Comparison of stent versus laser- and cephalostat-aligned periapical film-positioning techniques for use in digital subtraction radiography.

Digital subtraction radiography is a sensitive diagnostic technique that allows detection of subtle calcific changes in the jaws and teeth that would otherwise not be radiographically visible. However, a high failure rate associated with stent-based periapical film-positioning strategies combined with the complexity, expense, and time of image acquisition has limited the clinical utility of this technique. This study compares a new technique that uses film-positioning instruments, laser alignment beams, and a cephalostat with a previously validated method that used film positioners and elastic impression material. Two series of periapical radiographs were taken of six different anatomic areas of six phantoms using both techniques. Film pairs were digitally subtracted twice and analyzed. A paired t test for difference in standard deviation of mean pixel values revealed no difference in repositioning accuracy between the two techniques (p = .68). The new technique eliminates problems that are associated with the use of elastomeric impression materials.