In vitro evaluation of repair bond strength of composite: Effect of surface treatments with bur and laser and application of universal adhesive.

Objectives: This study aimed to assess the effect of surface treatment by bur and laser and application of universal adhesive on repair bond strength of composite resin.

Materials And Methods: A total of 120 composite blocks measuring 6×4×4 mm were fabricated of Filtek Z250 composite. All samples were subjected to 5,000 thermal cycles and divided into two groups for surface preparation by bur and by Er,Cr:YSGG laser (n = 60).