1327 ATR-FTIR Characterization of Dentin Surface Exposed to Collagen Cross-linking Agents

Saturday, March 24, 2012: 9:45 a.m. - 11 a.m.
Presentation Type: Poster Session
B. AYDIN1, M.M. BLAZE2, A. ROY2, M.G. VIANA3, and A.K. BEDRAN-RUSSO1, 1Department of Restorative Dentistry, University of Illinois - Chicago, Chicago, IL, 2Department of Chemistry, University of Illinois - Chicago, Chicago, IL, 3Department of Orthodontics, University of Illinois - Chicago, Chicago, IL
Objectives: To determine the degree of non-enzymatic collagen cross-linking of human crown dentin treated with various cross-linking agents used at different exposure times.

Methods: Dentin surfaces were analyzed using attenuated total reflectance fourier transform-infrared spectroscopy (ATR-FTIR). Spectra were recorded using a FTLA2000 Series spectrometer (ABB Bomem Inc.) in the range of 400-4000 cm-1 using single-beam with 4 cm-1 resolution and averaging 256 scans. Spectra from the same sections (N=5) were obtained at different timepoints: undemineralized, demineralized surface (20-sec 35% phosphoric acid), cumulative exposure to cross-linking agents: 5% glutaraldehyde, carbodiimide/N-Hydroxysuccinimide (5.75%/1.38% w:v in water), and grape seed extract (6.5 % and 30% GSE w:v in water) for 30-sec, 60-sec, 2-min, 5-min and 10-min. The data was statistically analyzed by Kruskal-Wallis test, followed by Mann-Whitney analysis for independent samples (cross-linking agents), and Wilcoxon signed-rank test for dependent values (different exposure times); 95% confidence level.

Results: The IR absorption peaks assigned to the dentin collagen; amide I and II band complexes observed between 1700-1600 cm-1, 1575-1520 cm-1 respectively and peaks assigned to the phosphate group of hydroxyapatite observed between 1105-1026 cm-1 were consistent with previous publications. After 5-min exposure to the cross-linking agents, 30% GSE group showed the highest intensity (p=0.016) for the peak observed approximately at 1653 cm-1, an indicator of intermolecular hydrogen bonded carbonyls. Also, the intensity of the peak indicating trivalent cross-linking in collagen (approximately at 1457 cm-1) was used to make direct comparisons of the efficacy of cross-linking agents, the average intensity of this peak was highest at 30% GSE group, compared to the other cross-linking agents.

Conclusions: Exposing dentin to cross-linking agents alters its chemical composition by increasing intra and interfibrillar cross-linking of type-I collagen. Grape seed extract induced the highest extend of hydrogen bonding and trivalent interfibrillar cross-linking of dentin collagen in comparison to other cross-linking agents.

This abstract is based on research that was funded entirely or partially by an outside source: NIDCR grants DE017740 and DE017740-04S1

Keywords: Chemical, Collagen, Dentin and cross-linking, ATR-FTIR