Dental Fiber-optic trans-illumination (FM) method of caries diagnosis is based on the principle of: A When Laser beam falls on carious enamel, it gives a bluish hue. B A fluorescent dye is taken up by carious dentine which can be viewed easily C There is a different index of light transmission for decayed or sound enamel. D The conductance of normal and decayed tooth tissue is different. 💡 Explanation Fiber-optic trans-illumination (FM) method of caries diagnosis is based on the principle of: ✓ Correct Answer: C. There is a different index of light transmission for decayed or sound enamel.