Occlusal characteristics in subjects with or without the ability to roll the tongue

The tongue represents an important intraoral muscular force which is in direct contact with the dental arches. The objective of the current study was to compare occlusal characteristics of patients who have the ability to roll their tongue (TR+) to those who cannot (TR-).

A hundred consecutive patients under orthodontic treatment were classified as TR+ (n=73) or TR- (n=27). Pre-treatment orthodontic study casts were used to measure intercanine and intermolar widths, arch lengths, space deficiency, overjet, overbite, presence or absence of posterior crossbite and the molar Angle class. For continuous variables, independent sample t-tests and Mann-Whitney U tests were used to examine differences between the groups. For dichotomous variables, chi-square tests were used to examine differences between groups.

TR+ patients showed larger mandibular inter-molar widths (1 mm, p<0.05) and less mandibular space deficiency (1.9 mm, p<0.05) than TR- patients. Mandibular space deficiency was present in the mandibular arch in 18.5% of TR+ compared to 49.3% in TR- patients (p<0.05).

The ability to roll the tongue may lead to differences in occlusal characteristics, namely an increase in mandibular intermolar width and a less mandibular space deficiency.