Distribuição de tensões em lesões cervicais não cariosas em função da geometria da lesão, da altura do suporte ósseo e das cargas oclusais

Abstract

A better understanding of non-carious cervical lesions (NCCLs) dynamics pose significant implications on clinical conducts and terapeutic interventions for these lesions. In this aspect, the use of computational methods contributes to the analysis of stresses generated in the cervical area, determining possible consequences of the presence of a lesion to dental structures. The purpose of this work was to investigate, by means of finite element analisys, the stresses magnitude and distribution in maxillary premolars with different NCCLs and different alveolar support heights when subjected to functional and non-functional loadings. From a geometric model of a sound maxillary second premolar and its supporting bone, cervical defects were carved to generate models with either U- or V-shaped lesions with three different depths: U1 and V1 (0.5 mm), U2 and V2 (1.0 mm), U3 and V3 (1.5 mm). For each type of lesion geometry and depth, the alveolar bone crest height was set to 3.0mm (B3), 4.0mm (B4) or 5.0mm (B5) of distance from the cement-enamel junction. The models were subjected to a 105N load applied either parallel (F1) or 450 obliquely (F2 and F3) in relation to the long axis. Stress amplification was observed with the presence of a lesion,being more evident in V-shaped and deeper lesions. The periodontal support height variation did not significantly alter the stress distribution in the cervical area, though a stress amplification was observed at the medium-apical third of the root with the reduction of alveolar support when subjected to oblique loadings. All models presented better stress distribution when subjected to F1 loading. The results suggest that stress amplification is generated by increasing depth and decreasing the radius of curvature of NCCLs. Still, the direction of occlusal loadings has greater influence on the stress distribution in the cervical area when compared to structural factors.