Salivary Interleukin-6 and Interleukin-18 Levels and Their Association with Dental Health in Children with Idiopathic Nephrotic Syndrome

Idiopathic nephrotic syndrome (NS) is associated with immune dysfunction and increased susceptibility to infections. Oral health may influence systemic inflammation and disease progression. This study aimed to evaluate the salivary levels of interleukin-6 (IL-6) and interleukin-18 (IL-18) in children with NS and their association with dental health, particularly caries prevalence and the consequences of untreated caries. A cross-sectional study was conducted on 86 children aged 5-17 years, including 40 NS patients and 46 healthy controls. Clinical dental examinations assessed caries prevalence using the dmft/DMFT index and the impact of untreated caries using the pufa/PUFA index. Unstimulated saliva samples were collected, and IL-6 and IL-18 concentrations were measured using enzyme-linked immunosorbent assay. NS patients exhibited a significantly lower prevalence of active carious lesions than controls (50% vs. 72%, <i>p</i> = 0.039). The DMFT index was lower in the NS group (<i>p</i> = 0.003). Salivary IL-6 levels were significantly reduced in NS patients compared to controls (<i>p</i> = 0.015), while IL-18 levels showed no significant difference. IL-6 positively correlated with decayed permanent teeth and pulp/periapical tissue diseases, whereas IL-18 correlated with white spot lesions and pulp infections. IL-6 and IL-18 could serve as potential non-invasive indicators of disease progression in NS patients.