We do indeed use the same medicine that dentists use to numb up the teeth, which is called lidocaine.
Dental blocks are effective when you are injecting and then performing surgeries in specific regions of the face. They would not be helpful if you were, let's say, treating the forehead. Localized numbing injections are done, usually with lidocaine (I prefer a mix of lido with and without epi). This allows the treated area to be numb, and still get proper blood flow. "This answer has been solicited without seeing this patient and cannot be held as true medical advice, but only opinion. Seek in-person treatment with a trained medical professional for appropriate care."