A better understanding of both the chemical and mechanical changes within dentin carious lesions is required for the development of new approaches to clinical management and repair of the damaged tissue.  Objective: To relate the changes of chemical properties to mechanical properties in the zones of dentin caries.  Methods: Extracted human carious molars (n=3) with occlusal dentin lesions were sectioned sagittally through the lesion center using a low-speed diamond saw. Only sections of dentin with occlusal caries that did not extend to the pulp and with surrounding sound dentin were used. Sections (5-µm-thick) were cut parallel to the saw-cut surface, placed on BaF2 disc and FTIR chemical images were collected from areas containing sound and carious dentin using the Spectrum Spotlight 300 system (Perkin Elmer) with 8 cm-1spectral resolution. The same specimens were sequentially polished under water for mechanical analysis and the elastic modulus of the region analyzed with FTIR was determined from acoustic images collected with the KSI WINSAM 200 scanning acoustic microscope (KSI, Herborn, Germany). Results: Interactive mechanical (elastic modulus) and chemical images (mineral/matrix ratios) were generated from the same region of sound/carious dentin at a lateral resolution of ~15 um. Distinct differences in chemical composition and elastic moduli were recorded for the zones of dentin caries (sound, transparent and caries-affected):

Conclusions: Fusion of chemical and mechanical imaging techniques provided a powerful means of understanding calcified tissues exhibiting markedly different properties.  The chemical and mechanical properties of the various zones within the caries lesion were directly correlated. Supported by NIH/NIDCR DE014392, DE015281, R0315735, R13DK069504.

Back to the Cariology Research Program
Back to the IADR/AADR/CADR 85th General Session and Exhibition (March 21-24, 2007)

Top Level Search