{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T19:31:29Z","timestamp":1786649489504,"version":"build-2736575974"},"reference-count":29,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"1","license":[{"start":{"date-parts":[[2025,12,1]],"date-time":"2025-12-01T00:00:00Z","timestamp":1764547200000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"abstract":"<jats:sec>\n                    <jats:title>BACKGROUND:<\/jats:title>\n                    <jats:p>Maxillary midline diastema (MMD) is a gap between the maxillary central incisors, posing cosmetic and psychosocial concerns for most patients. MMD results from multifactorial causes, including labial frenum, microdontia, genetics, and various oral habits. The purpose of this article was to review MMD, analyze its prevalence, describe a new shape-based classification, and identify potential causes with a focus on evidence-based practice.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>MATERIALS AND METHODS:<\/jats:title>\n                    <jats:p>\n                      This cross-sectional descriptive study utilized orthodontic clinical records of Saudi adults aged 18\u201330 years who had not sought orthodontic treatment. MMD presence was confirmed by examining dental models. Diastema size was measured at gingival, middle, and incisal levels using a Mitutoyo calliper with 0.1 mm accuracy. Pairs of Angle Class I models were used to ensure equivalent tooth size for specimens. Patient records were reviewed to determine etiologies, and Bolton\u2019s tooth size ratio was calculated for analysis. Statistical analyses included\n                      <jats:italic toggle=\"yes\">Z<\/jats:italic>\n                      -test, Shapiro\u2013Wilk test, paired\/independent\n                      <jats:italic toggle=\"yes\">t<\/jats:italic>\n                      -tests, and\n                      <jats:italic toggle=\"yes\">post-hoc<\/jats:italic>\n                      Bonferroni tests, conducted using SPSS version 26.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>RESULTS:<\/jats:title>\n                    <jats:p>\n                      The overall prevalence of MMD was 25% (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 96), with 67% occurring in males. Among malocclusions, MMD prevalence was 42% in Class I, 32% in Class II, and 26% in Class III. MMD size distribution was 0.5\u20131 mm (18%), 1\u20132 mm (38%), and &gt;2 mm (44%). A new shape-based classification identified trapezoidal (44%), triangular (40%), rectangular (12%), inverted triangular (2%), and biconcave (2%) forms. Major contributors included labial frenum elongation (25%), microdontia (19%), and midline shifting (72%). No significant differences in tooth sizes were found between MMD cases and Angle Class I controls (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &gt; 0.05). Differences at the three measurement levels were negligible (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &gt; 0.05) for both gender and malocclusion.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>CONCLUSION:<\/jats:title>\n                    <jats:p>This study highlights the polygenic nature of MMD and introduces a new shape-based classification. Key predisposing factors, such as midline shift and microdontia, were identified. These findings will guide clinicians in treating patients diagnosed with MMD.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.4103\/jos.jos_63_25","type":"journal-article","created":{"date-parts":[[2025,12,23]],"date-time":"2025-12-23T12:00:23Z","timestamp":1766491223000},"update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["Median diastema: Prevalence, novel classification, and evidence-based investigation"],"prefix":"10.4103","volume":"14","author":[{"given":"Mohammad Khursheed","family":"Alam","sequence":"first","affiliation":[{"name":"Department of Preventive Dentistry, Orthodontic Division, College of Dentistry, Jouf University, Sakaka, Saudi Arabia"},{"name":"Department of Dental Research Cell, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India"},{"name":"Department of Public Health, Daffodil International University, Dhaka, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nawadir Hamoud","family":"Alanazi","sequence":"additional","affiliation":[{"name":"College of Dentistry, Jouf University, Sakaka, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tethkar Mukhlef","family":"Alanzi","sequence":"additional","affiliation":[{"name":"College of Dentistry, Jouf University, Sakaka, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shahad","family":"Mohammad","sequence":"additional","affiliation":[{"name":"College of Dentistry, Jouf University, Sakaka, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mona Saleh","family":"Alazmi","sequence":"additional","affiliation":[{"name":"College of Dentistry, Jouf University, Sakaka, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Awsaf Murdhi","family":"Alruwaili","sequence":"additional","affiliation":[{"name":"College of Dentistry, Jouf University, Sakaka, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aynaa Fawaz","family":"AlRashed","sequence":"additional","affiliation":[{"name":"College of Dentistry, Jouf University, Sakaka, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohammad Younis","family":"Hajeer","sequence":"additional","affiliation":[{"name":"Department of Orthodontics, University of Damascus, Damascus, Syria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yahya Abdullah","family":"Alogaibi","sequence":"additional","affiliation":[{"name":"Aseer Specialized Dental Center, Abha, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2025,12]]},"reference":[{"key":"R1-20251223","first-page":"6810984","article-title":"Direct Midline Diastema Closure with Composite Layering Technique: A One-Year Follow-Up","volume":"2016","author":"Korkut","year":"2016","journal-title":"Case Rep Dent"},{"key":"R2-20251223","first-page":"5607594","article-title":"Zakria Jaija, Amr Ragab El-Beialy, Yehya A. Mostafa. Revisiting the Factors Underlying Maxillary Midline Diastema","volume":"2016","author":"Abdullah","year":"2016","journal-title":"Scientifica"},{"key":"R3-20251223","doi-asserted-by":"crossref","first-page":"740","DOI":"10.1016\/j.ajodo.2016.06.022","article-title":"Laypeople\u2019s perceptions of frontal smile esthetics: a systematic review","volume":"150","author":"Parini","year":"2016","journal-title":"Am J Orthod Dentofacial Orthop"},{"issue":"Suppl 1","key":"R4-20251223","doi-asserted-by":"crossref","first-page":"S162","DOI":"10.4103\/0975-7406.137435","article-title":"Changes in quality of life during orthodontic correction of midline diastema","volume":"6","author":"Nagalakshmi","year":"2014","journal-title":"J Pharm Bioallied Sci"},{"key":"R5-20251223","first-page":"6810984","article-title":"Direct midline diastema closure with composite layering technique: A one-year follow-up","volume":"2016","author":"Korkut","year":"2016","journal-title":"Case Rep 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