title: The influence of age on lip-line cant in adults: a cross-sectional study.
abstract: OBJECTIVE
  The aims of this study were to assess the direction and degree of lip-line cant in Korean adult orthodontic patients and to identify the effects of sex and age on changes in the cant severity.
  
  
  METHODS
  In this cross-sectional retrospective study, lip-line cant was measured in the frontal photographs of 585 Korean patients (92 men and 493 women) aged 18-48 years. The outcome variables (direction and degree of lip-line cant) were assessed in terms of predictor variables (sex, age, sagittal skeletal relationship, and menton deviation angle).
  
  
  RESULTS
  The direction of lip-line cant did not differ according to sex, age, or skeletal classification. Patients had 1.6° of lip-line cant on average before orthodontic treatment. Middle-aged adults displayed a significant trend toward a lower degree of lip-line cant compared to younger adults (p < 0.01). Multiple linear regression analysis showed that the degree of lip-line cant was weakly negatively correlated with age (p < 0.001).
  
  
  CONCLUSIONS
  While the direction of lip-line cant did not differ according to the parameters explored here, the degree of cant was correlated with age in adults, independent of menton deviation. Specifically, middle-aged adults tended to display significantly lower degrees of lip-line cant than did younger adults.
authors.affiliation: Department of Orthodontics, Institute of Craniofacial Deformity, College of Dentisrty, Yonsei University, Seoul, Korea.
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Private Practice, Seongnam, Korea.
authors.forename: Jung Suk
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Private Practice, Seongnam, Korea.
authors.forename: Cheol Soon
authors.initials: CS
authors.lastname: Kim
authors.affiliation: Department of Orthodontics, Institute of Craniofacial Deformity, College of Dentisrty, Yonsei University, Seoul, Korea.
authors.forename: Chung Ju
authors.initials: CJ
authors.lastname: Hwang
keywords: Adults; Age; Lip-line cant; Menton deviation