Biomechanical behavior of endocrowns in primary molars at different root resorption stages: A 3D finite element analysis

Abstract

This study investigated stress distribution in endocrown-restored primary molars during physiological root resorption using three-dimensional finite element analysis. Mandibular first primary molars were modeled at three resorption stages: no resorption, one-third resorption, and one-half resorption. Each model was restored with resin nanoceramic or lithium disilicate endocrowns. Vertical and oblique loads were applied. Von Mises stress and maximum principal stress were analyzed in the endocrown, adhesive layer, and residual tooth structure. The stress distribution was influenced by the material, loading direction, and degree of resorption. Lithium disilicate showed higher stress values. Oblique loading produced higher peak stresses than vertical loading did. With increasing root resorption, stresses gradually decreased and intergroup differences narrowed. Resin nanoceramic endocrowns showed more favorable biomechanical behavior. Physiological root resorption may reduce stress concentrations in endocrown-restored primary molars.