Rotary instrument finishing of microfilled and small-particle hybrid composite resins.

Tungsten carbide burs operated at high speeds for trimming and finishing microfilled composite resins are contraindicated as they disrupt the composite resin surface. Diamond burs operated at low speeds do not disrupt the surface on microfilled and small-particle hybrid composite resins. High-speed finishing with carbide burs on small-particle (hybrid) composite resins produces not only a nondisrupted surface but leaves the surface flat and smooth--free from the characteristic striations and grooves left by diamond burs.

Shear testing of the porcelain-metal bond.

A simple shear test was employed to determine the bonding strength of porcelain to a gold metal substrate and to a non-precious metal substrate after they had been aged in double-distilled water at 37 degrees C for four and 12 months. A 7.4% and 18.