Influência da abfração, morfologia radicular e carregamento no comportamento biomecânico de pré-molares superiores

Abstract

The aim of this study was to investigate the biomechanical behavior of maxillary premolar teeth regarding root morphology and depth of non-carious cervical lesion - abfraction, submitted to axial and oblique occlusal load. Threedimensional finite element analysis (3D FEA) and strain gauge test was used in extracted maxillary premolars. Single and birradicular roots premolar teeth 3D FEA models were developed using commercial FEA software. For 3D model generation was selected sound maxillary premolar. The tooth was chosen mapped with contact 3D scanner (Model, Roland). The enamel was degraded with hydrochloric acid-10% to perform the coronal dentin scan. Files with extension *. STL (steriolitográficos) were exported to Bio-CAD software (Rhinoceros-3D). Each tooth structure volumes were generated through the association of complex non-regular surfaces (NURBS). The models were exported to the finite element software (Femap, NoranEngineering, USA). Meshing, mechanical properties insertion and boundary conditions were performed in this software. The models generated were: sound, 1,25 mm and 2,5 mm abfraction teeth. A compressive static load of 100 N was applied: axially and 45° angle to the long axis on the palatine surface of the buccal cusp. Two strain gauge were bonded in teeth and these specimens were mounted in a mechanical testing machine. Birradicular sound, 1,25 mm and 2,5 mm abfraction teeth associated with oblique loading showed respectively the highest strain values among samples, 692,6 μS, 1043,31 μS and 1236,14 μS. Single root sound, 1,25 mm and 2,5 mm abfraction teeth associated with oblique loading showed the respective strain values 467,10 μS, 401,51 μS and 420,98 μS. Axial loading showed lower strain rates, ranging from 136.12 to 366.91 μS. The birradicular teeth with cervical furcation, greater lesion depths and oblique loading and the association of these factors promoted a higher stress concentrate in the tooth structure.