Mechanical characterization of proanthocyanidin–dentin matrix interaction

Department of Dental Materials, University of Sao Paulo, Sao Paulo, SP, Brazil.
Dental materials: official publication of the Academy of Dental Materials (Impact Factor: 3.77). 10/2010; 26(10):968-73. DOI: 10.1016/
Source: PubMed


To characterize the properties of dentin matrix treated with two proanthocyanidin rich cross-linking agents and their effect on dentin bonded interfaces.
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.
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. Resin-dentin bonds significantly increased following treatment with GSE regardless of the application time or adhesive system used.
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 resin-dentin bonds can be improved after 10 min dentin treatment.

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    • "Our recent research has shown that (O)PACs from certain plant sources can greatly improve the strength of demineralized dentin [3] [5] [16]. Accordingly, OPACs have the potential to be a viable resource of dental biomaterials [17]. "
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    ABSTRACT: Grape seeds are a rich source of polyphenols, especially proanthocyanidins (PACs), and are also known for the presence of galloylated oligomeric PACs (OPACs). The present study focuses on phytochemical methodology for grape seed (O)PACs and their potential role as dentin bio-modifiers to be used in restorative and reparative dentistry. A new method using centrifugal partition chromatography (CPC) was developed for the preparative separation of the grape seed (O)PACs. Orthogonal phytochemical profiling of the resulting CPC fractions was performed using C18 and diol HPLC, normal phase HPTLC, and IT-TOF MS analysis. A galloylated procyanidin dimer (1) was isolated from a CPC fraction in order to evaluate its potential to enhance dentin bio-mechanical properties. Moreover, it helped to evaluate the impact of the galloyl moiety on the observed bioactivity. Structure elucidation was performed using ESI-MS, 1D and 2D NMR analyses. For the first time, (1)H iterative full spin analysis (HiFSA) was performed on this type of molecule, enabling a detailed proton chemical shift and coupling constant assignment. The CPC fractions as well as 1 showed promising results in the dentin stiffness bioassay and indicate that it may be used as dental intervention material. Copyright © 2014. Published by Elsevier B.V.
    Full-text · Article · Dec 2014 · Fitoterapia
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    • "Apart from being a potential non-selective MMP inhibitor, PA has gained much attention over the past few years because of its crosslinking capabilities, which are beneficial for enhancing demineralized dentin matrix and improving resin-dentin bond strength. Castellan et al.11,12,13 reported that PA pre-treatment increased the immediate elastic modulus of dentin matrix and was effective even after bacterial collagenase challenge or 1-year of storage in artificial saliva. Additionally, it provided enhanced immediate adhesion and long-term stabilisation to demineralized dentin after 1-year of ageing in water. "
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    ABSTRACT: Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin (PA) for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin-dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2% chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.International Journal of Oral Science advance online publication, 9 May 2014; doi:10.1038/ijos.2014.22.
    Full-text · Article · May 2014 · International Journal of Oral Science
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    • "Recent studies evaluated the ability of PA rich extracts to increase short-and long-term mechanical properties of demineralized dentin [14] and the short-term dentin-resin bond strength [15]. Grape and cocoa seed extracts are well known as rich PA sources, where PA can be readily extracted with regular and nontoxic solvents, like water, acetone, and ethanol [16]. "
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    ABSTRACT: Purpose. This study investigated the long-term resin-dentin bond strength of dentin biomodified by proanthocyanidin-rich (PA) agents. Materials and Methods. Forty molars had their coronal dentin exposed, etched, and treated for 10 minutes with 6.5% grape seed extract (GSE), 6.5% cocoa seed extract ethanol-water (CSE-ET), 6.5% cocoa seed extract acetone-water (CSE-AC), and distilled water (CO). Samples were restored either with One-Step Plus (OS) or Adper Single-Bond Plus (SB). Bond strength test was performed immediately or after 3, 6, and 12 months. Results. Higher μ TBS were observed for GSE immediately (SB- 62.9 MPa; OS- 51.9 MPa) when compared to CSE-ET (SB- 56.95 MPa; OS- 60.28 MPa), CSE-AC (SB- 49.97 MPa; OS- 54.44 MPa), and CO (SB- 52.0 MPa; OS- 44.0 MPa) (P < 0.05). CSE outcomes were adhesive system and solvent dependant. After 12 months storage SB results showed no difference among treatment types (GSE- 57.15 MPa; CSE/ET- 54.04 MPa; CSE/AC- 48.22 MPa; CO- 51.68 MPa; P = 0.347),while OS results where treatment dependent (GSE- 42.62 MPa; CSE/ET- 44.06 MPa; CSE/AC- 41.30 MPa; CO- 36.85 MPa; P = 0.036). Conclusions. GSE and CSE-ET agents provided enhanced immediate adhesion and stabilization to demineralized dentin after long-term storage, depending on adhesive system.
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