This project consists of a scoping review designed to map and synthesize the available evidence regarding the influence of restoration thickness on the fracture resistance of conventional indirect composite resin restorations used in posterior teeth with structural loss. Tooth structure loss caused by erosive wear, biocorrosion, bruxism, and other non-carious conditions is increasingly prevalent and often requires conservative restorative management. Indirect composite resin restorations have become an important treatment option because they preserve tooth structure, provide favorable esthetics, and may offer adequate mechanical performance. However, despite their growing clinical use, limited evidence is available regarding the minimum thickness required for these restorations to withstand functional loading and maintain structural integrity over time. The purpose of this review is to systematically identify, organize, and summarize published studies that evaluate the relationship between restoration thickness and fracture resistance of conventional indirect composite resin restorations. Secondary aims include documenting methodological characteristics of the available studies, restorative designs evaluated (such as inlays and onlays), materials and cementation protocols used, aging procedures, loading methods, and reported failure modes. This review follows the methodological framework for scoping reviews and is conducted in accordance with the PRISMA-ScR reporting guidelines. Searches are performed in major electronic databases, including PubMed, Web of Science, and Scopus, with supplementary manual searches in Google Scholar. Eligible studies include laboratory and clinical investigations involving adult posterior teeth restored with conventional indirect composite resin restorations. Expected outcomes include: (1) identification of the current extent of evidence on restoration thickness and fracture resistance; (2) recognition of methodological trends and inconsistencies across studies; (3) clarification of whether greater restoration thickness or cusp coverage is associated with improved fracture resistance; and (4) identification of important gaps requiring future research, particularly standardized laboratory protocols and prospective clinical studies. The findings of this project are expected to support evidence-based clinical decision-making and guide future investigations on minimally invasive rehabilitation of structurally compromised posterior teeth.
Martins et al. (Thu,) studied this question.