Occlusion and hearing levels in elderly with many present teeth

Objective: Studies have suggested that occlusal disharmony may adversely affect not only the stomatognathic system but various other functions of the body. The purpose of this study was to clarify relationship between occlusion and hearing ability in elderly with many remaining teeth. Method: The study included 20 achievers of the 8020 goal (17 males, 3 female) living in Chiba Prefecture with a mean age of 81.6 years (80-87), an average of 28.1 present teeth and molar occlusion. None of them wore a denture. An audiometer (RION AA-79) was used to analyze audiogram output. The audiometric results were also studied in relation to occlusal contact area registered with Dental Prescale. Results: Ten subjects showed constant hearing levels in low to medium frequency ranges with a decrease in hearing level of high frequency sounds. Five subjects exhibited a bell-shaped curve with a peak in the medium frequency range. Five subjects exhibited other various shape. All subjects showed lower hearing levels of high frequency sounds. Right-left differences in occlusal contact area almost coincided with those in audiogram waveform, suggesting a correlation between the two. Mean hearing levels on the right and left sides were 33.3dB and 32.3dB with the three minutes method, 33.3dB and 31.2dB with the four minutes methodl, and 37.7dB and 36.7dB with six minutes method. Thus, hearing levels were very similar with no significant difference between the right and left sides. Conclusion: These results indicated that hearing levels of the elderly with many present teeth and well-balanced occlusal contacts had symmetrical hearing levels that were adequate for everyday conversation.