Posttreatment stability of an anterior open-bite by molar intrusion compared with 2-jaw surgery - a retrospective study

Abstract

Objectives: This study aimed to compare post-treatment stability in patients with anterior open-bite (AOB) between those treated surgically (orthognathic 2-jaw surgery) and non-surgically (molar intrusion using orthodontic miniscrews).

Materials and methods: All subjects had initial overbite (OB) < -1 mm and lateral cephalograms taken before treatment (T0), immediately after AOB correction (T1), after orthodontic treatment (T2), and at least 1 year after treatment (T3). The non-surgical group was enrolled retrospectively; then, the surgical group was matched by OB, sex, and age to the non-surgical group (n = 21 each). Changes in cephalometric measurements during treatment (T1-T0), finishing (T2-T1), and retention (T3-T2) periods were compared between two groups.

Results: OB increased by 4.5-5.1 mm during the treatment period with 3.3 mm upward movement of the maxillary first molar (U6) in both groups. Changes in OB were not significantly different between the groups: 0.5-0.9 mm increase during the finishing period but 1.0 mm decrease during the retention period (P > 0.05). U6 moved 0.5 mm downward in non-surgical group and 0.1 mm upward in the surgical group during the finishing period, and 1.0 mm and 0.4 mm downward in the non-surgical and surgical groups, respectively, during the retention period.

Conclusions: Post-treatment stability of AOB was similar for surgical and non-surgical methods (76.8 - 78.7%), although U6 moved more downward in the non-surgical group than in the surgical group.

Clinical relevance: AOB without severe skeletal deformity can be treated by either molar intrusion or orthognathic surgery with similar treatment outcome and stability.

Keywords: Mini screw; Molar intrusion; Open bite; Orthognathic surgery; Posttreatment stability.