Class II Malocclusion in Adult Patients: What Are the Effects of the Intermaxillary Elastics with Clear Aligners? A Retrospective Single Center One-Group Longitudinal Study

Aim: To evaluate the dental effects of the treatment with clear aligners and intermaxillary elastics in adult patients with Class II malocclusion. Material and methods: A sample of 20 Class II patients treated with Invisalign aligners (5 M and 15 F; mean age of 27.6 +/- 6.3 years) was included in this single-center one-group longitudinal study. Dental cast and cephalometric records were analyzed before (T0) and after treatment (T1). Data were analyzed with a t-test for paired data (p < 0.05). Results: There was a significant reduction of the Overjet (OVJ= -1.4 +/- 0.2; p <= 0.001) and a retroposition of upper incisors (U1-NPo = -1.3 +/- 1.7; p < 0.001). Furthermore, distalization of upper molars with an improvement of molar class (U6-PT Vertical = -0.93 +/- 0.97; p < 0.001; Molar Relation = -0.75 +/- 0.45; p < 0.001) was observed. A good control of the lower and upper incisor inclination was present, highlighted by the non-significant changes in these values (L1-GoGn = -0.12 +/- 5.4; p = 0.923; U1-AnsPns = -1.1 +/- 8.1; p = 0.551). In the lower arch, an increase in the intermolar diameter (0.6 +/- 1.0; p = 0.01) was present. Finally, there were no statistically significant changes in all the skeletal variables (ANPg = 0.005 +/- 0.687; p = 0.974; SN/MP = -0.47 +/- 1.9; p = 0.298). Conclusions: Treatment with Invisalign aligners shows a reduction of the Overjet, a retroposition of the upper incisors, good control of the lower incisors, and an improvement of the molar relationship.