Resolution of Untoward Nonauditory Stimulation and Cochlear Implant Performance Gain After Extraction of a Stainless Steel Dental Crown in a Patient With Cochlear Otosclerosis

Abstract

To report a unique case of untoward nonauditory stimulation and cochlear implant performance deterioration after the placement of a stainless steel dental crown. Clinical capsule report. Tertiary academic referral center. A 64-year-old female with a history of advanced otosclerosis and sequential bilateral cochlear implantation was evaluated at our institution for concerns of poor device performance. Approximately 3 years earlier, the patient had undergone stainless steel mandibular molar crown placement. After her dental procedure, she began experiencing worsening facial nerve stimulation, pain, and poor performance with the implant in her right ear. In-house device integrity testing demonstrated a series of phase reversals in the electrode voltages involving the mid-portion of the array that were consistent with otosclerosis and current shunting. The patient underwent removal of the mandibular crown 5 years after initial placement and experienced diminished facial nerve stimulation, resolution of pain, and a statistically significant improvement in monosyllabic word scores and speech in noise testing (Consonant-Nucleus-Consonant, 36%-76%; Bamford-Kowal-Bench Speech-in-Noise, 15-10.5 dB SNR). These findings were reproducible with serial audiometric testing over the subsequent 1.5 years, and she subjectively reported a substantial and lasting improvement in sound quality. We present the first published report documenting resolution of nonauditory stimulation and objective device performance improvement after stainless steel crown extraction. Although we cannot make any definitive conclusions based on a single report, it remains plausible that dental work incorporating metal substrates may interfere with device function through participation in aberrant current shunting in patients with otosclerosis.