Incisor extrusion with or without molar intrusion for the correction of anterior open bite with clear aligners and comparison of outcomes with fixed appliances incorporating temporary anchorage devices: A systematic review and meta-analysis

Abstract

Objective: This study aimed (1) to compare the effects of clear aligner treatment (CAT) and fixed appliances incorporating temporary anchorage devices (FATADs) on overbite and the vertical position of anterior and posterior teeth in open bite patients; (2) to assess the impact of CAT on increasing overbite and vertical tooth movement; and (3) to evaluate post-treatment stability. Methods: Electronic searches of Medline, Scopus, Cochrane Central, Embase, and the Virtual Health Library network portal, and manual searches were conducted up to April 2025. Human studies evaluating CAT for open bite correction and reporting pre- and post-treatment overbite (primary outcome) and vertical incisor and molar positions (secondary outcomes), with or without comparison to FATADs, were included. Study quality was assessed using design-appropriate tools. Results: Of 1,610 identified studies, 10 met the inclusion criteria (four non-randomized controlled trials and six before-and-after studies). CAT increased overbite by 2.77 mm, mainly through upper (0.87 mm) and lower (1.06 mm) incisor extrusion, without significant molar intrusion. Compared with CAT, FATADs achieved greater overbite correction and upper molar intrusion (1.64 mm and 1.88 mm, respectively). CAT showed greater lower incisor extrusion (2.35 mm), with no significant difference in upper incisor position. During retention, CAT maintained stability, with no significant changes in overbite (0.02 mm) or vertical tooth positions. Conclusions: CAT effectively increases overbite mainly through incisor extrusion but is less effective than FATADs for open bite correction via molar intrusion. The vertical position of the teeth remained stable during the retention period.