In vivo horizontal bending moments on implants.

To date, transverse and vertical forces applied eccentrically to the axis of dental implants in the molar area during oral function have not been quantified. A specially designed load cell placed directly in the implant allowed for measurements of bending moments. Results of both load directions were compared to each other and to the loads applied vertically along the implant axis. The stress in the bone-implant interface area caused by these three different types of loads was calculated by finite element analysis. The transverse loads during chewing resulted in the highest bending moments (170 Nmm mean maximum) and the highest stress in the bone (sigma max approximately 6.2 MPa) at the crest to the buccal side. Mesial implant moment was significantly less (52 Nmm mean maximum moment; sigma max approximately 1.3 MPa). Clenching in centric occlusion caused a bending moment either to the lingual or to the buccal side, depending on the occlusal contour (140 Nmm maximum).