Dental

Fiber-optic trans-illumination (FM) method of caries diagnosis is based on the principle of:

When Laser beam falls on carious enamel, it gives a bluish hue.

A fluorescent dye is taken up by carious dentine which can be viewed easily

There is a different index of light transmission for decayed or sound enamel.

The conductance of normal and decayed tooth tissue is different.