Hearing problems such as hearing loss and susurrus aurium are said to improve with occlusal treatment, but few objective clinical reports have been published in the dental field. We looked at the effect of occlusal treatment and chewing instruction on hearing ability in five patients who had an occlusal disorder and the unilateral chewing habit. The following results were obtained:
1. Unilateral chewing due to occlusal disorder may cause differences in hearing ability between the right and left sides (Cases 1, 2 and 3).
2. A reduction in the vertical dimension of occlusion is considered to be one of the factors that cause a decrease in hearing ability (Cases 4 and 5).
3. In all cases, occlusal treatment and chewing instruction lead to a improvement in hearing and to equalizing of hearing ability between low and high frequencies.
These clinical findings indicate that there is a relationship between changes in hearing ability and oral function.