Afferent sensory mechanisms involved in jaw gape-related muscle activation in unilateral biting.

Objectives: In unilateral biting or chewing, the working/balancing-side ratio (W/B-ratio) of masseter activities is inversely proportional to the jaw gape which was interpreted as a neuromuscular strategy to protect occlusion. This suggests that jaw separation is afferently perceived, raising the question how this perception might work. In related studies, isometric biting was exerted on rubber pieces that slightly yielded similar to compressed food in chewing.

Neuromuscular control of balancing side contacts in unilateral biting and chewing.

When jaw gape in unilateral biting or chewing narrows, the working/balancing side activity ratio (W/B ratio) of masseter muscles increases due to decrease of balancing side (BS) activity. This was interpreted as a neuromuscular strategy to delimit the impact of BS contacts during chewing. To test this hypothesis, we studied whether W/B ratios are associated with incidence of BS tooth contacts.

Influence of bite force on jaw muscle activity ratios in subject-controlled unilateral isometric biting.

Ratios of muscle activities in unilateral isometric biting are assumed to provide information on strategies of muscle activation independently from bite force. If valid, this assumption would facilitate experiments as it would justify subject-control instead of transducer-based force control in biting studies. As force independence of ratios is controversial, we tested whether activity ratios are associated with bite force and whether this could affect findings based on subject-controlled force.

Impact of arbitrary and mean transfer of dental casts to the articulator on centric occlusal errors.

When fabricating dental restorations, casts are usually transferred to the articulator based on arbitrary hinge axes or mean values instead of true hinge axis points. Using arbitrary hinge axis points or mean values can lead to occlusal errors if the vertical relation is changed in the articulator (e.g.

Indications for jaw gape-related control of relative muscle activation in sequent chewing strokes.

Jaw muscle activity ratios in unilateral isometric biting differ from ratios of unilateral chewing but approach the latter if the jaw gape in biting is made as small as the minimum interocclusal distance (MID) of chewing. Especially, the masseter working/balancing side ratio (W/B-ratio) becomes as asymmetric as in chewing, because of reduction in balancing side (BS) masseter activity. This behaviour of ratios might reflect a 'chewing-specific' motor strategy induced when isometric biting is performed with a 'chewing-like' gape.