Effect of cold plasma spray on microshear bond strength of repair composite resin in comparison with other surface treatments

Abstract

Following composite restorations, there is an obvious need for repair of them, which can be a challenging procedure in the clinical setting. This study aimed to assess the effect of surface treatment of composite with cold plasma spray (CPS) on microshear bond strength (µSBS) of repair composite in comparison with other surface treatments. A total of 120 discs (2 × 9 mm) were fabricated of Filtek Z250 composite. After aging by 5000 thermal cycles (5–55 °C), the samples were randomly divided into 4 groups (n = 30) for surface treatment by bur, Er,Cr:YSGG laser irradiation, sandblasting and CPS. After etching and application of Scotchbond Universal, Filtek Z250 repair composite was applied into Tygon tubes and bonded to the prepared surface. Half of the samples in each group (n = 15) were immersed in distilled water and incubated at 37 °C for 24 h. The other half was thermocycled. All samples then underwent µSBS test in a universal testing machine with a crosshead speed of 1 mm/min. The mode of failure was determined under a stereomicroscope. Data were analyzed by two-way ANOVA (p = .05). Aging (p = .13) and type of surface treatment (p = .44) had no significant effect on µSBS of repair composite. All failures were adhesive. Different surface treatments and aging process had no significant effect on µSBS of repair composite. However, application of CPS slightly increased the µSBS of repair composite after aging.