Objectives: Social media is a crowded space and posting images and photographs is an effective way to capture attention. People share photos, videos and ideas in order to convey a particular image of themselves to others. Orthodontic treatment can have a significant impact on patients’ lives and could therefore affect the content they share on social networks. The present study aimed to use artificial intelligence to analyse photographs posted on the social media platform Instagram (San Francisco, CA, USA) by orthodontic patients treated with clear aligners. Materials and methods: A total of 20 consecutive patients treated with clear aligners and with a public profile on Instagram were enrolled in the study. All photographs posted by each subject on their Instagram account were collected and evaluated at three time points: during the 6 months prior to the start of orthodontic treatment (T1), over the course of treatment (T2) and during the 6 months after removal of the aligners (T3). A total of 2676 images were collected and each one was analysed using facial recognition software (Amazon Rekognition, Amazon, Seattle, WA, USA). Results: Significant differences were found when analysing the presence of the patient in the images posted at the different time points; if compared to T1, patients occupied a larger area of their photos at T3 (P = 0.0032). Regarding the reliability of the artificial intelligence software, no statistically significant differences were found between the human and software analyses. Conclusion: Orthodontic treatment could have positive effects on patients’ perceived well-being and self-esteem, increasing their degree of openness and personal exposure to others. Keywords: aesthetics, aligners, artificial intelligence, orthodontics, self-esteem, social media

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

Objective: The aim of this study was to identify laypeople’s preferred facial profile aesthetics in order to obtain standard cephalometric measures that correlate with lay judgements of facial aesthetics. Materials and methods: The study participants were adult Italian laypeople (aged ≥ 18 years) with no prior knowledge of dentistry, recruited in a shopping centre in Italy. A silhouette was created for each cephalometric value (SNGoGn angle, SNA angle, SNB angle, Ls-E, Li-E and G’Sn-SnPg’ angle), then the initial values were increased and decreased by one and one and half times the standard deviation to obtain four other silhouettes for each group, creating six groups of five silhouettes. The primary outcome measure of the present study was the examiners’ personal preference out of the 30 silhouettes, rated on a visual analogue scale ranging from 0 to 100. Results: The highest-rated silhouettes from each group were Silhouette C (GoGn, 32 degrees) for the GoGn group with a mean visual analogue scale score of 71.5 ± 16.4 mm; H (SNA, 82 degrees) for the SNA group with 64.3 ± 20.1 mm; M (SNB, 80 degrees) for the SNB group with 71.4 ± 17.4 mm; R (Ls-E, −4 mm) for the Ls:E group with 66.2 ± 18 mm; W (Li-E, −2 mm) for the Li:E group with 65.9 ± 19.8 mm; and BB (G’Sn-SnPg’, 12 degrees) for the G’Sn-SnPg’ group with 72.6 ± 16.7 mm. Conclusions: The profiles with average values were rated as the most attractive. The age of the observers had a significant impact on the evaluation of profile features, influencing the scores for all parameters. Vertical characteristics seemed to influence profile perception more than anteroposterior features. Keywords: aesthetics, dental, face

Objective: To analyse the effects of clear aligner therapy (CAT) on patients affected by sleep bruxism, recording the effects of CAT on masseter contractions and the overall sleep bruxism index during sleep. Materials and methods: 40 subjects requiring orthodontic treatment and affected by sleep bruxism (17 men, 23 women, 26 ± 5 years) were enrolled and randomly assigned to either the CAT group, with 20 subjects undergoing orthodontic treatment with aligners (8 men, 12 women, 20 ± 6 years), or placebo group (9 men, 11 women, 25 ± 3 years), with 20 subjects wearing a Begg appliance without occlusal coverage. After dropouts were removed, the study was conducted on a total of 34 subjects (13 men, 21 women, 21 ± 6 years), with 17 in the CAT group (6 men, 11 women, 19 ± 4 years) and 17 (7 men, 10 women, 24 ± 3 years) in the placebo group, followed for 1 year. Sleep bruxism index and electromyographic signals were recorded using a portable electromyographic-electrocardiographic device (Bruxoff, Bioelettronica, Turin, Italy) at baseline (T0), after 1 month (T1), 3 months (T2), 6 months (T3) and 12 months (T4). Results: CAT produced no significant changes in the sleep bruxism index. A reduction in masseter contractions, more specifically general phasic contractions not related to sleep bruxism, was observed after 1 year of treatment in patients wearing clear aligners (P < 0.05). Conclusion: The use of CAT in orthodontic patients does not influence the sleep bruxism index, but can affect some specific electromyographic background signals. Keywords: clear aligners, electromyography, orthodontics, sleep bruxism

Objective: To describe the use of clear aligners to achieve mandibular molar distalization in patients with molar Angle Class III relationship. Materials and methods: Two patients, aged 31 and 23 years old, with molar Angle Class III relationship and canine Class III relationship are presented and discussed. The patients were non-growing patients, so treatment plans included the distalization of mandibular molars. Due to the aesthetic concerns, it was decided to correct the malocclusion only with clear aligners, without additional appliances. Results: Although the patients were non-growing, distalization of mandibular molars was obtained and Angle molar and canine Class I relationships were achieved. The perception of facial profile improvement was very motivating for patients and it helped to reinforce treatment compliance. Conclusions: The presentation of these case reports shows that the use of clear aligners was reliable in non-growing patients to correct canine and molar Class III relationships. Keywords: Class III malocclusion, Invisalign, mandibular molar distalization, non-growing patients

Objective: To describe the use of clear aligners to achieve mandibular advancement in patients with retrognathic mandible. Materials and methods: Four patients, aged 9 and 10 years old, with a molar Angle class II relationship and canine class II relationships and with convex profile with retruded mandible are presented and discussed. The patients were in correspondence of the pubertal peak, so treatment plans included the advancement of the mandible to possibly stimulate mandibular growth. Due to the aesthetic concerns of the patients and their parents, it was decided to correct the malocclusion by only using clear aligners, without additional appliances. Results: The important correction of canine and molar relationships was achieved within 6 to 8 months of treatment. The perception of facial profile improvement was motivating for patients and helped to reinforce treatment compliance. Conclusions: The presentation of these case reports shows that the use of clear aligners in growing patients to correct canine and molar class II relationships with retruded mandibles is successful. Keywords: case report, class II, growing patient, Invisalign, mandibular advancement

Objective: To update the scientific evidence relating to the efficacy of clear aligner treatment (CAT) in controlling orthodontic tooth movement (OTM). Materials and methods: International medical databases were searched to identify all peer-reviewed papers potentially relevant to the review. The quality of evidence was ranked using the Swedish Council on Technology Assessment in Health Care Tool criteria. Results: Twenty relevant articles were selected and the quality of evidence was high for three studies, moderate for 12 studies and low for five studies. Mesio-distal tooth movement revealed the highest predictability, with a molar distalization up to 2.5 mm and space closure of 7 mm performed with good control. Arch expansion is predictable up to 2 mm on molars. Improvements in Little's and PAR Index were reported in mild to severe malocclusions. Conclusion: The overall quality of available evidence was of moderate/high level. CAT aligns and levels the arches even in severe cases, with efficient control of incisors inclination. Arch expansion and tooth bodily movement are efficiently achievable movements with CAT. Keywords: clear aligners, Invisalign, invisible orthodontics, orthodontics