How old is she? Sheep don't usually lose molars until they are very old, and by then they would have no teeth left at the front. I have only seen 2 molars lost, from my very oldest ewes.
If she's youngish, then I can think of abscesses or a metabolic problem, but she will never grow those molars back.
If she's a hogg then someone else, one of the vets on here maybe, can advise as to whether young sheep replace their molars as they do their front teeth, for adult sized ones, or if they only have one set.
So it really depends on her age I think