successful results are achieved with alloplastic implants. John Shea introduced the use of Teflonprostheses in the restoration of hearing in otosclerosis and ever since this has been the most rewarding reconstructive middle ear opera­ tion. With the development of the intact canal wall techniques and the use of homologous implant materials the problems of middle ear surgery see­ med to be solved. However, we now know that closed techniques have dis­ advantages after longer post-operative periods and the use of homologous implant materials give problems. Collection of these implants is not al­ ways easy and the preservation is still in discussion. Furthermore, pro­ blems of resorption, rejection or fixation give uncertain post-operative results. Middle ear prostheses of different new implant materials are promoted by industry and good results are published, but also disappointments after shorter or longer periods.