The crown has come off! I’m sorry to say that your smile is now lost. You might want think about getting it fixed professionally or put a band-aid on for now but if this happens often in the future, then you should go see an expert who can reroute all of those nerves and tissues back into place The most common dental emergency patients find themselves facing when they come into our office are teeth crowned with metal because usually people don’t realize until its too late what kind/size bit was used by their dentist during treatment time.