NEFL and periodontitis: Figure 4B shows the top 30 genes in the RF classifier; CSF3 was the most important biomarker. Finally, we obtained a total of 13 key periodontitis biomarkers using importance >2 as the screening criterion. The heatmap revealed that NSG1 and NEFL were downregulated genes in the periodontitis group, and the remaining 11 were upregulated (Figure 4C). Each marker exhibited excellent diagnostic performance, with the lowest AUC of 0.831 and the highest of 0.916 (Supplementary Figure S1).