Frequency of anterior tooth characteristics - Possible practical forensic applications

Aim: This study aimed to collect data on the frequency of incisal edge fractures and overlapping teeth, and assess their possible applications in forensic practice.

Method: 105 sets of dental casts were analysed for incisal edge fractures and overlaps of the upper and lower anterior teeth by direct visual examination. Overlaps were defined as adjacent teeth in contact and overlapping when viewed from the occlusal plane. Ten overlap patterns were possible in each arch. Fractures were recorded as incisal, mesial-incisal, distal-incisal and mesial-incisal-distal. Dental casts came from a sample of adult patient (>16 years) who had not received orthodontic treatment.

Results: Twelve individuals (11%) presented with unrestored fractures involving the incisal edges of 15 (1%) of their anterior teeth. Unrestored fractures were present in 12.5% of males and 10% of females. Central incisor fractures occurred in 8 individuals (8%); half as many lateral incisors were fractured (4%); and only one individual (1%) had a fracture of a single canine tooth (1/420 = 0.24%).

Overlapping teeth were very common (84% of individuals). However upper laterals overlapping upper canines were found in only 9 individuals (9%), 2 of which exhibited bilateral symmetry (2%). Arches with no overlapping teeth were less common; 16% had no overlaps in both arches, 29% had no overlaps in the upper arch and only 7% had no overlaps in the lower arch.

Conclusions: Overlaps are common features however certain patterns are more distinctive. Incisal edge fractures are less common and may be useful discriminators in bite mark analysis.