Comparison between panoramic and intra-oral radiographs for the assessment of alveolar bone levels in a periodontal maintenance population

Abstract

Background: Information about the agreement between intra-oral (I-O) and panoramic (OPG) radiographs is limited. Aims: (1) To assess the agreement between I-Os and OPGs for direct measurements of the distance between the cemento-enamel junction (CEJ) and the alveolar bone level (BL) as well as the proportional values in relation to the root length (CEJ-BL/ root length), and (2) to explore the symmetry between the left- and right-side measurements. Material and Methods: I-Os and OPGs were studied in 292 periodontal maintenance subjects (mean age 55.5 years, SD ± 12.6) with on average 22.4 teeth (SD ± 4.1 range: 6-28). The images were measured using a PC software program. Site-based I-O and OPG values for CEJ-BL as well as CEJ-BL/root length were compared. OPG values of CEJ-BL/root length values between the left and right sides were also studied. Results: A total of 11,395 linear distances (CEJ-BL plus CEJ-apex) from the I-Os and 21,462 linear distances from the OPGs were measured. The intra-class correlation coefficients (ICCs) between sets of readings of CEJ-BL varied between 0.80 and 0.89 (p < 0.001), with the best agreement for tooth 22 (ICC: 0.89; 95% CI: 0.83-0.92). The ICCs for CEJ-BL/root length varied between 0.54 and 0.92. Mean differences between I-O and OPG values were in the 0.00-0.04 mm range for the CEJ-BL/root length comparisons. The maxillary anterior sextant demonstrated a 1.4 x enlargement by OPG for the CEJ-BL/root length comparisons. No distortions were observed for mandibular sextants. Left- and right-side symmetry of periodontal bone loss was demonstrated. ICC varied between 0.79 (95.00% CI: 0.71-0.84, p < 0.01) and 0.53 (95.00% CI: 0.36-0.65, p < 0.01). Conclusions: I-O and OPG radiograph readings are in great agreement. Alveolar bone loss appeared to have a symmetrical distribution pattern. Hence for periodontal assessments, OPG radiographic readings may, at least in part, substitute for full-mouth periapical radiographic evaluation.