Restricted tongue mobility and ankyloglossia in 6–8-year-old Vietnamese school children: prevalence and association with tongue strength and endurance

Generating adequate tongue pressure against the hard palate requires full-range mobility of the tongue. The study aimed to (1) determine the prevalence of restricted tongue mobility and ankyloglossia and (2) determine whether, in children with restricted tongue mobility, their condition also affects tongue pressure.

A cross-sectional study of healthy 6–8-year-old children from primary schools in central Vietnam was conducted in 2019. Restricted tongue mobility and ankyloglossia were graded using the tongue range of motion ratio (TRMR), with the tongue-tip-to-incisive papillae (TIP) for the anterior tongue tip and lingual–palatal suction (LPS) for the posterior two-thirds of the tongue. Tongue strength and tongue endurance were measured by the Iowa Oral Pressure Instrument. Statistical analysis investigated the associations between tongue mobility and tongue pressure measurement.

Five hundred twelve children (46.5% female, mean age 7.2 ± 0.2 years) were assessed. The prevalence of anterior ankyloglossia and restricted mobility was 17.5%, with 16.2% cases of less than 50% mobility and 1.3% cases of less than 25% mobility. The prevalence of posterior ankyloglossia and restricted mobility with less than 30% mobility was 28.9%. Anterior restricted mobility was not a predictor of reduced tongue pressure. Posterior restricted mobility in LPS was independently associated with tongue strength but not tongue endurance.

Restrictions of posterior tongue mobility in ankyloglossia are more frequent than restrictions in anterior tongue mobility. Reduced tongue strength is related to mobility and the severity of restrictions in the posterior tongue. These findings suggest that restricted posterior tongue mobility may affect tongue muscle weakness.