A dentist in London has started offering laser fillings which are supposed to be pain free. Preparing the tooth for filling takes about the same time as using conventional treatments but doesn't need pain killing injections or any drilling. Instead the laser heats the water molecules in the tooth leading to a build up of pressure which leads to a micro explosion as the decayed area of the tooth is removed. Because there is no pressure on the tooth there are fewer vibrations but the technique cannot be used on old mercury filling because the laser beam would reflect back off the metal surface towards the dentist. Prices for the treatment are higher starting at £75 compares to £40 for a normal NHS filling. I have been lucky enough never to have needed a filling but this sounds much less painful.