Evaluating the Influence of Ferrule Preparation on Zirconia Endocrown Efficacy in Primary Molars: A 3D Finite Element Analysis

This article assesses the effect of different ferrule preparations on the stress distribution in the primary second molar restored with zirconia crown.Four finite element models were created to simulate different ferrule heights: M1 (0 mm), M2 (1 mm), M3 (1.5 mm), and M4 (2 mm). A lower primary second molar was scanned to create a solid model, which was imported into finite element analysis software. Simulations included varying ferrule heights, material properties, and meshing. Models were subjected to 330 N occlusal loads at vertical, oblique, and lateral angles.The analysis revealed that stress within the endocrown body increased with greater ferrule height under vertical loading. Conversely, stress levels decreased with increased ferrule height under oblique and lateral loads. Under vertical load, peak stresses were recorded as follows: endocrown body (219.5 MPa for M1), cement layer (11.7 MPa for M1 and M4), remaining tooth (36 MPa for M1), cortical bone (59.7 MPa for M1), and cancellous bone (8.7 MPa for M1 and M4). Under oblique load, stress values increased as follows: cement layer (62.9 MPa for M4), remaining tooth (59 MPa for M1), and endocrown body (203 MPa for M1). Under lateral load, stress values increased as follows: endocrown body (321 MPa for M1), cement layer (100 MPa for M4), remaining tooth (94 MPa for M1), cortical bone (154 MPa for M1), and cancellous bone (15 MPa for M1).Ferrule height significantly influences stress distribution in the tooth structure and supporting bone. Higher ferrule heights enhance structural stability by reducing stress on underlying components.