evaluated patient satisfaction using the Oral Health Impact Profile 49 (OHIP-49) questionnaire for patients who received six implants in the severely resorbed maxilla and an implant-supported prosthesis that was delivered within 24 hours after surgery. Materials and Methods: Fifty-one edentulous patients with severe atrophy in the maxilla were included in the study, which was performed at two centers. Six implants were placed in the maxilla and loaded within 24 hours with a provisional restoration. The definitive restorations were delivered 20 to 24 weeks later. Patients were asked to complete the OHIP-49 questionnaire (which includes seven domains representing functional limitation, physical pain, psychologic discomfort, physical disability, psychologic disability, social disability, and handicap) prior to implant placement and on three subsequent occasions. The data were collected and analyzed and OHIP scores were compared over time. Results: Baseline satisfaction scores for the two different centers displayed no statistically significant differences. Treatment resulted in improved total OHIP-49 scores in both centers, with no significant difference between centers. Furthermore, no significant differences were observed in any of the individual pretreatment and posttreatment OHIP-49 domains between centers. All seven domains showed a statistically significant improvement posttreatment. Of the seven domains, social disability and handicap showed the least improvement and had the lowest pretreatment scores, indicating lower significance for these domains compared to the other domains during implant treatment. This study also indicated that domains one to five (functional limitation, physical pain, psychologic discomfort, physical disability, and psychologic disability) are the most important domains in patient satisfaction with implant therapy. Conclusion: Measurement with the OHIP-49 questionnaire displayed that patient satisfaction increases after treatment with a fixed restoration on implants loaded within 24 hours. Keywords: dental implants, oral health-related quality of life, patient satisfaction, treatment outcomes

Purpose: The present study summarizes the long-term clinical observations of edentulous patients treated with mandibular implant-supported overdentures. Materials and Methods: From 1984 to 1997, edentulous patients were consecutively admitted to treatment with mandibular implant overdentures. The treatment plan was to connect the dentures to only two implants by means of single ball anchors or bars; in patients with special oral conditions, three implants would be placed. Regular maintenance care was provided at least one time per year. The cumulative implant survival rate was calculated. Implant failures were described according to clinical signs at the time of removal and related to the patient's specific history. Crestal bone measurements were performed using computer software. Results: In all, 147 patients with 314 implants were evaluated for 10 to 24 years. Of these, 101 patients were still available; of the 46 patients who were not evaluated, 26 had died or were not ambulatory. Thirteen implants failed during the observation period, resulting in a cumulative survival rate of 85.9% after 24 years. The reasons for removal of implants were peri-implantitis (two implants) and mobility (11 implants). Mean crestal bone loss was 0.54 ± 0.7 mm per implant site after an average observation time of 16.5 ± 3.9 years. The duration of loading had a statistically significant effect on bone loss. Conclusions: The present data exhibit a satisfactory survival rate of implants. An individual analysis of implants with late failures did not reveal a typical failure pattern, but loss of implants without signs of infection was more frequent than loss of implants with signs of peri-implantitis. Keywords: crestal bone loss, dental implants, implant survival, long-term follow-up study, manifestation of failures

Purpose: Immediate loading has become an emerging technique because it has been shown to be a successful, time-saving procedure. Recently, immediate loading has been performed simultaneously with implant placement into fresh extraction sockets; excellent results have been achieved, but few reports are available with a long-term follow-up. The aim of the present study was to evaluate the difference in success rates in the maxilla between postextraction implants and implants placed in healed sites, both of which were immediately loaded, after a long-term follow-up. Materials and Methods: Between October 2001 and February 2003, 239 implants were inserted in 81 consecutively operated patients and immediately loaded; 138 implants were placed in fresh postextraction sites (57.7%) and 101 implants were placed in healed sites (42.3%). Two different implant systems were used in this study. Each implant was loaded within 72 hours of placement (60.3% at the time of surgery, 6.3% after 24 hours, 30.1% after 48 hours, and 3.3% after 72 hours). Preestablished success criteria were used to evaluate the success rate of the implants. Results: The mean follow-up was 6.7 years (range: 6.0 to 7.3 years). Only 8 of the 239 implants failed, for an overall success rate of 96.6%. Six of the failed implants were inserted in postextraction sites, and 2 had been placed in healed sites; the success rates were 95.7% and 98.0%, respectively. Statistical analysis revealed no significant differences between postextraction and healed sites. Conclusions: Immediate loading of immediate postextraction sites results in an implant success rate that is broadly comparable to that seen for implants placed in healed sites. Moreover, this procedure can provide predictable and favorable results in many different clinical conditions and for a long term. Keywords: dental implants, healed sites, immediate loading, long-term follow-up, maxillary implants, postextraction sites

