Frank Tay

Augusta University · Department of Endodontics

Dental caries is the most common oral disease and the most common cause of resin restorations. In minimally invasive dentistry, the principle behind cavity preparation is to remove external caries-infected dentin (CID) and preserve internal caries-affected dentin (CAD) and sound dentin (SD). The cavity floor is mainly composed of CAD, but the poor...

Biological mineralization is a natural process manifested by living organisms in which inorganic minerals crystallize under the scrupulous control of biomolecules, producing hierarchical organic-inorganic composite structures with physical properties and design that galvanize even the most ardent structural engineer and architect. Understanding the...

Dentin bonding is a dynamic process that involves the penetration of adhesive resin monomers into the extra-fibrillar and intrafibrillar demineralized collagen matrix using a wet-bonding technique. However, adhesive resin monomers lack the capacity to infiltrate the intrafibrillar space, and the excess water that is introduced by the wet-bonding te...

Carbodiimide (EDC)–based dentin primers preserve hybrid layer (HL) integrity. However, aging >1 y has not been investigated. The present study examined whether the cross-linking effect of EDC was reflected in dentin bond strength, endogenous enzymatic activity, and the chemical profile of the HL after 5-y aging in artificial saliva. Noncarious huma...

This study evaluated the use of a new collagen-reactive monomer (CRM), isocyanate-terminated urethane methacrylate precursor, which has covalent affinity to dental collagen, in the formation of dentin-resin bonds and compared it with 2 other dental adhesives. Dentin specimens were bonded with either the CRM-based adhesive (CBA), One-Step (OS; Bisco...

When damaged or fractured collagen-rich hard tissues are repaired by resin material, the collagen matrix may be used as a scaffold, after removal of the natural minerals, for resin monomers to penetrate and polymerize in-situ. Formation of a collagen-polymer hybrid biocomposite via mechanical hybridization provides a stable and strong link between...

Contemporary models of intrafibrillar mineralization mechanisms are established using collagen fibrils as templates without considering the contribution from collagen-bound apatite nucleation inhibitors. However, collagen matrices destined for mineralization in vertebrates contain bound matrix proteins for intrafibrillar mineralization. Negatively...

Instability of resin-dentin bonds is the Achilles' heel of adhesive dentistry. To address this problem, a chelate-and-rinse extrafibrillar dentin demineralization strategy has been developed that keeps intrafibrillar minerals within collagen fibrils intact to prevent activation of endogenous proteases that are responsible for collagen degradation w...

Purpose: The present study evaluated the influence of air entrapment within demineralized dentin on bond strength, nanoleakage, and degree of conversion. Materials and methods: A vacuum pump with adjustable pressure was used to control the gaseous pressure of a sealed container during the application of a two-step etch-and-rinse adhesive to demi...

Objective: To evaluate the efficacy of EDDY, a new sonic-powered irrigation system, in reducing intracanal bacteria load. Methods: Thirty-eight instrumented, autoclaved single-rooted human premolars were inoculated with Enterococcus faecalis (ATCC-29212) for 21 days. Two teeth were used as negative control without bacterial contamination. For th...

A chelate-and-rinse extrafibrillar calcium chelation dentin bonding concept has recently been developed and investigated for its effectiveness in improving resin-dentin bonding by bridging the gap between wet and dry dentin bonding. The objective of the present study was to evaluate the gelatinolytic activity of hybrid layers (HLs) created using th...

The use of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide HCl (EDC) has recently been investigated for its effectiveness in the prevention of collagen degradation over time and the improvement of resin-dentin bond durability. The objective of the present study was to evaluate the effects of a 0.3 M EDC-containing conditioner on endogenous enzymatic...

Objective: The present study examined the effect of a quaternary ammonium silane (QAS) cavity disinfectant on the viability of human dental pulp cells, dentine bond durability and nanoleakage of simplified etch-and-rinse adhesives. Methods: Etched dentine surface of third molars were randomly divided into two adhesive groups, Adper™ Single Bond...

Scaffold supplements such as nanoparticles, components of the extracellular matrix, or growth factors have been incorporated in conventional scaffold materials to produce smart scaffolds for tissue engineering of damaged hard tissues. Due to increasing concerns on the clinical side effects of using large doses of recombinant bone-morphogenetic prot...

