Oral submucous fibrosis (OSF) is caused by aberrant collagen deposition in the oral mucosa. A chronic, creeping, scarring disease of cavity often involving pharynx and upper oesophagus how it's been described for centuries. It most dangerous premalignant condition evolve into malignant tumours 1.5% to 15% cases. found primarily India, Pakistan, Sri Lanka, Bangladesh. Submucous fibrosis, ulcerat...