Effects of solvents on the early stage stiffening rate of demineralized dentin matrix

Fernanda C.P. Garcia, Masayuki Otsuki, David H. Pashley, Franklin R. Tay, Ricardo M. Carvalho

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)371-377
Number of pages7
JournalJournal of Dentistry
Volume33
Issue number5
DOIs
StatePublished - May 2005

Keywords

  • Acetone
  • Air
  • Collagen
  • Ethanol
  • HEMA
  • Methanol
  • Modulus of elasticity
  • Propanol
  • Stiffening rate

ASJC Scopus subject areas

  • Dentistry(all)

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