Cytotoxicity of different concentrations of PAH-ACP@pMSN on hMSCs (N=6). Notes: Statistical analysis was performed against the control (0 μg/mL). Columns labeled with the same color as the control group (blue) are not significantly different from the control (P>0.05). Columns labeled with red are not significantly different from each other (P>0.05)...

mRNA expression profiles of osteogenic target gene markers for unexposed hMSCs, hMSCs exposed to pMSN, and hMSCs exposed to PAH-ACP@pMSN. Notes: Values are means and standard deviations (N=3). Columns within each gene marker that are labeled with different designators are significantly different (P<0.0085) (uppercase letters for ALP, lowercase lett...

Alkaline phosphatase enzyme activities for unexposed hMSCs, hMSCs exposed to pMSN, and hMSCs exposed to PAH-ACP@pMSN. Notes: Values are means and standard deviations (N=6). Groups that are labeled with different uppercase letters are significantly different (P<0.05). Abbreviations: hMSCs, human bone marrow mesenchymal stem cells; pMSN, expanded-por...

Objectives: Demineralized dentin collagen release C-terminal cross-linked telopeptide (ICTP) and C-terminal peptide (CTX) during degradation. The present study evaluated the effects of dentin pre-treatment with K21, a quaternary ammonium silane (QAS), on matrix metalloproteinase (MMP) and cathepsin K-mediated collagen degradation. Methods: Denti...

Mineralization of fibrillar collagen with biomimetic process-directing agents has enabled scientists to gain insight into the potential mechanisms involved in intrafibrillar mineralization. Here, by using polycation- and polyanion-directed intrafibrillar mineralization, we challenge the popular paradigm that electrostatic attraction is solely respo...

The apical delta is an intricate system within the root canal and incompletely debridement may affect the long-term prognosis of root canal therapy. The aim of the present study is to investigate the morphologic features of apical deltas in human teeth with micro-computed tomography (micro-CT) using a centreline-fitting algorithm. One hundred and t...

Biomineralization in vertebrates is a ubiquitous and tightly regulated process which creates hierarchical structures for the skeleton. Because of the lack of understanding and applicability of cell-based or biological systems to achieve intrafibrillar mineralization, scientists adopted various in vitro methods to elucidate the mechanism of intrafib...

On page 6858, L.-N. Niu, J.-H. Chen, F. R. Tay, and co-workers opine that the seemingly discordant mechanisms proposed for intrafibrillar mineralization, despite their evolution from quite different contexts, represent different means in achieving the same end.

Purpose: To evaluate the bonding behavior of resin composite and different adhesives applied to demineralized or remineralized enamel. Methods: Bovine tooth crowns were polished to prepare a 5 mm2 enamel bonding area, and divided into five groups (n= 48) according to the surface treatment: CONT (sound enamel control), DEM (demineralized with aci...

The present study examined the mechanism for caries resistance and the pulp responses in vital teeth following the use of the augmented-pressure adhesive displacement technique. Dentin adhesives were applied to the surface of sound dentin disks in 4 experimental groups: non-antibacterial adhesive and gentle adhesive displacement (N-G), non-antibact...

Objectives: An experimental discoloration-free calcium aluminosilicate cement has been developed with the intention of maximizing the beneficial attributes of tricalcium silicate cements and calcium aluminate cements. The present study examined the effects of this experimental cement (Quick-Set2) on the mineralogenic characteristics of osteogenic...

This study tested whether activation of adrenoreceptors in chondrocytes has roles in degenerative remodelling of temporomandibular joint (TMJ) and to determine associated mechanisms. Unilateral anterior crossbite (UAC) was established to induce TMJ degeneration in rats. Saline vehicle, α2- and β-adrenoreceptor antagonists or agonists were injected...

Introduction: Natural bone has a complex hierarchical nanostructure composed of well-organized collagen fibrils embedded with apatite crystallites. Bone tissue engineering requires scaffolds with structural properties and functionality similar to the natural bone. Inspired by bone, a collagen-apatite (Col-Ap) nanocomposite was fabricated with bone...

Objective: To determine if acid-etched, cross-linked dentin can be dehydrated without lowering bond strength below that of cross-linked wet-bonded dentin in vitro. Methods: Using extracted human third molars, control acid-etched dentin was bonded with Single Bond Plus, using either the wet- or dry-bonding technique. Experimental acid-etched dent...

