Microtensile bond strength of resin cements to contaminated dentin: impact of blood, hemostatic agents, and mechanical cleaning

This in vitro study evaluated the effects of blood contamination, blood contamination followed by aluminum chloride hemostatic agent application, and subsequent mechanical cleaning on the microtensile bond strength of a conventional (CR) and a self-adhesive resin cement (SA). Thirty-two extracted human teeth were prepared to expose flat dentin surfaces and divided into four surface treatment groups: control (Group C), blood contamination (Group B), hemostatic agent application after blood contamination (Group H), and mechanical cleaning after blood contamination and subsequent hemostatic agent application (Group CL). Each group was divided into two subgroups, receiving either conventional resin cement with an etch-and-rinse protocol or a self-adhesive resin cement. After longitudinal sectioning, four rectangular resin-dentin sticks were collected from each tooth ( n = 16). A microtensile bond strength test (µTBS) was performed, followed by failure mode analysis and scanning electron microscopy evaluation. Data were analyzed using generalized estimating equations to account for tooth-level clustering (α = 0.05). Blood contamination significantly reduced µTBS in SA compared with all other surface treatment groups, whereas in CR, a significant reduction was observed only compared with the control group ( p < 0.05). When the two resin cements were compared, a significant difference was observed only for Group B, with lower bond strength for SA ( p < 0.001). The results suggest that blood contamination may adversely affect the bonding performance of both tested resin cements, with the self-adhesive resin cement showing greater susceptibility under blood-contaminated conditions, emphasizing the importance of adequate bleeding control during cementation.