Histologic Study of Regeneration of the Mandibular Condyle After Unilateral Condylectomy in the Rat

Publisher Website
Google Scholar
Abstract
Nine male Sherman strain rats were used in this study. Unilateral condylectomy was performed on the right side of 8 animals and unilateral condylotomy was performed on 1 animal. The unoperated side of each animal served as histologic control. The animals ranged in age from 24 - 40 days at operation and were sacrificed at varying intervals from 11-43 days post-operatively for histologic examination. Frontal sections were cut serially at various levels through the region of the squamoso - mandibular articulation. Six of the 8 rats showed regeneration of the head of the mandibular condyle. In addition the capsule was present and within it was the typical articular disc and superior and inferior synovial spaces. Regeneration was explained in terms of the chondrogenic tissue from which the condyle normally arises. In the presence of the articular disc regeneration conformed to the normal anatomic outline. The presence of infection did not prevent the regenerative process. Massive callus formation occurred at the severed end of the ramus and was considered to be a part of the healing process common to fractures of bone. This allowed for the eventual union of the ramus with the regenerating condyle. Regeneration failed to occur in 2 animals and histologic study showed the absence of both the articular capsule and the articular disc. The severed end of the ramus was rounded and slender and the squamoso-mandibular fossa showed moderate to marked atrophy. Union of the severed end of the ramus with the neck of the condyle occurred in the animal on which unilateral condylotomy was performed.