The International Journal of Oral & Maxillofacial Implants, 03/2008

The observation that clinical factors alone do not explain why some patients develop implant loss; the understanding of the osseointegrated implant failure as a complex, multifactorial process; and the observed aggregation of repetitive failure in certain individuals raise interesting questions related to host susceptibility to dental implant failure. Genetic analysis applied to dental implants began in the late 1990s, and since then, increased interest in genetic susceptibility to the phenotype has been demonstrated by several studies. These studies, however, have been based on and limited to candidate gene association analysis and were intended to find associations between specific alleles and/or genotypes of genetic markers and susceptibility to implant failure. The aim of this review is to provide a brief description of the current methodology for genetic analysis of complex traits, followed by a comprehensive review of the literature related to genetic susceptibility to dental implant failure and a discussion of different aspects of the applied methodology. Moreover, a novel approach of genome wide, case-control analysis is discussed as an alternative method to access genetic influence to dental implant failure mechanisms. Advances toward the elucidation of the genetic basis of dental implant loss may contribute to the understanding of why some patients do not respond to currently available treatments while others do and provide potential targets for effective screening, prevention, and treatment. For example, clinicians might be able to estimate, before the elective surgical procedure, the risk of a given patient to develop a negative individual host response. Keywords: dental implant, genetic approaches, implant failure, osseointegration, polymorphisms

Purpose: Osteogenic cells contribute to the process of osseointegration and graft consolidation. However, whether the cells survive low oxygen tension and maintain their responsiveness to natural and therapeutic growth and differentiation factors remains unknown. Materials and Methods: To determine the effects of low oxygen tension on osteogenic cell viability and responsiveness in vitro, human bone cells were placed into plastic pouches intended to create anaerobic conditions and were either simultaneously or subsequently exposed to supernatants from activated platelets or recombinant bone morphogenetic protein (BMP)-6. Results: Bone cells cultured for up to 72 hours under hypoxia moderately decreased their metabolic activity, which was paralleled by morphologic changes but not by cleavage of the apoptosis markers caspase-3 and poly(ADP)ribose polymerase. Hypoxia suppressed the mitogenic response of bone cells to platelet-released supernatant and the expression of osteogenic differentiation markers alkaline phosphatase and osteocalcin upon incubation with BMP-6. Stimulation of bone cells with platelet-released supernatant and BMP-6 immediately after re-establishment of normoxia caused a moderate cellular response. However, when bone cells were allowed to recover for 7 days under normoxia, their responsiveness was equal to that of cells not previously exposed to low oxygen tension. Conclusions: These findings suggest that osteogenic cells can survive transient hypoxia and retain their potential to respond to growth and differentiation factors once normoxia is re-established. The data also implicate that reoxygenation, and thus blood vessel formation, may be an important determinant for the process of osseointegration and graft consolidation. Keywords: bone augmentation, bone regeneration, graft consolidation, hypoxia, osteoblast, oxygen

Purpose: To investigate the healing of critical-size cranial bone defects (9-mm-diameter) in guinea pigs treated with a bovine bone-derived resorbable membrane. Materials and Methods: A sample of 42 guinea pigs was divided into test (n = 20), control (n = 20), and standard (n = 2) groups. A full-thickness trephine defect was made in the fronto-parietal bone of each animal. In the test group, the internal and external openings of the defect were each closed with a separate membrane, and the space between them was filled with blood clot and a central spacer. In the control group, the defect was filled only with the blood clot and spacer. At 1, 3, 6, and 9 months later, the calvarias (5 per period) for both the test and control groups were collected, fixed, radiographed, and histologically processed. The standard-group animals were sacrificed immediately after surgery and used to determine the initial size of defect radiographically. The areas of defects in the radiographs were measured with image-analysis software and were compared between groups and periods by multiple regression analysis with the Bonferroni correction. Results: At 1 and 3 months, newly formed woven bone was histologically observed in both test and control groups. Radiographically, this new bone occupied an average of 32% of the defect area at 1 month and 60% at 3 months in the test group. In the control group, 21% of the defect was filled at 1 month and 39% at 3 months. However, the differences between treatments were not statistically significant (P > .05). At 6 and 9 months, a significant increase in newly formed lamellar bone was seen histologically in both groups. Radiographically, for the test group, the new bone occupied an average of 82% of the defect area at 6 months and 96% at 9 months. For the control group, new bone composed an average of 45% of the defect area at 6 months and 40% at 9 months. The differences between the test and control groups were statistically significant at 6 and 9 months (P .05). Complete or almost complete filling of the defect was observed in several cases. Conclusion: It was concluded that the bovine bone-derived membrane is highly biocompatible and is able to promote good healing of critical-size defects in calvaria of guinea pig. Keywords: calvaria, collagen, critical-size bone defect, guided bone regeneration, membrane, xenograft

