The relationship between test methodology and elastic behavior of composites.

Comparisons were made of the Young's moduli obtained with tests that impose static, low-frequency, or high-frequency elastic deformations on dental composite systems. The frequency of the imposed stress was reflected in the absolute value of Young's modulus. However, the values obtained at different test frequencies could be compared and understood by taking into account this frequency dependence. It was thus found that the composite structure largely determined the type of reaction to the imposed stress. The fundamental period test permitted the greatest differentiation in the elastic behavior of the investigated composites.