The effect of the material used and the pulp chamber extension depth on stress distributions of endocrowns: A 3D finite element analysis

Purpose: The aim of this study was to examine the effects of materials used and length of extension into the pulp chamber on stress distribution in mandibular molar endodontic treated teeth with endocrown restoration using a 3D finite element analysis (FEA). Material and Methods: Three-dimensional finite element analysis models were obtained at 2 different pulpal extension depths by taking a tomography of a canal-treated mandibular molar tooth extracted for periodontal reasons: 2.5 mm (Model A), 3.5 mm (Model B). Models are divided into 3 groups according to material type: Vita Enamic (VE), Lava Ultimate (LU), IPS e.max CAD (EMX). There are also 2 different subgroups for the cement types used: NX3, and MaxCem Elite Chroma (MX) Maximum principal stress (MPa) values under 600 N vertical loads were investigated to evaluate the effect of restoration design, material type and cements used on stress distribution. Result: The maximum stress on the restoration was observed in the EMX material type (13,000 MPa) in the MX cement group in Model A, while the lowest was observed in the LU material (5,932 MPa) in the NX3 cement group in Model A. The highest stress areas for model A and model B were observed in the restoration areas corresponding to the enamel margins. Conclusions: Materials with higher elastic modulus show a high-stress area on the restoration surface, while the stress values they transmit are lower. Materials, where the elastic modulus is close to dentin have more homogeneous stress distributions within the restoration.