Purpose: The aim of this study was to perform qualitative and quantitative analyses of the effect of nicotine on autogenous bone block grafts and to describe events in the initial healing phase and the differences in the repair processes between animals exposed to nicotine and controls. Materials and Methods: Forty-eight female Wistar rats were randomly divided into 2 groups, the nicotine group and the saline group. All animals received either nicotine (3 mg/kg) or saline 4 weeks before the surgical procedure and continued to receive nicotine from surgery to sacrifice at 7, 14, or 28 days. The autogenous bone block graft was harvested from the calvaria and stabilized on the external cortical area near the angle of the mandible. Results: The histologic analyses of the nicotine group depicted a delay in osteogenic activity at the bed-graft interface, as well as impairment of the organization of the granulation tissue that developed instead of blood clot. Nicotine-group specimens exhibited less bone neoformation, and the newly formed bone was poorly cellularized and vascularized. The histometric analysis revealed significantly less bone formation in the nicotine group at both 14 days (23.75% ± 6.18% versus 51.31% ± 8.31%) and 28 days (42.44% ± 8.70% versus 73.00% ± 4.99%). Conclusion: Nicotine did jeopardize the early healing process of autogenous bone block grafts in rats but did not prevent it. Keywords: autograft, bone grafting, nicotine, wound healing

Objectives: The aim of this study was to determine the precision of the measurements of 2 craniometric anatomic points-glabella and anterior nasal spine-in order to verify their possibility as potential locations for placing implants aimed at nasal prostheses retention. Methods: Twenty-six dry human skulls were scanned in a high-resolution spiral tomography with 1-mm axial slice thickness and 1-mm interval reconstruction using a bone tissue filter. Images obtained were stored and transferred to an independent workstation containing e-film imaging software. The measurements (in the glabella and anterior nasal fossa) were made independently by 2 observers twice for each measurement. Data were submitted to statistical analysis (parametric t test). Results: The results demonstrated no statistically significant difference between interobserver and intraobserver measurements (P > .05). The standard error was found to be between 0.49 mm and 0.84 mm for measurements in bone protocol, indicating a high level of precision. Conclusions: The measurements obtained in anterior nasal spine and glabella were considered precise and reproducible. Mean values of such measurements pointed to the possibility of implant placement in these regions, particularly in the anterior nasal spine. Keywords: computer-assisted, extraoral implants, nasal prostheses, tomography

Purpose: The aim of this systematic review was to evaluate available evidence for a difference in the stability of peri-implant tissues between titanium abutments versus gold alloy, zirconium oxide, or aluminum oxide abutments. Materials and Methods: Studies were identified by examining several electronic databases and major dental implant, prosthetic, and periodontal journals. To be selected for the preliminary article pool, the article must have been written in the English language and published from 1980 to March 2007. Articles were sorted based on the nature of the study. In vitro studies and literature reviews were excluded. The included articles were clinical, human histology, and animal studies. Case reports, case series, uncontrolled clinical trials, and clinical studies with teeth treated as a control were excluded from the final review. Results: The initial article pool included 40 articles of which 9 met the inclusion criteria: 3 animal studies, 2 human histological studies, and 4 randomized clinical trials. Soft tissue recession was not accurately measured in the included clinical studies. Assessment of peri-implant tissues around zirconium oxide and titanium abutments was described only in animal and human histologic studies. Due to differences in study types, timing of follow-ups, and outcome variables, meta-analysis could not be performed. Conclusions: Included studies revealed that titanium abutments did not maintain a higher bone level in comparison to gold alloy, aluminum oxide, or zirconium oxide abutments. However, there is a lack of information about the clinical performance of zirconium oxide and gold alloy abutments as compared to titanium abutments. Keywords: abutment, aluminum, biologic width, crestal bone loss, gold alloy, implant, peri-implant soft tissues, zirconium

