Chemical study on acid treatment of collagen

Abstract

Acid treatment prior to dentin bonding is believed to cause structural changes in the dentin surface collagen. I attempted to elucidate this chemical change using IR and NMR spectrometers. The IR spectrum obtained after treating collagen with phosphoric or hydrochloric acid indicated a decrease in absorption based on the vibration of the secondary amido N-H. This suggests a cleavage of the peptide C-N bond containing a glycine or alanine N terminus. The NMR study using a collagen model, i.e., (Pro-Pro-Gly)_5, strongly supported the above result.