Lasers have been available for use in dentistry for several years but they are still not widely used in general practice due to expensive technology. The purpose of this research was to study the structure and properties of laser cut tooth surface and the way in which they react with materials to form an effectively bonded and sealed interface. The investigation of laser irradiated dentine showed that the reduction of microhardness by 30-50% compared to baseline dentine. Dentine debris was seen on the surface under SEM microscopy. The interface between the tooth surface prepared by the laser and glass ionomer cement was investigated using confocal microscopy. In addition, the microleakage of cavity prepared by bur and laser was compared. The adhesion of glass ionomer cement to Er, Cr:YSGG laser cut dentine was measured by means of both microtensile and shear bond strength tests. The mode of failure was assessed by microscopy. The optimal laser parameters were determined. It was found that the bond strength of glass ionomer cement to laser prepared dentine was generally not different from that to conventional cavity preparation. The use of a dentine conditioner had a significant effect on bond strength. This work suggests that the optimal parameters for use of the Er,Cr:YSGG laser to prepare cavities in dentine are a 4W power setting and a working distance of lmm.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:492103 |
| Date | January 2009 |
| Creators | Ekworapoj, Piyanart |
| Publisher | University of Newcastle Upon Tyne |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10443/1818 |
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