Purpose: The purpose of this study was to evaluate the bone healing kinetics around commercially pure titanium implants following inferior alveolar nerve (IAN) lateralization in a rabbit model. Materials and Methods: Inferior alveolar nerve lateralization was performed in 16 adult female rabbits (Oryctolagus cuniculus). During the nerve lateralization procedure, 1 implant was placed through the mandibular canal, and the IAN was replaced in direct contact with the implant. During the 8-week healing period, various bone labels were administered for fluorescent microscopy analysis. The animals were euthanized by anesthesia overdose, and the mandibular blocks were exposed by sharp dissection. Nondecalcified samples were prepared for optical light and scanning electron microscopy (SEM) evaluation. Results: SEM evaluation showed bone modeling/remodeling between the IAN and implant surface. Fluorochrome area fraction labeling at different times during the healing period showed that bone apposition mainly occurred during the first 2 weeks after implantation. Conclusions: The results obtained showed that bone healing/deposition occurred between the alveolar nerves in contact with a commercially pure titanium implant. No interaction between the nerve and the implant was detected after the 8-week healing period. Appositional bone healing occurred around the nerve bundle structure, restoring the mandibular canal integrity and morphology. Keywords: bone healing, dental implants, inferior alveolar nerve lateralization, light microscopy, scanning electron microscopy, titanium

Purpose: The purpose of this study was to investigate the efficiency of panoramic radiography, conventional (cross-sectional) tomography, and computerized tomography for location of the mandibular canal before implant placement in the posterior region of the mandible. Materials and Methods: Edentulous mandibles from 6 dry adult human skulls were used in this study. Four measurements (D1, D2, D3, D4) were made of 12 areas, one on each side of each mandible. Panoramic radiographs, conventional tomograms, and computerized tomograms were obtained. On each image, measurements were made for localization of the mandibular canal by one researcher. All measurements were repeated 3 times within a period of 3 weeks. Upon completion of imaging, the mandibles were surgically sectioned to provide direct measurements. The measurements obtained from the images were compared with direct measurements. Pearson correlation coefficients were calculated to detect statistical correlations between repeated measurements. The Dunnett t test was performed for statistical comparison of measurements from images and direct measurements. Results: Pearson correlation coefficients showed strong linear correlation for all measurements (P .01). No statistically significant difference was observed between direct measurement and D1, D2, or D4 (P .05), but a statistically significant difference for D3 (buccolingual width 5 mm under mandibular crest; Dunnett t test; P > .05) between measurements was obtained from the images and direct measurements. Conclusion: The measurements obtained from computerized tomographic images were more consistent with direct measurements than the measurements obtained from panoramic radiographic images or conventional tomographic images. Keywords: dental implant, imaging methods, mandibular canal, treatment planning

Dental implants have become an accepted method for tooth replacement and should be presented by dentists to patients as an alternative to replacing missing teeth. Patients in need of tooth replacement should be informed about dental implants, including the potential benefits, long-term survival statistics, risks, and potential complications. In addition, they should be informed about the importance of maintenance and long-term follow-up, including their specific responsibilities regarding the same. Fortunately, there is a wealth of evidenced-based research available that dental professionals may utilize to inform their patients. In addition, dental professionals may find answers to critical questions regarding implant therapy in the following guidelines developed by the Academy of Osseointegration (AO) based on recognized standards of care and the results of AO's 2006 Consensus Conference on the State of the Science on Implant Dentistry.

