Soft-tissue modification in Class III non-growing patients treated with Clear aligners: a prospective clinical trial

Roberta Lione ¹ Chiara Pavoni ¹ Francesca Gazzani ¹ Francesca Chiara De razza ^1,2 Letizia Lugli ^1* Paola Cozza ¹

• ¹ Saint Camillus International University of Health and Medical Sciences, Rome, Italy
• ² Sapienza University of Rome, Rome, Lazio, Italy

The aim of the present prospective study was to assess the soft tissue modifications induced by camouflage treatment with clear aligners in adult patients with mild Class III malocclusion. Patients were consecutively enrolled in the study sample according to the following inclusion criteria: adult age (≥19 years); permanent dentition including second permanent molars; skeletal Class I or slight Class III (-2° < ANB < +2°); normal skeletal divergency pattern (SN^GoGn, 27°-37°); Class III canine and molar relationship at baseline (T0), moderate lower arch crowding (≤ +4 mm); good compliance with aligners and elastics (≥ 20 hours/day). All subjects underwent the Lower Distalization Protocol, which included extraction of the lower third molars before starting treatment and a 50% sequential lower distalization, and Class III intermaxillary elastics (1/4 in., 6.5 oz) from buttons on upper first molars to precision cuts at the level of lower canines to reinforce the anchorage. Lateral cephalograms were taken at T0 (before treatment) and at the end of the clear aligner treatment (T1) with an average time interval of about 24 +/-6 months. A customized digitization regimen and cephalometric analysis was created to assess the aesthetic outcomes at T1. The significance level was set at P <0.05. The lower distalization supported by Class III elastics determined slight improvement of the facial aesthetic profile with no significant changes in the lower third of the face. A mild better projection of the upper lip was detected at the end of treatment, mainly due to the extensive use of Class III elastics.