Journal of Dental Research, Vol 79, 1579-1583, Copyright © 2000 by International & American Associations for Dental Research Online Journals
H+-induced tension development in demineralized dentin matrix
D. H. Pashley, Y. Zhang, R. M. Carvalho, F. A. Rueggeberg and C. M. Russell
Department of Oral Biology and Maxillofacial Pathology, School of Dentistry, Medical College of Georgia, Augusta 30912-1129, USA. dpashley@mail.mcg.edu
Recent atomic force microscopy studies have shown that acid-etching dentin
causes the surface to recede. The purpose of this work was to test the
hypothesis that acidic solutions can cause contraction of demineralized
dentin matrix. Small beams of dentin were cut from extracted human third
molars. The central region of each specimen was completely demineralized in
EDTA. Specimens held in a tester were immersed in acidic solutions, and the
amount of tension was recorded. Test variables included gauge length,
cross-sectional area, pre-strain, and pH. The results showed that immersion
of demineralized dentin in acidic solutions caused tension that was
directly related both to H+ concentration at pH < 2 and to pre-strain.
The contractile stress development (ca. 0.2-0.4 MPa) was sufficient to
cause a collapse of demineralized dentin matrix. The mechanism for this
effect probably involves H+-induced conformation changes in the collagen
matrix.