Purpose: This prospective randomized controlled trial aimed to compare single implant-supported mandibular molar restorations using either an immediate or a delayed loading protocol. Materials and Methods: Thirty subjects requiring single mandibular molar replacement were consecutively treated. One implant was placed in each patient. Fifteen subjects were assigned to delayed loading protocol and 15 to immediate loading protocol according to a randomization table. After insertion, the delayed loaded implants were connected to a healing abutment and restored after 3 to 4 months of healing without loading. The immediately loaded implants were loaded within 24 hours of surgery with a provisional restoration. The interim prosthesis was placed in centric occlusion. All contacts in lateral excursions were eliminated. At implant placement the maximum value of insertion torque was recorded. Radiographic bone level change was measured on periapical radiographs obtained at the time of implant placement and 12 months after loading. Means of the 2 groups were compared by Student t test and analysis of variance (ANOVA). The level of significance was set at .05. Results: No implants were lost in the delayed loading group (0/15), whereas 1 implant failed (1/15) in the immediate loading group. No differences were observed in relation to implant length or insertion torque between the groups. The average radiographic bone level change after 1 year of function was 1.2 ± 0.55 mm (range, 0.5 to 2.6 mm) and 0.77 ± 0.38 mm (range, 0.29 to 1.23 mm) for the delayed loaded and the immediately loaded implants, respectively. The difference in radiographic bone level change between the delayed and immediate loading groups was statistically significant (P = .022; CI = -0.79 to -0.06; Student t test). Conclusions: Immediate loading of wide-diameter implants supporting single restorations in mandibular molar sites seems to be a suitable clinical option. Moreover, the radiographic bone level change observed after 12 months of loading was significantly less for immediately loaded implants. Keywords: dental implants, immediate loading, randomized controlled trial

Purpose: The purpose of the current prospective multicenter study was to evaluate the 5-year implant success and peri-implant conditions of smooth-surface Brånemark System implants when using a novel technique including a 1-stage surgical procedure with early loading in edentulous mandibles. Materials and Methods: The study protocol included 1-stage surgery as well as placement of the definitive prosthesis within 6 weeks after implant insertion (ie, early loading). Clinical evaluation, as well as evaluation of function and esthetics, was performed at each follow-up visit. Radiographs were obtained at connection of the prostheses and at the 1-, 3-, and 5-year check-ups. Results: A total of 40 patients with a mean age of 56 years (range, 30 to 70) were included in the study. In all, 170 implants were placed in between the mental foramina, of which 120 implants in 30 patients were associated with overdenture treatment and 50 implants in 10 patients with fixed complete dentures. Twelve implants failed in 6 patients. The cumulative implant survival rate was 92.9% after both 1 and 5 years of follow-up. Another 3 implants were recorded as mobile but still in function when individually checked at the 5-year visit, which resulted in a cumulative success rate of 91.0%. Mean bone remodeling over the study period was less than 0.1 mm/y after the first year of loading, resulting in a mean marginal bone level of 0.66 mm (SD 0.73, n = 138) apical to the implant collar reference point after 5 years. Conclusions: One-stage, early loaded smooth-surface Brånemark System implants functioned well for the majority of patients with edentulous mandibles. Stable peri-implant conditions were observed. Bone remodeling resulted in a mean bone level above the first implant thread after 5 years. The somewhat lower success rate of 91.0% compared to a 2-stage procedure may be related to generous inclusion criteria and to a learning curve involving a novel treatment procedure. Keywords: early loading, edentulous mandible, endosseous smooth-surface implants, osseointegration

Introduction: The use of shorter implants offers a number of potential advantages if such utilization yields the same level of treatment success as the use of longer implants. The purpose of this retrospective study was to assess the survival of short implants in various clinical situations in function over time. Materials and Methods: A retrospective study was conducted of all patients treated between May 2000 and May 2007 who received endosseous implants that were less than 10 mm in length. Patient age, gender, location of implants, type of prosthesis, time in function, and stability of peri-implant crestal bone were assessed. Results: The retrospective analysis identified 2,073 implants of 6 mm, 7 mm, 8 mm, or 9 mm in length placed in a variety of clinical situations in 1,774 patients. Cumulative implant survival rates for implants in function in various areas of the mouth supporting single crowns or short-span fixed prostheses ranged from 98.1% to 99.7%. Each indication was examined with regard to individual success and failure rates and mean time in function. Conclusions: When utilized appropriately, implants of 6 to 9 mm in length demonstrate cumulative survival rates under function comparable to those reported for longer implants. Keywords: osseointegrated implants, short implants, treatment planning

