Prodelphinidins enhance dentin matrix properties and promote adhesion to methacrylate resin.

Objective: Investigate the bioactivity and stability of Rhodiola rosea (RR) fractions as a natural source of prodelphinidin gallate (PDg) on dentin collagen via analysis of the viscoelastic and resin-dentin adhesive properties of the dentin matrix.

Methods: The biomimicry and stability of RR subfractions (F1, F2, F3 and F4) with collagen were determined by dynamic mechanical analysis (DMA). DMA used a strain sweep method to assess the dentin matrix viscoelastic properties [storage (E'), loss (E"), and complex (E*) moduli and tan δ] after treatment, 7-, 30- and 90-days of storage in simulated body fluids (SBF).

Galloylated proanthocyanidins in dentin matrix exhibit biocompatibility and induce differentiation in dental stem cells.

Aim: Grape seed extract contains a complex mixture of proanthocyanidins (PACs), a plant biopolymer used as a biomaterial to improve reparative and preventive dental therapies. Co-polymerization of PACs with type I collagen mechanically reinforces the dentin extracellular matrix. This study assessed the biocompatibility of PACs from grape seed extract on dental pulp stem cells (DPSCs) in a model simulating leaching through dentin to the pulp cavity.

The stoic tooth root: how the mineral and extracellular matrix counterbalance to keep aged dentin stable.

Aging is a physiological process with profound impact on the biology and function of biosystems, including the human dentition. While resilient, human teeth undergo wear and disease, affecting overall physical, psychological, and social human health. However, the underlying mechanisms of tooth aging remain largely unknown.

Paradoxical effects of galloyl motifs in the interactions of proanthocyanidins with collagen-rich dentin.

Plant-derived proanthocyanidins (PACs) mediate physicochemical modifications to the dentin extracellular matrix (ECM). The structure-activity relationships of PACs remain largely unknown, mostly due to the varied complex composition of crude extracts, as well as the challenges of purification and mechanistic assessment. To assess the role of galloylated PACs as significant contributors to high yet unstable biomodification activity to the dentin ECM, we removed the galloyl moieties (de-galloylation) via enzymatic hydrolysis from three galloyl-rich PAC-containing extracts (Camellia sinensis, Vitis vinifera, and Hamamelis virginiana).

Targeting Trimeric and Tetrameric Proanthocyanidins of Bark as Bioactives for Dental Therapies.

The present study elucidated the structures of three A-type tri- and tetrameric proanthocyanidins (PACs) isolated from bark to the level of absolute configuration and determined their dental bioactivity using two therapeutically relevant bioassays. After selecting a PAC oligomer fraction via a biologically diverse bioassay-guided process, in tandem with centrifugal partition chromatography, phytochemical studies led to the isolation of PAC oligomers that represent the main bioactive principles of : two A-type tetrameric PACs, epicatechin-(2β→→7,4β→8)-epicatechin-(4β→6)-epicatechin-(2β→→7,4β→8)-catechin () and parameritannin A1 (), together with a trimer, cinnamtannin B1 (). Structure determination of the underivatized proanthocyanidins utilized a combination of HRESIMS, ECD, 1D/2D NMR, and H iterative full spin analysis data and led to NMR-based evidence for the deduction of absolute configuration in constituent catechin and epicatechin monomeric units.

Bonding crowns and bridges with resin cement: An American Dental Association Clinical Evaluators Panel survey.

Background: Bonding crowns and bridges with resin cement can improve retention and reinforcement of the restoration. However, there is variation in the steps taken by different practitioners to achieve this goal.

Methods: The authors developed a survey on bonding dental crowns and bridges with resin cement and distributed it electronically to the American Dental Association Clinical Evaluators (ACE) Panel on May 22, 2020.

Removal of water binding proteins from dentin increases the adhesion strength of low-hydrophilicity dental resins.

Objectives: To investigate the role of proteoglycans (PGs) on the physical properties of the dentin matrix and the bond strength of methacrylate resins with varying hydrophilicities.

