Basic ResearchEffect of Hydration on the Strain Gradients in Dental Hard Tissues after Heat and Cold Application
Section snippets
Specimen Preparation
Eight extracted bovine incisors maintained in deionized water at 4°C were used in this study. The teeth were transilluminated and excluded from the experiment if cracks were present. Specimens were prepared as 3-mm parallel-sided slabs along the sagittal plane, as mentioned in the previous literature (Fig. 1A) (12).
Experiments
Details of DMI used in this study are described elsewhere (12). The specimen gratings were produced by replicating a high-frequency cross-line grating (1200 lines/mm) onto the
Strain Distribution in Dental Hard Tissues
Fig. 2 shows the strain distribution pattern in dental hard tissues in the direction perpendicular to the dentinal tubules (U field) in the partially dehydrated and fully dehydrated conditions. The initial zero-order fringe pattern showed deformation after application of heat/cold stimuli. In fully hydrated condition, the DEJ showed highest strains as compared with enamel and dentin. In a fully hydrated tissue both heat and cold stimuli did not produce any significant change in strains in
Discussion
Sagittal section of bovine teeth (faciolingual plane) was examined in this study to evaluate the thermal strain distribution in enamel, dentin, and DEJ (11). This anatomical section was chosen because of the prominent gradients in mineralization and mechanical properties (elastic modulus and hardness) exhibited by dentin in this plane (18). The pulp tissue consists of a connective tissue system made up of cells and fibers embedded in an extracellular matrix. The extracellular matrix proteins
Acknowledgments
The authors disclose no conflicts of interest.
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2012, Journal of the Mechanical Behavior of Biomedical MaterialsCitation Excerpt :Numerous authors have already addressed the factor “moisture content of dentin” which decreases with patient's age (Arola and Reprogel, 2005), after endodontic treatment (Soares et al., 2007; Kishen and Asundi, 2005) and after bleaching (Betke et al., 2006) making these teeth more brittle than vital teeth (Kishen and Asundi, 2005; Jameson et al., 1993). Dehydrated dentin however has been shown to have a decreased toughness (Arola and Reprogel, 2005; Jameson et al., 1993) and fatigue crack growth resistance (Bajaj et al., 2006) and shows higher strains after the application of heat and cold stimuli (Shrestha et al., 2010). Furthermore, water loss may result in shrinkage of dentin which can cause the development of deleterious stresses.
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