Errors on dental bitewing radiographs.

The prevalence of common errors on posterior bitewing radiographs was assessed on 2409 pairs of films collected from different public dental clinics in the county of Buskerud, Norway. Only 4.6% fulfilled the criteria for correct bitewing radiographs. Incorrect position of the film was found in 42.7%. Exposures with wrong horizontal angulation of the central beam constituted 10.6%, and under/overaxial exposures 2.2%, of the sample. Cone cutting occurred in 4.3%. Disturbing spots were found on most of the films (88.1%); 7.7% of the films had been insufficiently washed. Other errors due to wrong darkroom procedures or equipment failures were more rarely observed. The present study has shown that unnecessary errors, reducing the readability of bitewing radiographs, are frequently found. Steps should be taken to improve the standard of the radiographs used for diagnosis.