The International Journal of Prosthodontics, 03/2011

Purpose: Clinicians often do not have the benefit of adequate safety or clinical data when evaluating the merit of either newly marketed implant devices or novel clinical procedures. This has been the case for dental implants following the initial documentation of their safety and efficacy and is demonstrated in the evolution of immediate load application. Following demonstration of safety and successful application of an implant in an animal study prior to its market release, this report provides the clinical outcomes for the first 100 Ti-Unite implants provided to 24 patients in a clinical practice over 9 years. Materials and Methods: An electronic record/clinical database review of consecutive early loaded implants from a multiple surgeon/single prosthodontist practice was conducted for quality assurance. Data extraction of standard exposure and outcome variables was accomplished by a trained individual not affiliated with the clinical practice. Results: The results revealed one failure before and none following definitive restoration with a variety of prostheses. The mean length of time from immediate to definitive restorations was 5.3 ± 1.1 months for crowns, 3.9 ± 1.3 months for fixed partial dentures, and 7.8 ± 4.1 months for mandibular "hybrid" prostheses. The most common unexpected findings during the initial three postinsertion visits were lost access restoration and cement failure. Conclusions: Pre-market animal data regarding the safety and success of a new implant used with an early loading protocol was replicated in the clinical results of the first 100 implants used in practice. Additionally, the clinical results are favorable when compared to conventional loading protocols from this same practice and provide helpful comparative metrics (delayed vs immediate loading) to use when discussing implant treatment with patients.

The aim of this randomized controlled trial was to evaluate the clinical performance of lithium disilicate fixed partial dentures (FPDs). Eighteen patients received lithium disilicate FPDs (study group), and 19 patients received porcelain-fused-to-metal FPDs (control). After 6 years, the survival probabilities were found to be 63% in the study group and 95% in the control group (log-rank test, P = .028). The data suggest that strict conditions should be considered before the use of lithium disilicate glass-ceramic for FPDs.

Purpose: The aim of this study was to review the published literature investigating the accuracy of fit of fixed implant frameworks fabricated using different materials and methods. Materials and Methods: A comprehensive electronic search was performed through PubMed (MEDLINE) using Boolean operators to combine key words. The search was limited to articles written in English and published through May 2010. In addition, a manual search through articles and reference lists retrieved from the electronic search and peer-reviewed journals was also conducted. Results: A total of 248 articles were retrieved, and 26 met the specified inclusion criteria for the review. The selected articles assessed the fit of fixed implant frameworks fabricated by different techniques. The investigated fabrication approaches were one-piece casting, sectioning and reconnection, spark erosion with an electric discharge machine, computer-aided design/computer-assisted manufacturing (CAD/CAM), and framework bonding to prefabricated abutment cylinders. Conclusions: Cast noble metal frameworks have a predictable fit, and additional fit refinement treatment is not indicated in well-controlled conditions. Base metal castings do not provide a satisfactory level of fit unless additional refinement treatment is performed, such as sectioning and laser welding or spark erosion. Spark erosion, framework bonding to prefabricated abutment cylinders, and CAD/CAM have the potential to provide implant frameworks with an excellent fit; CAD/CAM is the most consistent and least technique-sensitive of these methods.

Purpose: The aim of this literature review was to evaluate to what extent oral implant dentistry was integrated into undergraduate educational programs worldwide. Materials and Methods: An online search of PubMed (MEDLINE and additional life science journals) was performed for articles published from 1966 to January 2010 using combinations of select medical subject headings. Additionally, the ISI Web of Knowledge database (MEDLINE: 1950 to present, Web of Science: 1945 to present) was searched using "education" and "implant" as search terms. The online search was supplemented with a manual search of dental journals in the fields of education, prosthodontics, and implant dentistry and of the reference lists of selected full-text articles. Surveys comparing different undergraduate dental implant curricula and articles describing the undergraduate dental implant curriculum of a single university were identified. Postgraduate or continuing education programs for dental practitioners or master and specialist programs were excluded. Results: Twenty-five articles met the inclusion criteria of this review. The percentage of universities that included implant dentistry in undergraduate education increased from 51% in 1974 to 97% in 2006 for universities in the United States and to 100% for surveyed European universities. All curricula included lectures (mostly 1 to 20 hours) and 30% to 42% included laboratory courses, but the level of clinical experience differed greatly between surveyed universities. Conclusion: Because oral implant dentistry has become a standard treatment alternative, the undergraduate dental curricula should include its application in treatment planning, observation of placing and restoring implants, and treating patients with implant-retained or -supported restorations.

