Glutaraldehyde collagen cross-linking stabilizes resin-dentin interfaces and reduces bond degradation

This study evaluated the stability of resin-dentin interfaces treated with glutaraldehyde-containing agents, and assessed collagen degradation in dentin matrices treated with Gluma. Microtensile bond strength (μTBS) was evaluated 24 h and 6 months after treatment with three desensitizers (Gluma Desensitizer, Gluma Desensitizer Power Gel, and MicroPrime G) and two etch-and-rinse adhesives (Comfort Bond & Desensitizer and iBond TE). Demineralized beams of human dentin were treated with water or Gluma, and the degradation of collagen in these beams was assessed by quantification of the dry mass loss and of the amount of hydroxyproline released from hydrolyzed specimens after 1 or 4 wk. All groups demonstrated significant reduction in μTBS after 6 months, except for Gluma Desensitizer and iBond TE groups, which showed decreases of 7.2% and 10.8%, respectively. The most prevalent failure mode was 'mixed'. Significantly less hydroxyproline was released from Gluma-treated beams than from control beams after 4 wk. Beams treated with Gluma yielded significantly less dry mass loss than did beams in the control group. Collagen cross-linking with glutaraldehyde-containing agents may assist in the stabilization of resin-dentin bonds by reducing the amount of collagen solubilized from dental matrices in the hybrid layer. In turn, this may contribute to the preservation of adhesive interfaces.