Repair of aged bulk-fill composite with posterior composite: Effect of different surface treatments.

Objective: In the present study, the ability of posterior resin composite to repair aged bulk-fill resin composite and vice versa were assessed by shear bond strength testing.

Materials And Methods: Resin composite substrates were aged and surfaces were abraded with abrasive papers, then bulk-fill substrates were repaired with posterior resin composite and vice versa using different surface treatments (no surface treatment [control]; etching with 37% phosphoric acid [H PO ] for 20 seconds; etching with 10% hydrofluoric acid [HF] for 20 seconds; etching with 37% H PO for 20 seconds + adhesive application; etching with 10% HF for 20 seconds + adhesive application; adhesive application only). Shear bond strengths (SBS) were then measured and surface roughness values (Ra) were determined.