A dental material comprising a copolymer which comprises at least 10% by weight of a polymeric unit of at least one of the following monomers: ##STR1## wherein R.sup.1 and R.sup.2 are each H, CH.sub.3 or CF.sub.3, R.sup.3 is H, CH.sub.3 or F, A is --CH.sub.2 --, --CH.sub.2 CH.sub.2 --, --CH.sub.2 CH(CH.sub.3)--, --CH(OH)--, --CH.sub.2 CH(OH)CH.sub.2 --, --CH(OCOCH.sub.3)--or --CH.sub.2 CH(OCOCH.sub.3 (CH.sub.2 --, A' is the same group as A or --CH.sub.2 CH.sub.2 CH.sub.2 --, 2 is an alkylene group having 2 to 10 carbon atoms, m and n are each zero or a number of 1 to 5, p is a number of 1 to 3, q is a number of 1 to 5, provided that at least one of R.sup.1 and R.sup.2 is CF.sub.3 when R.sup.3 is H or CH.sub.3.