Effects of Natural Cross-Linkers on the Stability of Dentin Collagen and the Inhibition of Root Caries in vitro

Abstract

Purpose: To evaluate the effects of dentin collagen modifications induced by various cross-linkers on the stability of collagen matrix and the inhibition of root caries. Materials and Methods: The following cross-linkers were tested: 5% glutaraldehyde (GA), 0.5% proanthocyanidin (PA), 0.625% genipin (GE). In the first experiment, cross-linker-treated demineralized human root dentin was digested with bacterial collagenase, centrifuged, and the supernatants were subjected to amino acid analysis to determine collagen content. The residues were analyzed by SDS-PAGE and hydroxyproline analysis. In the second experiment, bovine root surfaces were conditioned with phosphoric acid, treated with the cross-linkers, incubated with Streptococcus mutans and Lactobacillus acidophilus for 1 week and the root caries inhibition was evaluated with confocal microscopy. Lastly, the ability of the bacteria to colonize the root surface was evaluated. In this experiment slabs of bovine root were treated with the cross-linkers and incubated in a suspension of S. mutans and L. acidophilus. The slabs were washed, resuspended in water, glucose was added, and the pH measured. Results: While all collagen was digested with collagenase in the control groups, only a small proportion was solubilized in the GA-, PA-, and GE-treated groups. The root caries was significantly inhibited by treatment with PA or GA. Drops in pH in the cross-linker-treated groups were essentially the same as in the untreated group. Conclusion: Naturally occurring cross-linkers, especially PA, could be used to modify root dentin collagen to efficiently stabilize collagen and to increase its resistance against caries.

Shear Bond Strength of Composite to Deep Dentin After Treatment With Two Different Collagen Cross-linking Agents at Varying Time Intervals

“…This is in accordance with the findings of Macedo and others, 14 who showed that the application of 6.5% grape seed extract and 5% gluteraldehyde to caries-affected and sound dentin significantly improved the microtensile bond strength of composite to dentin. Similarly, Walter and others 31 showed that 0.5% proanthocyanidin efficiently stabilized collagen and increased its resistance to caries compared to 0.625% genipin and 5% gluteraldehyde. Bedran-Russo and others 12 found that naturally occurring cross-linking agents such as 0.5% proanthocyanidin and 0.625% genipin are capable of stabilizing demineralized dentin collagen more effectively compared to 5% gluteraldehyde.…”

<I>In vitro</I> effect of hesperidin on root dentin collagen and de/re-mineralization

“…The organic layers of dentin are important in hampering the lesion progression and preventing further demineralization challenges 11) . In previous studies using collagenase, the proteolytic degradation of demineralized matrix was said to enhance the susceptibility of dentin lesions to acid-dependent demineralization 32,33) . Recent studies have demonstrated that CHX possesses a potent anti-proteolytic effect due to its ability to inhibit activity of MMPs in carious dentin 16) .…”

Effects of Chemical Cross-linkers on Caries-affected Dentin Bonding

“…The amount of digested matrix was calculated as a proportion of the residues (undigested) to the supernatants (digested) on a dry weight basis (Walter et al, 2008). Statistical analysis was performed by twoway ANOVA and Fisher's PLSD test (α = 0.05).…”