Water distribution in dentin matrices: Bound vs. unbound water

Kelli A. Agee, Anuradha Prakki, Tariq Abu-Haimed, Ghada H. Naguib, Manar Abu Nawareg, Arzu Tezvergil-Mutluay, Debora L.S. Scheffel, Chen Chen, Seung Soon Jang, Hyea Hwang, Martha Brackett, Geneviéve Grégoire, Franklin R. Tay, Lorenzo Breschi, David H. Pashley

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


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. Significance 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.

Original languageEnglish
Pages (from-to)205-216
Number of pages12
JournalDental Materials
Issue number3
StatePublished - Mar 1 2015

Bibliographical note

Publisher Copyright:
© 2014 Academy of Dental Materials.


  • Adhesive dentistry
  • Bound water
  • Bulk water
  • Collagen
  • Dentin
  • Hydrogen bonding

ASJC Scopus subject areas

  • General Materials Science
  • General Dentistry
  • Mechanics of Materials


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