Objective: The present study tested the central hypothesis that selective demineralisation of dentine extrafibrillar minerals by lowering the phosphoric acid concentration improves the quality of the resin-dentine interface. Methods: Dentine surfaces were etched with different concentrations of phosphoric acid (1, 5, 10, 20, 30 or 40wt%). Scanni...

The present study evaluated the effectiveness of a dicalcium and tetracalcium phosphate-based desensitizer in reducing dentin permeability in vitro. Dentin fluid flow was measured before and after treatment of dentin with patent dentinal tubules using 1 or 3 applications of the dicalcium and tetracalcium phosphate containing agent TeethmateTM (TM)...

Many reports have indicated that resin bond strengths to noncarious sclerotic cervical dentin are lower than bonds made to normal dentin. This is thought to be due to tubule occlusion by acid-resistant mineral salts, preventing resin tag formation following acid etching. The purpose of this review was to critically examine what is known about the s...

Objectives: The objective of the presentin vitro study was to evaluate the canal wall smear layer removal capacity and mineral content distribution of root canal dentine after irrigation with QMix, 7% maleic acid (MA) and 17% ethylenediaminetetraacetic acid(EDTA). Methods: Forty single-rooted teeth were subjected to root canal instrumentation an...

Unlabelled: To investigate the contribution of nanolayering on resin-dentin bond durability, two phosphoric acid ester resin monomers, 10-methacryloyloxy-decyl-dihydrogen-phosphate (10-MDP) or its analog, methacryloyloxy-penta-propyleneglycol-dihydrogen-phosphate (MDA), were examined for their affinity for mineralized dentin powder in a column chr...

The present in vitro study evaluated the secondary caries resistance potential of acid-etched human coronal dentin bonded using augmented pressure adhesive displacement in conjunction with an experimental antibacterial adhesive. One hundred and twenty class I cavities were restored with a commercial non-antibacterial etch-and-rinse adhesive (N) or...

Statement of significance: Highlight of the Research Using molecular simulation, ethanol infiltration into the demineralized dentin collagen structures is investigated. It is discovered that alignment of the collagen triple helices in the gap regions is altered by the contact with the ethanol, resulting into the infiltration of the ethanol molecul...

Introduction: The morphologic features of accessory canals (ACs) were investigated by using micro computed tomography technique with a centerline fitting algorithm. Methods: Ninety-three 3-mm-long apical root segments with unobstructed ACs were scanned by micro computed tomography at 2.5-μm scanning resolution. After automatic segmentation, a ce...

Quaternary ammonium methacryloxy silicate (QAMS)-containing acrylic resin demonstrated contact-killing antimicrobial ability in vitro after three months of water storage. The objective of the present double-blind randomised clinical trial was to determine the in vivo antimicrobial efficacy of QAMS-containing orthodontic acrylic by using custom-made...

Statement of significance: It has been reported that collagen molecules in dentin matrices are packed too close together to allow permeation of adhesive monomers between them. Resin infiltration, in this view, would be limited to extrafibrillar spaces. Our work suggests that monomers equilibrate with collagen water in both water and ethanol-satura...

Objectives: 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) has been shown to cross-link dentin type I collagen. Increased cross-linking usually elevates the glass transition temperature of polymers. The aim of this study was to evaluate the cross-linking reaction promoted by EDC in different aqueous concentrations by measuring...

Objectives: To evaluate the bonding of resin-cement to yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) via silica coating followed by silanization, and three one-bottle universal adhesives, with or without prior conditioning using a zirconia primer. Methods: Y-TZP specimens (n=160) were conditioned by tribochemical silica coating and s...

Self-assembled nanolayering structures have been reported in resin-dentin interfaces created by adhesives that contain 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP). These structures have been hypothesized to contribute to bond durability. The objective of the present study was to determine the extent of nanolayering in resin-dentin interfa...

Statement of significance: Concepts of collagen biomineralization have been reasonably well established in the past few years and intrafibrillar mineralization of collagen fibrils can be predictably achieved with analogs of matrix proteins using solution-based systems. However, solution-based systems have their limitations in clinical applications...

