The occlusal interference during adolescent period makes some effects on growth and development and morphological changes. And so, if we could predict the timing and results of orthodontic treatment who have occlusal interference during
adolescent
period, it may be helpful for diagnosis and treatment planning of orthodontic treatment. For about those, the purpose of this study was to evaluate the effects of the posterolateral displacement by the metal casting crown with inclined pathway on
the
mandibular condyle and morphologic changes of mandible in the rat.
The experimental animals were thirty six Sprague-Dawley male rats of 8 weeks old. Eight of them was used as control group, and experimental group 1 (continuous appliance wearing gropup) was composed of sixteen the experimental group 2 (appliance
removal
group after worn the appliances during 3 months) was composed of remaining twelve. The animals of experimental grouop 1 were sacrificed after 1, 2, 3, 6, months from beginning of the experiment and experimental group 2 were sacrificed 1, 2, 3
months
after removal of the appliance from worn the appliance during 3 months. Both of mandible and temporomandibular joint were observed histologically and radiologically.
@ES The results were as follows :
@EN 1. In experimental group 1, the mandibular length and lower posterior height were decreased with experimental period, while the lower anterior height was increased, and the curvature of lower incisors and lingual inclination of anterior
alveolar
bone were profound as compared with control group.
2. In experimental group 1, both of the thickness of the condylar cartilage were thinned in the posterosuperior region, and this phenomenon was more prominent on right than left in 3-Mo experimental period and both sides were marked thinned in
6-Mo
experimental period.
3. In experimental group 2, the lower anterior height was low and lower posterior height was high as compared with experimental group 1, and the curvature of lower incisors and lingual inclination of anterior alveolar bone were recovered to
control
group.
4. In experimental group 2, both of the thickness of the condylar cartilage were thickened in the posterosuperior region, and this phenomenon was more prominent with experimental period .
5. In experimental group 2, the mandibular length was short, lower anterior height was hight, the curvature of lower incisors were profound, and in histologically, both of the thickness of the condylar cartilage were thickened in the
posterosuperior
region as compared with control group.
As shown above, the occlusal interfernce affected the condylar cartilage, curvature of lower incisor, inclination of anterior alveolar bone, mandibular length, and anterior and posterior height. When the interference was removed, significant
recover was
found in condylar cartilage, mandibular length, and posterior height. Although no significance was found, other items of measurement showed trends for recovery. (KOREA J. ORTHOD 1994 ; 24(2) : 275-294.
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