Investigations on the dynamics of water in structural dentine

Abstract

The aim of this study was two fold: (1) to investigate the nature and degree of water loss at 21°C (dehydration) and relate these findings with (2) strains produced in dentine structure during water loss and regain. The nature and degree of water loss was investigated using Nuclear-Magnetic Resonance Spectroscopy and gravimetric analysis. Digital Moiré Interferometry (DMI) was used to study the patterns of strain distribution during water-loss (dehydration) and water-regain (rehydration) at 21°C. The gravimetric analysis showed that dentine exhibited a biphasic response in water-loss. An initial rapid phase followed by a gradual and steady phase. DMI showed that dehydration induced strains were formed within dentine in three phases. These experiments highlighted that the major portion of free water from dentine was lost rapidly from the surface and the dentinal tubules, as soon as they are exposed to 21°C (55% RH). DMI showed that dehydration produced strains in the dentine structure after an initial latent period. Rehydration caused almost complete reversal of the dehydration induced water-loss and strains.