The influence of dental cavity on biomechanical stress and strain distribution: A finite element analysis

Understanding tooth biomechanics is essential for creating effective and durable dental restorations. While intact teeth are inherently resilient, cavity preparation compromises structural integrity, increasing fracture risk.

This study utilized finite element analysis (FEA), the dominant in silico method for biomechanical investigation, to evaluate how cavity size influences stress and strain distribution in a three-dimensional mandibular molar model derived from micro-computed tomography.

An FEA simulation was conducted on three tooth models (intact tooth, conservative cavity, and extensive cavity) under a 565 N occlusal load. Given the nonnormally distributed data, nonparametric statistical analysis (Kruskal-Wallis and Mann-Whitney tests) was performed.

The analysis revealed a direct, significant correlation between cavity size and maximum stress magnitude. The intact tooth exhibited the lowest maximum stress (96.18 MPa), which significantly increased to 165.72 MPa (conservative) and 185.32 MPa (extensive). Conversely, the maximum strain capacity was highest in the intact tooth (0.007503) and decreased in prepared teeth (0.006031 for conservative and 0.006217 for extensive), suggesting cavity preparation amplifies localized stress while reducing the tooth's overall flexibility.

The findings confirm that cavity size is the most crucial determinant of structural risk. A conservative approach mechanically preserves tooth function. Furthermore, the lingual cusp and the cervical area were identified as the primary mechanical weak points under functional load.