Inflammatory papillary hyperplasia of the palate (IPHP) is a tissue-reactive overgrowth characterized by hyperemic mucosa with nodular or papillary appearance in the palate. The exact pathogenesis is still unclear. In this study, the presence of Candida albicans in the epithelial lining was evaluated using the indirect immunofluorescence staining technique. Strongly stained C albicans was observed only in the lesions of the IPHP group. Therefore, the detection of C albicans in almost all samples from IPHP tissue enabled a suggestion as to the microbial etiology of the disease, since the use of dental prostheses was reported.

A survey demonstrated that angled abutments for external-hex implant platforms are difficult to place because of the handling of the components and screwdriver. The purpose of this study was to evaluate the performance of a device facilitating the placement of prefabricated angled abutments. This new instrument features improved ergonomics and is based on the design of a modified pickup impression coping. Forty experienced professionals tested two methods of placing angled abutments in a typodont on implants replacing a maxillary central incisor and a maxillary first molar. Using the new device, the abutments could be placed with a 43.9% reduction in time compared to the original manufacturer's instrument.

This study aimed to clarify the efficacy of a newly developed self-adjusting magnetic attachment (SMAT) that allowed 0.4 mm of vertical and 8 degrees of rotational movements using an in vitro model. Comparison between the SMAT and a conventional magnetic attachment (CMAT) was performed for the retentive force under different dislodgement directions. Lateral forces to the abutment were also compared among the SMAT, CMAT, dome-shaped magnetic attachment, and a ball attachment. The SMAT maintained retentive force more effectively than the CMAT, even in oblique directions of dislodgement. A smaller lateral force to the abutment was found for the SMAT compared to the CMAT or ball attachment.

Purpose: The aim of this study was to evaluate the mechanical properties of different attachment systems used for mandibular single-implant overdentures and to compare their wear/deformation features with clinical performance in patients after 1 year. Materials and Methods: Three attachment systems were evaluated: large 5.9-mm titanium nitride-coated ball attachments with plastic matrices, standard 2.25-mm uncoated titanium alloy ball attachments with Dalla Bona-type gold alloy matrices, and Locator attachments of titanium nitride-coated patrices and nylon matrices. The hardness and elastic modulus of the systems were determined using the nanoindentation technique. Twelve attachments from each system were used in 36 edentulous patients to support mandibular single-implant overdentures. After 1 year, 5 samples from each system were retrieved and evaluated for wear changes under a scanning electron microscope. Results: The titanium nitride-coated patrices, regardless of system, appeared unchanged and did not require any maintenance. Extensive wear was evident in the uncoated titanium alloy patrices and Dalla Bona-type gold alloy matrices, resulting in high maintenance (15 activations). Minimal wear was observed in the plastic matrices with minimal maintenance (2 replacements). The Locator nylon matrices showed extensive deformation and deterioration with a substantial need for maintenance (16 replacements). The performance of the patrices was related to hardness, while that of the matrices was related to the creep response. Conclusions: Large ball attachment systems of titanium nitride-coated patrices and plastic matrices reflect favorable wear behavior and clinical performance. These attachments are recommended for patients receiving mandibular single-implant overdentures.

