Clinical marginal and internal gaps of zirconia all-ceramic crowns.

PURPOSE: Marginal and internal gaps of NobelProcera crown zirconia were clinically evaluated using silicone materials. MATERIALS AND METHODS: Ninety-one crowns were examined before final cementation, and white and black silicone materials were used to record the marginal and internal fit. The silicone materials were sectioned bucco-lingually and mesio-distally, and the thickness of the silicone layers was measured using a microscope. Sixteen reference points were measured on each specimen, and mean marginal and internal gaps were obtained. Mean marginal gaps among anterior, premolar, and molar tooth groups, in addition to mean gaps at the reference points within the groups, were compared using two-way ANOVA and Games-Howell analysis. RESULTS: The marginal mean values were the smallest among all tooth groups, and the largest were at the rounded shoulders. There were no significant differences in the mean marginal gaps among the three tooth groups, while there were significant differences in the mean marginal and internal gaps of each tooth group. CONCLUSIONS: The mean marginal gap of the NobelProcera crown zirconia was 44.2 µm, which is within clinically accepted standards.

Clinical evaluation of posterior all-ceramic FPDs (Cercon): a prospective clinical pilot study.

PURPOSE: This study prospectively evaluated the clinical performance of posterior zirconium-oxide-based all-ceramic fixed partial dentures (FPDs). METHODS: Forty-two abutments of 21 Cercon FPDs were fitted in 20 patients at the Tsurumi University Dental Hospital from August 2005 to August 2006. The performance of these FPDs was evaluated using the California Dental Association (CDA) quality assessment system at baseline and at all follow-up examinations. RESULTS: All FPDs were examined after a mean observation period of 28.1 (+/-3.4) months. During the observation period, no fracturing of FPDs was seen. All of the FPDs examined were rated as satisfactory with regard to all factors at the follow-up examinations based on the CDA quality assessment criteria. CONCLUSION: Within the limitations of this short-term clinical study, no core framework fractures were seen. According to the CDA criteria, 100% of the FPDs were rated as satisfactory during this observation period.