Effect of Piezocision on Molar Intrusion in Open-bite Treatment Using a Modified MEAW Technique

Purpose: The aim of this retrospective study was to investigate whether a piezocision technique influences molar intrusion in open-bite cases.

Methods: In all, 30 patients with open-bite malocclusion were assigned to one of two groups: the piezocision group comprised 15 patients who were treated using curved arches and anterior elastics with the simultaneous combination of piezocision which was performed interdentally in the upper posterior region, while the control group comprised 15 patients who were treated with the same treatment mechanics without piezocision. In both groups, after leveling and aligning, upper 0.017 × 0.025 accentuated curve and lower 0.017 × 0.025 reversed curve of Spee NiTi archwires were placed. Anterior vertical elastics were applied between laterals and the canines on both sides. The effects of treatments were investigated on cone-beam computed tomography images acquired before use of elastics and after correction of open-bite.

Results: Open-bite closure was achieved in 2.85 ± 0.85 and 4.1 ± 1.58 months in the piezocision and control groups, respectively, while total treatment lasted 1.4 ± 0.42 and 1.7 ± 0.43 years, respectively. Extrusion of lower posterior teeth (p < 0.05) was observed together with extrusion of incisors and canines (p < 0.001) in the piezocision group, while only incisors and canines were extruded in the control group (p < 0.001). There were no significant differences between the groups (p > 0.05) except significant lower incisor extrusion (p < 0.05) and counter-clockwise rotation of the lower occlusal plane in the piezocision group (p < 0.001).

Conclusion: The duration of open-bite correction was significantly shorter in the piezocision group. No molar intrusion was observed in either group. Open bite correction was achieved mainly by extrusion and retrusion of the incisors while maintaining upper molar positions.