All‐ceramic single crowns supported by zirconia implants: 5‐year results of a prospective multicenter study

Abstract Objectives To assess survival/success rates and patient‐reported outcome of zirconia‐based posterior single crowns (SCs) supported by zirconia implants in a prospective two‐center study after five years of observation. Material and methods Forty‐five patients were restored with 45 zirconia implant‐supported posterior SCs composed of zirconia frameworks hand‐layered with a leucite‐reinforced feldspathic ceramic. Survival rates of SCs were assessed and technical success was evaluated according to modified United States Public Health Care (USPHS) criteria. Furthermore, patient‐reported outcome measures (PROMs) were assessed by applying visual analog scales (VAS). Wilcoxon matched‐pairs signed‐rank test, mixed‐effects ordered logistic regression, and linear mixed models were used to evaluate time effects on response variables. Results Forty patients were available after a mean observation period of 61.0 ± 1.4 months. One SC had to be replaced, resulting in a Kaplan–Meier (KM) survival estimate for the SCs of 97.5 ± 2.47%. Since nine reconstructions showed at least in one category a major deviation from the ideal (five major chippings, four with increased occlusal roughness, one significant crevice, and one pronounced over‐contouring), the KM success estimate was 79.3 ± 5.8%. Incidence of chipping ( n = 19) and occlusal roughness ( n = 35) was frequent ( p < 0.001). All PROMs at prosthetic delivery except for speech ( p = 0.139) showed significantly improved VAS scores (81%–94%; p < 0.001) compared to pre‐treatment evaluations. Thereafter, no decrease in satisfaction could be observed until the 5‐year follow‐up (93%–97%). Conclusion Veneered zirconia‐based SCs supported by zirconia implants showed high survival rates and highly satisfied patients' needs. However, significant incidence of technical complications is compromising the clinical long‐term outcome for this indication.