{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T20:58:39Z","timestamp":1792789119429,"version":"4.5.0"},"reference-count":38,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T00:00:00Z","timestamp":1789948800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Zhejiang University School of Medicine Education Reform Project","award":["jgyb2025018"],"award-info":[{"award-number":["jgyb2025018"]}]},{"name":"Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine Research and Development Project","award":["RD2022YYYB04"],"award-info":[{"award-number":["RD2022YYYB04"]}],"id":[{"id":"https:\/\/ror.org\/041yj5753","id-type":"ROR","asserted-by":"crossref"}]},{"name":"Empirical Teaching Research Project of Zhejiang University","id":[{"id":"https:\/\/ror.org\/00a2xv884","id-type":"ROR","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: Lip-closing strength (LCS) is an objective measure of perioral muscle function, yet its associations with sagittal and vertical skeletal patterns and mouth-breathing screening status in school-aged children have not been well characterized. This study aimed to investigate the associations between LCS and demographic characteristics, sagittal and vertical skeletal patterns, and mouth-breathing screening status in children undergoing orthodontic assessment. Methods: A cross-sectional study was conducted on 379 children aged 7\u201312 years presenting for initial orthodontic evaluation. LCS was measured using a custom-built dynamometer with a lip-button attachment. Sagittal and vertical patterns were classified by lateral cephalometry (ANB, SN\u2013MP angles), and mouth-breathing screening status was assessed using a validated questionnaire (Habitual Mouth-Breathing Score \u2265 4 defined as screen-positive). Multivariable linear regression was performed with LCS as the outcome. Results: The mean LCS was 4.61 \u00b1 1.58 N. Skeletal Class II (4.41 \u00b1 1.33 N) and screen-positive mouth breathing (median 3.97 N) were associated with significantly lower LCS compared to Class I and screen-negative participants, respectively. Age, sex, and vertical pattern showed no significant association. In adjusted analysis, skeletal Class I (B = 0.575, \u03b2 = 0.180, 95% CI: 0.268\u20130.882) and Class III (B = 0.867, \u03b2 = 0.188, 95% CI: 0.416\u20131.317) were associated with significantly greater LCS relative to Class II (p &lt; 0.001 for both), whereas screen-positive mouth breathing was associated with significantly lower LCS (B = \u22120.808, \u03b2 = \u22120.267, 95% CI: \u22121.099 to \u22120.517, p &lt; 0.001). Conclusions: Lower LCS was associated with skeletal Class II pattern and positive mouth-breathing screening status. The observed differences were modest, and their clinical significance remains uncertain. LCS should not be used as a standalone diagnostic or treatment-planning indicator.<\/jats:p>","DOI":"10.3390\/diagnostics16183065","type":"journal-article","created":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T12:50:03Z","timestamp":1789995003000},"page":"3065","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Factors Associated with Lip-Closing Strength in Children Undergoing Orthodontic Assessment: A Cross-Sectional Study"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0723-4056","authenticated-orcid":false,"given":"Linxian","family":"Fang","sequence":"first","affiliation":[{"name":"Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou 310000, China"},{"name":"Zhejiang Provincial Clinical Research Center for Oral Diseases, Zhejiang Key Laboratory of Oral Biomedical, Hangzhou 310000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"given":"Jin","family":"Zhao","sequence":"additional","affiliation":[{"name":"Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou 310000, China"},{"name":"Zhejiang Provincial Clinical Research Center for Oral Diseases, Zhejiang Key Laboratory of Oral Biomedical, Hangzhou 310000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"given":"Jian","family":"Wang","sequence":"additional","affiliation":[{"name":"Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou 310000, China"},{"name":"Zhejiang Provincial Clinical Research Center for Oral Diseases, Zhejiang Key Laboratory of Oral Biomedical, Hangzhou 310000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"}]},{"given":"Dingzhuo","family":"Jiang","sequence":"additional","affiliation":[{"name":"Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou 310000, China"},{"name":"Zhejiang Provincial Clinical Research Center for Oral Diseases, Zhejiang Key Laboratory of Oral Biomedical, Hangzhou 310000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"}]},{"given":"Tao","family":"Qiu","sequence":"additional","affiliation":[{"name":"Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou 310000, China"},{"name":"Zhejiang Provincial Clinical Research Center for Oral Diseases, Zhejiang Key Laboratory of Oral Biomedical, Hangzhou 310000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"}]},{"given":"Ying","family":"Shi","sequence":"additional","affiliation":[{"name":"Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou 310000, China"},{"name":"Zhejiang Provincial Clinical Research Center for Oral Diseases, Zhejiang Key Laboratory of Oral Biomedical, Hangzhou 310000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"}]},{"given":"Yafen","family":"Zhu","sequence":"additional","affiliation":[{"name":"Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou 310000, China"},{"name":"Zhejiang Provincial Clinical Research Center for Oral Diseases, Zhejiang Key Laboratory of Oral Biomedical, Hangzhou 310000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4122-4786","authenticated-orcid":false,"given":"Zhifang","family":"Wu","sequence":"additional","affiliation":[{"name":"Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou 310000, China"},{"name":"Zhejiang Provincial Clinical Research Center for Oral Diseases, Zhejiang Key Laboratory of Oral Biomedical, Hangzhou 310000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"72","DOI":"10.2319\/020509-78.1","article-title":"Maximum closing force of mentolabial muscles and type of malocclusion","volume":"80","author":"Jung","year":"2010","journal-title":"Angle 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