title: Three-dimensional assessment of upper lip positional changes according to simulated maxillary anterior tooth movements by white light scanning.
abstract: OBJECTIVE
  Esthetic improvements during orthodontic treatment are achieved by changes in positions of the lips and surrounding soft tissues. Facial soft-tissue movement has already been two-dimensionally evaluated by cephalometry. In this study, we aimed to three-dimensionally assess positional changes of the adult upper lip according to simulated maxillary anterior tooth movements by white light scanning.
  
  
  METHODS
  We measured changes in three-dimensional coordinates of labial landmarks in relation to maxillary incisor movements of normal adults simulated with films of varying thickness by using a white light scanner.
  
  
  RESULTS
  With increasing protraction, the upper lip moved forward and significantly upward. Labial movement was limited by the surrounding soft tissues. The extent of movement above the vermilion border was slightly less than half that of the teeth, showing strong correlation. Most changes were concentrated in the depression above the upper vermilion border. Labial movement toward the nose was reduced significantly.
  
  
  CONCLUSIONS
  After adequately controlling several variables and using white light scanning with high reproducibility and accuracy, the coefficient of determination showed moderate values (0.40-0.77) and significant changes could be determined. This method would be useful to predict soft-tissue positional changes according to tooth movements.
authors.affiliation: Department of Orthodontics, School of Dentistry, Dankook University, Cheonan, Korea.
authors.forename: Hwee-Ho
authors.initials: HH
authors.lastname: Kim
authors.affiliation: Department of Orthodontics, School of Dentistry, Dankook University, Cheonan, Korea.
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Department of Orthodontics, School of Dentistry, Dankook University, Cheonan, Korea.
authors.forename: Kyung-Suk
authors.initials: KS
authors.lastname: Cha
authors.affiliation: Department of Orthodontics, School of Dentistry, Dankook University, Cheonan, Korea.
authors.forename: Dong-Hwa
authors.initials: DH
authors.lastname: Chung
authors.affiliation: Department of Orthodontics, School of Dentistry, Dankook University, Cheonan, Korea.
authors.forename: Sang-Min
authors.initials: SM
authors.lastname: Lee
keywords: Esthetics; Lip changing; Soft tissue; Three-dimensional scanner