tooth enamel vs enamel

tooth enamel and enamel both are nouns.

Word	Noun	Adjective	Verb	Adverb
tooth enamel	Yes	No	No	No
enamel	Yes	No	Yes	No

As nouns, tooth enamel and enamel are synonyms defined as:

tooth enamel and enamel: hard white substance covering the crown of a tooth

tooth enamel (noun)	enamel (noun)
hard white substance covering the crown of a tooth	any smooth glossy coating that resembles ceramic glaze
	a paint that dries to a hard glossy finish
	hard white substance covering the crown of a tooth
	a colored glassy compound (opaque or partially opaque) that is fused to the surface of metal or glass or pottery for decoration or protection

tooth enamel (verb)	enamel (verb)
	coat, inlay, or surface with enamel