Postural distortion of human bite marks on skin occurs when photographing a bite mark in a body position other than the position of the body at the time of biting. Postural distortion in the bite mark may introduce significant changes in both the shape and size of the recorded marks. As a result, the analysis of the marks may be hindered and a proper comparison between the bite mark and the causal dentition may be precluded. Therefore, a method by which postural distortion in a bite mark photographic record can be evaluated and eliminated with minimal operator subjectivity is required. This study describes the development of an objective technique for evaluating postural distortion in bite mark photographic records and for minimising postural distortion during photography of bite marks. The source for developing these techniques was provided by digitally analysing the symmetry of dental arches in a defined population including males and females (236 subjects) whose ages ranged between 20 and 30 years. The analysis resulted in quantifying a mathematical relationship between the biting edges of each homologous pair of the anterior teeth and specified reference lines. The validity of the analytical method of dental arch symmetry is discussed. The developed techniques were applied to posturally distorted (test) bite marks. The results demonstrate the validity of the developed techniques in determining postural distortion and recording correct images (shown to resemble the biters dentition) of the test bites. Suggestions for further work are proposed.

Occlusal asymmetries are common in orthodontic patients. A treatment option for correcting moderate asymmetries is asymmetric extractions. This study evaluated post-treatment dental arch symmetry in patients treated with unilateral premolar extractions. Post-treatment casts of 60 patients were divided into four treatment groups based on the history of occlusal asymmetry and the treatment plan. DesignCAD3000 software (Upperspace Corporation, Pryor, OK) was used to evaluate asymmetrically treated arches for symmetry. The four treatment groups were compared to identify differences in arch asymmetry based on treatment. The lateral incisor and canine were found to be more palatal on the extraction side in patients treated with unilateral extractions (P < .001). Arch length increased (P < 0.001) and area under the arch decreased (P < 0.01) on the extraction side. On average, patients with asymmetric extractions did not finish with more arch asymmetry than those without asymmetric extractions.