Bone Active Periodontitis Treatments: Radiographic Measurement Reliability

Objectives: To establish radiographic measurement reliability for a study to determine the effects of vitamin D and calcium on alveolar bone.

Methods: Photostimulable phosphor radiography was used to ensure accurate X-ray transmission measurements. Patients were rigidly attached to the X-ray tube by means of a vacuum coupling device and custom cross-arch bite plates with occlusal registration. Baseline and repeat bitewing radiographs were obtained of the mandibular posterior teeth of 41 subjects. Custom software and NIH ImageJ were used for image registration and measurements. Cementoenamel-junction-alveolar crest-height (CEJ-AC) measurements were made at the mesial and distal of posterior teeth. Percent X-ray transmission of alveolar bone was determined, and alveolar crest change measurements were made from subtraction images. We calculated the root-mean-square standard deviation (RMS-SD), the 95% confidence interval (95% CI) of the RMS-SD, and the least significant change (LSC) that can be considered statistically significant with 95% confidence.

Results: We made 41 x-ray transmission measurements for 41 subjects. The RMS-SD was 2% (1-2%, 95% CI), with a LSC RMS SD of 4%. Twenty-nine CEJ-AC measurements for 29 subjects had a RMS-SD of 0.18mm (0.14-0.24mm) and a LSC RMS SD of 0.49mm. Twenty-seven alveolar crest-height change measurements for 27 subjects had a RMS-SD of 0.02mm (0.02-0.03mm) and a LSC RMS SD of 0.06mm.

Conclusions: Our abilities to obtain the same baseline and repeat measurements (reliability) for CEJ-AC distances and x-ray transmission measurements are similar to what we and others have reported. We are, however, unaware of a report of better alveolar-crest-height-change reliability than we report here for a reasonably large sample (n=27) of subjects. The reliability for alveolar-crest-height-change is encouraging for clinical studies. This study was supported by USPHS grants R21 DE016918-01A2 and M01 RR00036.