Condylar changes after contralateral mandibular osteotomy in the rabbit

Use of human amniotic membrane as an interpositional material in treatment of temporomandibular joint ankylosis

PURPOSE

The aim of the study was to demonstrate whether the human amniotic membrane (HAM) as an interpositional material could prevent temporomandibular joint (TMJ) reankylosis in the randomized rabbit model.

MATERIALS AND METHODS

In our experimental study, 24 New Zealand white rabbits were used and all right joints were operated. The rabbits were divided into 2 groups. The first group was specified as the demonstration group (n = 8). In this group, fibrous ankylosis formation was shown experimentally. The rabbits in the second group, the treatment group (n = 16), were divided into 2 subgroups: gap arthroplasty, performed in group A (n = 8); and HAM, used as an interpositional arthroplasty material in group B (n = 8).

RESULTS

In all rabbits, the range of jaw movements and weight decreased after induction of ankylosis. After surgical treatment of fibrous ankylosis, the vertical, right, and left movements of the jaw and weights of rabbits increased immediately. The results were evaluated clinically, macroscopically, histologically, and radiologically. There was a statistically significant difference in the jaw movements between groups A and B (P < .05). All operated joints in group A showed fibrous adhesions across the gap, and the articular surface was irregular with osteophytes and bony islands on the joint surface. In group B, no fibrous adhesions were observed.

CONCLUSION

It was concluded that interpositional arthroplasty with HAM was superior to gap arthroplasty in the rabbit model in preventing ankylosis.

Diagnostic image analyses of activator treated temporomandibular joint in growth and maturing stages

This study evaluates the condylar response to activator in growth and in maturing patients using radiographs and magnetic resonance images (MRI). Seven patients (four in growth and three in maturing stages) treated for mandibular distal occlusion were studied. In all seven patients, lateral roentgen cephalograms, panoramic radiograms, and MRIs were made before and following functional treatment. All patients' mandibles advanced during treatment. Downward and forward mandibular growth was observed by superimposition of lateral cephalograms. On the condylar posterosuperior regions for both groups, double contours were sometimes observed on the panoramic radiograms following therapy. These double contours coincided with an area of high intensity in the MRIs for both groups. In the mature adult group, the double contours were more clearly observed when compared with those in the growth group. There were differences in the condylar adaptation types between the growth and mature development stages. Condylar adaptation to the newly created mandibular position was nevertheless found even in adult patients.