A 3-year follow-up study of all-ceramic single and multiple crowns performed in a private practice: a prospective case series

Abstract

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 three-year 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 tooth-supported, 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% 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%. 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.

Three- to nine-year survival estimates and fracture mechanisms of zirconia- and alumina-based restorations using standardized criteria to distinguish the severity of ceramic fractures

“…In the present study, no core fractures were observed on SC restorations. These results are in agreement with previous studies that included alumina-based [35] and zirconia-based [14,16,17] single crowns. Still, fractures of alumina cores for single-unit restorations have been reported in a number of other clinical studies [1,9,10,36,37].…”

“…Clinical data on zirconia-based SCs are scarce. In short-term studies, failure rates ranged from 0 to 11.2 % at 2-5 years [12][13][14][15][16][17]. However, the rates of "biological" and "other complications" were not specified relative to "fractures of the ceramic" [13,17].…”

Primary Zirconia Crown Restorations for Children with Early Childhood Caries

“…Its mechanical properties, which are similar to those of stainless steel, allow for a substantial reduction in core thickness. Cyclical stresses are also well tolerated by this extremely biocompatible material (8,11,12,13).…”

“…Zbog svojstava sličnih nehrđajućem čeliku znatno se može smanjiti debljina materijala za jezgru. Taj izrazito biokompatibilni materijal dobro podnosi klinička naprezanja (8,11,12,13). Na tržištu se mogu nabaviti gotove krunice od cirkonija za restauraciju mliječnih inciziva i one se neposredno adhezivno cementiraju na zubna tkiva.…”

“…Indeed, most published studies have been laboratory-controlled investigations, and the majority of these clinical evaluations have reported data on small numbers of patients (12).…”