Introduction: Most published data on relapse in open bite maxillo-mandibular deformities give raw results but do not suggest any specific therapy. Indeed, their authors compare the various osteotomy techniques but without identifying risk factors for relapse (dysfunctional or architectural). We studied the predictive value of occlusal plane tilting, in the long-term relapse of open bite maxillo-mandibular deformity.
Material and method: Fifty patients were included between 1996 and 2007. For each patient, Delaire cephalometric analysis was performed on preoperative, immediate and late postoperative teleradiographs. Immediate real postoperative occlusal plane tilting was analyzed and compared with "ideal" theoretical occlusal plane tilting (calculated with Delaires' analysis). The patients were classified in two groups: one with slight discrepancy between these two planes (+/-3.75 degrees) and one with large discrepancies between these two planes (greater than 3.75 degrees or lesser than 3.75 degrees).
Results: Postoperative relapse was seven times more frequent when the postoperative plane tilting was superior to +/-3.75 degrees in reference to the ideal plane.
Discussion: Postoperative occlusal plane tilting is a predictive factor of postoperative open bite relapse.