This study utilized the PRISMA 2020 framework alongside the Newcastle-Ottawa Scale (NOS) assessment tool during the screening process to conduct a systematic review of the fracture rates of zirconia (ZrO2) ceramic crowns in clinical practice. The primary objective was to investigate the factors influencing to the failure of zirconia ceramic crowns. The literature search employed targeted keywords including veneered fixed dental prostheses, zirconia, and all-ceramic single crowns. Inclusion criteria encompassed randomized controlled trials (RCTs) and cohort studies with a minimum follow-up duration of three years and at least 20 cases. Non-clinical reports and those exclusively addressing long-span fixed dental prostheses were excluded from the analysis. Of the eleven high-quality reports selected, only three reported crown fracture rates consistent with the clinically recommended threshold of 4.4%. To mitigate fractures in ZrO2 ceramic crowns used in dental restorations, precision is essential in both research and clinical practice. Multiple factors influence fracture incidence in fixed dental prostheses, including ceramic material thickness, connector dimensions, pontic span, type of cementation, and ceramic surface treatment. Preventative strategies focus on reducing occlusal overload by narrowing the occlusal table, decreasing cusp inclination, modifying load direction, minimizing non-axial forces, and selecting lighter occlusal contacts. Additionally, the integration of screw access channels and mechanical circulation in implant-supported prostheses may lower average fracture loads. Lastly, ensuring the precise alignment of the screw access channel at the center of the occlusal surface is critical to avoid off-center occlusal contacts during subsequent evaluations and measurements.
Chang et al. (Tue,) studied this question.