The Effect of Sodium Fluoride on Otosclerotic Activity as Determined by Strontium 85

Abstract

Sodium fluoride (NaFl) has the effect of changing active foci of otosclerosis to quiescence. Strontium⁸⁵ (Sr⁸⁵) was used to determine the process of calcium deposition in normal canal wall bone and in the footplates of patients with bilateral otosclerosis before and after the administration of NaFl. The first surgery was performed on the poorer hearing ear. Fragments from oval window bone initially showed up to 34 times as much radioactivity as fragments from canal wall bone. The patients then took 25 mg of NaFl daily for six months. None failed to close and maintain gap closure within 11 dB for five months. The same evaluation was done on the bone of the footplate after surgery on the second ear. There was little or no more radioactivity in the footplate bone than in the ear canal wall bone used as a control, indicating cessation or diminution of activity at the otosclerotic focus. Prior to initiating this study, other patients with familial, progressive, purely sensorineural loss showed little or no hearing loss progression after undergoing fluoride therapy. We now recommend 25 mg daily for individuals with progressive hereditary sensorineural hearing loss and evidence of otosclerosis by polytomography.