Clinical evaluation of tooth-supported zirconia-based fixed dental prostheses: A retrospective cohort study from the AIOP clinical research group

Purpose: The aim of this retrospective cohort study was to evaluate the clinical performance of tooth-supported zirconia-based fixed dental prostheses (FDPs) made by 15 members of the Italian Academy of Prosthetic Dentistry over a time period of up to 5 years. Materials and Methods: Ninety-eight patients were treated with a total of 137 zirconia-based FDPs in anterior and posterior regions using primarily chamfer or knife-edge tooth preparations. The cohort group with parafunctional habits was compared with patients without parafunctional habits according to the esthetic, functional, and biologic United States Public Health Service criteria modified by the FDI World Dental Federation. Results: The estimated cumulative survival of all restorations was 94.70% \ub1 1.25% standard error (SE), whereas the estimated cumulative success decreased to 89.78% \ub1 2.58 SE. Mechanical failures, including three zirconia framework fractures, two hairline cracks, nine chippings, and one delamination of the ceramic veneering, were recorded during the 1-to 5-year observation period. An odds ratio of 2.02 (95% confidence interval: 0.67 to 6.12) showed a moderate association between parafunction and failure. Conclusions: Zirconia-based tooth-supported FDPs showed promising clinical results over a period of up to 5 years. Technical complications were more commonly detected in patients with parafunctional habits

Clinical evaluation of zirconia-based restorations on implants: A retrospective cohort study from the AIOP clinical research group

Purpose: The aim of this retrospective cohort study was to evaluate the clinical performance of zirconia-based implant-supported single crowns and fixed dental prostheses (FDPs) made by 15 members of the Italian Academy of Prosthetic Dentistry (AIOP) over a time period of up to 5 years. Materials and Methods: One hundred thirtyone patients were treated with a total of 210 zirconia-based single crowns and FDPs on implants in anterior and posterior regions. A cohort group with parafunctional habits was compared with patients without parafunctional habits according to the esthetic, functional, and biologic United States Public Health Service criteria modified by the FDI World Dental Federation. Results: The estimated cumulative survival (ECS) and standard error (SE) of all restorations on implants was 91.95% \ub1 1.39%, and the estimated cumulative success (ECSs) and SE was 88.37% \ub1 1.72%. The ECS of single crowns and FDPs was 91.25% \ub1 3.69% and 95.23% \ub1 2.28%, respectively, and the estimated cumulative success rates were 88.84% \ub1 2.05% and 87.96% \ub1 3.16%, respectively. Mechanical failures, including four zirconia core fractures, three hairline cracks, four chippings, and five delaminations of the ceramic veneering material, were recorded during a 1-to 5-year observation period. The odds ratio of 3.39 (95% confidence interval: 1.18 to 9.73) showed a moderate association between parafunction and failure. Conclusions: Zirconiabased implant-supported restorations showed encouraging clinical results over a period of up to 5 years, but more clinical data are needed before these restorations can be considered a viable treatment alternative. Mechanical failures were primarily observed in patients with parafunctions

Internal- vs external-connection single implants: A retrospective study in an italian population treated by certified prosthodontists

Purpose: The design of an implant connection that allows prosthetic suprastructures to be attached to implants has long been debated in the dental literature. The goal of this retrospective study was to evaluate the 5-year clinical results for a large number of single implants restored by certified prosthodontists in an attempt to establish whether different clinical outcomes could be detected for external- or internalconnection implants. Materials and Methods: All single implants with internal or external connections inserted in 27 private dental practices from January 1, 2003 to December 31, 2007 were evaluated. An initial statistical analysis was performed to describe the sample population at baseline and then to compare the two types of implant-abutment connection configurations and their clinical outcomes. All data were statistically analyzed with STATA12 (StataCorp). Results: Twenty-eight of the 85 active members of the Italian Academy of Prosthetic Dentistry (AIOP) participated in this study. The sample included 1,159 patients and 2,010 implants. Of the implants, 75 were dropped because there was no information about follow-up. Of the remaining implants, 1,431 (74.0%) were followed for at least 5 years, and 332 implants (17.2%) were followed for more than 8 years. Nearly 99% (98.9%) of the implants survived. The difference between the survival frequencies of the two types of implant-abutment connection configurations was not significant for each negative event (log-rank test, P > .05). There was no difference between the two types of implants regarding restoration fracture, implant screw loosening, and peri-implant disease. Conclusion: Within the limitations of this study, it can be suggested that there is no difference in clinical outcomes of single restorations joined to internal- or external-connection implants