In vitro Study of Root Fracture Treated by CO2 Laser and DP-bioactive Glass Paste

Background/PurposeAn 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.MethodsThe DP-bioglass powder was based on a Na 2O-CaO-SiO 2-P 2O5 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).ResultsThe main crystal phase of DPGP was monocalcium phosphate monohydrate (Ca(H 2PO4) 2·H 2O) and the phase transformed to dicalcium phosphate dihydrate (CaHPO4 ·2H 2O) after mixing DPGP with dentin powder (DPG-D). Additionally, γ-Ca 2P 2O7 and b-Ca 2P 2O7 were identified when DPG-D was lased by CO2 laser. The reaction temperature was between 500°C and 1100°C. SEM results demonstrated that the fracture line was effectively sealed by DPGP.ConclusionThe chemical reaction of DPGP and dentin indicated that DPGP combined with CO2 laser is a potential regimen for the treatment of vertical root fracture.