Adhesive bonding of various materials to hard tooth tissues. VI. Forces developing in direct-filling materials during hardening.

The strength of the adhesive bond between o direct-filling and the cavity walls of a tooth must exceed 49 kg./cm. 2 (700 psi), which is a conservative estimate of the tensile stress that develops during the hardening of such material. The corresponding stress for a silicate cement would be about 35 kg./cm. 2 (500 psi).