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

OBJECTIVE: To determine if acid-etched, cross-linked dentin can be dehydrated without lowering bond strength below that of cross-linked wet-bonded dentin in vitro.

METHODS: Using extracted human third molars, control acid-etched dentin was bonded with Single Bond Plus, using either the wet- or dry-bonding technique. Experimental acid-etched dentin was treated with 5mass% grape seed extract (GSE) in different solvents for 1min before undergoing wet vs dry resin-dentin bonding with Single Bond Plus. Completely demineralized dentin beams were treated with 5% GSE for 0, 1 or 10min, before measuring stiffness by 3-point flexure. Other completely demineralized beams were treated similarly and then incubated in buffer for 1 week to measure the collagen solubilization by endogenous dentin proteases.

RESULTS: 24h microtensile bond strengths (μTBS) in wet and dry controls were 53.5±3.6 and 9.4±1.8MPa, respectively (p<0.05). 5% GSE in water gave μTBS of 53.7±3.4 and 39.1±9.7MPa (p<0.05), respectively, while 5% GSE in ethanol gave μTBS of 51.2±2.3 and 35.3±2.0MPa (p<0.05). 5% GSE in 5% EtOH/95% water gave wet and dry μTBS of 53.0±2.3 and 55.7±5.1MPa (p>0.05). Cross-linking demineralized dentin with 5% GSE increased stiffness of dentin and decreased collagen degradation (p<0.05).

SIGNIFICANCE: 5% GSE pretreatment of acid-etched dentin for 1min permits the dentin to be completely air-dried without lowering bond strength.