title: Effect of acidic solutions on the microhardness of dentin and set OrthoMTA and their cytotoxicity on murine macrophage.
abstract: OBJECTIVE
  To evaluate the effects of three acids on the microhardness of set mineral trioxide aggregate (MTA) and root dentin, and cytotoxicity on murine macrophage.
  
  
  METHODS
  OrthoMTA (BioMTA) was mixed and packed into the human root dentin blocks of 1.5 mm diameter and 5 mm height. Four groups, each of ten roots, were exposed to 10% citric acid (CA), 5% glycolic acid (GA), 17% ethylenediaminetetraacetic acid (EDTA), and saline for five minutes after setting of the OrthoMTA. Vickers surface microhardness of set MTA and dentin was measured before and after exposure to solutions, and compared between groups using one-way ANOVA with Tukey test. The microhardness value of each group was analyzed using student t test. Acid-treated OrthoMTA and dentin was examined by scanning electron microscope (SEM). Cell viability of tested solutions was assessed using WST-8 assay and murine macrophage.
  
  
  RESULTS
  Three test solutions reduced microhardness of dentin. 17% EDTA demonstrated severe dentinal erosion, significantly reduced the dentinal microhardness compared to 10% CA (p = 0.034) or 5% GA (p = 0.006). 10% CA or 5% GA significantly reduced the surface microhardness of set MTA compared to 17% EDTA and saline (p < 0.001). Acid-treated OrthoMTA demonstrated microporous structure with destruction of globular crystal. EDTA exhibited significantly more cellular toxicity than the other acidic solutions at diluted concentrations (0.2, 0.5, 1.0%).
  
  
  CONCLUSIONS
  Tested acidic solutions reduced microhardness of root dentin. Five minute's application of 10% CA and 5% GA significantly reduced the microhardness of set OrthoMTA with lower cellular cytotoxicity compared to 17% EDTA.
authors.affiliation: Department of Conservative Dentistry, Dental Research Institute, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Soram
authors.identifier: 0000-0002-8843-2144
authors.initials: S
authors.lastname: Oh
authors.affiliation: Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada.
authors.forename: Hiran
authors.identifier: 0000-0001-6484-5932
authors.initials: H
authors.lastname: Perinpanayagam
authors.affiliation: Department of Conservative Dentistry, Wonju Severance Christian Hospital, Yonsei University, Wonju, Korea.
authors.forename: Yoon
authors.identifier: 0000-0001-9813-8531
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Bendilde St. Margaret's School, St. Louis Park, MN, USA.
authors.forename: Jae-Won
authors.identifier: 0000-0003-0912-5400
authors.initials: JW
authors.lastname: Kum
authors.affiliation: Department of Conservative Dentistry, Dental Research Institute, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Yeon-Jee
authors.identifier: 0000-0002-3931-7668
authors.initials: YJ
authors.lastname: Yoo
authors.affiliation: Department of Conservative Dentistry, Dental Research Institute, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Sang-Min
authors.identifier: 0000-0002-6310-8161
authors.initials: SM
authors.lastname: Lim
authors.affiliation: Department of Conservative Dentistry, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Seok Woo
authors.identifier: 0000-0003-4461-3274
authors.initials: SW
authors.lastname: Chang
authors.affiliation: Department of Conservative Dentistry, Dental Research Institute, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Won-Jun
authors.initials: WJ
authors.lastname: Shon
authors.affiliation: Department of Conservative Dentistry, Dental Research Institute, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Woocheol
authors.initials: W
authors.lastname: Lee
authors.affiliation: Department of Conservative Dentistry, Dental Research Institute, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Seung-Ho
authors.identifier: 0000-0003-2594-2283
authors.initials: SH
authors.lastname: Baek
authors.affiliation: Department of Conservative Dentistry, Dental Research Institute, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Kee-Yeon
authors.identifier: 0000-0002-3032-3498
authors.initials: KY
authors.lastname: Kum
keywords: Citric acid; EDTA; Glycolic acid; OrthoMTA; SEM; Vickers surface microhardness