Cross-linked dry bonding: A new etch-and-rinse technique

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Polymer Chemistry

Background:

• Dental adhesives are crucial for bonding restorative materials to tooth structure.
• Dentin bonding is often sensitive to moisture, with dry bonding techniques typically yielding lower bond strengths than wet bonding.
• Acid-etched dentin is susceptible to collagen degradation and loss of mechanical properties upon dehydration.

Purpose of the Study:

• To investigate whether acid-etched dentin can be dehydrated after cross-linking without compromising bond strength.
• To evaluate the effect of grape seed extract (GSE) as a cross-linking agent on dentin properties and bond strength.

Main Methods:

• Human third molars were acid-etched and bonded using wet or dry techniques with a dental adhesive.
• Experimental groups were pretreated with 5% GSE in various solvents before wet or dry bonding.
• Demineralized dentin beams were treated with GSE to assess changes in stiffness and collagen degradation.

Main Results:

• Dry bonding of control dentin resulted in significantly lower bond strengths (9.4 MPa) compared to wet bonding (53.5 MPa).
• Pretreatment with 5% GSE in a 5% ethanol/95% water solution allowed for dry bonding with bond strengths comparable to wet bonding (55.7 MPa vs. 53.0 MPa).
• GSE treatment increased dentin stiffness and reduced collagen degradation by endogenous proteases.

Conclusions:

• Pretreatment of acid-etched dentin with 5% GSE in a specific solvent mixture enables effective air-drying without reducing bond strength.
• GSE acts as a cross-linking agent, enhancing dentin's mechanical properties and resistance to degradation.
• This finding offers a promising strategy to overcome the moisture sensitivity challenges in dentin bonding procedures.