Agreement between panoramic and intra-oral radiography in the assessment of marginal bone height

Panoramic and intra-oral radiographs from 400 consecutive patients were evaluated for the assessment of the marginal bone height. Two hundred panoramic radiographs were exposed with the rotational technique and 200 with the intra-oral X-ray tube technique. Measurements of the approximal marginal bone level were independently performed by two observers. Complete agreement between panoramic and intra-oral radiographs was, on average, obtained in 55% and 49% of the sites, respectively. When the criterion for agreement was widened to include recordings with a difference of +/- 1 mm, the agreement was on average 87% irrespective of the techniques compared. The agreement varied with tooth type and severity of the marginal bone loss. Angular bony defects and furcation involvements were recorded separately. For angular bony defects there was a variation in agreement from 33% to 46% for the rotational technique and from 35% to 51% for the intra-oral X-ray tube technique depending on localization. Furcation involvements of the molars were equally recorded in 60% and 59%, respectively, but in only 12% and 28% for the upper premolars. Interobserver agreement was 58% for the intra-oral radiographs, 60% and 59% for the two panoramic techniques. Mean intra-observer agreement was 68%, 66% and 68%. It is concluded that panoramic radiography can often be used for the assessment of marginal bone loss alone, supplemented when necessary by intra-oral radiographs.