ACCURACY OF BITE MARK OVERLAYS - A COMPARISON OF 5 COMMON METHODS TO PRODUCE EXEMPLARS FROM A SUSPECTS DENTITION

Physical comparison of a suspect's teeth to a bite mark injury using h ollow volume comparison overlays is a common forensic odontology techn ique. Several methods are used to record characteristics of the size, shape and position of the teeth and to generate overlays. These includ e computer-based, radiographic, xerographic and hand-traced methods. F ive common overlay production methods were compared using digital imag es of dental study casts as a reference standard. Area of the biting e dges of the anterior teeth and relative rotation of each anterior toot h were measured and compared. The computer-based production method was determined to be the most accurate of those studied. It produced accu rate representations of the biting edges of the teeth in an objective manner. The radiographic method was determined to be more accurate tha n the xerographic method with respect to tooth area measurement. The o pposite is true with respect to tooth rotation. Hand-traced methods, f rom either wax impressions of teeth or directly from study casts, were determined to be inaccurate and subjective. It is recommended that fo rensic odontologists discontinue the use of hand-traced overlays in bi te mark comparison cases.