Acoustic evaluation of earmoulds in situ: a comparison of impression and earmould materials

Laboratory research has been carried out on the accuracy of both ear impression and earmould materials. The present work was undertaken to assess such materials in vivo. An objective clinical method of earmould evaluation was developed, based on estimation of the attenuation in the acoustic feedback path. The method was used to assess the acoustic performance of earmoulds made from three earmould materials of different texture, when prepared from two different impression materials. It was shown that the choice of impression material made a significant difference to earmould performance. For greatest accuracy, addition cured silicone impression materials are recommended.