Objective: The aim of this study was to compare wide-diameter implants placed in mature bone versus implants inserted in postextraction bone. Material and Methods: A retrospective case study was made; the sample was composed of subjects who had had wide implants placed in the molar area between 2003 and 2005. Two groups were formed: implants placed in mature bone and implants in postextraction bone. A protocol was prepared in which patient age, sex, oral hygiene, implant length, type of prosthesis, and antagonist dentition were collected. After 12 months, data relating to the clinical and radiologic conditions of the implants and the success rate (criteria of Buser et al) were recorded. A statistical analysis of the variables was made (t test, Pearson correlation coefficient, analysis of variance, chi-square). Results: The study examined 162 implants placed in 100 patients. Of the 162 implants, 130 were placed in mature bone and 32 in postextraction bone. Four implants placed in mature bone failed in 4 patients (success rate of 96.9%). None of the implants placed in postextraction bone failed. Conclusions: The placement of wide-diameter implants in recent molar extraction sites has been shown to achieve similar results to implants placed in healed mature bone after 12 months of follow-up, within the limitations of this study. Keywords: immediate implants, wide-diameter implants

Purpose: This study was carried out to quantify the effect of an alkali-modified surface on implant stability during healing using an animal model. Materials and Methods: A total of 24 screw-shaped, self-tapping, commercially pure titanium dental implants, divided into a test group (implants with an alkali-modified surface or "biosurface") and a control group (implants with a turned, machined surface) were inserted without pretapping in the tibiae of 3 beagle dogs. The resonance frequency analysis method was used to measure the implant stability quotient (ISQ) 0, 1, 3, 9, and 12 weeks after implantation. The animals were sacrificed after 2, 5, and 12 weeks, and the bone-implant contact (BIC%) was evaluated histomorphometrically. Results: The difference in the osseointegration rates (DISQ/Dhealing time) between the implants with alkali-modified surface (biosurface) and those with a turned, machined surface was evaluated as a mean of 0.843 ISQ/week within the first 9 weeks of healing. The mean increase in the secondary implant stability was found to be proportional to the mean increase in the BIC at healing period earlier than 5 weeks. Discussion: The characteristics that differed between the implant surfaces, ie, specific surface area, contact angle, and hydroxylation/hydration, may represent factors that influence the rate of osseointegration and the secondary implant stability. Conclusion: The alkali-treated surface enhances the secondary stability in the early stages of healing compared to the turned, machined surface, as a consequence of faster BIC formation. Keywords: alkali-etched surface, bioactive surface, dental implants, histometric analysis, resonance frequency analysis, secondary stability

Purpose: Immediate loading of oral implants has been extensively documented in different clinical indications, but no studies on heavy smokers have been reported. The aim of this study was to evaluate the long-term success and the peri-implant soft and hard tissue conditions around immediately occlusal loaded implants in edentulous jaws of heavy smokers. Materials and Methods: Implants (progressive thread design and platform switching) were connected with their abutments and splinted immediately after surgery using cross-arch fixed temporary restorations. Provisional fixed prostheses had centric occlusal contacts and group function in the lateral movements of the mandible (immediate occlusal loading). Patients were advised to adhere to a soft diet for the first 6 to 8 weeks of healing to reduce excessive loading in the bone-implant interface. The definitive restorations were delivered 4 to 8 weeks after surgery and cemented temporarily to evaluate the peri-implant soft tissue condition after removal of the restoration. Clinical and radiographic indices were evaluated at the start of loading and at 3-month intervals after loading. Results: After a mean loading period of 33.7 ± 19.0 months (range, 6 to 66 months), 1 implant was mobile. All clinical indices had values in normal ranges. The Periotest values decreased with time, indicating increased security of implants in bone. Crestal bone level was stable, with only 2 sites presenting minimal vertical bone loss and 6 presenting minimal horizontal bone loss. In all other sites no bone loss was observed. Results of this study demonstrated a long-term success (98.6%) of immediately loaded implants placed in occlusal function in smokers restored with fixed cross-arch implant-supported restorations. Conclusions: This study showed that immediate loading of oral implants may be successful in heavy smokers under some circumstances. Keywords: implant, immediate loading, smoking