Methods: Dentin were obtained from crowns of human molars. Enzymatic removal of PGs followed a standard protocol using 1 mg/mL trypsin (Try) for 24 h.

Long-term Evaluation of Dentin Matrix Stability and Gelatinolytic Activity after Dentin Pretreatment with Caffeic Acid Phenethyl Ester.

Purpose: To investigate the long-term effect of 0.05% or 0.1% caffeic acid phenethyl ester (CAPE) on dentin matrix stability and hybrid layer stability, using an etch-and-rinse (Adper Scotchbond Multipurpose/ASB) or a self-etch adhesive (Clearfil SE Bond/CSE).

Dimeric Proanthocyanidins on the Stability of Dentin and Adhesive Biointerfaces.

A dentin biomodification strategy with selective proanthocyanidin (PAC)-enriched extracts reinforces dentin and dentin-resin interfaces. Enrichment of the extracts according to the degree of polymerization allows exploration of bioactive principles of PACs and structure-activity relationships. This study investigated the sustained dentin matrix biomodification and dentin-resin bioadhesion of 2 fractions consisting exclusively of B-type PAC dimers with or without a single galloyl motif (specifically, DIMER and DIMER) and their precursor material, enriched grape seed extract (e-GSE; ).

Proanthocyanidin Dimers and Trimers from Provide Diverse Structural Motifs for the Evaluation of Dentin Biomodification.

Aimed at exploring the dentin biomodification potential of proanthocyanidins (PACs) for the development of dental biomaterials, this study reports the phytochemical and dental evaluation of nine B-type PACs from grape seed extract (GSE). Out of seven isolated dimers (-), four new compounds (, , , and ) involved relatively rare -catechin or -epicatechin monomeric flavan-3-ol units. Low-temperature NMR analyses conducted along with phloroglucinolysis and electronic circular dichroism enabled unequivocal structural characterization and stereochemical assignment.

Long-term nanomechanical properties and gelatinolytic activity of titanium tetrafluoride-treated adhesive dentin interface.

Objective: This study investigated the effects of dentin pretreatment with 2.5% titanium tetrafluoride (TiF) on nanomechanical properties, and the in situ gelatinolytic activity of the dentin-resin interface, for up to 6 months.

Methods: Twenty-four human teeth were prepared by exposing occlusal flat dentin surfaces, and were randomly assigned to experimental groups, according to application or non-application of a TiF pretreatment, and to the adhesive systems (Clearfil SE Bond or Scotchbond Universal).

Evidence to the role of interflavan linkages and galloylation of proanthocyanidins at sustaining long-term dentin biomodification.

Objectives: The interactivity of proanthocyanidins (PACs) with collagen modulates dentin matrix biomechanics and biostability. Herein, PAC extracts selected based on structural diversity were investigated to determine key PAC features driving sustained effects on dentin matrices over a period of 18months.

Methods: The chemical profiles of PAC-rich plant sources, Pinus massoniana (PM), Cinnamomum verum (CV) and Hamamelis virginiana (HV) barks, as well as Vitis vinifera (VV) seeds, were obtained by diol HPLC analysis after partitioning of the extracts between methyl acetate and water.

Long-term evaluation of the stability of dentin matrix following treatments with aqueous solutions of titanium tetrafluoride at different concentrations.

Objective: The purpose of this study was to investigate the effects of aqueous solutions of different concentrations of titanium tetrafluoride (TiF) on dentin matrix stability up to six months.

Design: Dentin specimens prepared from fifteen nonerupted molars were demineralized and randomly distributed into groups: 2.5% TiF, 4% TiF 1000 ppm NaF, and control (distilled water).

An Overview of Dental Adhesive Systems and the Dynamic Tooth-Adhesive Interface.

From the conception of resin-enamel adhesion to today's contemporary dental adhesive systems, clinicians are no longer afraid of exploring the many advantages brought by adhesive restorative concepts. To maximize the performance of adhesive-based restorative procedures, practitioners must be familiar with the mechanism of adhesion, clinical indications, proper handling, the inherent limitations of the materials and the biological challenges. This review provides an overview of the current status of restorative dental adhesives, their mechanism of adhesion, mechanisms of degradation of dental adhesive interfaces, how to maximize performance, and future trends in adhesive dentistry.

