fine-tooth comb vs examination

fine-tooth comb and examination both are nouns.

Word	Noun	Adjective	Verb	Adverb
fine-tooth comb	Yes	No	No	No
examination	Yes	No	No	No

As nouns, examination is a hypernym of fine-tooth comb; that is, examination is a word with a broader meaning than fine-tooth comb:

Other hypernyms of fine-tooth comb include scrutiny.

fine-tooth comb (noun)	examination (noun)
a method of examining in minute detail	the act of examining something closely (as for mistakes)
a comb with teeth set close together	the act of giving students or candidates a test (as by questions) to determine what they know or have learned
	a detailed inspection of your conscience (as done daily by Jesuits)
	a set of questions or exercises evaluating skill or knowledge
	formal systematic questioning