Purpose: In this prospective study, bone formation in human extraction sockets augmented with Bio-Oss Collagen after a 12-week healing period was quantified and compared to bone formation in unaugmented extraction sockets. Materials and Methods: Selected patients with four-walled extraction sockets were included in this prospective study. After extraction, the sockets were randomly augmented using Bio-Oss Collagen or left to heal unfilled without raising a mucoperiosteal flap. At the time of implant placement, histologic specimens were obtained from the socket and analyzed. Statistical analysis was performed using the Wilcoxon signed-rank test. Results: Twenty-five patients with a total of 39 sockets (20 augmented, 19 unaugmented) were included in the study and the histologic specimens analyzed. All specimens were free of inflammatory cells. The mean overall new bone formation in the augmented sites was 25% (range, 8%-41%) and in the unaugmented sockets it was 44% (range, 3%-79%). There was a significant difference in the rate of new bone formation between the grafted and ungrafted sockets and a significant difference in the bone formation rate in the apical compared to the coronal regions of all sockets, independent of the healing mode. Conclusion: This descriptive study demonstrated that bone formation in Bio-Oss Collagen-grafted human extraction sockets was lower than bone formation in ungrafted sockets. Bone formation occurred in all specimens with varying degrees of maturation independent of the grafting material and was initiated from the apical region. Keywords: bone grafting, bovine bone mineral, collagen, extraction socket, socket preservation

Purpose: The aim of this multicenter prospective study was to provide data from a case series supporting the use of short dental implants with oxidized surfaces to treat partially edentulous patients. Materials and Methods: The implants used had an oxidized surface, a tapered design, and a short length (8.5 mm or shorter). All implants were placed in posterior edentulous areas that were affected by high bone resorption (available bone height < 10 mm). Implant success was established according to predetermined criteria. Results: Records were available for 107 implants used to treat 46 patients (69.2% were 7 mm long, and 30.8% were 8.5 mm long); 80.4% were placed in the posterior mandible, and 19.6% were placed in the posterior maxilla. With regard to restorations, 27.1% of implants were restored with single crowns, 16.8% with a single cantilever, and 56.1% with fixed prostheses. After a 1- to 3- year follow-up, 105 implants are still functioning; only 2 implants have been lost, for a survival rate of 98.1%. In all, 4 of the 107 implants placed failed to meet the success criteria, resulting in a success rate of 96.3%. The mean marginal bone loss was 0.6 ± 0.2 mm. Conclusions: The results of this study suggest that short oxidized implants should be regarded as a possible solution for the restoration of posterior teeth in highly resorbed areas. Keywords: dental implants, oxidized surface, posterior teeth, short implants

Purpose: This prospective case series evaluated the use of a new synthetic resorbable membrane with autogenous bone, either alone or in combination with anorganic bovine bone-derived mineral, for horizontal ridge augmentation and subsequent implant placement. Materials and Methods: Particulated autogenous bone, either alone or in combination with anorganic bovine bone-derived mineral, was used for lateral ridge augmentation and covered with a new synthetic resorbable membrane (glycolide and trimethylene carbonate) to treat knife-edged ridges and prepare them for implant placement. Ridge measurements were obtained before and after augmentation, complications were recorded, and biopsy specimens were examined histologically. Results: Fifty-eight implants were placed in 22 patients with 25 surgical sites in knife-edged ridges. No complications were associated with this treatment. Clinical measurements revealed an average of 5.56 mm (± 1.45 mm) of lateral ridge augmentation after an average of 8.12 months (± 2.32 months) of graft healing. Clinically, all treated ridges were sufficient in width for subsequent implant placement. All implants have survived, with an average follow-up period of 45.88 months (± 12.43 months). Histologic analysis of the selected augmentation sites showed new bone formation and good incorporation of the bovine bone mineral particles. Conclusion: The high implant survival rate and the low complication rate show the potential of this technique for the treatment of horizontal augmentation of lateral ridges and the efficacy of the new resorbable synthetic membrane. Keywords: anorganic bovine bone-derived mineral, autogenous bone, guided bone regeneration, horizontal augmentation, resorbable membrane, sinus graft

