title: In vitro study of root fracture treated by CO2 laser and DP-bioactive glass paste.
abstract: OBJECTIVE
  An ideal material has yet to be discovered that can successfully treat vertical root fracture. Therefore, the purpose of this study was to use a continuous-wave CO2 laser of medium-energy density to fuse DP-bioactive glass paste (DPGP) to vertical root fracture.
  
  
  METHODS
  The DP-bioglass powder was based on a Na2O-CaO-SiO2-P2O5 system and it was mixed with phosphoric acid (65% concentration) with a powder/liquid ratio of 2 g/4 mL to form DPGP. The interaction of DPGP and dentin was analyzed by means of X-ray diffractometer (XRD) and differential thermal analysis/thermogravimetric analysis (DTA/TGA). Root fracture line was filled with DPGP followed by CO2 laser irradiation and the result was examined by scanning electron microscopy (SEM).
  
  
  RESULTS
  The main crystal phase of DPGP was monocalcium phosphate monohydrate (Ca(H2PO4)2.H2O) and the phase transformed to dicalcium phosphate dihydrate (CaHPO4.2H2O) after mixing DPGP with dentin powder (DPG-D). Additionally, gamma-Ca2P2O7 and beta-Ca2P2O7 were identified when DPG-D was lased by CO2 laser. The reaction temperature was between 500 degrees C and 1100 degrees C. SEM results demonstrated that the fracture line was effectively sealed by DPGP.
  
  
  CONCLUSIONS
  The chemical reaction of DPGP and dentin indicated that DPGP combined with CO2 laser is a potential regimen for the treatment of vertical root fracture.
authors.affiliation: School of Dentistry, Graduate Institute of Clinical Dentistry, College of Medicine, National Taiwan University, University Hospital, Taipei, Taiwan.
authors.forename: Yin-Lin
authors.initials: YL
authors.lastname: Wang
authors.forename: Bor-Shiunn
authors.initials: BS
authors.lastname: Lee
authors.forename: Ching-Li
authors.initials: CL
authors.lastname: Tseng
authors.forename: Feng-Huei
authors.initials: FH
authors.lastname: Lin
authors.forename: Chun-Pin
authors.initials: CP
authors.lastname: Lin
mesh_terms: D003738:Dental Cements / Q000627:therapeutic use*; D006801:Humans; D066298:In Vitro Techniques; D007180:Incisor; D054020:Lasers, Gas; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D014082:Tooth Fractures / Q000628:therapy*; D014092:Tooth Root / Q000293:injuries; D014961:X-Ray Diffraction
chemical_list: C418024:DP-bioactive glass paste; D003738:Dental Cements