title: Evaluation of the Ca ion release, pH and surface apatite formation of a prototype tricalcium silicate cement.
abstract: OBJECTIVE
  To evaluate the Ca2+-releasing, alkalizing and apatite-like surface precipitate-forming abilities of a prototype tricalcium silicate cement, which was mainly composed of synthetically prepared tricalcium silicate and zirconium oxide radiopacifier.
  
  
  METHODS
  The prototype tricalcium silicate cement, white ProRoot MTA (WMTA) and TheraCal LC (a light-cured resin-modified calcium silicate-filled material) were examined. The chemical compositions were analysed with a wavelength-dispersive X-ray spectroscopy electron probe microanalyser with an image observation function (SEM-EPMA). The pH and Ca2+concentrations of water in which the set materials had been immersed were measured, and the latter was assessed with the EDTA titration method. The surface precipitates formed on the materials immersed in phosphate-buffered saline (PBS) were analysed with SEM-EPMA and X-ray diffraction (XRD). Kruskal-Wallis tests followed by Mann-Whitney U-test with Bonferroni correction were used for statistical analysis (α = 0.05).
  
  
  RESULTS
  The prototype cement contained Ca, Si and Zr as major elemental constituents, whereas it did not contain some metal elements that were detected in the other materials. The Ca2+concentrations and pH of the immersion water samples exhibited the following order: WMTA = prototype cement > TheraCal LC (P < 0.05). All three materials produced Ca- and P-containing surface precipitates after PBS immersion, and the precipitates produced by TheraCal LC displayed lower Ca/P ratios than those formed by the other materials. XRD peaks corresponding to hydroxyapatite were detected in the precipitates produced by the prototype cement and WMTA.
  
  
  CONCLUSIONS
  The prototype tricalcium silicate cement exhibited similar Ca2+-releasing, alkalizing and apatite-like precipitate-forming abilities to WMTA. The Ca2+-releasing, alkalizing and apatite-like precipitate-forming abilities of TheraCal LC were lower than those of the other materials.
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.|Yamamoto Dental Clinic, Takarazuka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
authors.forename: L
authors.initials: L
authors.lastname: Han
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Noiri
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.|Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Okiji
mesh_terms: D001031:Apatites / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D003738:Dental Cements / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D017640:Silicates / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
chemical_list: D001031:Apatites; D017610:Calcium Compounds; D003738:Dental Cements; D017640:Silicates; C506393:tricalcium silicate; D015040:Zirconium; C028541:zirconium oxide; D002118:Calcium
keywords: TheraCal LC; apatite-forming ability; bioactivity; calcium ion release; mineral trioxide aggregate; tricalcium silicate