"Several years ago, a client brought me a box turtle that had been hit by a car. I used fiberglass to repair his broken shell and then released him in my woods. Recently, while walking on my hillside, I spotted an odd pattern in the leaves. To my amazement, there was my old patient with the fiberglass still on... years later! Sometimes, being a vet is the best thing there is."From the Facebook page of the Hocking Hills Animal Center, via Bored Panda.
Addendum: There is relevant information re repairing turtle shells in this discussion thread.