Water distribution in dentin matrices: Bound vs. unbound water
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Data
2015-03-01
Autores
Agee, Kelli A.
Prakki, Anuradha
Abu-Haimed, Tariq
Naguib, Ghada H.
Abu Nawareg, Manar
Tezvergil-Mutluay, Arzu
Scheffel, Debora L. S. [UNESP]
Chen, Chen
Jang, Seung Soon
Hwang, Hyea
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Editor
Elsevier B.V.
Resumo
Objective. This work measured the amount of bound versus unbound water in completely-demineralized dentin.Methods. Dentin beams prepared from extracted human teeth were completely demineralized, rinsed and dried to constant mass. They were rehydrated in 41% relative humidity (RH), while gravimetrically measuring their mass increase until the first plateau was reached at 0.064 (vacuum) or 0.116 g H2O/g dry mass (Drierite). The specimens were then exposed to 60% RH until attaining the second plateau at 0.220 (vacuum) or 0.191 g H2O/g dry mass (Drierite), and subsequently exposed to 99% RH until attaining the third plateau at 0.493 (vacuum) or 0.401 g H2O/g dry mass (Drierite).Results. Exposure of the first layer of bound water to 0% RH for 5 min produced a -0.3% loss of bound water; in the second layer of bound water it caused a -3.3% loss of bound water; in the third layer it caused a -6% loss of bound water. Immersion in 100% ethanol or acetone for 5 min produced a 2.8 and 1.9% loss of bound water from the first layer, respectively; it caused a -4 and -7% loss of bound water in the second layer, respectively; and a -17 and -23% loss of bound water in the third layer. Bound water represented 21-25% of total dentin water. Chemical dehydration of water-saturated dentin with ethanol/acetone for 1 min only removed between 25 and 35% of unbound water, respectively.Signcance. Attempts to remove bound water by evaporation were not very successful. Chemical dehydration with 100% acetone was more successful than 100% ethanol especially the third layer of bound water. Since unbound water represents between 75 and 79% of total matrix water, the more such water can be removed, the more resin can be infiltrated. (C) 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
Descrição
Palavras-chave
Adhesive dentistry, Bound water, Bulk water, Collagen, Dentin, Hydrogen bonding
Como citar
Dental Materials. Oxford: Elsevier Sci Ltd, v. 31, n. 3, p. 205-216, 2015.