Teeth study right to have change of heart (7)
I believe the answer is:
denture
'teeth' is the definition.
(I have seen 'False teeth ' mean 'denture' so perhaps 'teeth' could also mean 'denture')
'study right to have change of heart' is the wordplay.
'study' becomes 'den' (den can mean an office or study).
'right' becomes 'te' (I can't justify this - if you can you should believe this answer much more).
'to have' indicates putting letters inside.
'change' becomes 'turn' (turn is a kind of change).
'of heart' indicates the central letters (I've seen 'heart' mean this).
The central letters of 'turn' are 'ur'.
'te' enclosing 'ur' is 'ture'.
'den'+'ture'='DENTURE'
Can you help me to learn more?
(Other definitions for denture that I've seen before include "False teeth plate" , "Set of artificial teeth" , "Set of false teeth" , "Plate with artificial teeth" .)