Pathology Linea alba is A A type of frictional hyperkeratosis that appears as a linear white line in buccal mucosa. B Usually present as ulcers C Traumatic implantation of amalgam particles into mucosa. D Caused by a chemical in tobacco smoke that stimulates melanin production. 💡 Explanation Linea alba is ✓ Correct Answer: A. A type of frictional hyperkeratosis that appears as a linear white line in buccal mucosa.