Back tooth (5)
I believe the answer is:
molar
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">back tooth</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for molar that I've seen before include "Grinding tooth in the back of a mammal's mouth" , "Moral (anag.)" , "that could be capped" , "Chewer and grinder" , "Dealing with masses" .)