Reducing the incompatibility between two-step adhesives and resin composite luting cements

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• Adverse interactions between resin luting cements and etch-and-rinse adhesives can compromise bond strength.
• Chemically cured (CC) resin cements and light-cured (LC) systems exhibit different polymerization behaviors.
• Dentin permeability can influence the stability of adhesive bonds.

Purpose of the Study:

• To evaluate if an oxalate desensitizer (BisBlock) can mitigate adverse interactions between a two-step etch-and-rinse adhesive (One-Step Plus) and chemically cured resin luting cement (Variolink II).
• To determine the effect of BisBlock on reducing dentin permeability and improving adhesive coupling.
• To assess the impact of polymerization timing (immediate vs. delayed) on bond strength with and without BisBlock.

Main Methods:

• Human third molars were used, with dentin surfaces either treated with BisBlock (BB) or untreated (NB).
• Resin luting cement was applied in light-curing (LC) or chemical-curing (CC) modes, with immediate (IM) or delayed (DP) polymerization.
• Microtensile bond strength testing was performed, followed by fractographic analysis using scanning electron microscopy (SEM).

Main Results:

• Delayed polymerization significantly reduced bond strength for both LC and CC cements compared to immediate activation.
• BisBlock approximately doubled the bond strength of CC cement but did not affect LC cement.
• SEM analysis revealed voids in the luting cement without BisBlock, except in the immediately light-cured group, confirming bond strength findings.

Conclusions:

• BisBlock effectively reduced incompatibility between the etch-and-rinse adhesive and chemically cured resin cements.
• The oxalate desensitizer improved bond strength in delayed polymerization modes for both cement types.
• BisBlock is a viable option to enhance the performance of resin cements with etch-and-rinse adhesives, especially when delayed polymerization occurs.