Role of proteoglycans on the biochemical and biomechanical properties of dentin organic matrix.

Objective: Proteoglycans (PGs) are multifunctional biomacromolecules of the extracellular matrix of collagen-based tissues. In teeth, besides a pivotal regulatory role on dentin biomineralization, PGs provide mechanical support to the mineralized tissue and compressive strength to the biosystem. This study assessed enzymatic protocols for selective PGs removal from demineralized dentin to determine the roles of these biomacromolecules in the bulk mechanical properties and biostability of type I collagen.

Encapsulation of grape seed extract in polylactide microcapsules for sustained bioactivity and time-dependent release in dental material applications.

Objective: To sustain the bioactivity of proanthocyanidins-rich plant-derived extracts via encapsulation within biodegradable polymer microcapsules.

Methods: Polylactide microcapsules containing grape seed extract (GSE) were manufactured using a combination of double emulsion and solvent evaporation techniques. Microcapsule morphology, size distribution, and cross-section were examined via scanning electron microscopy.

Oligomeric proanthocyanidins released from dentin induce regenerative dental pulp cell response.

Unlabelled: Proanthocyanidins (PACs) are plant-derived, multifunctional compounds that possess high interactivity with extracellular matrix (ECM) components. The documented affinity of PACs for type-I collagen is directly correlated with their structural features and degree of polymerization. In this investigation, centrifugal partition chromatography (CPC) was used to sequentially deplete less active monomeric and polymeric PACs from a crude Pinus massoniana bark extract to create refined mixtures enriched in oligomeric PACs.

Absolute Configuration of Native Oligomeric Proanthocyanidins with Dentin Biomodification Potency.

The structurally complex oligomeric proanthocyanidins (OPACs) are promising biomimetic agents, capable of strengthening the macromolecular backbone of teeth via intermolecular and intermicrofibrillar cross-linking. This study establishes analytical methods capable of determining the absolute configuration of the catechin-type monomeric units of underivatized OPACs. This preserves the capacity of their biological evaluation, aimed at understanding the inevitably stereospecific interactions between the OPACs and dentin collagen.

Biostability of the Proanthocyanidins-Dentin Complex and Adhesion Studies.

Oligomeric proanthocyanidins (OPACs) are potent and renewable natural bioactives possible to be refined into chemically standardized mixtures for biological applications. Herein, we found that multiscale interactions of OPACs with the dentin matrix create tight biointerfaces with hydrophobic methacrylate adhesives on wet surfaces. An enriched mixture of OPACs, with a known phytochemical profile, was produced from grape seed crude extract ( Vitis vinifera; enriched grape seed extract [e-GSE]) and applied to dentin matrices to determine changes to the mechanical properties and biodegradability of the dentin matrix and favorable resin adhesion mechanisms.

Effect of Bioactive Primers on Bacterial-Induced Secondary Caries at the Tooth-Resin Interface.

Secondary caries at the tooth-resin interface is the primary reason for replacement of resin composite restorations. The tooth-resin interface is formed by the interlocking of resin material with hydroxyapatite crystals in enamel and collagen mesh structure in dentin. Efforts to strengthen the tooth-resin interface have identified chemical agents with dentin collagen cross-linking potential and antimicrobial activities.

Experimental primers containing synthetic and natural compounds reduce enzymatic activity at the dentin-adhesive interface under cyclic loading.

Objective: To evaluate the effect of experimental primers (chlorhexidine, enriched mixture of proanthocyanidins, and doxycycline) on the adhesive properties and gelatinolytic activity at dentin-resin interfaces of occlusal Class I restorations.

Methods: The inactivation of enzymes by the experimental primers was assessed by fluorescence assay and gelatin zymography. To assess the adhesive properties, occlusal Class I cavities were prepared in sound human molars, etched with phosphoric acid and restored with one of the primers and an etch-and-rinse adhesive system (Adper Single Bond Plus-3M ESPE).