Effect of Blood Decontamination Procedures on the Microshear Bond Strength of Resin-modified Glass Ionomer Cement to Resin Composite.

OBJECTIVE: To investigate the effect of decontamination procedures on the microshear bond strength (muSBS) of blood-contaminated resin-modified glass ionomer cement (RMGIC) bonded to resin composite (RC). METHODS: Eighty RMGIC disc specimens were allocated into 5 groups (n=16). All groups except Group 2 were contaminated with blood. Group 1 had no decontamination procedure, Group 3 was decontaminated by rinsing, Group 4 was decontaminated by 34% phosphoric acid etching, and Group 5 was decontaminated by 5% sodium hypochlorite application. RMGIC specimens were subsequently bonded with RC using a universal adhesive in self-etch mode. muSBS tests were conducted using a universal testing machine at a crosshead speed of 1 mm/min. Failure mode analysis was conducted on RMGIC fracture surfaces under a scanning electron microscope. RESULTS: muSBS results indicated that Group 4 had the highest mean muSBS value of 6.22 +/- 2.14 MPa, while Group 1 had the lowest mean muSBS value of 3.53 +/-1.67 MPa. Significant differences were observed in the muSBS of Group 2 with no contamination (p=0.023) and Group 4 with decontamination by phosphoric acid-etching (p=0.003) when compared to Group 1 with blood contamination. No statistically significant differences (p>0.05) were observed between all other groups' muSBS. For all groups, the predominant mode of failure was adhesive failure between the RMGIC-RC interface, with a few mixed failures in RMGIC for Groups 2-5. CONCLUSIONS: Blood contamination before adhesive application significantly reduced the muSBS between RMGIC and RC. Phosphoric acid etching was the most effective blood decontamination procedure to improve the muSBS.