Just because a tooth has calcified does not mean it is or will become necrotic. Quite the contrary. According to Andeasen, 22% of traumatized undergo calcific metamorphosis. Holcomb and Gregory found that only 7% become necrotic. They recommended treatment only if a periapical lesion developed. Walton found that a pulp space is always present histologically even if it is not visible radiographically. Negotiating a “histologically present” canal does not make for a fun afternoon. (unless you are an endodontist working on keeping your finger calluses)
Pulpal testing should not be trusted with calcified teeth. Most of the time a tooth with pulp canal obliteration will be nonresponsive to cold testing. Electric pulp testing cannot be trusted. Jacobsen found that only 50% of the time a vital calcified tooth would have a positive response to electric pulp testing.
Many times poor aesthetics of a calcified tooth is the chief complaint. The darker shade of the tooth is due to the increase of dentin thickness and not necessarily an indication of necrosis. Elective treatment with internal bleaching can be completed to correct this in many cases. To get an exact shade match a veneer may be best.