Just so you can plan for it. This is my vain attempt at humor. When a crown that is over 20 years old falls out, it will require a check for cavities and re shaping of the tooth. Lots of numbing medicine is required. This then requires a new crown. Then the rest of the day is spent cranky and tired. I would recommend a nap. Then in two weeks I get the new crown and hopefully it will fit.
Tomorrow must be a better day.