Subsurface degradation of resin-based composites

Abstract

Objectives: To determine the depth of a degraded subsurface layer produced in dental composites as a result of exposure to lactic acid or NaOH, by observing the penetration of AgNO3 solution. Methods: Specimens were prepared from four resin composites; Point 4 (Kerr), Premise (Kerr), Filtek Supreme (3M/ESPE), Ceram X (Dentsply), and two polyacid-modified resin composites; Dyract (Dentsply) and F2000 (3M/ESPE). The specimens were immersed in distilled water for 1 week, transferred to one of three aqueous media at 60 °C for 2 weeks; distilled water, 0.01 mol/L lactic acid or 0.1N NaOH, washed and immersed in 50% (w/w) aqueous silver nitrate for 10 days at 60 °C and placed in a photodeveloper s..