Introduction: Adding antibacterial agents to a dentin conditioner used for a glass ionomer cement (GIC) has been shown to be antibacterial; however, it is not known whether this antimicrobial conditioning agent affects the bond strength to dentin in situ. This study applied GIC to antibacterial conditioned dentin without rinsing and determined whether there is an affect on the material's bond strength.
Materials and methods: Chlorhexidine acetate (CX), benzalkonium chloride (BC) and cetrimide (CT) were added to Dentin Conditioner (DC) (GC Corp, Japan) at 1% and 5% concentrations. Molars were sectioned coronally to expose dentin, onto which 50 microl of the test conditioners was applied for 20 seconds with a gentle scrubbing action and the residual liquid was blotted dry, as would occur under "field" conditions when performing atraumatic restorative therapy. To serve as the control, the DC was left in situ and compared to the DC that was washed off. Proportioned Fuji IX GIC (GC Corp, Japan) was built-up on the prepared dentin surface and varnish was applied and stored for 24 hours. An annular saw was used to create sticks of GIC bonded to dentin, with a bonding area 1 mm2. After 24 hours, the specimens were tested to failure in a Universal testing machine at a crosshead speed of 1 mm/minute.
Results: Five percent CX-DC was not tested, as it formed a precipitate. Results in MPa: DC-not washed, 9.3 +/- 2.4; DC-washed, 9.3 +/- 2.5; 1% BC-DC, 8.8 +/- 2.5; 1% CX-DC, 8.7 +/- 2.7; 1% CT-DC, 8.2 +/- 1.7; 5% CT-DC, 8.1 +/- 2.7; 5% BC-DC, 5.4 +/- 1.0. One-way ANOVA showed that there was a significant difference between the test groups (p < 0.05), and Tukey's studentized range test showed that only 5% BC-dentin conditioner left in situ was significantly different from the other groups.
Conclusion: Under the conditions tested, only the 5% BC-DC left in situ affected the bond strength of Fuji IX to dentin.