###### Abstract  
One of the most frequent head and neck cancers is oral cancer, with less than half of those diagnosed surviving five years. Despite breakthroughs in the treatment of many other cancers, the prognosis for people with OSCC remains dismal. The conventional methods of detection include a thorough clinical examination, biochemical investigations, and invasive biopsies. Early identification and treatment are important for a better chance of extending a patient's life. Early diagnosis may be possible by identifying biomarkers in biological fluids. Currently, the primary method for diagnosing oral lesions is a visual oral examination; however, such a technique has certain drawbacks, as individuals are recognized after their cancer has advanced to a severe degree. The first section of this review discusses several diagnostic techniques for cancer detection, while the second section discusses the present state of knowledge about known existing predictive markers for the timely identification of malignant lesions, as well as disease activity tracking. The aim of the paper is to conduct a critical review of existing oral cancer diagnostic processes and to consider the possible application of innovative technology for early detection. This might broaden our diagnostic choices and enhance our capacity to identify and treat oral malignant tumors more effectively.  
oral cancer; OPMD; OSCC; early diagnosis; biomarkers; treatment +
Footnote †: journal: Medical  
lead to OC. OPMDs are a group of different oral mucosal lesions that are more likely to become cancerous. The lip, tongue, gums, palate, and other parts of the oral mucosa are the most pervasive sites of OC, as classified by the International Classification of Diseases (ICD) [4]. A lot of people who have oral cancer have a lot of different things going on in their mouths, including smoking, drinking too much alcohol, not brushing their teeth, and having long-term viral infections, such as the human papillomavirus (HPV) [5; 6; 7; 8]. Tobacco use (in every form) is an important cause of cancer, particularly in underdeveloped nations. People who chew pan, which is made of piper betel leaves mixed with area nut, lime, catechu, cinnamon, and other ingredients, are more likely to contract OC than people who smoke cigarettes. This is especially true in India, which has the highest cancer rate in the world [10]. Periodontal diseases are also a high-risk factor for OC, and they are more common in the Indian population, where it is mostly caused by the practice of chewing paan [11]. Chewing paan induces extended exposure of the oral mucosa, as well as abrasion of the epithelial linings. Smokeless tobacco consumption, both orally and nasally, has been linked to potentially malignant oral diseases and malignancies of the oral cavity. Tumorigenesis and inflammation caused by bacterial and viral infections, as well as inflammatory bowel illnesses, also play a major role in the development of cancer [11]. The exposure to harsh environmental circumstances, lack of information, and behavioral risk factors are the key indicators of this OC to be a worldwide incidence. The risk factors for OC vary by geographical area and the lifestyle habits of the people who live there. In Western nations, the primary risk factors are smoking and alcoholism. This is in contrast to South Asian countries, where betel nut eating and smoking are more prevalent [12]. This review paper provides a crisp view on conventional and recent advanced diagnostic methodologies used in the detection of OC. This paper also highlights recent molecular biomarkers used in diagnosis and detection.