The maximum class size for those students whose special education needs consist primarily of the need for specialized instruction which can best be accomplished in a self-contained setting cannot exceed 15 students (15:1), or 12 students in a State-operated or State-supported school (12:1), except that:
The permanent crown will fit, look, and feel better than the temporary after all the proper and necessary adjustments has been made. Most dentists will check your bite when the temporary is out and again when the permanent crown is in place (not cemented yet). The two should feel the same.
A well made temporary crown can be made to last upwards of 2+ years if necessary (but the crown and tooth needs to be followed closely, examined every 3 months or so to make sure that the temporary crown is still serviceable and that there is no leakage of the cement).