The Costco Gas Station hours are usually longer than the Costco Warehouse opening hours, so make sure that you are viewing the Costco Gas Station hours, and not the Store Hours, if you search through an app or with google maps.
All dental hygienists in the United States must be licensed by the state in which they practice, after completing a minimum of two years of school and passing a written board as well as a clinical board exam. State requirements vary by state, and are controlled by state dental boards.
All 50 states mandate that orthodontists are licensed. Not only must they be licensed as dentists, states also require a separate orthodontist license. The dental license necessitates the passing of an exam, but those becoming orthodontists must complete more specialized schooling and possibly another exam.