A study is reported comparing the diagnostic yield of panoramic and posterior bitewing radiographs when used to image periodontal bone disease. It is concluded that there is a high concordance between the findings from the two types of radiographs but that the concordance varies with the degree of bone loss and tooth type. Consequently when panoramic radiography is used in clinical practice, the examination should be supplemented by intraoral radiographs in regions when image quality is poor in the panoramic image and where there are structures of special interest.