TY - JOUR
T1 - Effects of solvents on the early stage stiffening rate of demineralized dentin matrix
AU - Garcia, Fernanda C.P.
AU - Otsuki, Masayuki
AU - Pashley, David H.
AU - Tay, Franklin R.
AU - Carvalho, Ricardo M.
N1 - Funding Information:
Supported, in part, by grants: 300481/95-0, 474226/03-4 from CNPq; 01/06140-1 and 02/06682-1 from FAPESP, Brazil; and by grant DE 014911 from the NIDCR, Bethesda, MD, USA. We are grateful to Mr Kazuo Kato for the illustrations.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2005/5
Y1 - 2005/5
N2 - Objectives. To monitor the stiffening rate of demineralized dentin matrix at the early stages after exposure to different neat solvents. Methods. Dentin beams approximately 0.8×0.7×8.0 mm were obtained from human third molars. After covering their ends with resin composite, the middle exposed length of 4.0 mm (gauge-length) was demineralized in 0.5 M EDTA (pH 7.0) for 7 days. The specimens were gripped by a testing machine, pre-loaded to 10 g and cyclically stressed in tension to 5% strain, for 30 repeated cycles (total 20 min) at 0.6 mm/min while immersed in water (control). Then, water was replaced by either 100% acetone, methanol, ethanol, propanol, HEMA or air and the specimens subjected to the same cyclic protocol. The maximum apparent modulus of elasticity (EMax) was calculated for every cycle, plotted as a function of time and subjected to regression analysis. Stiffening rate was calculated as changes in E (min). Regression analysis examined the relationship between E and time for each solvent. Data were analyzed by one-way ANOVA and Student-Newman-Keuls test at α=0.05. Results. Regression analysis showed that E increased significantly with time in all water-free solvents (R 2=0.8-0.99). Stiffening rate was higher for acetone (0.9 MPa/min) and ethanol (0.8 MPa/min), intermediate for air (0.7 MPa/min), methanol (0.6 MPa/min) and propanol (0.5 MPa/min), lower for HEMA (0.2 MPa/min) and practically none for water (0.07 MPa/min) with p<0.05. Conclusions. The solvent-induced stiffening rate of demineralized dentin matrix is both time and solvent-dependent. The ability of solvents to promptly stiffen the demineralized dentin matrix may be important in maintaining the resin-infiltrated matrix expanded during the solvent evaporation stage of resin bonding.
AB - Objectives. To monitor the stiffening rate of demineralized dentin matrix at the early stages after exposure to different neat solvents. Methods. Dentin beams approximately 0.8×0.7×8.0 mm were obtained from human third molars. After covering their ends with resin composite, the middle exposed length of 4.0 mm (gauge-length) was demineralized in 0.5 M EDTA (pH 7.0) for 7 days. The specimens were gripped by a testing machine, pre-loaded to 10 g and cyclically stressed in tension to 5% strain, for 30 repeated cycles (total 20 min) at 0.6 mm/min while immersed in water (control). Then, water was replaced by either 100% acetone, methanol, ethanol, propanol, HEMA or air and the specimens subjected to the same cyclic protocol. The maximum apparent modulus of elasticity (EMax) was calculated for every cycle, plotted as a function of time and subjected to regression analysis. Stiffening rate was calculated as changes in E (min). Regression analysis examined the relationship between E and time for each solvent. Data were analyzed by one-way ANOVA and Student-Newman-Keuls test at α=0.05. Results. Regression analysis showed that E increased significantly with time in all water-free solvents (R 2=0.8-0.99). Stiffening rate was higher for acetone (0.9 MPa/min) and ethanol (0.8 MPa/min), intermediate for air (0.7 MPa/min), methanol (0.6 MPa/min) and propanol (0.5 MPa/min), lower for HEMA (0.2 MPa/min) and practically none for water (0.07 MPa/min) with p<0.05. Conclusions. The solvent-induced stiffening rate of demineralized dentin matrix is both time and solvent-dependent. The ability of solvents to promptly stiffen the demineralized dentin matrix may be important in maintaining the resin-infiltrated matrix expanded during the solvent evaporation stage of resin bonding.
KW - Acetone
KW - Air
KW - Collagen
KW - Ethanol
KW - HEMA
KW - Methanol
KW - Modulus of elasticity
KW - Propanol
KW - Stiffening rate
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U2 - 10.1016/j.jdent.2004.10.013
DO - 10.1016/j.jdent.2004.10.013
M3 - Article
C2 - 15833392
AN - SCOPUS:17044407987
SN - 0300-5712
VL - 33
SP - 371
EP - 377
JO - Journal of Dentistry
JF - Journal of Dentistry
IS - 5
ER -