The ultimate goal of this proposal is to fully characterize dentin and modify it to enhance adhesion to it. The emphasis in the next five years will be on expanding our efforts beyond normal circumpulpal dentin to include other types of dentin. Normal dentin structure exhibits variation in structure and properties with location, but there are also many dentins, including primary, secondary, tertiary, coronal, root, sclerotic, transparent, carious, demineralized, remineralized, and hypermineralized. They reflect alterations in the fundamental components of the structure as defined by changes in their arrangement, interrelationships or composition. Several have important implications for our ability to develop long lasting adhesion or bonds to this structure. Progress in diverse areas including adhesion to dentin and dentin physiology require a thorough knowledge of the basic microstructure, composition and components of dentin. In the prior period, we studied normal dentin as a complex composite material that needed ot be understood from the materials science perspective. We developed some unique methods for its study, including x-ray tomographic microscopy, atomic force microscopy, and atomic force microscopy nanohardness. In addition, we began the process of defining some of its important compositional, mechanical and physical properties as related to microstructure. Although significant progress has been made, we have evaluated only one dentin type, and the knowledge gained will form a critical reference base for understanding other types. Thus in the next period we will focus on important variations of dentin which are encountered in many clinical situations. The program project will encompass four projects. The first, Characterization of Normal and Altered Forms of Dentin, is a comprehensive investigation of different types of dentin to understand their microstructures and composition on a microscopic level. We will use many of the same analytical methods as in the last project period, such as scanning electron microscopy/energy dispersive x-ray analysis (SEM/EDS). Fourier transform infrared spectroscopy (FTIR), x-ray tomographic microscopy (XTM), atomic force microscopy (AFM), and x-ray diffraction (XRD). The second project, Mechanical Properties and the Structure of Dentin, will define the mechanical properties of the constituent parts of dentin (i.e. peritubular, intertubular) and how they vary with intratooth position, age, or gender. Nanohardness and modulus will be measured using the atomic force microscopy. The third project, The Resin-Dentin Interdiffusion Zone, will test the hypotheses that the resin-dentin interdiffusion zones formed by two types of adhesives have the same substructure and that the substructure does not vary with dentin depth or altered form of dentin.

National Institute of Health (NIH)
National Institute of Dental & Craniofacial Research (NIDCR)
Research Program Projects (P01)
Project #
Application #
Study Section
Special Emphasis Panel (ZDE1-YS (32))
Program Officer
Kousvelari, Eleni
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University of California San Francisco
Schools of Dentistry
San Francisco
United States
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Brauer, Delia S; Hilton, Joan F; Marshall, Grayson W et al. (2011) Nano- and micromechanical properties of dentine: Investigation of differences with tooth side. J Biomech 44:1626-9
Brauer, Delia S; Marshall, Grayson W; Marshall, Sally J (2010) Variations in human DEJ scallop size with tooth type. J Dent 38:597-601
Chang, Jolie L; Brauer, Delia S; Johnson, Jacob et al. (2010) Tissue-specific calibration of extracellular matrix material properties by transforming growth factor-? and Runx2 in bone is required for hearing. EMBO Rep 11:765-71
Staninec, Michal; Meshkin, Neda; Manesh, Saman K et al. (2009) Weakening of dentin from cracks resulting from laser irradiation. Dent Mater 25:520-5
Pugach, M K; Strother, J; Darling, C L et al. (2009) Dentin caries zones: mineral, structure, and properties. J Dent Res 88:71-6
Ho, Sunita P; Senkyrikova, Pavla; Marshall, Grayson W et al. (2009) Structure, chemical composition and mechanical properties of coronal cementum in human deciduous molars. Dent Mater 25:1195-204
Staninec, Michal; Nguyen, Harrison; Kim, Paul et al. (2008) Four-point bending evaluation of dentin-composite interfaces with various stresses. Med Oral Patol Oral Cir Bucal 13:E81-4
Balooch, M; Habelitz, S; Kinney, J H et al. (2008) Mechanical properties of mineralized collagen fibrils as influenced by demineralization. J Struct Biol 162:404-10
Hsu, Kuang-Wei; Marshall, Sally J; Pinzon, Lilliam M et al. (2008) SEM evaluation of resin-carious dentin interfaces formed by two dentin adhesive systems. Dent Mater 24:880-7
Koester, Kurt J; Ager 3rd, Joel W; Ritchie, Robert O (2008) The effect of aging on crack-growth resistance and toughening mechanisms in human dentin. Biomaterials 29:1318-28

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