Purpose: This study surveyed dental implant treatment in children up to age 16 years in Sweden between 1985 and 2005, with special reference to young children with ectodermal dysplasia (ED) and anodontia in the lower jaw. Materials and Methods: A questionnaire was sent to Swedish specialist clinics in oral and maxillofacial surgery and prosthetic dentistry. Also, the teams who had treated children with ED were asked to submit their records for these children for a discussion on reasons for implant failure. Results: Six out of 30 specialist centers (20%) in Sweden had treated 26 children with dental implants between 1985 and 2005. Twenty-one patients had received 33 implants to replace teeth missing from nonsyndromic agenesis or trauma at ages 14 or 15 years; 2 (6.1%) of these implants were lost. Five children with ED received 14 implants at 5 to 12 years of age; 9 (64.3%) of these implants were lost before loading. Conclusions: Dental implant placement has been a rarely used treatment modality in Swedish children less than 16 years old in the last 20 years. The failure rate in children treated because of tooth agenesis was only slightly higher than that reported for adult individuals, whereas in young children with ED and anodontia in the mandible, implants seemed to present special challenges, and the failure rate was very high. The small jaw size and peroperative conditions, rather than ED per se, were thought to be the main risk factors. Centralizing implant operations in young children with ED and monitoring outcomes in implant registers are strongly advocated. Keywords: children, dental implants, ectodermal dysplasia, failure, rare disorders

Purpose: Two noninvasive methods to measure dental implant stability are damping capacity assessment (Periotest) and resonance frequency analysis (Osstell). The objective of the present study was to assess the correlation of these 2 techniques in clinical use. Materials and Methods: Implant stability of 213 clinically stable loaded and unloaded 1-stage implants in 65 patients was measured in triplicate by means of resonance frequency analysis and Periotest. Descriptive statistics as well as Pearson's, Spearman's, and intraclass correlation coefficients were calculated with SPSS 11.0.2. Results: The mean values were 57.66 ± 8.19 implant stability quotient for the resonance frequency analysis and -5.08 ± 2.02 for the Periotest. The correlation of both measuring techniques was -0.64 (Pearson) and -0.65 (Spearman). The single-measure intraclass correlation coefficients for the ISQ and Periotest values were 0.99 and 0.88, respectively (95% CI). No significant correlation of implant length with either resonance frequency analysis or Periotest could be found. However, a significant correlation of implant diameter with both techniques was found (P .005). The correlation of both measuring systems is moderate to good. It seems that the Periotest is more susceptible to clinical measurement variables than the Osstell device. The intraclass correlation indicated lower measurement precision for the Periotest technique. Additionally, the Periotest values differed more from the normal (Gaussian) curve of distribution than the ISQs. Both measurement techniques show a significant correlation to the implant diameter. Conclusion: Resonance frequency analysis appeared to be the more precise technique. Keywords: damping capacity assessment, implant stability, osseointegration, resonance frequency analysis

Purpose: There is little information available about radiographic bone changes around immediately restored implants in periodontally compromised patients. The aims of this study were to evaluate the effect of immediate restoration on radiographic bone changes and to compare radiographic changes between arches and between healed and extraction sites in periodontally susceptible patients. Materials and Methods: Patients received periodontal treatment. "All in one" implant surgery was then performed: Hopeless teeth were extracted, debridement around remaining adjacent teeth was performed, implants were inserted guided by a surgical stent, and a prefabricated screwed provisional restoration was immediately delivered on selected implants. Periapical radiographs using a parallelism appliance were taken at implant surgery and 6 and 12 months postsurgery. The distance between the alveolar crest and the implant shoulder was measured at the mesial and distal aspect of each implant. Bone changes were compared between immediately restored, submerged, and nonrestored implants; between arches; and between healed and extraction sites. Results: Nineteen patients received 74 implants. Twelve implants in 4 patients failed within the first 6 months. Mean bone changes (± SE) between baseline and 12 months ranged between -1.19 ± 0.19 mm and -1.88 ± 0.3 mm. No difference was found between restored versus nonrestored sites or between maxillary and mandibular sites. Bone loss was slightly higher in healed sites. Conclusions: First-year bone changes around immediately restored dental implants in periodontally susceptible patients were slightly higher than most reports in the literature. This indicates a potential influence of periodontal disease on the success rate of dental implants. Keywords: bone loss, dental implants, immediate loading, periodontal disease

