Contaminate false teeth, biting article (8)
I believe the answer is:
denature
'contaminate' is the definition.
(thesaurus)
'false teeth biting article' is the wordplay.
'false teeth' becomes 'denture' (I've seen this before).
'biting' is an insertion indicator (I've seen this in other clues).
'article' becomes 'a' (indefinite article).
'denture' going around 'a' is 'DENATURE'.
(Other definitions for denature that I've seen before include "Change" , "Contaminate" , "Take away the inherent properties of" , "Spoil" .)