FORCES AND MOMENTS GENERATED AT THE DENTAL INCISORS DURING FORCEFUL BITING IN HUMANS

A miniature load sensor capable of measuring all forces and all moment s simultaneously at a single location in space was used to assess the magnitude and direction of loads that affect the dental incisors durin g forceful, static biting. While prior approaches have not measured al l necessary six degrees of freedom during biting, the complete set of loads is needed to serve as realistic boundary conditions for analytic al or computational models of mandibular mechanics. Four subjects were asked to perform controlled and repetitive edge-to-edge incisal bitin g activities. Customized devices were used to rigidly hold the load se nsor in place at pre-specified tooth separations of less than 1 mm. Th e results yielded force resultants with a magnitude range of 24.5 to 2 8.4 N. This range was intentionally limited in magnitude to avoid dama ge to the internal strain gauge assembly of the sensor. In all cases, the highest force component was oriented upwards. An additional simult aneous moment resultant (range: 8.9-17.0 N cm) with a main moment comp onent oriented backwards and downwards towards the oral cavity was als o detected. These data suggest that in order for the biting loads to b e composed of six DOF, the remaining forces acting on the mandibular f orce system (i.e. muscular and/or articular) may indeed be non-coplana r and non-concurrent. Although useful for static biting activities, th e bulk of the sensor would probably preclude meaningful measurements d uring dynamic events such as chewing or swallowing. (C) 1997 Elsevier Science Ltd.