RESULTS	In the femtosecond laser group , no significant differences in pH were observed between the three subgroups after docking and the femtosecond laser surgical procedure : low ( 6.55 0.09 [ range : 6.53 to 6.57 ] ) , medium ( 6.54 0.07 [ range : 6.52 to 6.55 ] ) , and high ( 6.42 0.00 [ range : 6.40 to 6.44 ] ) level of gas bubbles .\