In time, right filling of teeth can be damaging (11)
I believe the answer is:
detrimental
'be damaging' is the definition.
('detrimental' can be a synonym of 'damaging')
'in time right filling of teeth' is the wordplay.
'in' indicates putting letters inside.
'right' becomes 'r' (common abbreviation).
'filling' means one lot of letters goes inside another.
'of teeth' becomes 'dental' (I've seen this before).
'time' placed around 'r' is 'trime'.
'trime' put within 'dental' is 'DETRIMENTAL'.
'can' is the link.
(Other definitions for detrimental that I've seen before include "not helpful" , "Causing harm" , "which is bad for one" , "Tending to cause harm" , "Harmful; admit, relent (anag.)" .)