الخلاصة

This study depends on the soluting of differential equation a ccomplished the following :- Calculating (time whitening , density with time , time with Temperature using laser Er:YAG wavelength (2940nm) . mathematical relation have been studied with the following (density , time whitening , time activation , Temperature) . The result of research showed that density increases with time whitening , through which we can notice obtain typical designs for this type of laser and study effects compartion with other type The laser Er:YAG beam is fully absorbed in the gel and does not penetrate to the hard tissue or the lip.