关键词: 唇肌力量, 鼻呼吸习惯, 张口呼吸习惯, 青少年, 错??畸形

Abstract: Objective    By measuring the lip muscle strength of adolescent patients with average-angle profiles and different breathing habits，this study aims to analyze the effects of breathing habits，sagittal skeletal relationship，age，and gender on lip muscle strength，thereby providing references for perioral muscle function training. Methods    A total of 560 adolescent patients with average-angle profiles who visited the Department of Orthodontics and the First Outpatient Clinic of the Stomatological Hospital affiliated to China Medical University between June 2022 and March 2025 were selected. All patients were divided into a nasal breathing habit group（normal nasal breathing，denoted as B）and a mouth breathing habit group（exhibiting mouth breathing habits，denoted as K），with 280 patients in each group. Patients in both groups were further subdivided into skeletal Class Ⅰ［0.7° ≤ ANB（angle formed by the maxillary alveolar ridge，nasal root，and mandibular alveolar ridge） ≤ 4.7°，denoted as Ⅰ］and skeletal Class Ⅱ（ANB > 4.7°，denoted as Ⅱ），male（denoted as M）and female（denoted as F），and aged 9 - 12 years（denoted as 1）and > 12 - 16 years（denoted as 2）. This resulted in the following subgroups：BⅠM1，BⅠM2，BⅠF1，BⅠF2，BⅡM1，BⅡM2，BⅡF1，BⅡF2，KⅠM1，KⅠM2，KⅠF1，KⅠF2，KⅡM1，KⅡM2，KⅡF1，and KⅡF2，with 35 patients in each subgroup. Lip muscle strength was measured for all patients using a lip muscle measurement and training device（Patent No.ZL202210078382.4）developed in collaboration with the Shenyang Institute of Automation，Chinese Academy of Sciences. Results    The lip muscle strength in the mouth-breathing habit group was（50.01 ± 7.58）gf，while that in the nasal-breathing habit group was（130.37 ± 3.66）gf，showing a statistically significant difference between the two groups（t = -159.839，P < 0.001）. The lip muscle strengths for the BⅠM1，BⅠM2，BⅠF1，BⅠF2，BⅡM1，BⅡM2，BⅡF1，BⅡF2，KⅠM1，KⅠM2，KⅠF1，KⅠF2，KⅡM1，KⅡM2，KⅡF1，and KⅡF2 subgroups were（142.33 ± 3.57），（163.54 ± 2.17），（128.49 ± 4.58），（131.29 ± 3.63），（111.92 ± 2.51），（119.24 ± 3.75），（109.75 ± 4.22），（116.41 ± 4.89），（52.48 ± 9.62），（51.91 ± 9.85），（48.93 ± 5.82），（50.83 ± 5.26），（49.85 ± 5.62），（48.84 ± 6.57），（49.16 ± 7.12）and（48.12 ± 9.32）gf，respectively. Among these，statistically significant differences in lip muscle strength were found between the following subgroup pairs：BⅠM1 vs. BⅡM1，BⅠM2 vs. BⅡM2，BⅠF1 vs. BⅡF1，BⅠF2 vs. BⅡF2，BⅠM1 vs. BⅠF1，BⅠM2 vs. BⅠF2，BⅡM1 vs. BⅡF1，BⅡM2 vs. BⅡF2，BⅠM1 vs. BⅠM2，BⅠF1 vs. BⅠF2，BⅡM1 vs. BⅡM2，and BⅡF1 vs. BⅡF2（all P < 0.05）. In contrast，no statistically significant differences were observed between the following subgroup pairs：KⅠM1 vs. KⅡM1，KⅠM2 vs. KⅡM2，KⅠF1 vs. KⅡF1，KⅠF2 vs. KⅡF2，KⅠM1 vs. KⅠF1，KⅠM2 vs. KⅠF2，KⅡM1 vs. KⅡF1，KⅡM2 vs. KⅡF2，KⅠM1 vs. KⅠM2，KⅠF1 vs. KⅠF2，KⅡM1 vs. KⅡM2，and KⅡF1 vs. KⅡF2（all P > 0.05）. Conclusion    Adolescent patients with average-angle profiles and different breathing habits exhibit varying lip muscle strength. Patients with mouth-breathing habits demonstrate lower lip muscle strength than those with nasal-breathing habits. Among patients with nasal-breathing habits，differences in sagittal skeletal relationship（skeletal Class Ⅰ and Class Ⅱ），age group（9 - 12 years and > 12 - 16 years），and gender are associated with variations in lip muscle strength.

Key words: lip muscle strength, nasal-breathing habit, mouth-breathing habit, adolescents, malocclusion