Efficacy of FDA guidelines for ordering radiographs for caries detection

This study evaluated the effect on caries diagnosis of using the Food and Drug Administration (FDA) guidelines for ordering radiographs on a sample of new adult patients seeking general dental care at a dental school clinic. These guidelines recommend posterior bitewing views accompanied by supplemental periapical views as indicated by the patient's clinical signs or symptoms. We compared the findings from the use of this protocol to those from a full-mouth set of radiographs made on the same new patient. We examined 490 patients and ordered periapical radiographs in accordance with the FDA guidelines, namely, when there was some clinical sign or symptom suggesting the need for radiographs. A full-mouth set of radiographs was obtained, and both the full and selected sets were evaluated separately. We found that 95% of our patients had one or more carious lesions, with an average of 5.7 carious teeth per patient. Of the 2808 carious teeth detected in the study, 1949 (69%) were found radiographically and 1564 (56%) were found clinically. Indeed, 1244 (44%) of the carious teeth were detected only by radiographic examination. Use of the FDA guidelines resulted in a 43% reduction in the number of radiographs ordered. Reduction in the number of images made on patients resulted in failure to detect 93 lesions (3.3%) located on 88 teeth in 11.4% of the study patients. Most of the missed lesions (2.9%) were radiographically confined to the enamel of anterior maxillary teeth. Only 36 of the missed lesions (1.6% of all radiographic lesions) extended into the dentin. We believe that this number is very small and most likely inconsequential compared with the considerable diversity among dentists regarding radiographic detection of caries, as well as the diversity of opinion regarding the indications for restorative treatment.