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, ro ot fractures are usually treated by root amputation, hemisection or tooth e xtraction. 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 deve loped 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 pa rts: (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 int eractions 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-bioact ive glass paste by means of X-ray diffractometer (X RD), Fourier transformi ng infrared spectroscopy (FTIR), differential thermal analysis/thermogravim etric 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 suc cessfully developed a DP-bioactive glass paste which could form a melting g lass within seconds after exposure to a medium energy density continuous-wa ve CO2 laser. The paste will be used in the near future to bridge the ename l or dentin surface crack by the continuous-wave CO2 laser. (C) 2000 Publis hed by Elsevier Science Ltd. All rights reserved.