Outcome of zirconia partial fixed dental prostheses made by predoctoral dental students: A clinical retrospective study after 3 to 7 years of clinical service.

STATEMENT OF PROBLEM: Zirconia has an established role in fixed prosthodontics, especially for single crowns. Whether it is durable enough for fixed dental prostheses (FDPs) in the long term is yet unclear. PURPOSE: The purpose of this retrospective study was to evaluate the outcome of FDPs made by predoctoral students after 3 to 7 years of clinical service. MATERIAL AND METHODS: A total of 102 patients received 120 zirconia FDPs (range, 3-12 units; mean, 4.5 units) between 2007 and 2010. Materials used were Zirkonzahn Zirconia (Zirkonzahn), NobelProcera Zirconia (Nobel Biocare), and Prettau Zirconia (Zirkonzahn). Veneering porcelain was hand-layered on Zirkonzahn Zirconia (GC Initial Zr; GC Europe) and Nobel Procera Zirconia (VITA VM 9; VITA Zahnfabrik). Prettau Zirconia was monolithic and had no veneering porcelain. Success and survival rates were calculated using Kaplan-Meier survival analysis. Ethics approval was obtained from the Ethical Committee of the Northern Ostrobothnia Hospital District (100/2013). RESULTS: The 76 participants examined (75%) had received 88 zirconia FDPs. The mean follow-up period was 4.9 years (range, 3-7 years). The most common complication was chipping of the veneering porcelain in 13 of 88 FDPs (14.7%). The success rate of the zirconia-based partial FDPs after 4.9 years was 89%, and the survival rate was 100%. CONCLUSIONS: The success rate of the zirconia-based partial FDPs after 4.9 years was 89%, and the survival rate was 100%.

Veneered zirconia crowns as abutment teeth for partial removable dental prostheses: a clinical 4-year retrospective study.

STATEMENT OF PROBLEM: The mechanical properties of zirconia suggest that it might serve as a material for abutment crowns for partial removable dental prostheses (RDPs). Only limited clinical evidence is available for the use of ceramics as abutment crowns. PURPOSE: The purpose of this retrospective clinical study was to evaluate the outcome of veneered zirconia single crowns in abutment teeth for RPDs in participants treated by predoctoral students. MATERIAL AND METHODS: Thirty-seven veneered zirconia single crowns in 17 participants (9 men and 8 women; mean age 62.5 years) were prepared as abutment teeth for a clasp-retained RDP with a metal framework: 22 crowns with an occlusal rest seat and 15 crowns with both an occlusal rest seat and retentive clasps. The mean follow-up time was 4.2 years (2.9 to 5.4 years). In a clinical examination, the anatomic form of the crown, marginal fidelity (the border between the crown and the tooth was felt with an explorer), wear of the ceramic surface in the rest seat, and fracture of the veneering porcelain were examined and assessed as good, acceptable, or unacceptable. The retention and stability of the RDPs were recorded as good, moderate, or poor. RESULTS: The complications found were fracture of the veneering porcelain (11%) and fracture of the occlusal rest seat (3%). Wear of porcelain at the occlusal contact point was found in 24% of the zirconia single crowns. Wear of the ceramic surfaces of the rest seats for the RDPs was not found. The retention was good in all RDPs. The stability was good in 73% and moderate in 23% of the RDPs. CONCLUSIONS: Veneered zirconia single crowns are suitable in abutment teeth for RDPs with a metal framework. Fracture in the veneering porcelain remains a problem with veneered zirconia, although the zirconia surface in the rest seats for RDPs showed no wear.

Outcome of zirconia single crowns made by predoctoral dental students: a clinical retrospective study after 2 to 6 years of clinical service.

STATEMENT OF PROBLEM: Zirconia has established its role as a reliable ceramic material for fixed prostheses. PURPOSE: The purpose of this retrospective study was to evaluate the outcome of zirconia single crowns made by predoctoral students after 2 to 6 years of clinical service. MATERIAL AND METHODS: A cohort of 88 patients treated with zirconia single crowns (mean 3 crowns per patient, range 1 to 12 crowns) from 2007 to 2010 by predoctoral dental students was identified. The patients were invited to attend a clinical examination. RESULTS: Sixty-six participants (75%) took part in the clinical follow-up (30 women and 36 men; mean age 60.4 years, range 19 to 81 years). Altogether, 190 teeth with single crowns were examined, and the mean follow-up time was 3.88 years (1.85 to 6.04 years). The most common complications were chipping of veneering porcelain (4%) and loss of cementation (4%). The success rate of the zirconia single crowns after 2 to 6 years was 80% and the survival rate 89%. CONCLUSIONS: Zirconia crowns can be successfully used in predoctoral dental education. The success rate of zirconia single crowns after 2 to 6 years was 80% and the survival rate was 89%, in accordance with previous studies.

Early complications and short-term failures of zirconia single crowns and partial fixed dental prostheses.

STATEMENT OF PROBLEM: Ceramic single crowns fabricated from newer materials, especially zirconia, have shown relatively high survival rates. However, early reversible complications may increase the risk of an irreversible failure later. PURPOSE: The purpose of the study was to evaluate the early complications and short-term failures of zirconia single crowns and partial fixed dental prostheses (FDPs) made by predoctoral dental students. MATERIAL AND METHODS: Data were collected from the patient records. Altogether, 264 zirconia single crowns and 120 FDPs (342 abutments and 190 pontics) were fabricated for 173 patients between 2007 and 2010. Early complications were recorded during the prosthetic treatment phase, and short-term failures were recorded during the first year in use. RESULTS: The most frequent early complications were localized gingival irritation (1.9% of single crowns and 2.5% of FDP) and postoperative tooth sensitivity (0.4% of single crowns and 3.3% of FDPs). Pulp exposure during preparation was recorded in 3 abutment teeth of the FDPs. The most frequent short-term failure was chipping of the veneering porcelain (0.8% for single crowns, 0.8% for FDPs). One crown lost cementation because of poor retention (0.4%), and 2 FDPs failed because of framework fractures (1.7%). CONCLUSIONS: The most frequent early complications were localized gingival irritation and postoperative tooth sensitivity, and the most frequent short-term failure was chipping of the veneering porcelain.