Objective: To investigate the influence of blood and saliva contamination on the microshear bond strength (μSBS) between resin-modified glass ionomer cement (RMGIC) and resin composite (RC).
Methods and materials: Eighty RMGIC discs were allocated into four groups (n=20). Group 1 received universal dental adhesive application in a self-etch mode followed by a build-up with RC. Group 2 received saliva as a contaminant, Group 3 received blood as a contaminant, Group 4 received a 1:1 blood-saliva mixture as a contaminant. Specimens from Groups 2, 3, and 4 were submerged into their respective contaminants for 15 seconds and dried prior to the adhesive application, followed by the protocol for Group 1. All specimens were stored in distilled water for 24 hours. Subsequently, the bonded specimens were subjected to μSBS testing using a universal testing machine. Failure mode of the debonded RMGIC surfaces was examined using scanning electron microscopy.
Results: The μSBS from groups 1-4 were 10.76 ± 3.03 MPa, 9.36 ± 2.54 MPa, 6.55 ± 1.67 MPa and 8.42 ± 2.79 MPa, respectively. Contamination by blood and blood-saliva significantly decreased the μSBS (p<0.001, p=0.029). Saliva contamination alone had no statistically significant effect on the μSBS (p=0.524). A statistically significant difference in the mode of failure was detected between the experimental groups (p=0.012).
Conclusion: Saliva contamination has no influence on μSBS between RMGIC and RC when it is dried thoroughly, while blood and blood-saliva contamination reduced μSBS between RMGIC and RC even when dried thoroughly.
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