Water content and apparent stiffness of non‐caries versus caries‐affected human dentin

Abstract

Caries-affected dentin contains less mineral and more water than surrounding normal dentin. Such dentin should be less stiff and should shrink more than normal dentin when dried. The purpose of this study was to test the relationships between the stiffness, shrinkage, and water content of caries-affected versus normal dentin. Extracted human carious third molars were stained with caries-detector dye and the occlusal surfaces ground down until only caries-affected dentin remained, surrounded by normal dentin. Dentin disks were prepared from these crowns placed in a aluminum well positioned under a modified thermal mechanical analyzer. Changes in specimen height and stiffness were measured following drying or static loading in both caries-affected and surrounding normal dentin. Core samples of these two types of dentin were used to gravimetrically measure water content. Two-way ANOVA and regression analysis was used to test the relationship between shrinkage versus water content, stiffness versus water content, and stiffness versus shrinkage. Cariesaffected dentin was found to be less stiff and contained more water than normal dentin (p < 0.05). Regression analysis revealed highly significant inverse relationships between stiffness and water content, and stiffness and shrinkage (p < 0.0005).

Long-term effect of Er:YAG laser on adhesion to caries-affected dentin

“…These findings corroborate with other studies that evaluated the BS of natural or artificially prepared CAD [28,29]. The higher water volume in CAD [30] reduced calcium, phosphate, and magnesium levels [31] due to successive demineralization cycles, hindering the development of chemical bonds [30] to this tissue. Moreover, the higher porosity of the intertubular dentin and the lower hardness of the tissue [32] could also decrease BS.…”

Matrix Metalloproteinases and Other Matrix Proteinases in Relation to Cariology: The Era of ‘Dentin Degradomics'

“…Attempts to remineralize demineralized dentin should thus provide for crystallization in the gap zones [Balooch et al, 2008;Bertassoni et al, 2011]. Even though direct comparison cannot be done, it is interesting to note that caries-affected (sclerotic) dentin has similar relative reduction in stiffness (79%) and increase in shrinkage after drying (76%) compared to normal dentin [Ito et al, 2005].…”

“…However, experimental studies with rapid de-remineralization cycles do not allow potential time-related changes in the dentin organic matrix that might occur in natural lesions. As pointed out by Ito et al [2005], dentinal carious lesions develop over months and even years, after thousands of episodes of demineralization, neutralization and remineralization. Quantitative characterizations have shown that carious lesions are far from identi- Ito et al, 2005].…”

“…As pointed out by Ito et al [2005], dentinal carious lesions develop over months and even years, after thousands of episodes of demineralization, neutralization and remineralization. Quantitative characterizations have shown that carious lesions are far from identi- Ito et al, 2005]. Attempts to create 'natural' caries lesions with caries-infected and -affected dentin by demineralizing normal dentin in vitro have not been very successful.…”

Laser Application for Restorative Dentistry

“…In this way a minor amount of energy is required for the ablation of dentin that is more rich in water [ 21 -23 ] and even less for caries [ 24 ], while a greater amount is required for the ablation of decayed or highly mineralised enamel.…”