The comparison of antemortem and postmortem radiographs is widely accepted as a fundamental method in forensic dental identification. Since intraoral dental radiographs are an essential diagnostic and treatment aid in dental practice, they are a component of most patients' dental records. The BW, a nonscreen film used to detect interproximal dental caries, is the most commonly taken radiograph. The sample for this study consisted of 560 BW's selected from a large number exposed by the same dentist over a 30-year period. Initially, radiographs of intact, unrestored dentition were selected. The yield was minimal in the adult population, but there was a substantial number from teenage patients who had grown up during the years when the local water supply was fluoridated. Radiographs of restored teeth were accepted only if the presence of the restorations did not help the identification process. BW examinations of the same patient over varying time spans were used to construct the matched pairs of simulated antemortem/postmortem radiographs. A total of 83 individuals composed the 140 matched pairs of BW's. The matched sample consisted of radiographs taken at intervals of 1 to 15 years. The study shows that BW's are a valid tool for forensic identification. Although the prevalence of unique metallic restorations is decreasing, this radiograph often contains enough anatomic characteristics to be a highly useful comparative tool. Even a relatively inexperienced observer was able to make matches and nonmatches with a high degree of accuracy. 1 table, 1 figure, and 6 references