The immediate effect of different mandibular positions on muscle force in the upper and lower limb: A pilot study in asymptomatic subjects

Abstract

It has been suggested that occlusal splints can improve muscle strength in athletes by affecting the mandibular position. However, research in this area is scarce and conflicting. This pilot study evaluated the upper and lower limb muscle force in three different mandibular positions and assessed the repeatability of these measurements. Twenty one healthy subjects (13 males – 8 females) aged 18-24 years were recruited among physiotherapy students based on strict criteria. Included subjects were free of any temporomandibular, oral or musculoskeletal disorders. For each subjects individually a hard wax bite of 2-4 mm in maximal occlusion was made. Grip strength was measured using the Biometrics® dynamometer. Isometric muscle force of the quadriceps was measured using a BIODEX® dynamometer. Muscle force in shoulder abduction muscles was measured using a MicroFET® dynamometer. Three trials within each session, and in a random order, were done in each of three mandibular positions: 1) closed in maximal occlusion; 2) active mouth opening; 3) closed on wax bite in maximal occlusion. This procedure was repeated after a one week period. To control for confounding of mandibular position, within-session trials and test day, a linear mixed covariance model approach was used. No significant differences were found in muscle force between the three mandibular positions for any of the muscle groups tested (p >0.05). Good repeatability was demonstrated within one session and between two separate days. Findings indicate that in asymptomatic subjects, muscle force in the limbs was not influenced by altered mandibular position.