Evaluation of middle ear function in primary dentition children with posterior cross bite

Abstract

Posterior cross bite in the primary dentition causes not only functional disorders in jaw movements but also maxillofacial asymmetry. Previous reports have demonstrated a functional relationship between the stomatognathic system and middle ear. The purpose of this study was to investigate the association between cross bite and middle ear function. Thirteen children with posterior cross bite (mean age 5.3 years) and 10 children with normal occlusion (mean age 5.5 years) in the primary dentition were examined. The size of the primary tooth crowns and primary dental arches was measured in dental models. The middle ear compliance was measured on a tympanogram using Impedance Audiometer SI-50I (Morita Co.). Differences among the measured values of Static Compliance, Pressure, and Ear Clearance in the left and right ears were computed as absolute values and the pattern of tympanograms observed. The following results were obtained: (1) There was no significant difference in the mesiodistal width of the primary tooth crown. In the cross bite group, the arch width of maxilla was smaller than that of the normal Japanese standard of 5-year-olds. (2) Regarding the pressure, there was significant difference between children with posterior cross bite and normal occlusion. (3) Regarding tympanogram, in the normal group, 90% showed symmetrical Type A (normal range for tympanogram) on both sides, and in the cross bite group, 53.8% showed symmetrical Type A and 7.7% showed Type As (restricted tympanogram) on both sides. Type C (retracted tympanogram) indicating eustachian tube abnormality was not seen in the normal group, however, in the cross bite group, it was seen in 7.7% of the right and 23.1% of the left side ears. (4) There was no correlation between incisor midline shift and the pressure. It was concluded that children with posterior cross bite were at a significantly increased risk for middle ear dysfunction.