The "teeth gag screw" is a dental instrument used in oral surgery and dental procedures. It's typically a screw-like device that is part of a dental gag, which is a tool used to hold a patient's mouth open during procedures. The teeth gag screw helps secure the dental gag in place, allowing the dental professional to work comfortably and effectively within the patient's mouth. This instrument ensures proper access and visibility during dental surgeries or treatments.