Korean J Orthod.  1980 Dec;10(1):29-36.

An experimental study on the effect of posterior displacement of the mandible on the temporomandibular joint in rats

• Park KJ

Abstract

Inclined plane, one of frequently used orthodontic appliances, may cause posterior displacement of mandible and injure the normal growth of temporomandibular joint. So author carried out the mandibular posterior displacement experimentally indyced by inserting inclined plane in the rat incisors in order to investigte the histological reactions occuring in the temporomandibular joint of experimental animals. Following results were obtained. 1. The posterior displacement of condyle resulted in the widening of anterior synovial space with anterior condylar hyperplasia and posterior condylar atrophy. In addition, tissue changes were more severe in young rats than in adult rats. 2. The tissue reactions were localized only to condylar head and there were no evidence of traumatic features in young rats. In adult rats, hemorrhage was an additional finding 1 week after experiment. 3. The remodelling processes were accmpanied by the increasing or reduction of fibrous layer and subsequent replacement by cartilage layer occured massively and abruptly in young rats, it occured slightly and slowly in adylt rats. 4. The remodelling process of injured condyle occured from 1 week to 4 weeks after experiment and completed between 8 weeks after experiment.

MeSH Terms

Adult
Animals
Atrophy
Cartilage
Head
Hemorrhage
Humans
Hyperplasia
Incisor
Mandible*
Orthodontic Appliances
Rats*
Temporomandibular Joint*