ivory vs dentine

ivory and dentine both are nouns.

Word	Noun	Adjective	Verb	Adverb
ivory	Yes	No	No	No
dentine	Yes	No	No	No

As nouns, dentine is a hypernym of ivory; that is, dentine is a word with a broader meaning than ivory:

ivory: a hard smooth ivory colored dentine that makes up most of the tusks of elephants and walruses
dentine: a calcareous material harder and denser than bone that comprises the bulk of a tooth

Other hypernyms of ivory include dentin.

ivory (noun)	dentine (noun)
a shade of white the color of bleached bones	bone (calcified tissue) surrounding the pulp cavity of a tooth
a hard smooth ivory colored dentine that makes up most of the tusks of elephants and walruses	a calcareous material harder and denser than bone that comprises the bulk of a tooth