A simple paralleling instrument for superimposing radiographs of the molar regions.

A simple, disposable paralleling device to produce identical radiographs of the maxillary and mandibular molar regions is described. Its precision was determined by taking serial radiographs of several patients. No deformations were found when enlargements of the radiographs were made. Identical tracings were produced during analysis with a computer-assisted densitometric technique. The new device is inexpensive and could be used advantageously for qualitative and quantitative longitudinal studies.