Increase is noted on gold tooth (7)
I believe the answer is:
incisor
'gold tooth' is the definition.
(thesaurus)
'increase is noted on' is the wordplay.
I cannot quite understand how this works, but
'is' is found in the answer.
'on' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for incisor that I've seen before include "oral equipment" , "Ivory perhaps" , "Canine" , "something with bite" , "Narrow-edged tooth" .)