Silicone Materials for Ear Impressions

Abstract

Comparative properties have been determined for some commonly used ear impression materials (condensation reaction silicones) and some recently developed dental products (addition reaction silicones). Experiments have included measurement of dimensional stability, weight change on storage, viscosity, syringing characteristics, the energy required to tear the material and the stress relaxation characteristics. The major finding is that of the superb dimensional stability of the addition-cured silicones, which show no significant shrinkage over time. This is in contrast to a linear shrinkage of the order of 0.5% over a 48-hour period for the condensation silicones.

Mechanical properties of elastomeric impression materials

“…The mould was notched in the middle in a lengthwise manner. The notch had a depth of 0-25 mm, and this provided a guide line for the tear to grow along a predetermined axis (Nolan & Combe, 1985). Specimens were left in the mould for 30 min from the start of mixing.…”

Comparison of Traditional Impression and 3D Ear Scanning Techniques, Earmold Comfort, and Audiology Clinical Implications: A Pilot Study

“…Fourth, there are possible ear impression defects during shipping, especially for those made from acrylic materials which will be affected by temperature and humidity and will shrink by 2-5% 48 h after the impression is formed [19,20]. The shrinkage rate is 0.1% and 0.5% for addition-cured and condensation-cured silicone materials, respectively [20,21].…”