2017 Volume 55 Issue 4 Pages 458-466
We determined the direction of lip closure force in children with normal occlusion and those with maxillary protrusion, and also compared tongue pressure between those groups. In addition, the prevalence of dental caries and lip closing habit was investigated using questionnaire findings. Among pediatric patients aged 8-11 years old who visited Kyushu Dental University Hospital, 15 with normal occlusion and 15 with maxillary protrusion were randomly selected as subjects for the present study. Measurements obtained using a multi-directional lip closing force measurement system showed no significant difference in regard to direction-specific lip closure force between the groups. On the other hand, the normal occlusion group had a significantly higher impulse value as compared to the maxillary protrusion group. As for tongue pressure, no significant difference was observed between the groups. Furthermore, there was no correlation found between tongue pressure and comprehensive lip closure force. Our investigation of dental caries prevalence also revealed no significant difference between children with normal occlusion and those with maxillary protrusion. Additionally, no correlation was found between comprehensive lip closure force and caries prevalence in our subjects with normal occlusion, whereas there was a negative correlation noted in those with maxillary protrusion. In our evaluation of lip closing habit investigated by questionnaire, children with maxillary protrusion were able to open their mouth more easily. Finally, there was no correlation observed between allergic predisposition and maxillary protrusion.
