Practice-Based Study on CAD/CAM Inlays, Onlays, and Crowns: Longevity and Risks

This prospective, multicenter, practice-based cohort study aimed to analyze factors associated with the success of all-ceramic inlays, onlays, and crowns. All-ceramic indirect restorations placed in a practice-based research network (Ceramic Success Analysis) were analyzed. Data were evaluated from 12,468 patients with restorations manufactured by CAD/CAM (computer-aided design/computer-aided manufacturing) and placed between 1994 and 2023 by 303 dentists. Restorations with at least 1 follow-up visit were included (n = 17,725). Additionally, restorations were followed for ≥5 y, and all failures were included (n = 4,635). At the last follow-up visit, crown restorations were classified as successful if no intervention was required (e.g., no renewal, repair, or recementation). Failure included lost restorations and those needing any reintervention. Multilevel Cox proportional hazards models were used to evaluate the association between a range of predictors and time of success or survival. Within a mean (SD) follow-up of 3.3 y (3.5; all-years scenario) and 8.6 y (3.7; 5-y scenario; maximum, 25 y), 940 restorations failed (annual failure rate: 5 y, 2.7%). The main failure types were fracture of the ceramic (n = 151), endodontic complications (n = 87), and fracture of the tooth (n = 77). In both scenarios, endodontic treatment (hazard ratio [95% CI]: 5 y, 1.6 [1.4 to 1.9]), a positive papilla bleeding index (1.2 [1.1 to 1.4]), and use of an EVA instrument (1.8 [1.4 to 2.0]) significantly increased the failure rate as compared with nonpresence/nonuse (P ≤ 0.043). Furthermore, ZrO₂ (0.6 [0.4 to 0.9]) significantly increased the time until any failure (P = 0.027). For CAD/CAM-manufactured all-ceramic restorations, high success rates could be found up to 25 y. Furthermore, after 8 y, tooth-, technique-, and material-level factors were significantly associated with failure (German Clinical Trials Register DRKS00020271).