RESEARCH ARTICLE The Prevalence of Lip Vermilion Morphological Traits in a 15-Year-Old Population Caryl Wilson, 1 Rebecca Playle, 2 Arshed Toma, 1 Alexei Zhurov, 1 Andy Ness, 3 and Stephen Richmond 1 * 1 Department of Orthodontics, University Dental Hospital, Heath Park, Cardiff, UK 2 Department of Medical Statistics, University Dental Hospital, Cardiff, UK 3 School of Oral and Dental Sciences, Lower Maudlin Street, Bristol, UK Manuscript Received: 1 September 2011; Manuscript Accepted: 14 May 2012 The aim of this study is to describe and categorize the various lip vermilion morphological traits, prevalence, and associations present in a 15-year-old population The instrument we devel- oped was checked for the reliability of assessment. The study is a cross-sectional study of lip vermilion morphology in 2,246 fifteen-year-old children. Three-dimensional surface laser scans were taken of the children, and a classification scale was derived and assessed for intra- and inter-reliability. The prevalence of lip vermilion morphological traits and associations was identified. Certain features are found to be likely to be associated with each other: thin philtrum and smooth/deep indentation of the phil- trum; wide philtrum and smooth/normal gradient, flat/absent Cupid’s bow and smooth/normal/indentation near nose, V-shaped Cupid’s bow and indentation in middle/deep groove; thin upper lip vermilion and deep groove; thick upper lip vermilion and smooth philtrum; acute nasolabial angle and upper lip double border and thick upper lip vermilion; obtuse nasolabial angle and thin upper lip vermilion. In conclusion, we present a new method to identify the various morphological features of the vermilion of the lips. The prevalence of morpho- logical traits has been identified in this 15-year-old population. In addition, the association of lip traits has been reported. This classification scale may be utilized to ascertain prevalence of features amongst other ethnic groups, to gain knowledge of what is considered to be attractive features, and to determine genotype/phenotype associations. Ó 2012 Wiley Periodicals, Inc. Key words: lip vermilion morphology; lip shape; cupid’s bow; lip phenotype; vermilion of the lip INTRODUCTION The lips are important for verbal and non-verbal communication, mastication, maintaining an oral seal and are seen as an important factor in facial and sexual attractiveness. A significant amount of literature has been written on the lips in respect to cleft lip and palate repair [Veau, 1931; Millard, 1958]; and change in lip contour as a result of surgical positioning of the maxilla and mandible [Dann et al., 1976; Ferrario et al., 1999]. However, very little has been written on the characteristics of the vermilion of the lips in a normal population. A recent three-dimensional study on a small sample of 109 5- to 6-year-old children created four categories for the philtrum; triangular, parallel, concave, and flat [Mori et al., 2005]. An expert group has produced a series of definitions and deviant traits related to the vermilion of the lips [Carey et al., 2009]; but there is no population-based data to identify and describe normal variation nor indeed the reliability of assessment. The aim of this article is to describe the various lip traits and associations present in a 15-year-old population and assess the reliability of assessment. PATIENTS AND METHODS The Sample This study is based on three-dimensional facial data collected from 15-year-old children as part of the Avon Longitudinal Study of Parents and Children (ALSPAC) [Golding et al., 2001]. This prospective study recruited pregnant women living in the former county of Avon in South-West England who had an estimated delivery date of between April 1, 1991 and December 31, 1992. The cohort was made up of 14,541 pregnancies that resulted in 13,971 singletons/twins that were alive at 1 year of age. It could be suspected that about 1% of the children could have fetal alcohol syndrome (FAS) [Sampson et al., 1997]. None of the children in our analysis had enough clinical features in-terms of *Correspondence to: Stephen Richmond, BDS, FDS RCS, MScD, PhD, FHEA, Applied Clinical Research and Public Health, Cardiff Dental School, Heath Park, Cardiff CF14 4XY, UK. E-mail: richmonds@cf.c.uk Article first published online in Wiley Online Library (wileyonlinelibrary.com): 3 December 2012 DOI 10.1002/ajmg.a.35515 How to Cite this Article: Wilson C, Playle R, Toma A, Zhurov A, Ness A, Richmond S. 2013. The prevalence of lip vermilion morphological traits in a 15-year-old population. Am J Med Genet Part A 161A:4–12. Ó 2012 Wiley Periodicals, Inc. 4