I was asked to ask my dentist in fethiye and he said that there are 3 methods but he would only reccomend one.
The cheap ones are chemical and are not advised, can't remember the best one as I don't want my teeth whitening my friend does.
If you email me i will give you the name of the dentist, he is in Fethiye and is situated about 500yrds from the dolmus drop off.
I think he did the safe whitening for 500 pounds.