Mechanical characterization of proanthocyanidin–dentin matrix interaction

Abstract

Objectives-To characterize the properties of dentin matrix treated with two proanthocyanidin rich cross-linking agents and their effect on dentin bonded interfaces.Methods-Sound human molars were cut into 0.5 mm thick dentin slabs, demineralized and either treated with one of two cross-linking agents (grape seed -GSE and cocoa seed -COE extracts) or left untreated. The modulus of elasticity of demineralized dentin was assessed after 10 or 60 min and the swelling ratio after 60 min treatment. Bacterial collagenase was also used to assess resistance to enzymatic degradation of samples subjected to ultimate tensile strength. The effect of GSE or COE on the resin-dentin bond strength was evaluated after 10 or 60 min of exposure time. Data were statistically analyzed at a 95% confidence interval.Results-Both cross-linkers increased the elastic modulus of demineralized dentin as exposure time increased. Swelling ratio was lower for treated samples when compared to control groups. No statistically significant changes to the UTS indicate that collagenase had no effect on dentin matrix treated with either GSE or COE. Dentin-resin bonds significantly increased following treatment with GSE regardless of the application time or adhesive system used.Significance-Increased mechanical properties and stability of dentin matrix can be achieved by the use of PA-rich collagen cross-linkers most likely due to the formation of a PA-collagen complex. The short term dentin-resin bonds can be improved after 10 minutes dentin treatment.

Effect of dental tissue conditioners and matrix metalloproteinase inhibitors on type I collagen microstructure analyzed by Fourier transform infrared spectroscopy

“…20 The Proanthocyanidin have been demonstrated to increase the ultimate tensile strength and elastic modulus of demineralized dentin. 14,40 According to the results obtained in this study, it could be concluded that type I collagen fibers from human dentin or bovine Achilles deep tendon are structurally similar when evaluated by ATR-FTIR spectroscopy. The 35% phosphoric acid used for surface conditioning for a short period of time (15 s), significantly altered the organic content of amide, proline and hydroxyproline.…”

“…In this way, the acid phosphoric was applied for 15 s, necessary to etch dentin before the application of an etch-and-rinse adhesive system; the application time for distilled water and 2% chlorhexidine digluconate was 60 s, accordingly to the literature 11 ; the application time for EDTA was 60 s, accordingly to the literature 10 ; and the application time selected for the proanthocyanidin solution was 60 min, accordingly to the literature. 13,14 After the immersion time had elapsed, each collagen membrane was carefully removed with a sterile clinical forceps, which was changed for each sample. After the immersions, the membranes of groups G1 and G4 (immersed in water and 2% chlorhexidine, respectively) were only lightly dried with filter paper (Whatman No.…”

“…11,12 The use of agents promoting crosslinking between collagen fibrils, such as proanthocyanidin, has recently been reported in the literature as a step to be performed before the adhesive procedure, in an attempt to prevent degradation of the bond interface. 13,14 Proanthocyanidin interacts with collagen in four different ways: by covalent interaction with proteins, 15 ionic interactions, 16 hydrogen bridge formation, 17 or hydrophobic interactions. 18 All of these different interactions keep the collagen protein structure intact, even after it has been cleaved by an enzyme.…”

Dual function of proanthocyanidins as both MMP inhibitor and crosslinker in dentin biomodification: A literature review

“…In a study conducted by Maciel et al 47) , the acetone group showed lower swelling values compared to distilled water group, the probable causes of this phenomenon can be the higher ability of the acetone-saturated collagen fibrils to form interpeptide bonds and the absence of the plasticizing effect of water in the acetone group. In another study, Castellan et al reported that both GSE and COE derived PA can decrease the swelling ratio and water sorption rate of collagen matrix 45) . In this study, no statistically significant changes were occurred in UTS values of dentin matrix treated with either GSE or COE whilst both of these groups, showed a considerable difference in UTS values in comparison with the control group.…”

“…It is assumed that stiffening effect induced by crosslinkers may reduce the risk of collagen collapse after demineralization and dentin overdrying, and hence, may permit more hydrophobic adhesives to enter into interfibrilar spaces 44) . As a rule, a stiffer dentin matrix is a so more suitable collagen substrate for hybridization 45) . Bedran-russo et al demonstrated that GSE PA can increase the stiffness and ultimate tensile strength of demineralized dentin in a concentration-related and time-dependent manner 28,29) .…”