Change of Lip Curvature Through Extraction and Non-Extraction Orthodontic Treatment

Backgroud: Orthodontic treatment plans face challenges when deciding on tooth extraction, particularly when the retraction of incisors leads to a flattening of the lip curvature. Despite the significance of this issue, quantitative measurements of curvature have not been previously undertaken. This...

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Main Authors: Boosung Kim, Young Ho Kim, Soo Min Lee, Un-Bong Baik, Janghoon Ahn, Jeong Won Shin, Hwa Sung Chae
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/14/24/11715
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author Boosung Kim
Young Ho Kim
Soo Min Lee
Un-Bong Baik
Janghoon Ahn
Jeong Won Shin
Hwa Sung Chae
author_facet Boosung Kim
Young Ho Kim
Soo Min Lee
Un-Bong Baik
Janghoon Ahn
Jeong Won Shin
Hwa Sung Chae
author_sort Boosung Kim
collection DOAJ
description Backgroud: Orthodontic treatment plans face challenges when deciding on tooth extraction, particularly when the retraction of incisors leads to a flattening of the lip curvature. Despite the significance of this issue, quantitative measurements of curvature have not been previously undertaken. This study presents novel soft tissue measurements, namely SAL (A’toSn-Ls) depth, SAL angle, PBL (B’toLi-Pg) depth, and angle, as tools for assessing lip curvature. The aim of this study was to assess whether new parameters demonstrated more pronounced flattening of the upper and lower lips in the extraction group compared to the non-extraction group. Methods: A total of sixty-two patients diagnosed with skeletal Class I malocclusion and treated with extraction or non-extraction orthodontic treatment were included and compared. Cephalometric measurements were analyzed and compared between the initial and final stages of treatment. Results: The difference in SAL (1.99°) and PBL (4.41°) angles and other soft tissue measurements between the groups was not statistically significant. Multiple regression analysis yielded the equation: ΔSAL = 0.66ΔU1 tip – 0.98ΔL1 tip – 1.58. Conclusions: Flattening of the upper lip was not significantly displayed on moderate anchorage. Consequently, orthodontic treatment accompanying the retraction of the upper incisors does not always result in obtuse lip profiles.
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spelling doaj-art-86c41511d8eb4e8da0b605d0e206958e2025-08-20T02:53:40ZengMDPI AGApplied Sciences2076-34172024-12-0114241171510.3390/app142411715Change of Lip Curvature Through Extraction and Non-Extraction Orthodontic TreatmentBoosung Kim0Young Ho Kim1Soo Min Lee2Un-Bong Baik3Janghoon Ahn4Jeong Won Shin5Hwa Sung Chae6Department of Orthodontics, Institute of Oral Health Science, Ajou University School of Medicine, Suwon 16499, Republic of KoreaDepartment of Orthodontics, Institute of Oral Health Science, Ajou University School of Medicine, Suwon 16499, Republic of KoreaInstitute of Human Nutrition, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USADepartment of Orthodontics, Institute of Oral Health Science, Ajou University School of Medicine, Suwon 16499, Republic of KoreaDepartment of Orthodontics, Gwangmyeong Hospital, Chungang University, Gwangmyeong 14353, Republic of KoreaDepartment of Orthodontics, Institute of Oral Health Science, Ajou University School of Medicine, Suwon 16499, Republic of KoreaDepartment of Orthodontics, Institute of Oral Health Science, Ajou University School of Medicine, Suwon 16499, Republic of KoreaBackgroud: Orthodontic treatment plans face challenges when deciding on tooth extraction, particularly when the retraction of incisors leads to a flattening of the lip curvature. Despite the significance of this issue, quantitative measurements of curvature have not been previously undertaken. This study presents novel soft tissue measurements, namely SAL (A’toSn-Ls) depth, SAL angle, PBL (B’toLi-Pg) depth, and angle, as tools for assessing lip curvature. The aim of this study was to assess whether new parameters demonstrated more pronounced flattening of the upper and lower lips in the extraction group compared to the non-extraction group. Methods: A total of sixty-two patients diagnosed with skeletal Class I malocclusion and treated with extraction or non-extraction orthodontic treatment were included and compared. Cephalometric measurements were analyzed and compared between the initial and final stages of treatment. Results: The difference in SAL (1.99°) and PBL (4.41°) angles and other soft tissue measurements between the groups was not statistically significant. Multiple regression analysis yielded the equation: ΔSAL = 0.66ΔU1 tip – 0.98ΔL1 tip – 1.58. Conclusions: Flattening of the upper lip was not significantly displayed on moderate anchorage. Consequently, orthodontic treatment accompanying the retraction of the upper incisors does not always result in obtuse lip profiles.https://www.mdpi.com/2076-3417/14/24/11715extraction vs. non-extractionsoft tissue responseaestheticslip curvature
spellingShingle Boosung Kim
Young Ho Kim
Soo Min Lee
Un-Bong Baik
Janghoon Ahn
Jeong Won Shin
Hwa Sung Chae
Change of Lip Curvature Through Extraction and Non-Extraction Orthodontic Treatment
Applied Sciences
extraction vs. non-extraction
soft tissue response
aesthetics
lip curvature
title Change of Lip Curvature Through Extraction and Non-Extraction Orthodontic Treatment
title_full Change of Lip Curvature Through Extraction and Non-Extraction Orthodontic Treatment
title_fullStr Change of Lip Curvature Through Extraction and Non-Extraction Orthodontic Treatment
title_full_unstemmed Change of Lip Curvature Through Extraction and Non-Extraction Orthodontic Treatment
title_short Change of Lip Curvature Through Extraction and Non-Extraction Orthodontic Treatment
title_sort change of lip curvature through extraction and non extraction orthodontic treatment
topic extraction vs. non-extraction
soft tissue response
aesthetics
lip curvature
url https://www.mdpi.com/2076-3417/14/24/11715
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