One of the most common reasons that dentists have to do a lot of adjustments on a new crown is failure to start their treatment with a complete examination and plan their treatment.
Be aware of any discrepancies in the bite
Many patients have a discrepancy between the way their teeth fit together when they chew (or their maximum intercuspal position) and how they bite when their joints are seated (or in centric relation). So if the dentist is unaware of the discrepancy, or if they think it's okay to just work in the maximum intercuspal position, then this could lead to problems.
Leave enough space for the restorative material
So when we prepare a tooth for a crown that may be guiding that patient into their acquired bite, once that occlusal contact is prepped away, then the patient naturally has a seating of the joint on that side. So all of the careful occlusal reduction that we've just done vanishes as that joint seats. And as a result of the condyle seating, we've actually given the lab inadequate space for our restorative material. So when we receive the crown back, we may have a lot of adjustments to do.
On the other hand, when we take the time at the beginning of treatment to develop a perfected and a stable occlusion with centric holding stops on all the teeth, then we can avoid unnecessary adjustments at the end of treatment.
To learn more about centric relation vs. maximum intercuspation and treatment planning, register for our course Functional Occlusion - From TMJ to Smile Design.