Mould constituents in the middle ear, a hearing-aid complication.

During the placement of a mould for a hearing-aid by a hearing-aid dispenser, moulding material entered the middle ear through pre-existent perforations in the tympanic membrane in both ears. Besides hearing loss, there were no other symptoms. Surgical removal of the moulding material by tympanotomy was necessary, and was complicated by encirclement of the ossicles by the material. All the material could be removed and the hearing was saved. Recommendations for an improved procedure of mould-making are made including more detailed information of the otoscopic findings at the prescriptions for hearing-aid moulds.