Periapical Lesion Grade and Sinus Mucosal Thickness in Severe Periodontitis

Severe periodontitis (Stage III-IV) frequently coexists with apical periodontitis, both of which can contribute to Schneiderian membrane thickening (SMT). This study quantifies the association between periapical lesion severity and SMT in a well-defined cohort of severe periodontitis, aiming to improve the preoperative risk assessment using cone-beam computed tomography (CBCT).

CBCT images from 330 patients diagnosed with Stage III-IV periodontitis complicated by apical periodontitis in maxillary posterior teeth were analysed. SMT was measured at standardised sites, and periapical lesion severity was graded using the CBCT periapical index (CBCT-PAI). Differences in SMT according to sex, periodontal stage and tooth position were evaluated, and correlations between CBCT-PAI and SMT were assessed using nonparametric tests and Spearman's rank correlation.

Increased SMT was observed in both stage III and stage IV periodontitis, no significant difference between stages. SMT also exhibited a bilateral distribution pattern. Analysis of individual teeth revealed that the SMT showed a modest but statistically significant correlation with the severity of apical periodontitis (Stage III: ρ = 0.213, P < .001; Stage IV: ρ = 0.244, P < .001). Notably, SMT was particularly pronounced in the maxillary first molar (P < .001), which may reflect their close anatomical relationship with the sinus floor.

In patients with severe periodontitis, SMT showed a modest association with the severity of coexisting apical periodontitis. Differences in SMT distribution were observed across different tooth positions; this may also be related to anatomical and functional factors.

These findings provide supportive information for preoperative periodontal and dental assessments in patients requiring implant surgery, and may assist in preoperative risk assessment.