The lack of durability of resin-dentin bonds results in enormous health care costs as tooth-colored restorations require frequent replacement due to deteriorating interfacial coupling of resin composites to dentin. Our overall hypothesis is that the lack of durability involves degradation of both the resin and collagen phases of the hybrid layer that creates the interracial coupling. Due to the wet bonding technique, adhesive formulations are more hydrophilic than in the past. Hydrophilic resins in the adhesive promote nonuniform water absorption that creates water-filled voids and channels that accelerate hydrolysis of ester bonds in the polymers. We propose to follow the rate of these processes nondestructively by measuring changes in the electrical impedance of resins. Long-term bonding studies in vitro and in vivo show the loss of collagen from the hybrid layer. Collagen fibrils in the dentin matrix appear to be hydrolyzed in vitro, even in the absence of bacteria, by matrix metalloproteinases (MMPs) that were trapped in the matrix during its formation, and that slowly attack the demineralized collagen fibrils infiltrated with resin. This overall hypothesis will be tested by experiments designed to contrast the stability of hydrophilic versus hydrophobic resins; we will also test the stability of collagen matrices when they are fully demineralized versus when they are bonded to demineralized matrices that are within 10 um of mineralized dentin that can slowly expose more MMPs, or when MMPs in dentin are inactivated by heat or enzyme inhibitors. A variety of inhibitors of MMPs will be tested to determine if they can prevent the loss of the mechanical properties of the matrix that leads to low bond strengths and coupling failures. Hopefully, a nonspecific inhibitor of MMP (e.g. chlorhexidine or bisphosphonates) can be applied as a pretreatment during bonding or incorporated into bonding resins to greatly improve the durability of resin-dentin bonds. Alternative approaches such as the use of fluoride-containing resins will be evaluated in an attempt prevent matrix demineralization that we believe is responsible for the exposure of MMPs from the underlying mineralized matrix. This comprehensive approach to improving the durability of resin-dentin bonds should ultimately save billions of dollars in health care and much human suffering.

National Institute of Health (NIH)
National Institute of Dental & Craniofacial Research (NIDCR)
Research Project (R01)
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Oral, Dental and Craniofacial Sciences Study Section (ODCS)
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Drummond, James A
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Georgia Regents University
Schools of Dentistry
United States
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Zhang, Zihou; Mutluay, Mustafa; Tezvergil-Mutluay, Arzu et al. (2017) Effects of EDC crosslinking on the stiffness of dentin hybrid layers evaluated by nanoDMA over time. Dent Mater 33:904-914
Arola, Dwayne D; Gao, Shanshan; Zhang, Hai et al. (2017) The Tooth: Its Structure and Properties. Dent Clin North Am 61:651-668
Apolonio, Fabianni M; Mazzoni, Annalisa; Angeloni, Valeria et al. (2017) Effect of a one-step self-etch adhesive on endogenous dentin matrix metalloproteinases. Eur J Oral Sci 125:168-172
Niu, Li-Na; Jee, Sang Eun; Jiao, Kai et al. (2017) Collagen intrafibrillar mineralization as a result of the balance between osmotic equilibrium and electroneutrality. Nat Mater 16:370-378
Arola, Dwayne (2017) Fatigue testing of biomaterials and their interfaces. Dent Mater 33:367-381
Zhang, Zihou; Beitzel, Dylan; Majd, Hessam et al. (2017) Fatigue resistance of dentin bonds prepared with two- vs. three-step adhesives: Effect of carbodiimide. Dent Mater 33:1340-1350
Zhou, Jianfeng; Chiba, Ayaka; Scheffel, Debora L S et al. (2016) Cross-linked dry bonding: A new etch-and-rinse technique. Dent Mater 32:1124-32
Zhang, Zihou; Beitzel, Dylan; Majd, Hessam et al. (2016) Effect of carbodiimide on the fatigue crack growth resistance of resin-dentin bonds. Dent Mater 32:211-22
Tian, F; Zhou, L; Zhang, Z et al. (2016) Paucity of Nanolayering in Resin-Dentin Interfaces of MDP-based Adhesives. J Dent Res 95:380-7
Ryou, Heonjune; Turco, Gianluca; Breschi, Lorenzo et al. (2016) On the stiffness of demineralized dentin matrices. Dent Mater 32:161-70

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