bite plate vs dental appliance

bite plate and dental appliance both are nouns.

Word	Noun	Adjective	Verb	Adverb
bite plate	Yes	No	No	No
dental appliance	Yes	No	No	No

As nouns, dental appliance is a hypernym of bite plate; that is, dental appliance is a word with a broader meaning than bite plate:

bite plate: a removable dental appliance that is worn in the palate for diagnostic or therapeutic purposes
dental appliance: a device to repair teeth or replace missing teeth

bite plate (noun)	dental appliance (noun)
a removable dental appliance that is worn in the palate for diagnostic or therapeutic purposes	a device to repair teeth or replace missing teeth