A histochemical study of temporal muscle fibers in denture wearers and subjects with natural dentition.

Biopsy specimens from temporal muscle of denture wearers and subjects with natural dentition were studied by biochemical staining methods. Size and distribution of fiber types were estimated in sections stained for myofibrillar ATPase at pH 9.4. The mean sizes of Type 1 ,* Type 2 and intermediate fibers in denture wearers did not differ from those of the corresponding types of fibers in subjects with natural dentition. In the denture series, Type 2 fibers were smaller in subjects who rated their dentures as deficient than they were in those whose dentures were good. The frequency of intermediate fibers was low in both series. The mean percentage distribution of Type 2 fibers in specimens from the internal surface of the temporal muscle was significantly lower in the denture series than in the specimens from subjects with natural dentition. It is suggested that the low content of Type 2 fibers in the specimens from the internal surface of the temporal muscle of denture wearers and the small size of Type 2 fibers in subjects who rated their dentures as deficient may be attributed to altered functional demands. [ABSTRACT FROM AUTHOR]