The Influence of Saliva and Blood Contamination on Bonding Between Resin-modified Glass Ionomer Cements and Resin Composite

Objective: To investigate the influence of blood and saliva contamination on the microshear bond strength (mu SBS) 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 mu SBS testing using a universal testing machine. Failure mode of the debonded RMGIC surfaces was examined using scanning electron microscopy. Results: The mu SBS 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 mu SBS (p<0.001, p=0.029). Saliva contamination alone had no statistically significant effect on the mu SBS (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 mu SBS between RMGIC and RC when it is dried thoroughly, while blood and blood-saliva contamination reduced mu SBS between RMGIC and RC even when dried thoroughly.