On the self-perception of jaw positions in man

A longitudinal study shows that, in the short-term, dentate subjects are able to match fairly well the magnitude of jaw separations to any of three types of memorized standards (imagined, verbally imposed and physically imposed) of various dimensions. All subjects showed instability of the comparison mechanism or long-term changes in the engram. About 66 per cent of the matches were performed with the same precision. The relative precision of the matches is almost independent of the size of the standard. The absolute precision of matching of dentate subjects is similar to that of edentulous subjects. In half of the experiments, the subjects showed a match that equals the magnitude of the verbal standard or the real standard. The subjects tend to give more accurate matches when they refer to a verbal standard than when they refer to a real standard, but the long-term instability of matching is much greater when the subjects refer to a verbal standard than when the subjects refer to a real standard.