Chlorhexidine Effect on Bond Strength of Resin-Modified-Glass-Ionomer over 12-months aging

Methods: Cylindrical moulds, placed on flat polyalkenoic acid (Cavity Conditioner®,GC) conditioned dentin surfaces of 90 human teeth embedded in resin, were filled with a RMGI (Fuji II LC®, GC), with (n=45) or without (n=45) the prior application of a 0.05 % CHX solution. Within each group, SBS was determined after 24h (n=15), 6-months (n=15), and 12-months (n=15) storage in water at 37 °C. The results were analyzed with two-way ANOVA followed by Tukey multiple means comparisons (p<0.05). The type of bond failure (adhesive/cohesive/mixed) was noted and analyzed with chi-square test (p<0.05).

Results: After 24h, the SBS of RMGI was not significantly different with (9.0±2.8 MPa) or without (8.3±0.6 MPa) the application of CHX. After 6-months, however, SBS increased significantly in the group without CHX (12.7±3.4 MPa) but remained unchanged in the CHX group (9.4±4.0 MPa). Similar results without CHX (12.6 ± 3.8 MPa) and with CHX (9.5 ± 3.2 MPa) were obtained after 12-months. No significant differences in the type of debonding were found between the various groups tested.

Conclusions: The application of 0.05 % CHX after dentin conditioning did not seem to have affected the 24h SBS of RMGI. However, the 6-and 12-months SBS were significantly lower for CHX treated samples, possibly due to CHX interference with both the bonding mechanism and the maturation reaction of RMGI.