Treatment of vertical open bite with molar intrusion and assessment of its stability in cephalograms

Aim: The aim of our study was to verify effectiveness and stability of the results in therapeutic methods affecting vertical position of molars in patients after pubertal growth spurt in relation to facial skeleton, overbite and position of incisors with negative overbite and high angle of the mandibular line. Material and method: The sample included 41 patients treated by the same orthodontist in his private orthodontic practice. All patients had permanent complete dentition, negative overbite and angle of jaw bases over 38°. The sample was divided into 3 groups according to therapeutic techniqueɸ – relative intrusion of molars, intrusion of molars, extraction therapy. Assessment was done in cephalograms made prior to treatment (T1), after treatment (T2), and at least 2.5 years after treatment (T3). We monitored the following changes: position of the mandible in autorotation, length of lower face height, vertical position of molars and incisors, overbite, inclination of upper and lower occlusal plane in relation to vertical position of molars. We wanted to establish to what extent the continued growth affects stability of therapy results in individual groups. Results: Mandibular autorotation is the result of treatment methods focused on relative or absolute intrusion of upper molars. The change in parameters after therapyɸ– posteriorotationɸ– was recorded in all groups, and it is probably the result of continuing growth tendency to posteriorotation. Significant change in the length of lower anterior face height was found in the extraction groupɸ– the values were higher. Significant change was recorded only in the extraction group with molar extrusion. Following the therapy, we recorded extrusion in all groups, however, they were not significant. We also observed deeper bite and change in the position of upper incisorsɸ– extrusionɸ– in all patients. Bite was opened in the groups after active molars intrusion and after premolars extraction. Conclusion: Comparison of the parameters between individual groups of patients suggests that, to some extent, it is possible to compensate vertically open bite with vertical position of molars. Radiographs made after the therapy show that the continued growth tendency leads to reopening of bite.