The aim of this presentation is to assess skeletal and dental changes during mandibular molar distalization performed with clear aligners in permanent dentition. Patients with a skeletal Class I or slight Class III malocclusion (-2°< ANB <2°), Class III permanent molar and canine relationship, normodivergence (SN^GoGn angle from 27° to 37°), permanent dentition with fully erupted upper and lower second molars, mild crowding in the lower arch (≤ 4 mm), good compliance during treatment (wearing aligner time, ≥ 20 h per day, wearing elastics time ≥ 20 h per day) were included. Each patient underwent a non-extractive comprehensive treatment protocol with clear aligners (Invisalign, Align Technology, Santa Clara, CA, USA) by means of sequential mandibular molar distalization, up-righting, and alignment. The protocol comprised the extraction of the wisdom teeth in the lower arch and the use of attachments and Class III elastics. Changes were considered after all refinements (T2-T1 = 22 months). Data was normally distributed and T2–T1 changes were assessed using t-tests (P <0.05). Lower second molars moved distally 2.15 mm, associated with a significant distal tipping (-15 degrees). Similar results were observed at the level of first molar, with a mean distal movement of 1.05 mm and a significant distal tipping (-11 degrees). No significant changes were found on the sagittal and vertical skeletal variables. In conclusion, small amounts of lower molar distalization are possible through clear aligners. Distal tipping movement of the second and first molars with an increasing of lower arch perimeter and improvements in sagittal dental relationships.
Learning Objectives:
After this session, attendees will be able to:
Evaluate the effects of the distalization protocol in the lower arch by means of clear aligners, highlighting the possibilities and the limits of this treatment strategy.
Provide tips and tricks for managing lower molar distalization selecting patients who can be successful treated with this option.
Provide an accurate description of effects on the occlusal plane, anterior facial height and molar extrusion at the end of treatment in Class III subjects.
