Thirty-six Class I cavities in mandibular molars from 18 schoolchildren were filled with Profile or Adaptic using the acid etch technique. Impressions were taken at 6-month intervals and abrasion was recorded by measuring the increasing height of the exposed cavity walls on cast models. The mean abrasion for Adaptic was 61.4 micron per yr and for Profile 28.7 microns per yr.
