Journal of Aligner Orthodontics, 01/2021

Objective: Clinicians’ and laypeople’s aesthetic perceptions differ significantly. Lay observers’ background, social status and perceptions of beauty can vary; on the other hand, clinicians should also consider patients’ racial and individual characteristics. The present systematic review therefore aimed to assess laypeople’s evaluations of facial profiles and identify any acceptability thresholds. Materials and methods: An electronic search was conducted of nine databases (PubMed, PubMed Central, National Library of Medicine [NLM], Embase, Cochrane Central Register of Controlled Trials [Central], Web of Knowledge, Scopus, Google Scholar and Latin American and Caribbean Health Sciences Literature [LILACS]) using the search terms “(Profile* OR Facial) AND (esthetic* OR aesthetic* OR prominence) AND (perception OR perspective OR evaluation OR awareness OR attention OR attractiveness)”. Results: Of the 13,621 analysed articles, 20 were selected for the final review process. Twelve of these investigated the perception of profile aesthetics using profile photographs and eight using profile silhouettes, with one of the latter eight studies using lip profile silhouettes specifically. Three main features were identified: profile convexity (straight profiles were considered most appealing in men, whereas a retruded chin position was preferred in women), facial height ratio (a mesiodivergent pattern was most appealing) and lip position (profiles with the upper and lower lip behind the E-line were considered most attractive). Conclusions: Acceptability thresholds for profile aesthetic characteristics were not obtained due to heterogeneity of measurements and the facial profiles preferred by laypeople were skeletal Class I, mesofacial or brachyfacial type, with lips behind the E-line. Adult observers preferred a more retruded profile compared with younger observers. Keywords: aesthetics, dental, face, personal satisfaction, profile

Objective: The aim of this pilot study was to measure the activity of the masseter in young adults treated with clear aligner therapy using ambulatory electromyography.  Materials and methods: The electromyographic activity in the right masseter muscle of 6 young adults (3 female, 3 male, 18.8 ± 4.3 years) undergoing clear aligner therapy over 4 weeks (week 1 baseline without aligners [T0], week 2 with a dummy passive aligner [T1], week 3 with the first active aligner [T2] and week 4 with the second active aligner [T3]) was recorded using portable electromyographic data loggers. A mixed-effects model was used to test differences in surface electromyographic activity over the four experimental conditions.  Results: The surface electromyographic activity of the masseter increased significantly with aligners compared to baseline. It also increased significantly from T0 to T1 (P < 0.001), and increased from T1 to T2 (P = 0.024). There was no statistically significant difference between T2 and T3 (P = 0.799).  Conclusions: Clear aligner therapy in young adults is associated with an increase in masticatory muscle activity, possibly due to an increase in parafunctional tooth clenching. Keywords: active aligner, clear aligner therapy, dummy aligner, masticatory muscle activity, surface electromyography, young adults

In adult cases of deep bite requiring retraction of the maxillary anterior teeth, bringing about vertical intrusion using an aligner appliance alone is considered difficult. The present case involved a patient with Angle Class II, division 2 malocclusion, presenting with the chief complaints of excessive gingival display and crowding. Temporary anchorage devices were placed in the maxillary alveolar gingiva, and intrusion of the maxillary anterior teeth was performed using precision cuts and traction via elastics in the anterior region of the aligner. This report presents the treatment results that were achieved in a short period of time using these mechanics. Keywords: clear aligner, deep bite, gummy smile, incisor intrusion, temporary anchorage devices

Use of clear aligners to correct a variety of types of orthodontic malocclusion has become widely accepted by dental professionals. Some clinicians, however, have expressed the opinion that aligners are not an effective treatment for certain complex corrections, for example the appropriate closure of large (≥ 3 mm) interdental spaces. This article presents a case in which multiple large (3 to 5 mm) spaces were optimally closed using aligners only. An auxiliary technique utilising elastics and orthodontic buttons is also presented to show how non-tracking teeth can be effectively repositioned to be in the proper position in the aligner. Keywords: aligners, large spaces, large tongue, non-tracking solution, root control, trim line