Radiographic indices are currently underutilized, primarily due to their complexity and inconsistent standardization. This study aimed to propose a new radiographic index to assist clinicians in evaluating interproximal alveolar bone loss (iABL) in relation to root length among periodontitis patients. A retrospective analysis was conducted on 50 anonymized dental panoramic tomograms (DPTs) from patients diagnosed with periodontitis. The most affected site in each quintet was visually assessed by one investigator and 20 volunteer clinicians, and the results were compared against a gold standard measurement. Intra-examiner reliability was quantified using the Kappa coefficient, while inter-examiner reliability employed the intra-class correlation coefficient; validity was examined with Cramér’s V test. The mean intra-examiner agreement for iABL severity and pattern was 0.808 (K) and 0.802 (K), respectively. Inter-examiner agreement was higher when evaluating iABL severity compared to pattern or furcation involvement, with mean correlation values of 0.892 and 0.739, respectively. A strong correspondence was observed between the visual assessments and gold standard measurements. Within the study’s limitations, the newly proposed radiographic index shows promise as a straightforward, reliable, and valid tool to aid clinicians in assessing the extent and severity of iABL in patients with periodontitis.
