PURPOSE: The purpose of this systematic review was to examine the existing evidence on dental proportion to evaluate the existence of RED proportions in the esthetic smile in different geographic regions.

MATERIAL AND METHODS: A systematic search was conducted by reviewing different databases. The focused question was "Does RED proportion exist in esthetically pleasing smiles in different populations around the world?" The search included articles with a combination of MeSH keywords based on dental proportion from January 2000 to July 2020. The titles and abstracts were identified by using a search protocol. Full text of the articles was independently evaluated. The systematic review was modified to summarize the relevant data. The general characteristics, outcomes, and quality of studies were reviewed and analyzed systematically.

RESULTS: Seventeen studies were selected from the reviewed articles. Three studies were conducted in Europe, 10 in South Asia, and 4 in Western Asia. Eleven studies found that the mean perceived ratio of anterior teeth was not constant when progressing distally. Five studies reported that the ratio was constant in a small percentage of their populations, and 1 suggested that the ratio was constant if it remains between 60% and 80%. The central-to-LI and Ca-to-LI proportion values were not constant. Overall, the Ca-to-LI proportion values were higher than the central-to-LI proportions.

METHODS: A cross sectional study was conducted on a sample of 527 children from four schools located in Lahore, Pakistan. A 14-point questionnaire was developed, using existing measures of peer pressure, and popularity. The selected questions were modified to investigate the issues of dental aesthetics and integrated into the WHO oral health questionnaire for children.

RESULTS: More than 50 % of the participants indicated popularity issues regarding dental aesthetics. 63.5 % of the responses indicated an influence of relatives and friends, whereas 38 % responses reported of harassment and bullying at schools. Regression analysis shows that the females were 1.99 times more likely to get comments from relative or friends about their teeth and 2.17 times more likely to be bullied or harassed at school due to their teeth when compared to the males. Fathers with a higher education brought about higher popularity and peer pressure issues. Mothers with a higher education were less likely to cause popularity and peer pressure issues than mothers with a lower education. Popularity and peer pressure were both significantly related to higher dental visitation.

METHODS: Patients in the permanent dentition requiring maxillary and mandibular fixed orthodontic treatment with a preadjusted edgewise appliance were eligible for inclusion. Patients attending 4 hospital departments (United Kingdom and Italy) were randomly allocated to 1 of 4 treatment interventions: (1) BioCosmetic (Forestadent, Pforzheim, Germany), 0.017 in; (2) Titanol (Forestadent), 0.016 in; (3) TP Aesthetic (TP Orthodontics, La Porte, Ind), 0.014 in; and (4) Tooth Tone (Ortho Organizers, Calsbad, Calif) 0.016 in. Block randomization with block sizes of 4 and 8 was used to ensure an allocation ratio of 1:1:1:1. The primary outcome was alignment efficiency determined by the reduction in Little's irregularity index (mm). Secondary outcomes were color change using the Commission Internationale de L'Eclairage L*a*b* system and percentage of coating loss. Blinding was only applicable to outcome assessment of alignment efficiency. Regression models with Sidak's multiple comparison of means were used to analyze the data.

RESULTS: One hundred fifty patients (300 dental arches) were allocated to the treatment interventions, including 61 male and 89 female subjects with a mean age of 16.60 years. The average duration of follow-up was 63.65 days. Baseline characteristics for the archwire groups were similar. One patient was lost to follow-up. Five percent (n = 15) of the archwires fractured: BioCosmetic, 5.3% (n = 4); Titanol, 6.8% (n = 5); TP Aesthetic, 5.3% (n = 4); and Tooth Tone, 2.7% (n = 2). We analyzed 283 dental arches for alignment efficiency. There was no statistically significant difference for mean reduction in irregularity between the archwire groups (P = 0.627): BioCosmetic (n = 71), 3.86 mm (95% CI, 3.31-4.41); Titanol (n = 69), 4.51 mm (95% CI, 4.00-5.02); TP Aesthetic (n = 71), 4.13 mm (95% CI, 3.49-4.78); and Tooth Tone (n = 72), 4.21 mm (95% CI, 3.89-4.46). There was a statistically significant difference between archwire groups for color change (P = 0.001) and percentage of coating loss (P = 0.001), with BioCosmetic performing best in both parameters.

CONCLUSIONS: There was no difference between the archwires for alignment efficiency. BioCosmetic performed statistically significantly better than did the other groups for both color change and coating loss.

REGISTRATION: This trial was registered with the East Midlands NHS Research Ethics Committee (12/EM/0190).

METHODS: The published English version of PIDAQ was pilot tested on 12- to 17-year-old adolescents, resulting in a few modifications to suit the Malaysian variety of English. Psychometric properties were tested on 393 adolescents who attended orthodontic practices and selected schools. Malocclusion was assessed using the Malocclusion Index, an aggregation of Perception of Occlusion Scale and the Aesthetic Component of the Index of Orthodontic Treatment Need, by the subjects (MI-S) and investigators (MI-D). Data were analysed for internal consistency and age-associated invariance, discriminant, construct and criterion validities, reproducibility and floor and ceiling effects using AMOS v.20 and SPSS v.20.

RESULTS: The item Don't like own teeth on video of the Aesthetic Concern (AC) subscale was not relevant to a large proportion of participants (11.7%). Therefore, it was removed and the Malaysian English PIDAQ was analysed based on 22 items instead of 23 items. Confirmatory factor analysis showed good fit statistics (comparative fit index: 0.902, root-mean-square error of approximation: 0.066). Internal consistency was good for the Dental Self-Confidence, Social Impact and Psychological Impact subscales (Cronbach's alpha: 0.70-0.95) but lower (0.52-0.62) though acceptable for the AC subscale as it consisted of only 2 items. The reproducibility test was acceptable (intra-class correlations: 0.53-0.78). For all PIDAQ subscales, the MI-S and MI-D scores of those with severe malocclusion differed significantly from those with no or slight malocclusion. There were significant associations between the PIDAQ subscales with ranking of perceived dental appearance, need for braces and impact of malocclusion on daily activities. There were no floor or ceiling effects.

METHODS: A random sample of 800 schoolchildren aging 11-15 years was selected from different schools in the city of Dhaka, Bangladesh. The Dental Health Component (DHC) and Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) were assessed as normative treatment need. The Decayed, Missing, Filled Teeth (DMFT) index was used to record caries experience. Children were interviewed on the perception of orthodontic treatment need. Parents also completed a questionnaire on the perception of their child's orthodontic treatment need, assessed by AC/ IOTN.

RESULTS: According to the DHC/IOTN, only 24.7% were in the category of definite need (grade 4-5) for orthodontic treatment. A significant difference was found between the clinician/children and clinician/parents perceived AC score of IOTN (p= 0.0001). Multiple logistic regression showed children with a higher DMFT were significantly more likely to need orthodontic treatment, according to the DHC of IOTN.