16S rRNA of health saliva
Total microbial genomic DNA was extracted from saliva samples and amplified using specific primers for the V3-V4 regions of the 16S rRNA gene, followed by purification and quantification. The PCR products were sequenced on an Illumina PE300 platform, and high-quality sequences were processed using FastP, FLASH, and the DADA2 plugin in Qiime2 for detailed analysis.