METHODS	Thirty premolars were divided into three groups : I - high-speed handpiece + 37 % phosphoric acid ; II - Er : YAG laser ( 350 mJ , 4 Hz and 112 J/cm ( 2 ) ) + 37 % phosphoric acid ; and III - Er : YAG laser ( 350 mJ , 4 Hz and 112 J/cm ( 2 ) ) + Er : YAG laser ( 80 mJ , 4 Hz , and 25 mJ/cm ( 2 ) ) .\