RNA interference (RNAi) or Post-Transcriptional Gene Silencing is a strong mechanism of gene silencing which is moderated by MicroRNAs (miRNAs), underlying many fields of eukaryotic biology. The miRNAs are small noncoding RNAs and a gene regulation expression system which showing a tissue-specific expression pattern, and inhibits protein synthesis. For the first time, miRNA has been seen in Caenorhabditis elegans. They play an important role in signaling pathways of various diseases especially periodontal disease during periodontal inflammation and oral cancers. The most important miRNAs in periodontal diseases and oral squamous cell carcinoma are miR-142-3p, miR-146a, miR-155, miR-203, and miR- 223. One of the most important diseases in association with gingival infectious is periodontal diseases which if left untreated, would lead to tooth loss. Hence, the aim of the present study is to focus the effects of miRNAs and their targets in diseases which are mentioned above.