Oral perception in tongue thrust and other oral habits

Oral stereognosis is the ability of the mouth to recognize shape and texture. Oral shape recognition is sensitive to repetition and to topical mucosal anesthesia. Age, upper and lower arch perimeter, and labiolingual dysfunction also interact with oral stereognosis. The purpose of this investigation was to define the influence of age, arch size, and oral dysfunction on oral stereognosis when submitted to repeated trials. Fifty subjects were selected before orthodontic treatment. Each subject underwent 4 trials: T1 and T4 without anesthesia and strictly similar, T2 with topical anesthesia of the tongue, and T3 with topical anesthesia of the palate. Five test pieces or stimuli were used. The recognition time (RT) of each stimulus, the perimeter of upper and lower anterior dental arch, and the labiolingual dysfunction index (LLDI) were the main variables statistically evaluated. Subjects with a mild degree of dysfunction needed more time to recognize the stimuli in T3 when compared with T2. The number of RT3 > RT2 was 2.5 +/- 1.12 in the group with a low LLDI (12 +/- 1.5), and 1.57 +/- 0.63 in the group with an LLDI of 16 +/- 2.5 (P > .05). This may be attributed to different manipulation of the test pieces between the 2 groups, which could have been modified through sensory deprivation. Bolus recognition before the swallowing act needs to be paralleled to stereognostic performance.