Hemimandibular hyperplasia is a developmental asymmetry characterized by three-dimensional enlargement of the hemimandible and the hyperplasia mainly appears on the condyle, the ramus, the mandibular body and the symphysis of the mandibular bone.
Hemimandibular hyperplasia have some morphologic characteristics, that is; it stops at the midline of the symphsis, the chin deviates to the unaffected site, the lower mandibular border is asymmetrical, the occlusal plane is tilted and the patients have different types and degrees of malocclusion.
The oral and maxillofacial department, Dental Faculty, Pyongyang Medical College,
After the preoperative orthodontic treatment, the 79 patients with hemimandibular hyperplasia were divided into a study and a control group. The patients in the study group had condylectomy on the affected site and those in the control group had bilateral sagittal split ramus osteotomy (SSRO).
The postoperational maximum interincisal opening(50.5±0.14) was significantly larger than the preoperational one(46.5±0.21) in the study group. (p<0.05)
On the other hand, the postural and the transverse maxillary symmetry on the affected sites were respectively 14.4±0.11, 73.4±0.31 in the study group and respectively 15.3±0.32, 73.9±0.22 in the control group.
While the menton deviation and the left/right ramus ratio were significantly changed in the study group after the operations (respectively 2.1±0.22, 0.34±0.10, p<0.05), the left/right ramus ratio didn't show the significant difference between the preoperations and postoperations in the control group.
In conclusion, the condylectomy on the affected site improved the facial asymmetry more significantly as compared to SSRO in the patients with hemimandibular hyperplasia.
The oral and maxillofacial department, Dental faculty, Pyongyang Medical College,
