Outcome prediction in open bite cases.

Some anterior open bites close spontaneously, others do not. It would be advantageous if the orthodontist had some means of predicting the spontaneous outcome in open bite patients. One-hundred-and-twenty-seven patients having open bite were recorded longitudinally for a minimum period of 3 years using cephalometric radiographs. The open bite closed spontaneously in 50 per cent of a prepuberal group aged between 7 and 10 years, in 49 per cent of a puberal group aged 11-14 years, and in 44 per cent of a post-puberal group aged between 14 and 21 years when first seen. Data from cephalometric analysis of the first film in each case was analysed using discriminant function analysis. The analysis correctly predicted the outcome in 88 per cent of the prepuberal group, in 74 per cent of the puberal group, and in 94 per cent of the post-puberal group. The accuracy of the prediction equation was checked in a new sample of 35 subjects with open bite observed over at least 2 years so that the spontaneous outcome was known. The equation correctly predicted the outcome in 79 per cent of prepuberal, in 80 per cent of puberal, and in 100 per cent of post-puberal patients in the second sample.