Universal Adhesives: Setting Characteristics and Reactivity with Dentin.

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Universal dental adhesives offer simplified clinical application.
• Understanding their performance is crucial for predictable clinical outcomes.
• Variations in formulation can significantly impact adhesive properties.

Purpose of the Study:

• To evaluate and compare the performance of six commercial universal dental adhesives.
• To assess key properties including degree of conversion, micro-hardness, oxygen inhibition, demineralization, and shear bond strength.
• To correlate adhesive properties with their interactions with dentin.

Main Methods:

• Tested adhesives: Adhese Universal (ADU), All-Bond Universal (ABU), Clearfil Universal Bond Quick (CBQ), G-Premio Bond (GPB), Prelude One (PRO), and Scotchbond Universal (SBU).
• Evaluated properties: degree of C=C conversion (DC%), Vickers micro-hardness (VHN), oxygen inhibition (OI), dentin demineralization (DM%), insoluble salt formation (AS%), and shear bond strength (SBS).
• Statistical analyses included one-way ANOVA, Tukey's test, and Weibull analysis.

Main Results:

• Significant variations observed in DC (67.2-82.5%), VHN (1.1-6.6 VHN), OI (5.6-18.6 μm), DM% (10.6-69.3%), AS% (15.9-26%), and SBS (29.3-16.6 MPa).
• Scotchbond Universal (SBU) showed highest micro-hardness, while G-Premio Bond (GPB) exhibited highest demineralization.
• Clearfil Universal Bond Quick (CBQ), Adhese Universal (ADU), All-Bond Universal (ABU), and Scotchbond Universal (SBU) demonstrated superior shear bond strength.
• All adhesives exhibited mixed failure modes.

Conclusions:

• Despite sharing the 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) monomer, universal dental adhesives exhibit distinct performance characteristics.
• Differences in co-monomers, solvents, and catalysts influence film properties, reactivity, and dentin bonding capacity.
• Clinical selection should consider these formulation-dependent variations for optimal bonding and longevity.