Effects of Air Abrasion and Acid Etching on the Microleakage of Preventive Class I Resin Restorations: An In Vitro Study

Abstract: Purpose: To evaluate the effects of air abrasion, acid etching, and the combination of both procedures on the microleakage of preventive Class I resin restorations.
Materials and Methods: Eighty-four extracted human molar teeth were randomly assigned to seven groups with 12 teeth each. Occlusal fissures were opened with a diamond bur and etched with phosphoric acid (groups I and VI); prepared with a diamond bur without etching (group VII); air abraded with the KCP 1000, using SO-pm aluminum oxide particles without etching (group 11), and with phosphoric acid etching (group 111); or air abraded with 27-pm aluminum oxide particles without etching (group IV), and with phosphoric acid etching (group V). Preparations were filled with a low-viscosity resin composite (Liquicoat, groups I to V) or with a low-viscosity poly acid-modified resin composite (PrimaFlow, groups VI and VII). Six teeth in each group were thermo-cycled (5°-55°C, 2500 cycles). Dye penetration (methylene blue) was evaluated in ordinal scale.
Results: The number of non-thermocycled and thermocycled specimens revealing no microleakage was as follows: group I, 6 and 1; group II, 2 and 2; group III, 4 and 3; group IVY 0 and 0; group V, 1 and 0; group VI, 3 and 2; and group VII, 0 and 0, respectively. No significant differences existed between the thermocycled specimens and non-thermocycled specimens, except within group I.