Statement of significance: Long-term oral consumption and injections of nitrogen-containing bisphosphonates (N-BPs) may result in death of the jaw bone when there is traumatic injury to the bone tissues. To date, there is no effective treatment for such a condition. This work reported the use of an ionic cocktail derived from water-soluble borate...

Statement of significance: Long-term oral and intravenous use of nitrogen-containing bisphosphonates (N-BPs) may result in bisphosphonate-related osteonecrosis of the jaw (BRONJ) due to the suppression of normal bone turnover. There is no effective treatment for such a complication to date. This work reported the use of an ionic cocktail derived f...

Statement of problem: The clinical failure of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) substrates may be attributed to their susceptibility to low-temperature degradation (LTD). The acceleration of LTD by multiple veneering firings of Y-TZP remains poorly understood. Purpose: The purpose of this in vitro study was to evaluate th...

Objective: Success in adhesive dentistry means long lasting restorations. However, there is substantial evidence that this ideal objective is not always achieved. Current research in this field aims at increasing the durability of resin-dentin bonds. The objective of this paper is to examine the fundamental processes responsible for the aging mech...

Objective: This study evaluated the ability of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) to improve the stability of demineralized dentin collagen matrices when subjected to mechanical cycling by means of Chewing Simulation (CS). Methods: Demineralized dentin disks were randomly assigned to four groups (N=4): (1) immersi...

Objective: To characterize the effect of an EDC pretreatment on the fatigue crack growth behavior of resin-dentin bonds. Methods: Bonded interface Compact Tension (CT) specimens were prepared using a three-step etch-and-rinse adhesive and hybrid resin-composite. Adhesive bonding of the treated groups included a 1min application of an experimenta...

Objective: The objective was to assess a new approach for evaluating the changes in stiffness of decalcified dentin by polar solvents and a collagen cross-linker. Methods: Fully demineralized dentin beams and sections of etched coronal dentin were subjected to indentation loading using a cylindrical flat indenter in water, and after treatment wi...

Discoloration-resistant calcium aluminosilicate cement has been formulated to overcome the timely problem of tooth discoloration reported in the clinical application of bismuth oxide-containing hydraulic cements. The present study examined the effects of this experimental cement (Quick-Set2) on the viability and proliferation of human dental pulp s...

Objectives: In pulpal revascularization, a protective material is placed coronal to the blood clot to prevent recontamination and to facilitate osteogenic differentiation of mesenchymal stem cells to produce new dental tissues. Although mineral trioxide aggregate (MTA) has been the material of choice for clot protection, it is easily displaced int...

Nanotechnology is currently driving the dental materials industry to substantial growth, thus reflecting on improvements in materials available for oral prevention and treatment. The present review discusses new developments in nanotechnology applied to dentistry, focusing on the use of nanomaterials for improving the quality of oral care, the pers...

The aim of this study was to evaluate the effects of hydrofluoric (HF) acid, acetic acid, and citric acid treatments on the physical properties and structure of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) at ambient temperature. In total, 110 bar-shaped zirconia specimens were randomly assigned to 11 groups. The specimens in the contr...

This study examined the effects of matrix metalloproteinase-inhibiting solutions and aging methods on the bond strength between resin composite and human dentin. Crown segments of 105 human non-carious molars were bonded using simulated pulpal pressure at 20 cm water pressure. The teeth were randomly split into 5 groups according to the solution ap...

The present study tested whether activation of the sympathetic tone by aberrant joint loading elicits abnormal subchondral bone remodeling in temporomandibular joint (TMJ) osteoarthritis. Abnormal dental occlusion was created in experimental rats, which were then intraperitoneally injected by saline, propranolol or isoproterenol. The norepinephrine...

Objectives: Identification of the mechanism of chemical coupling of a phosphate ester monomer to zirconia via a computational modeling approach enables materials scientists to design new coupling agents that can resist hydrolytic degradation of bonds made by methacrylate resins to zirconia. We investigated the possibility of chemical bonding betwe...

Fatigue of resin-dentin adhesive bonds is critical to the longevity of resin composite restorations. The objectives were to characterize the fatigue and fatigue crack growth resistance of resin-dentin bonds achieved using two different commercial adhesives and to identify apparent "weak-links". Bonded interface specimens were prepared using Adper S...

Antimicrobial Molecule K-21, Inhibit Replication of Enveloped, and Un-Enveloped DNA, and RNA Viruses