Effects of bite raising and occlusal awareness on tongue thrust in untreated children

The purpose of this study was to determine the influence of conscious bite (occlusal awareness), with or without immediate bite raising, on tongue thrust during swallowing and speech. A total of 110 untreated children (age range, 7-12 years; mean, 9 years 8 months) were examined with various extraoral and intraoral observation tests. Subjects were divided according to sex and score on the labiolingual dysfunction index (LLDI) into high (LLDI-H) and weak (LLDI-W) dysfunction groups. A special, previously tested chocolate paste was used to map tongue and tooth contacts during task performance, including conscious bite (occlusal awareness) with and without bite raising. The bite was raised with an overlay or provisional occlusal plane placed unilaterally on the maxillary right molar. The results did not show any difference between boys and girls, but other findings were related to the LLDI score. Habitual mouth closure and swallowing without the provisional occlusal plane produced less pronounced bite contact in the LLDI-H group. Swallowing with conscious bite increased the bite contact in both groups but predominantly in the LLDI-H group. Tongue thrust reacted inversely to bite contacts: it was reduced when occlusion was perceived with and without bite raise but somewhat more with the provisional occlusal plane. The LLDI-W group was less affected. Tongue thrust was inhibited in both groups during speaking with bite raising and occlusal awareness. These results indicate that conscious bite helps to control the tongue. Slight raising of the bite increases occlusal awareness and its inhibiting effect on tongue thrust. A provisional occlusal plane or a similar overlay might be a useful adjunct in training the tongue to retrude in subjects with oral dysfunction.