Finite Element Analysis Of The Adhesive Interface In Cervical Lesion

Objective: To analyze the influence of type of restorative material on the distribution of tensile stress in the adhesive interface on cervical lesions in lower pre-molars by Finite Element Analysis (FEA).

Method: Two 2D FEA models of a mandibular premolar were created, using MSC.Patran and MSC.MarcMentat. The tooth design included enamel, dentine, pulp, adhesive interface and restoration of cervical lesion. One model simulated a restorative material with lower elastic modulus (E= 5.300Mpa) and the other with a traditional elastic modulus value (E = 16.600 MPa). The materials were considered elastic, isotropic, linear, and homogeneous. An oblique load (100N) was applied in 3 nodes of the buccal cuspide. The nodes above 5mm of the restoration cervical region were constrained in all degrees of freedom. The maximum principal stress (σ₁) distribution were analyzed.

Result: Considering the interfaces between dentin-adhesive and adhesive-composite, the model of composite resin simulating traditional E showed lower values of σ₁ (8.17 MPa – adhesive-dentin; 7.6 MPa – adhesive-composite) compared with model with lower E, however showed higher values of tensile stress along both interfaces (Figures 1 and 2). While the model with lower E showed higher values of σ₁ (9.8 MPa – adhesive-dentin; 7.3 MPa – adhesive-composite) however less concentration of tensile stress along the interfaces, demonstrated on Figure 1and 2.

Conclusion: The adhesive interface is responsible for the longevity of adhesive restorations, thus the choice of composite resin with a low modulus of elasticity for restoration on cervical lesions appears to be more consistent.