Takashi Murakami1, Tomoki Kataoka1, Junpei Tagawa1, Takashi Yamashiro2, Hiroshi Kamioka3. 1. *Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University. 2. **Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Osaka University, Japan. 3. *Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, kamioka@md.okayama-u.ac.jp.
Abstract
UNLABELLED: Summary Objectives: The purposes of this study were to investigate whether the antero-posterior and vertical facial type variations influenced the favoured lip positions and to elucidate whether the favoured lip positions differed between orthodontists and laypersons. METHODS: An average profile was constructed from a Japanese female with Class I occlusion and a well-balanced profile, as assessed by several cephalometric analyses. Nine facial types were composed by morphing the chin antero-posteriorly and/or vertically. Thirteen morphed lip profiles were constructed by moving the lips antero-posteriorly in the nine facial types, respectively. Seventy-seven Japanese laypersons and 30 orthodontists were asked to choose the top three most-favoured lip positions for each facial type. RESULTS: The protruded lip positions were significantly favoured for all the mandibular protrusive facial types. The retruded lip positions were significantly favoured for the short facial type of the antero-posteriorly average and mandibular retrusive-short facial types. Among the mandibular protrusive facial types, the protruded lip positions were significantly favoured for the long facial type. The retruded lip positions were statistically more attractive for orthodontists than laypersons on the antero-posteriorly average-short, mandibular protrusive-short, mandibular retrusive-vertically average, antero-posteriorly average-vertically average, and mandibular retrusive-long facial types. LIMITATIONS: Our data were limited by the specific ethnic groups and variety of facial types. CONCLUSION: The favoured antero-posterior lip position was affected by not only the antero-posterior facial disproportion but also by the vertical dimensions. The favoured lip positions differed between orthodontists and laypersons. These results might be helpful in deciding between extraction and non-extraction treatment in borderline cases.
UNLABELLED: Summary Objectives: The purposes of this study were to investigate whether the antero-posterior and vertical facial type variations influenced the favoured lip positions and to elucidate whether the favoured lip positions differed between orthodontists and laypersons. METHODS: An average profile was constructed from a Japanese female with Class I occlusion and a well-balanced profile, as assessed by several cephalometric analyses. Nine facial types were composed by morphing the chin antero-posteriorly and/or vertically. Thirteen morphed lip profiles were constructed by moving the lips antero-posteriorly in the nine facial types, respectively. Seventy-seven Japanese laypersons and 30 orthodontists were asked to choose the top three most-favoured lip positions for each facial type. RESULTS: The protruded lip positions were significantly favoured for all the mandibular protrusive facial types. The retruded lip positions were significantly favoured for the short facial type of the antero-posteriorly average and mandibular retrusive-short facial types. Among the mandibular protrusive facial types, the protruded lip positions were significantly favoured for the long facial type. The retruded lip positions were statistically more attractive for orthodontists than laypersons on the antero-posteriorly average-short, mandibular protrusive-short, mandibular retrusive-vertically average, antero-posteriorly average-vertically average, and mandibular retrusive-long facial types. LIMITATIONS: Our data were limited by the specific ethnic groups and variety of facial types. CONCLUSION: The favoured antero-posterior lip position was affected by not only the antero-posterior facial disproportion but also by the vertical dimensions. The favoured lip positions differed between orthodontists and laypersons. These results might be helpful in deciding between extraction and non-extraction treatment in borderline cases.