Abstract: A bite block where, in a first embodiment, the mouthpiece is flanked by laterally-extending arms that define large, inverted "U"-shaped finger-accommodating openings so that a surgeon may guide a surgical tool by placing fingers within those openings. The mouthpiece has a cylindrical throughbore that receives the surgical instrument. The upper and lower teeth of the patient are supported by flat upper and lower support walls that are formed integrally with the mouthpiece, and each support wall includes a retention ridge that helps keep the mouthpiece in the patient's mouth. Upper and lower flanges extend above and below the plane of their respective support walls, so that the mouthpiece cannot enter the patient's mouth even when the surgeon pulls back the patient's lips to their limit.