ABSTRACT
<p><b>OBJECTIVE</b>To study the boundary between orthodontic and surgical treatment in correction of anterior open bite.</p><p><b>METHODS</b>70 cases (18.0 ages in average) treated orthodontically and 14 cases (25.1 ages in average) treated surgically were chosen. 154 hard and soft tissue measurements were analyzed by statistical software.</p><p><b>RESULTS</b>A diagnostic index, L1MP, was gained with simple factorial analysis. L1MP </= 89.5 was bound to be treated with surgery. A discriminate function, Z = -0.80188 L1MP + 0.91401 Age + 0.671111 Antigonial notch-MP + 0.599992 SNPg, was produced by multiple factorial discriminate analysis. Z < O is an indication of orthodontic treatment.</p><p><b>CONCLUSION</b>The diagnostic index and discriminate function were both useful in determining which method to be chosen in treatment of anterior open bite. The discriminate function was tested to be more efficient than the diagnostic index.</p>