Sir, I respond to the Letter Patient safety: Cochlear implants.1 In dentistry monopolar electrosurgery is more often used than bipolar for aesthetic and restorative purposes,2 but monopolar instruments are contraindicated in patients with cochlear implants.2,3,4 If bipolar electrosurgical instruments are used, the tip of the cautery should be at least 3 cm away from the implant location.4 Monopolar diathermy should not be performed in the head and neck region and bipolar diathermy is contraindicated in sites within 2 cm of the cochlear implant.5

Dentists should never use microwave diathermy, shortwave diathermy and ultrasound diathermy on these implant patients.6 These procedures may irreversibly damage the cochlear implant and neurons of inner ear.5 Transcutaneous electrical nerve stimulation (TENS) therapy is used as one modality to treat TMJ pain7 but should not be used in patients with a cochlear implant.6 External parts of the implant should be removed when ultrasound tooth cleaning machines are used.6 Ultrasonic imaging and therapy is contraindicated in these patients.4 The speech processor of the cochlear implant should be switched off, removed and kept away from the room containing X-ray equipment while taking dental radiographs.6 Patients with Nucleus 24 cochlear implants can undergo a magnetic resonance imaging (MRI) scan up to 1.5 Tesla by using a splint and head bandage.8 A recent study observed that an MRI scan can cause pain, magnet displacement, and polarity reversal of the magnet and surgery may be required for removal and reinsertion of the magnet.9 External components of the implant should be removed during MRI scans, gamma camera and radiotherapy with cobalt units/linear accelerator.4,6 Patients' cochlear implant teams should be consulted before these procedures. Cone beam computed tomography, computed tomography, electric pulp test, panoramic radiograph and digital radiograph are quite safe in these patients.