A specimen positioning device for dental radiographic identification--image geometry considerations.

Preventative dental treatment has reduced caries incidence and thereby rendered dental identification, in caries-free individuals, more difficult. An alternate method comparing spatial relationships of dental structures in digitized superimposed antemortem and postmortem radiographs has been previously developed. This paper examined the limitations of this technique and demonstrates a positioning device suitable for reproducing antemortem radiographic image geometry. The paper also examined three specific aspects of image geometry namely horizontal angulation, vertical angulation and focal film distance. Deviations in horizontal angulations between antemortem and postmortem radiographs by as little as 5 degrees makes identification difficult. Changes in vertical angulation or focal-film distance had no affect. This procedure, and the positioning device used to accurately replicate antemortem image geometry is an economical, easy to use adjunct to current methods of dental identification.