INJURED WAS IN THE PROCESS OF CHANGING AN TOOTHPOINT RETAINER PIN. IT WAS STRUCK WITH A 20 LB SLEDGE HAMMER AND THE TOOL REBOUNDED OUT OF THE PIN HOLE AND STRUCK INJURED IN THE FACE, LACEATING HIS RIGHT UPPER LIP AND BREAKING A TOOTH. WAS TAKEN TO E.R. WHERE HIS FACE WAS X-RAYED AND THE RESULTS WERE NEGATIVE.