Morphological alterations in the elastic fibers of the rabbit craniomandibular joint following experimentally induced anterior disk displacement

Elastic fibers are important components of the connective tissue thai anaches the articular disk of the craniomandibular joint (CMJ) to the skull and mandible. Biopsies of the articular disk proper and bilaminar zone (BZ) tissues from patients with anterior disk displacement (ADD) have shown previously that there is a marked loss of elastic fibers. In the present study. The effects of inducing ADD on the elastic fibers in the rabbit CMJ disk proper, BZ and condylar cartilage were investigated. The right CMJ was exposed surgically and the discal attachments were severed except for the BZ attachmcnts. Then, the disk was displaced anteriorly and sutured to the zygomatic arch. The CMJs were removed after 1, 2 or 6 wee ks and processed for histochemical demonst ration of elastic fibers. The results showed osteoa rt hritic changes following ADD. and a significant decreasc in the number of the clastic fibers in the disk proper and BZ. The remaining clastic fibe rs were abnormal in their appearance and orientation. In addition, ADD led to the appearance of fine elastic fibe rs among the chondrocytes in the hyaline cartilage of the condyle that were not present in the cartilage of the control condyle. We conclude that incluced ADD can lead to a significant loss of elastic fibers in the articular disk, and result in the appearance of elastic fibers within the cartilage of the mandibular condyle.