title: Degree of conversion of a methacrylate-based endodontic sealer: a micro-Raman spectroscopic study.
abstract: BACKGROUND
  Recently, a methacrylate-based obturation system, Resilon/RealSeal SE, has been developed to replace gutta-percha and traditional sealers. As a resin-based material, degree of conversion (DC) is one of the most important characteristics. The aim of this study was to investigate the time-dependent change of DC of RealSeal SE as well as the influence of canal moisture and root canal depth on it.
  
  
  METHODS
  DC of RealSeal SE, either self-cured or dual-cured (n = 8 in each group), was calculated according to the Raman spectra obtained at different times after mixing. Thirty extracted teeth with single canal were instrumented and divided randomly into 2 groups in terms of different canal drying methods. In the ethanol group, excess distilled water in root canal was removed with paper points followed by 95% ethanol. In the paper points group, root canals were blot-dried with paper points until the last one appeared dry. DC of RealSeal SE was calculated from serial cross sections (2, 5, and 8 mm from the apex) obtained 1 week after obturation with Resilon/RealSeal SE.
  
  
  RESULTS
  Significant increase in DC of RealSeal SE was observed in 1 week (P < .01), with little change afterwards (P > .05). DC of sealer in ethanol group was significantly higher than in paper points group (P < .01). However, DCs of RealSeal SE at different levels of tooth sections were not significantly different (P > .05).
  
  
  CONCLUSIONS
  Both self-cured and dual-cured RealSeal SE achieved stable DC after 1 week. Root canal moisture was a critical factor in determining DC of RealSeal SE.
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Wan-Cui
authors.initials: WC
authors.lastname: Wu
authors.forename: Deepti
authors.initials: D
authors.lastname: Shrestha
authors.forename: Xi
authors.initials: X
authors.lastname: Wei
authors.forename: Jun-Qi
authors.initials: JQ
authors.lastname: Ling
authors.forename: Wei-Hong
authors.initials: WH
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D003188:Composite Resins / Q000737:chemistry* / Q000627:therapeutic use; D003763:Dental Leakage / Q000517:prevention & control; D018772:Dental Marginal Adaptation; D003786:Dental Pulp Cavity / Q000187:drug effects*; D003804:Dentin / Q000187:drug effects; D006801:Humans; D012387:Root Canal Filling Materials / Q000737:chemistry* / Q000627:therapeutic use; D012389:Root Canal Obturation / Q000379:methods*; D013059:Spectrum Analysis, Raman; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003188:Composite Resins; C511498:Real Seal composite resin; D012387:Root Canal Filling Materials; C486892:resilon sealer; D014867:Water