The Effect of Alterations of the Facial Musculature on the Facial Skeleton and Dental Arch form of the Rat

Abstract

Various portions of the facial musculature were removed in 1-mo. old rats to determine the effects on the development of the bony architecture of the face and alveolar arches. 6 different operations were performed on groups of 3 rats each; litter mates served as controls. No significant changes were noted following sacrifice at the age of 4.5 mos. in those animals in which the buccinator muscle had been removed, (both unilateral and bilateral); or in those in which the superior or inferior portion of the orbicularis oris muscle had been removed; or when the orbicularis had been removed unilaterally. Those animals in which the entire orbicularis oris muscle had been removed showed evidence of reduction in the dimensions of the nasal bones and the maxillary diastema length as compared with the controls.