Hi. There are two main factors in painless extraction - one, good anesthesia and two, absence of acute infection. If a tooth with severe pain or swelling is extracted, it will be painful. With good anesthesia, however, tooth extraction is painless in the absence of an acute infection. By "painless" we mean there will be no sensation of pain, but there may be sensation of pressure as the tooth is pulled out.
For anesthesia, you will feel a prick before the area goes numb and as the anesthetic medicine spreads inside. With the Wand STA, you will still feel the prick but the anesthetic is deposited very slowly at a controlled rate, making it more comfortable.