RESUMO
AIM: The aim of this study was to evaluate the long-term clinical outcomes of zirconia-based prostheses used for tooth-supported or implant-supported single crowns and fixed dental prostheses (FPD). METHODS: The authors conducted a prospective analysis of 562 zirconia core restorations supported by endodontically treated teeth or titanium implant in 276 patients in a general dental private practice, with a follow-up period of 15 years. The study was stopped after patients achieved 15 yrs of follow-up. The study analyzed the failure and complication rates of single and multiple crowns, based on Kaplan Meier analysis. RESULTS: During follow-up period, there were 26 complications and 156 failures. The crown level analysis revealed a cumulative failure rate of 28.33% and complication rate of 8.47% for zirconia crowns after 15 years. The complication rate was found to be higher for titanium implant-supported than for natural teeth-supported crowns. The different types of crown-based failure include: veener fracture 5.01% (N = 29), metal zirconia led to 14.85% (N = 86) loss of retention, and 1.73% (N = 10) loss of crown due to extraction. CONCLUSION: Based on these findings, zirconia core restorations appear to be a reliable long-term solution for crowns and fixed dental prostheses. CLINICAL RELEVANCE: The study suggests that zirconia restorations can be successfully used for long-term prostheses on natural teeth or implants supported. The study results provide clinicians valuable information when selecting prosthetic restorations material.
RESUMO
OBJECTIVES: Zirconia-based prostheses are commonly used for aesthetic crown and fixed restorations, although follow-up data are limited, especially for implant-supported crowns. The aim of this study was to evaluate the threeyear clinical results of the installation of 463 zirconia core crowns by a general dental private practice. METHODS: This study followed 142 patients (69 men and 73 women; aged 28-82 years) who had received 248 single crowns (202 tooth-supported, 36 implant-supported) and 225 multiple units of up to six elements (81 toothsupported, 144 implant-supported). Clinical events, including fracture and loss of retention, secondary caries, and marginal integrity, were recorded. The overall failure rate was computed for the fractured and lost prostheses. Aesthetic, functional, and biological properties were rated, and patient satisfaction was investigated. RESULTS: During the three-year follow-up period, four patients were lost from the study (18 crowns, 4 percent of the total crowns). Three of the zirconia prostheses suffered fractures in more than three units (11 crowns; one- vs. three-year follow-up, p,0.05, Wilcoxon signed-rank test), and the cumulative prosthesis survival rate was 98.2 percent. Twelve units lost retention and were re-cemented, and no secondary caries of the abutment teeth were reported. The aesthetic, functional, and biological properties were generally well-rated, and there were no differences between tooth- and implant-supported crowns. The lowest scores were given regarding the anatomical form of the crowns, as some minor chipping was reported. Relatively low scores were also given for the periodontal response and the adjacent mucosa. Overall, patient satisfaction was high. CONCLUSIONS: At the three-year follow-up, the zirconia-core crowns appeared to be an effective clinical solution as they had favorable aesthetic and functional properties. Only the marginal fit of the prostheses should be improved upon.