Abstract
The stress relaxation behavior of human dentin in a compression test was investigated.Cylindrical specimens, 1mm in diameter and 2mm in length, were prepared with a hollow drill made of pure copper.High testing speed of about 250%/min was used to give initial stress, and the stress relaxation test was done in water at test temperatures of 0, 23, 36, and 50℃.Human dentin showed temperature-dependent stress relaxation, and was found to be isotropic with respect to stress relaxation.However variations in stress relaxation with age were observed.The mean percent stress relaxation of dentin was 10〜20%, and this value was about 2〜3 times that of human enamel and 0.2〜0.3 times that of composite resin.Dentin, etched by 30% phospholic acid showed about two-fold stress relaxation.
