A common strategy in the non-extraction treatment of Class II molar relationship is maxillary molar distalization, which could increase lower face height and cause clockwise mandibular rotation. The aim of this retrospective study was to analyse the effects on vertical dentoskeletal dimension of young adults treated with sequential distalization with orthodontic aligners. Lateral cephalometric radiographs of 10 subjects (8 females 2 males; mean age 22.7 ± 5.3 years) treated with upper molars sequential distalization with orthodontic aligners (Invisalign, Align Technology, San Josè, California, USA) were analyzed. No statistically significant difference was observed for the primary outcome SN-GoGn between T0 and T1 and it was recorded a mean variation of 0.1 ± 2.0 degrees. Statistically significant differences were found in the linear position of the upper molars (6-PP, 7-PP) the molar class relationship parameter (MR) and the upper incisive inclination (1^PP) with at least p < 0.01. Upper molar distalization with orthodontic aligners guarantee an excellent control of the vertical dimension representing an ideal solution for the treatment of hyperdivergent or openbite subjects. It also allows an excellent control of the incisal torque without loss of anchorage during the orthodontic procedure.

Background and objectives: The aim of this study is to evaluate mandibular elevator muscles activity and pain on palpation in the early stages of orthodontic treatment with clear aligners using surface electromyography (sEMG). Materials and methods: Surface electromyography (sEMG) activity and pain level on muscle palpation of masseter and anterior temporalis muscles were recorded in a sample of 16 adult subjects (aged 18–32 years; mean 22.5 +/− 3.5 SD) undergoing orthodontic treatment with clear aligners before the treatment (T0), after 1 month of treatment (two clear aligners) (T1), and after 3 months of treatment (T2) (six clear aligners). A chi-square test for nominal data, a Friedman test, and a Wilcoxon-signed rank test as post hoc analysis were applied. Results: No statistically significant differences in muscular pain were observed. At T1, the sEMG activity of masseter muscles at mandibular rest position showed a statistically significant reduction, but after 3 months (T2), the data appeared similar to T0 (p = 0.03 and p = 0.02). Conclusions: During the treatment with clear aligners, subjects could experience an initial reduction in the masseter basal activity after 1 month of treatment. This effect tends to decrease to baseline levels after 3 months of therapy.

Objective: This pilot study is a prospective controlled clinical trial, designed to evaluate the short-term clinical results (the plaque index) of an educational/motivational program for home oral hygiene, directed to children and adolescents who live in family-homes. Methods: The setting of the project was the province of Milan (Italy), where two family-homes were selected. The study group included 26 children (16 females and 10 males) aged between 7 and 15 years, of Italian nationality, from the family-home communities. The control group included 26 children (15 females and 11 males, aged between 7 and 15 years) of Italian nationality, matched for age and gender distribution with the study group, that were not in a socially disadvantaged condition. Collection of the plaque index (PI) was performed at t0. Then, all basic oral hygiene instructions were given to all children/adolescents and their educators. Education and motivation were repeated in the same way after 4–7 weeks (T1), and after 10–12 weeks (T2). The PI was taken also at T1 and T2. Results: An improvement in the PI was generally found in both groups, but there was no statistically significant difference between the two groups over time. Multivariate analysis of variance (MANOVA) revealed a statistically significant effect of time [F (1, 52) = 90.73, p < 0.001], regardless of the assignment group, in consequence of which the plaque index presented a moderate and significant improvement. Conclusion: The present data confirm the validity of the educational/motivational program to improve oral hygiene in children/adolescents, regardless of the assignment group.