Purpose: The purpose of this study was to retrospectively evaluate the clinical results of the implant-retained auricular prosthesis. Materials and Methods: Data were collected from 46 patients who were treated between 1992 and 2004 with implant-retained auricular prostheses. A total of 156 implants and 1 plate (Epitec System) were placed in 46 patients, including 23 EO System implants, and 133 Brånemark implants. The implant survival rate was 100%. Twenty patients with 53 implants were re-examined to evaluate the peri-implant soft tissue status. Two clinical peri-implant parameters were applied, skin probing depth and sulcus fluid flow rate. Results: No adverse skin reactions were observed in 22 implants. Skin pockets were found in all of the 53 reexamined implants, which indicates the need for greater skin reduction. The mean skin probing depth and sulcus fluid flow rate were 2.1 ± 0.9 mm and 1.8 ± 1.3 mm, respectively, and a significant positive correlation was found between these 2 parameters. Conclusions: From these results, it can be concluded that the implant-retained auricular prosthesis promises long-term stability for patients with severe defects or total loss of the ear. Furthermore, sulcus fluid flow rate is a valuable parameter for the evaluation of peri-implant soft tissue. Keywords: auricular prostheses, extraoral implants, osseointegration, peri-implantitis

Purpose: The aim of this study was to obtain histometric measurements of bone and peri-implant mucosal tissue contact with implants of 2 sintered porous-surfaced designs. The "short-collar" design had a collar height (smooth coronal region) of 0.75 mm, while the "long-collar" model had a smooth coronal region of 1.8 mm. Materials and Methods: Implants (2 per side) were placed in healed mandibular extraction sites of 4 beagle dogs using a submerged technique. After 4 weeks of healing, they were uncovered and used to support fixed partial dentures for a 9-month period. After sacrifice, specimens were retrieved and nondemineralized sections were examined histometrically to determine the most coronal bone-to-implant contact (first BIC) using the microgap as a reference and standard mucosal parameters of "biologic width". Results: Significant (P = .001) differences in first BIC were found between designs (1.97 mm for long-collar versus 1.16 mm for short-collar implants) for posteriorly located implants but not for anteriorly located ones (1.21 mm versus 1.38 mm; P = .40). If crestal bone loss involved sintered surface, fibrous connective tissue ingrowth was observed to replace lost bone. No significant differences in peri-implant mucosal measurements (total peri-implant mucosal thickness; length of the epithelial component of this mucosa, and thickness of the connective tissue component) were detected between implant designs. Conclusions: Results suggest that "biologic width" accommodation drives initial crestal bone loss with sintered porous-surfaced implants. Histometric data obtained for bone contact showed no significant differences between the long- and short-collar implant designs. Keywords: biologic width, bone remodeling, collar height, sintered porous-surfaced dental implants

This report presents a clinical case in which distraction osteogenesis was used for the vertical repositioning of an implant already osseointegrated in the maxillary right central incisor area. An adhesive prosthesis was cemented over the neighboring teeth to accomplish this procedure. The prosthesis was made with a temporary cylinder directly over the implant to guide its repositioning. After incision and osteotomy, the area that contained the implant was fixed with an implant mount screw. After initial gingival healing (7 days), activation of the distraction was begun. The screw was activated with a full turn thrice a day, for a total of 1.0 mm per day for 7 consecutive days. Thereafter, the bone was allowed to heal for 3 months. Distraction osteogenesis led to a better implant-crown relationship, even after the osseointegration of the implant, thus improving the esthetic results. Keywords: distraction osteogenesis, osseointegrated implants, vertical osseous defects

Implant-based prosthetic restoration and oral rehabilitation is a very popular modality of treatment, with excellent success rates. Although a relatively safe procedure, implant insertion has its risks, which have been described in the literature. This article describes an as-yet unreported complication following implant insertion-salivary gland injury. The characteristics of salivary gland injury are examined, and 4 cases in which the salivary apparatus was injured or obstructed during 1 of the phases of implant therapy are presented. Keywords: implants, ranula, salivary gland injury, sialoendoscopy