Treatment of tooth fracture by medium energy CO2 laser and DP-bioactive glass paste: compositional, structural, and phase changes of DP-bioglass paste after irradiation by CO2 laser.

Nowadays, fractured teeth are difficult to treat effectively. Currently, root fractures are usually treated by root amputation, hemisection or tooth extraction. If the fusion of tooth fracture by laser were possible, it would offer a different therapy to repair fracture teeth. We tried to use a developed DP-bioactive glass paste to fuse or bridge the tooth crack line by a medium energy continuous-wave CO2 laser. The study is divided into three parts: (1) The compositional and structure changes in tooth enamel and dentin after laser treatment; (2) The phase transformation and recrystallization of DP-bioactive paste during exposure to the CO2 laser; (3) The thermal interactions and bridge mechanism between DP-bioactive glass paste and enamel/dentin when they are subjected to CO2 laser. The present report will focus on the second part that will examine the changes of laser-exposed DP-bioactive glass paste by means of X-ray diffractometer (XRD), Fourier transforming infrared spectroscopy (FTIR), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and scanning electron microscopy (SEM). From the study, we could find that the temperature increase due to laser irradiation is greater than 900 degrees C and that the DP-bioactive glass paste could be melted in a short period of time after irradiation. In the study, we successfully developed a DP-bioactive glass paste which could form a melting glass within seconds after exposure to a medium energy density continuous-wave CO2 laser. The paste will be used in the near future to bridge the enamel or dentin surface crack by the continuous-wave CO2 laser.