Longitudinal observation of condylar position in anterior crossbite at the mixed dentition during orthodontic treatment

: We investigated the condylar position by transcranial radiography which can be put daily clinical use easily. The patients are 8 anterior crossbite at the mixed dentition (4 functional crossbite and 4 skeletal crossbite). We observed their condylar positions before treatment (average age is 9.3 years old), after correction of overbite (average age is 10.0 years old) and 3-4 years after correction of overbite (average age is 14.0 years old). The results were as follows: 1. Condylar position of 7 cases changed after correction of overbite. The differences between right and left condylar position of six in seven cases had been recognized before treatment decreased after correction of overbite. Their condylar position were stable during the observation period of 3-4 years after correction of overbite. The condylar position of the other one case closed to fossa and then relapsed 3-4 years later. 2. Condylar position of only one case hasn't changed during the observation. 3. In functional crossbite cases, there were some differences between right and left condylar position before treatment, but no differences after crossbite correction. In skeletal crossbite cases, there was no tendency of the changing on their condylar position through treatment. 4. The changing to same direction was observed in the decrease of differences on condylar position and in the result of frontal cephalogram analysis. 5. There wasn't special relationship between changing of condylar position and orthodontic appliances. 6. TMJ dysfunction was observed in the case which has significant difference in its condylar positions before treatment and in the other case in which difference was not corrected after treatment. We recognized the usefulness of transcranial radiography for orthodontic treatment.