A device is disclosed that dynamically seals the collet of a high-speed surgical or dental drill from the ingress of contaminating substances with which the tool or collet of the drill comes into contact, such as blood, saliva, saline, tissue, bone chips, and tooth particles. The dynamic seal comprises an impeller and a bearing that rotatably supports both the impeller and a surgical tool; furthermore, the seal may be disposed within a burguard that is mounted on the distal end of a surgical drill. The spinning impeller has a disc portion that imparts a centrifugal force to the flow of contaminating substances and thereby pumps the flow entering through the tool opening radially outward through discharge holes in the burguard housing. The dynamic seal further includes an O-ring for sealing against the tool shaft and blocking the contaminating substances from continuing up the tool bore and into the collet of the surgical drill. A backring retains the O-ring in place.