The fracture of restorations used for diastema closure is a clinical concern. The objective of this study was to perform a finite element-based comparative analysis of functional stress patterns in composite resin veneer restorations used for diastema closure to determine the influence of factors such as the preparation design, proximal extension, loading level, and vector of stress (loading angle). Three-dimensional finite element stress analysis was performed on a maxillary central incisor model to examine the stress distribution resulting from a nanofilled composite veneer restoration with 4 different extensions of unsupported composite (0.5, 1.0, 1.5, or 2.0 mm) and 2 different preparation designs (partial or full) under 3 loads (50, 150, or 250 N) and 3 loading angles (60°, 90°, or 125°). The maximum stress was found to be concentrated on the full-preparation design with a 0.5-mm mesial extension under a 250-N load and 60° loading angle. The minimum stress was found with the partial-preparation design with a 0.5-mm mesial extension under a 50-N load and 90° loading angle. Based on the results of the present study, a partial-preparation design is preferred when nanofilled composite resins are used for diastema closure.
Keywords: diastema closure; finite element analysis; nanofilled composite resin; stress analysis.