electromagnetic energy of the laser beam traces the entire treatment area 42 or 43 according to a pattern as shown in fig6 the tracing pattern can be a spiral pattern 41 a raster pattern or a random pattern 44 when a laser beam impinges upon a spot in the treatment area 42 or 43 a plume of tissue material may be emitted during the next step moving the laser beam to a randomly selected location as shown by the pattern 44 can avoid any interaction between the treatment laser beam and the plume and instead the laser beam is directed to the tissue to be treated prior to commencing treatment using the treatment laser beam as described above it may be beneficial for an operator to ensure that the treatment laser beam would in fact impinge upon all of the treatment area in a uniform manner and not impinge upon the tissue not to be treated to this end the marking laser 16 described above with reference to fig1 can be used the marking laser 16 e g a he u2014 ne laser traces the treatment area 42 or 43 substantially similarly as the treatment laser beam would because both laser beams are focused along the axis 2 and both laser beams are directed using the system schematically shown in fig4 the marking laser 16 however lacks power to ablate or adversely affect dental tissue in the area 42 or 43 and hence may not inadvertently damage the dental tissue within or adjacent to the treatment.