Prediction of abnormal growth in class III malocclusions.

Four significant factors have been identified in the lateral cephalometric head film which would indicate the likelihood of the patient growing in an abnormal Class III manner. The normal person grows approximately the same amount from nasion to nasion as he does on the corpus axis of the mandible. The abnormal Class III syndrome grows greater increments on the mandible than at the cranial base. For the purpose of determining the accuracy of computer prediction of abnormal growth, fourteen skeletal Class III cases were selected from the files of the Hokkaido University Orthodontic Department. A significant relationship was shown between abnormal growth and the sum of the standard deviation from the normal of the four cephalometric "predictor measurements." These data would give the clinician insight as to which patients might require early orthopedic treatment (chin cup), conventional orthodontic treatment, or surgical orthodontic correction after growth is complete. This is the first published demonstration of computerized cephalometric methods showing the ability to distinguish between normal and abnormal growth in a particular patient type. It is hoped that, through the comparison of thousands of predictions with actual data, more recognizable abnormal growth patterns will appear in the future.