Purpose: The mandibular two-implant overdenture has been shown to be a highly successful treatment. However, overdenture patients who desire a fixed prosthesis may not be satisfied with a removable overdenture. This prospective study sought to compare prosthetic outcomes, patient satisfaction, and survival rates of implants between two-implant-supported overdentures (IODs) and three-implant-supported fixed dentures (ISFDs). Materials and Methods: Twenty completely edentulous patients were randomly and equally assigned to two groups. New conventional complete dentures were made, and the mandibular denture was used as a surgical guide during implant placement. Implants were placed in one stage, followed by a mandibular denture soft reline (provisional loading). Ball attachments were inserted at 8 weeks, and ISFDs were delivered at 16 weeks. IODs were connected to the attachments at 8 weeks, using each patients's existing denture. The definitive ISFDs were fabricated using computer-aided design/computer-assisted manufacture milled titanium frameworks and acrylic resin base and teeth. Patient satisfaction and panoramic radiographs were investigated at 6 and 12 months. Results: Both treatments had significant and positive effects on patient satisfaction and quality of life. None of the 50 implants placed had failed at 12 months of follow-up; therefore, the implant survival rate was 100%. Prosthetic complications were generally rare and easily manageable. Conclusions: Both the treatment modalities-the ISFD supported by three implants and the IOD supported by two implants-significantly and similarly improved patient satisfaction and oral health-related quality of life, and prosthetic complications were relatively rare for both treatments. Three implants can be used to support a mandibular fixed prosthesis; however, a longer observation period is needed to validate this treatment modality. Keywords: dental implant, mandibular fixed denture, mandibular overdenture, patient satisfaction, prosthetic outcome

Purpose: This case series evaluated the peri-implant tissue response following extraction and immediate placement and restoration of an implant in conjunction with subepithelial connective tissue grafting (SCTG) and bone grafting in the esthetic zone. Implant success rates and the peri-implant tissue response were also reported. Methods and Materials: Ten patients (four men, six women) with a mean age of 48 years (range, 35 to 70) underwent extraction and immediate tooth replacement with SCTG and were evaluated clinically and radiographically presurgically (T0), immediately after immediate tooth replacement and SCTG (T1), and at 3 months (T2), 6 months (T3), and 12 months (T4) after surgery. Data was analyzed using Friedman and Wilcoxon signed-ranks tests at the significance level of α = .05. Results: At 1 year, all implants remained osseointegrated, with an overall mean marginal bone change of +0.10 mm and a mean facial gingival level change of -0.05 mm. Modified Plaque Index scores showed that patients were able to maintain a good level of hygiene throughout the study. Papilla Index scores indicated that at T4, more than 50% papilla fill was observed in 80% of all sites. Conclusions: The results of this case series suggest that, in addition to a favorable implant success rate and peri-implant tissue response, the facial gingival level around single immediately placed implants can also be maintained following connective tissue grafting when proper three-dimensional implant positioning is achieved and bone is grafted into the implant-socket gap. Keywords: biotype, esthetics, gingival biotype, gingival recession, IIPP, immediate implant placement, immediate loading, immediate provisionalization, papilla, single tooth replacement

The facial soft tissue form of dental implants is influenced by a variety of biologic, surgical, and restorative factors. Implants and/or restorative components that are positioned facially present a challenge to created ideal facial soft tissue contours. The following case reports display how modification of the restorative components, namely, abutment and crown, will influence the soft tissue height and contour when minor tissue discrepancies exist due to nonideal implant placement. Keywords: abutment, dental implant, malposed, recession, soft tissue form

Rheumatoid polyarthritis is a systemic autoimmune disease characterized by chronic synovitis and bone damage associated with significant functional disability and morbidity. This case report describes a 4-year follow-up of a 56-year-old female receiving polymedication for severe rheumatoid polyarthritis and osteoporosis with a fully edentulous maxilla treated with two osseointegrated implants supporting a removable mandibular prosthesis. No practitioner wanted to use implants to stabilize her mandibular prosthesis because of the health risks involved. This report encourages the dental practitioner to be familiar with the symptoms and oral manifestations of rheumatoid polyarthritis in order to help manage this disease when patients lose all of their teeth. Keywords: implants, rheumatoid polyarthritis, systemic autoimmune disease