The influence of fluoridation of drinking water on the long-term hearing results of stapedectomy.

The long-term hearing results of stapedectomy were assessed in 294 patients with otosclerosis living in an area where the natural waters have a very low fluoride content. Only patients with an initially successful outcome were included. Patients having an additional known cause of hearing loss were excluded. The mean follow-up period was 9 yr. From the best hearing levels achieved 6 to 12 months after surgery, the mean air conduction thresholds showed an annual impairment of 0.4 to 1.1 dB/year and bone conduction thresholds an annual impairment of 0.5 to 1.0 dB/year. There was no significant difference between patients drinking fluoridated tap water and those drinking low-fluoride water. It is concluded that a daily sodium fluoride intake of 1 to 3 mg in a low-fluoride area is too small to have a significant effect on hearing impairment after stapedectomy.