Early detection is critical for a positive outcome in most types of cancer, including oral squamous cell carcinoma (OSCC). Saliva has been used as a diagnostic medium for OSCC, with proteins, mRNA, and DNA being employed as salivary biomolecules for their detection. Somatic mutations of tumor-specific DNA are related to the onset and development of malignancy, which can be detected in saliva, plasma, or other body fluids. Saliva has a higher abundance of tumor-specific DNA from oral tumors compared to tumors in other parts of the body. Tumor-related viruses such as HIV and human herpes virus (HHV) can also be detected in saliva and are associated with cancers of the oral cavity and other sites. Salivary miRNAs and long noncoding RNA (lncRNA) have also shown potential as biomarkers for OSCC detection. RNA molecules, such as mRNA and microRNA, have emerged as promising biomarkers for cancer detection, including OSCC. Studies have shown that levels of miR-125a and miR-200a in saliva are significantly lower in OSCC patients than in healthy individuals, highlighting the potential of salivary miRNAs as diagnostic tools for oral cancer. Additionally, long noncoding RNAs (lncRNAs) have been found in detectable amounts in saliva and may serve as potential markers for OSCC. Therefore, RNA molecules in saliva have significant potential as biomarkers for the detection of oral cancers. Salivary proteins have the potential to be used as biomarkers for cancer diagnosis. Salivary biomarkers, including CA15-3, c-erbB2, CA-125, and P53, have been reported to be increased in patients with oral cavity and other site cancers. Hyaluronidase, IL-6, and IL-8 have been suggested as potential biomarkers for head and neck squamous cell carcinoma (HNSCC). Additionally, studies have shown that palate, lung, and nasal epithelium clone protein (PLUNC) and zinc-α-2glycoprotein are overexpressed in the saliva of cancer patients, providing potential targets for new HNSCC analyses. Salivary cytokines such as IL-4, IL-10, IL-13, and IL-1RA have also been found to be increased in the saliva of patients with OSCC. TNF-α levels have been shown to be higher in moderately and poorly differentiated tumours than in well-differentiated and stage IV tumours, and there is a positive correlation between the histological grading of OSCC and TNF-α. Overall, salivary proteins have shown promising results as biomarkers for cancer diagnosis and further research is needed to explore their potential in clinical settings. 3. Biosensors: Recent Lab-on-Chip and Nanotechnology driven Advances