Method: A 3D FEA model of maxillary premolar single root and birradicular was developed using commercial FEA software. Point loads of 100N were apllied axial and 45° from the vertical on the palatine of the buccal cusp from de models: sound and abfraction lesion with 1,25 and 2,5mm depth. Patterns of strain observed in the FEA model were confirmed in the laboratory using strain gages on extracted premolars mounted in a testing machine.
Result: Birradiculares sound teeth, with lesion of 1,25 mm and 2,5 mm associated with oblique loading showed respectively the highest values of deformation between samples, 692,6 µS, 1043,31 µS and 1236,14 µS. In sequence, single-rooted sound teeth, with lesion of 1,25 mm and 2,5 mm associated with oblique loading showed the respective values of deformation 467,10 µS, 401,51 µS and 420,98 µS. Axial loading showed lower rates of deformation, ranging from 136.12 to 366.91 µS.
Conclusion: The birradiculares teeth with cervical furcation, greater lesion depths and oblique loading and the association of these factors promoted a larger strain concentrate in the tooth structure.