Assessment of growth activity in the mandibular condyles by single-photon emission computed tomography (SPECT)

Background: Unilateral condylar hyperplasia can lead to marked and disfiguring changes in the face and occlusion. A method of determining side-to-side differences in condylar activity is an important step in managing this condition. Aims: To determine the growth activity in normal mandibular condyles and to devise an index of side-to-side differences in condylar activity in different individuals. Methods: Thirty eight patients, ranging from 13 to 34 years, who were undergoing skeletal scintigraphy for a variety of conditions agreed to participate in this study. No subjects had clinical or radiographic signs of mandibular hyperplasia. After injection of 25 mci Tc99 the uptake by the right and left mandibular condyles was measured and the side-to-side differences used to calculate an index. Results: The maximum side-to-side differences were 6.2 per cent (Right side versus Left side: 53.1 per cent and 46.9 per cent respectively) in the male patients and 5.7 per cent in the female patients (Right side versus Left side: 52.85 per cent and 47.15 per cent respectively). Conclusions: The variation in growth activity in normal right and left mandibular condyles was less than 6.2 per cent.