The application of an 810 nm diode laser either alone or in combination with sodium fluoride gel in treating dentin hypersensitivity is effective and better than the application of a 650 nm diode laser either alone or in combination with sodium fluoride gel. In addition, applying a 650 nm diode laser either alone or in combination with sodium fluoride gel has slight effectiveness in treating dentine hypersensitivity, and it is believed that a single treatment session with a 650 nm diode laser was not enough to obtain the required pain reduction.