Maxillary molar distalization with clear aligner therapy and infrazygomatic temporary skeletal anchorage devices

A limited amount of maxillary molar distalization can be achieved with sequential molar distalization with clear aligner therapy (CAT), accompanied by significant distal crown tipping. Thus, combining CAT with temporary skeletal anchorage devices (TSADs) has been proposed, but a detailed evaluation is lacking.

This retrospective study evaluated pretreatment and postanterior retraction cone-beam computed tomography (CBCT) images and intraoral scans of adult patients treated with CAT + infrazygomatic TSADs with at least 1 mm of programmed maxillary first molar distalization. Achieved tooth movement shown on the CBCT and intraoral scan was compared with the prescribed ClinCheck tooth movement.

This study included 38 sides from 21 patients (17 females and 4 males; aged 28.71 ± 4.16 years at pretreatment). At the crown level, approximately 1 mm of molar distalization was achieved (maxillary first molar, 1.05 mm [-0.8, 3.6] based on intraoral scans, 0.80 mm [-1.1, 3.4] based on CBCTs; maxillary second molar, 0.95 mm [-1.8, 4.4] based on intraoral scans, 1.25 mm [-1.9, 3.7] based on CBCTs), which is significantly lower than the prescribed movement (maxillary first molar, 3.05 mm [1.0, 5.6]; maxillary second molar: 3.05 mm [0.9, 6.1]). Limited crown distal tipping and mesial-out rotation, but significant buccal expansion and intrusion of the maxillary molars were also observed. In addition, a negative correlation was detected between the amount of prescribed molar distal movement and the distalization efficacy.

TSADs did not significantly improve the efficacy of maxillary molar distalization with CAT but provided more bodily movement and intrusion of the molars.