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Whipps Cross University Hospital NHS Trust The Effect of Extraction and Non-extraction Orthodontic Treatment on Smile Aesthetics in Caucasian Females Parmjit Singh*, Margaret Collins Results Background Patients seek orthodontic treatment with aesthetic improvement as a primary goal of treatment. Males and females scored non-extraction and extraction smiles similarly. Poor smile aesthetics have been associated with premolar extraction treatment.1 Lay people and orthodontists scored similarly with higher scored awarded to non-extraction smiles: Extraction therapy is said to decrease smile width and flatten profiles. 8 Score This age old debate shows no signs of abating. 10 Aim 6 Orthodontist Lay Person 4 2 0 To test the hypothesis that non-extraction and 4 premolar extraction post-orthodontic female Caucasian patient smiles are scored equally by male and female lay people and male and female orthodontists. Subjects and Method 0 20 40 60 80 100 Assessment The descriptive statistics for lay people and orthodontists are shown below: Group n minimum maximum mean standard deviation 95% confidence interval 50 3.20 7.80 5.93 1.12 5.61/6.25 50 3.00 7.00 5.24 1.03 4.95/5.54 50 2.40 7.60 5.33 1.24 4.98/5.68 50 2.00 7.40 4.82 1.13 4.50/5.14 Orthodontists: The study adopted a hospital based retrospective design. Non-extraction 5 non-extraction and 5 extraction subjects were selected from cases previously used for the MSc and MOrth examinations. Extraction A standardised smile photograph was taken.2 Extraction Lay People: Non-extraction The non-extraction smiles are shown in the left column and the extraction smiles in the right column below: Non-extraction smiles were scored more favourably than extraction smiles by both lay people (p<0.01) and orthodontists (p<0.03). The photographs were inserted into a photo album. This difference was attributed mainly to lip position, tooth alignment, tooth colour and tooth shape. 100 assessors were recruited comprising 50 lay people and 50 orthodontists. Few made reference to the broadness of the smile or buccal corridor space.3 Each group was made up of 25 male and 25 female assessors. Assessors were asked to familiarise themselves with the photographs in the album. A questionnaire was then completed by going through the album again using a visual analogue scale: 0 1 2 3 Very unattractive 4 5 6 7 8 9 10 Very attractive Assessors were finally asked to name the factor that most influenced their scores. Smile scores were analysed using a Univariate Analysis of Variance. Using 10 assessors, the reproducibility of the smile scores was evaluated with a Wilcoxin Signed Rank Test and no significant difference was found. Conclusions Lay people and orthodontists awarded higher scores to non-extraction smiles in this sample of Caucasian females. This difference could not be attributed to the type of treatment (non-extraction or extraction). The alleged detrimental effects of extraction therapy should be questioned. References 1. Witzig JW, Spahl TJ. The clinical management of basic maxillofacial orthopaedic appliances. Littleton (Mass), 1987: PSG Publishing Company. 2. Trumble A. A brief history of the smile. New York, 2004: Basic Books 3. Frush JP, Fisher RD. The dynesthetic interpretation of the dentogenic concept. J Pros Dent 1958; 8: 558-581. *Contact details: [email protected]