Effects of sodium copper- and sodium iron-chlorophyllin primers on resin bonding to dentin

This study evaluated the effects of two chlorophyll derivatives, sodium copper chlorophyllin (Cu-Chl) and sodium iron chlorophyllin (Fe-Chl), on the bond strength between a self-curing luting agent (4-META/MMA-TBB resin) and dentin. Five aqueous primers containing 35% 2-hydroxyethylmethacrylate with 0.007% Cu-Chl, 0.07% Cu-Chl, 0.007% Fe-Chl, 0.07% Fe-Chl, or neither Cu-Chl nor Fe-Chl (no-Chl) were prepared. The extracted human dentin surfaces were etched with 10% phosphoric acid (10PA), primed, and bonded to a resin block using the 4-META/MMA-TBB resin. A conventional etching agent (10-3) and 10PA without primer (PA/no-primer) were used as controls. The microtensile bond strength was determined after 48 h. The arithmetic medians for 20 stick specimens were calculated and statistically analyzed using a nonparametric Steel-Dwass test (α = 0.05). The maximum bond strength was achieved in the 0.007% Cu-Chl group, followed by those in the 0.07% Cu-Chl, 0.07% Fe-Chl, 10-3, 0.007% Fe-Chl, no-Chl, and PA/no-primer groups. No significant difference was observed between 0.007% Fe-Chl, 0.07% Fe-Chl, and 10-3. The bond strength to dentin etched with 10PA was influenced by the type and concentration of the chlorophyll derivatives applied. Cu-Chl rather than Fe-Chl should be useful as a component of surface treatment agents for bonding 4-META/MMA-TBB resin to dentin.