Influência do número de implantes, tipos de conexão e condições de carga, no ambiente biomecânico de reabilitações totais mandibulares

Abstract

The aim of this study to evaluate the influence of different implant numbers, connection types and loading conditions on the biomechanical behavior of mandibular full-arch implant-supported rehabilitation in delay loaded protocol. Computer tomography based finite element models comprising a totally edentulous mandible and Ø 3.8 x 13-mm implants, abutments, abutment screws, bar retaining screw and bar were constructed. Different implant configurations (3, 4 and 5 implants) and loading conditions (symmetrical, unilateral and posterior with diverse loading magnitudes) were simulated for both external hex (EH) and Morse-taper connections (MT). Were evaluated peak equivalent strain (EQV strain) in the bone and the peak von Mises stress (EQV Stress) in abutment screw and bar retaining screw. Considering the same loading design, a significantly higher bone strain levels were observed for EH, comparing to MT connection. Implant number do not have a significant influence on strain magnitudes in bone, for neither the connection types. Regarding the EQV Stress in abutment screw, MT connection type presented significantly lower stress values, comparing to EH connection. The EQV stress in implant system (i.e. abutment screw and bar retaining screw) has an inverse relationship with the implant number. Morse-taper connection type significantly decreases the strain levels in periimplant bone and the EQV stress in abutment screw, however, showed higher EQV stresses in the retaining screws of the bar. A smaller number of implants in an inferior full-arch rehabilitation rather increase the stress in abutment and bar retaining screws. Balanced adjustments of the loading improve the biomechanics of an mandibular full-arch rehabilitation.