Comparison of direct digital and conventional intraoral radiographs in detecting alveolar bone loss

Intraoral radiographs are important diagnostic aids in periodontics. The authors conducted a study to compare estimates of bone levels from direct digital and conventional radiographic under normal clinical use.

A full-mouth series of conventional radiographs was taken for each of 25 subjects who had periodontitis. A long cone paralleling technique was used for periapical, or PA, images, and a paper sleeve with biting tab was employed for bitewing, or BW, images. A set of direct digital radiographs matching the conventional radiographs was taken for each subject under the same conditions. The distance from the cementoenamel junction to the interproximal alveolar crest on all readable surfaces was measured.

Examiners measured 857 PA image sites and 315 BW image sites matched on both radiographic systems. Paired t test showed significant differences in bone levels between the two systems. Measurements from conventional PA images were higher in all maxillary sextants (P < or = .02), and measurements from digital PA images were higher in mandibular anterior sextants (P = .007). Measurements in digital BW images were higher in mandibular posterior sextants (P = .002). A chi2 analysis of categorical bone levels (normal, early-to-moderate loss or advanced loss) showed significant differences between the imaging systems in revealing bone levels in both PA (P < .04) and BW (P < .001) images. Digital radiographs showed a higher number of sites with bone loss than did conventional radiographs.

Under normal clinical use, alveolar bone levels revealed on intraoral direct digital radiographs differ from those revealed on conventional radiographs.

Intraoral direct digital radiographs are not an equivalent substitute for conventional radiographs in evaluating alveolar bone levels.