Bone age of young orthodontic patients for skeletal maturity assessment

Objectives: The purpose of this research was to evaluate the bone age and growth potential in malocclusion by using the Computer Aided Skeletal Maturity Assessment System(CASMAS) Methods: In order determine the accuracy of the CASMAS system, we first used the Nakazawa bone age evaluation method to calculate bone age in sixteen wrist bones and then made a comparison No significant difference was found between the two evaluations. The subjects consisted of 66 young orthodontic patients (28 male and 38 female,9~11 years old, average age, 10 years 0 months) distributed into three classes by lateral cephalogram analysis: a maxillary protrusion group (ANB ³5 degrees), a mandibular protrusion group (ANB £0 degrees) and a normal skeletal group (5 degrees>ANB>0 degrees). The hand-wrist radiographs of the subjects were evaluated by CASMAS (A mode: the third middle phalanx, B mode: the third middle phalanx and radius). Results: The average bone ages were 9 yr 1 month and 9 yr 5 months in the maxillary protrusion group, 11 yr0 months and 11 yr 3 months in the mandibular protrusion group and 10 yr 5 months and 10 yr 0 months in the normal skeletal group, for A mode and B mode, respectively A significant difference was found between the three groups (p<0.01). CASMAS was capable of predicting final stage total mandibular length (condylion-gnathion) at the termination of growth There was no significant difference between the three groups. Conclusion: Bone age in the maxillary protrusion group indicated low skeletal maturity and that of the mandibular protrusion group indicated high skeletal maturity in young orthodontic patients. CASMAS needs to be improved for a more accurate prediction of total mandibular length.