Morphology of the Labial Frenum by Age-Cohort: A Cross-Sectional Study

Background/Objectives: The morphology of the maxillary labial frenum varies between indi- viduals. However, little is known about the pattern of changes that are observed across develop- mental stages. This study aims to (1) compare the attachment and tension characteristics of the maxillary and mandibular labial frenum across different age groups, and (2) assess the association between frenum morphology and diastema development. Methods: Cross-sectional observational study involving 1068 subjects who presented for routine dental examinations. The morphology and palpable tension of the labial frenum along with the presence or absence of diastema were assessed. Results: The maxillary labial frenum exhibited distinct age-related differences in at- tachment site and tension. Papillary and papillary penetrating attachments were most predominant in children aged < 3 years, transitioning to a higher incidence of gingival and mucosal attach- ments by ages 3-6 years of age. Infants and young children also showed an increased incidence of palpable tension in the maxillary labial frenulum, which decreased significantly with age. The mandibular labial frenum did not demonstrate significant age-dependent variations. Diastema was significantly more common in certain maxillary labial frenum phenotypes. Conclusions: The maxillary labial frenum appears to change by around 3-6 years of age. Among other potential functional consequences, a persistently low and tight maxillary labial frenum may affect diastema development. The mandibular labial frenum does not appear to change over time.