Comparative Evaluation of Root Concavity Prevalence and Types in First Premolars Among Stage II Periodontitis Patients and Periodontally Healthy Individuals: A Cross-Sectional Case–Control Study

Abstract This study aimed to compare the distribution of root concavity types in maxillary and mandibular first premolars between patients with stage II periodontitis and periodontally healthy individuals using cone-beam computed tomography (CBCT). In this analytical cross-sectional case–control study, we analyzed the distribution of root concavities in CBCT scans of 278 proximal root surfaces of first premolars: 118 surfaces in 16 patients (mean age 40.88 ± 3.73) diagnosed with stage II periodontitis and 160 surfaces in 23 periodontally healthy controls (mean age 39.22 ± 3.5). Proximal root surfaces were evaluated and classified according to the Ong and Neo concavity classification system. The distribution of concavity types was assessed by periodontal status, tooth type, arch, and root-surface location. Generalized estimating equations (GEEs) were used to account for clustering of multiple root surfaces within participants. Binary GEE logistic regression evaluated factors associated with the presence of root concavities, site-specific GEE models compared individual concavity types between groups, and an additional GEE model compared coronal-origin (types II–III) and apical-origin (types IV–V) concavities. The overall prevalence of root concavities did not differ significantly between patients with stage II periodontitis and periodontally healthy controls (odds ratio [OR] = 0.87; 95% confidence interval [CI]: 0.60–1.27; p = 0.466). Type III concavities were significantly more frequent on the mesial surface of maxillary first premolars in the stage II periodontitis group, and patients with periodontitis had higher odds of exhibiting coronal-origin concavities (types II–III) than periodontally healthy controls (adjusted OR = 2.35; 95% CI: 1.25–4.44; p = 0.008). Although the overall prevalence of root concavities was similar in patients with stage II periodontitis and periodontally healthy individuals, periodontal disease was associated with differences in concavity morphology, particularly an increased prevalence of coronally originating concavities and type III concavities on the mesial surface of maxillary first premolars. These findings suggest that root concavity morphology should be considered a local anatomical modifier during periodontal risk assessment and treatment planning.