Methods for treating a wellbore. An example method includes positioning a conduit in the wellbore. The conduit is a liner hanger or a tie-back liner. The conduit includes a conduit body and a reactive metal sealing element disposed on the conduit body. The reactive metal sealing element includes a reactive metal having a first volume. The method further includes contacting the reactive metal with a fluid that reacts with the reactive metal to produce a reaction product having a second volume greater than the first volume. The method further includes contacting a surface adjacent to the reactive metal sealing element with the reaction product.