Hi, my son (17) had to have a crown made and when we went to get it installed it didn't fit correctly. The dentist says his tooth shifted and wants us to pay an additional $135 to have another one made. Is it common for teeth to shift that much in about 4-5 weeks time? I'm wondering if the mold was done correctly.. Thanks

I would agrue this point, a tooth shifts very slowly but an error in the mold is far more likely. The dentist needs to bite this bullet.

A tooth would never move far enough within 4-5 weeks for a crown to be ill fitting, it does sound like the impression was taken poorly, or perhaps the technician created a bad fitting crown, but the blame is not yours and in no way shape or form should you be expected to pay up.