Radiological Evaluation Of Fracture Line Stability During Functional Loading After Miniplate Fixation Of Mandibular Angle Fractures

Suh, Chang Ho; Bae, Jung Soo; Chin, Byung Rho

Abstract

After miniplate fixation of mandibular angle fractures, fracture line stability during functional loading was evaluated. Using panoramic radiographs, 15 mandibular angle fracture patients who were treated by open reduction and one miniplate fixation along the external oblique ridge, were evaluated at postoperative 1, 4 and 8 weeks. At each time, 2 radiographs were taken: one taken during maximum biting of hardened silicone sheet on the affected side molar area and the other on the non-affected side. The distraction gap of inferior border of mandible at each time and each side was measured and these data were analysed statistically with clinical findings. The differences of inferior border distraction gap during hardened silicone sheet biting on the affected side molar area and on the non-affected side molar area at 4 week radiographs were smaller than those of 1 week's except one case. At 8 week's radiographs, the fracture lines were so stabilized that it was almost impossible to find the gap differences except one case and there were increased radiopacity along the entire fracture lines. Clinically, bony union was confirmed in all cases during plate removal performed at postoperative 6 month. By statistical analysis(paired t-test), the inferior border distraction gap during biting of hardened silicone sheet on the affected side was significantly reduced during 1 and 4 week interval(p<0.01). The differences of inferior border distraction gap during biting on the affected side molar area and on the non-affected side molar area were also significantly reduced at 1 and 4 week interval(p<0.01). But the inferior border distraction(compression) gap during non-affected side biting was not significantly changed. From these findings, it could be concluded that fracture line stability during functional loading after one miniplate fixation of mandibular angle fractures stems mainly from reduction of inferior border distraction gap during affected side biting on time interval. According to these radiographic and clinical findings, the clinical superiority of one miniplate fixation technique in mandibular angle fracture treatment could be confirmed.