Purpose: This retrospective cohort study investigated the clinical effectiveness of preformed oval-shaped glass fiber posts in combination with a dual-curing composite resin core material in endodontically treated premolars presenting an oval root canal cross-section and restored with all-ceramic crowns over up to 45 months. Materials and Methods: The study population comprised 134 patients and 154 endodontically treated premolars, with varying degrees of hard tissue loss, restored by means of oval-shaped fiber-reinforced posts. Inclusion criteria were premolars presenting an oval-shaped root canal, symptom-free endodontic therapy, root canal treatment with a minimum apical seal of 4 mm, application of rubber dam, and the need for a post and core complex because of coronal tooth loss. Four groups were defined based on the number of preserved coronal walls after endodontic treatment and before core buildup. Survival rate of the post and core restorations was determined using Kaplan-Meier analysis, and statistical analysis was performed using the log-rank test (P < .05). Results: The posts and cores were examined clinically and radiographically. The mean observation period was 42.3 ± 2.7 months. The overall survival rate was 95.45%. Comparisons revealed that the difference between premolars with no coronal wall retention and premolars that had maintained one to four coronal walls was statistically significant (P = .0006). On the contrary, comparison between premolars with one and two residual walls was found to be not significant for the overall survival rate (P = .0698). Conclusion: A satisfactory clinical performance was observed for preformed oval-shaped glass fiber posts. Survival was higher for teeth retaining three and four coronal walls.

If optical scanning is used for crown fabrication, variability in preparation depth may be a limitation. Therefore, this preliminary laboratory study evaluated marginal fit in relation to preparation depth. Three dies with different preparation depths between the vestibular and oral regions were fabricated. Ten zirconia copings were manufactured for each die, and marginal gaps were examined. Increasing differences in preparation depth influenced the size of the marginal gap between the vestibulo-oral and mesiodistal regions significantly (P < .001). This study shows primarily that differences in preparation depth resulted in decreasing marginal precision.

This study aimed to evaluate the fracture resistance of cement-retained metal-ceramic implant-supported posterior crowns. Three groups of 10 restorations each were tested: group A (cement-retained using zinc phosphate), group B (cement-retained using zinc oxide-eugenol), and group C (cement-retained using zinc phosphate but with an occlusal screw-access hole). All specimens were thermocycled and vertically loaded in a universal testing machine. Mean values of fracture loads were calculated and analyzed statistically. The cement-retained restorations without an occlusal screw-access hole showed significantly higher mean fracture loads than those having one. The type of cement did not affect the porcelain fracture resistance significantly.

The purpose of this study was to analyze and compare scanning electron microscopy (SEM) observations of ball attachments that had been worn by patients during three periods of clinical use. One hundred forty-four specimens of ball anchor attachments (gold alloy matrix and titanium patrix) were studied by SEM after periods of approximately 1, 3.5, and 8 years of clinical use. Twenty new attachment components were examined as controls. SEM images revealed signs of mechanical wear for the ball attachments studied. The surfaces of the titanium patrix were associated primarily with roughening after short-term use, whereas surfaces of the gold alloy matrix showed wear, roughening, and loss of microscopic material in the form of flakes. Severe mechanical wear on both surfaces was noted after longer periods of use. The mechanical changes were not correlated with patientmediated observations regarding the time-dependent retentive efficacy of the attachments. One year of clinical wear appeared to have limited effect on the ball attachment tested. Conversely, longer periods of use led to marked modifications in shape of the matrix and patrix components.

The purpose of this study was to test intraorally the effect of a cobalt-chromium cast reinforcement embedded in the denture base of a maxillary complete denture on the distribution of stress. Eight subjects were selected randomly, and three designs of a cobalt-chromium alloy bar were embedded in the dentures. A strain gauge was attached at three positions around the midline of the polished surface of each denture. Strain in the reinforced dentures was significantly less than strain in dentures without reinforcement. These observations suggest that a cast cobaltchromium reinforcement reduces strain and could contribute to fracture avoidance deformation in maxillary complete dentures.