That really depends on gear at that level. In fact, when I was doing Iron Tombs (the defiant 18ish dungeon) I ran them as Justicar/Druid specs. Killed relatively slow but they did well on mana. And at that level, 5 druid pets (just put 2 points in it for the pet and the shield) were enough to keep me healed pretty well with the occasional DoL thrown in.
http://rift.zam.com/en/stc.html?t=00ra_.qhMo.b
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