There are many ways to prep a tooth for crown restorations, most of them are bad or even lazy ways to prep a tooth. Are you giving the lab the best situation to build a crown for your patients? Laboratory technicians are challenged with making restorations work with bad data or impressions and even preps, the quality of a restoration, if it is a crown, denture, partial or even night guards starts in the dental office, if what you are giving your lab is inaccurate or sloppy well that is what your patient will get back an inaccurate or sloppy restoration. This is why is is important to make sure the work in a dental office is done correctly. Studies tell us that shoulder preps are ideal for ceramic crown restorations such as Emax, Zirconia, Lava, and other modern day materials we use for crowns. If you want to read in depth about a study of preps read this article from Dentistry Today.
There are many sales reps out there that tell us we can do a feather edge prep on emax and zirconia, but this simply is false, each material has certain parameters that guide us to make a crown that fits well, strong and looks esthetic in the patients mouth. The fact is, no matter what system is used, a certain amount of room is needed . This is especially true in the area of the margin and cervical third. Many times, our lab technicians have to work with chamfers that are too shallow or even nonexistent. The resulting crowns can be bulky and far less aesthetic, especially in the cervical third. The solution is to prepare a deeper, definitive chamfer.
There are times when we get a case and we see that the preps need to have shoulder margins or the preps are out of alignment with the patients mouth ( this will cause some teeth to stick out more than others because we need a certain amount of thickness to build a strong restoration), we can already see that the crowns won’t look as good as they need to be for the patient, please don’t be one of those Doctors that says “Do the best you can” its basically saying you won’t help the patient have a better quality smile. Obviously there are some cases that are extremely difficult and some that are truly hard to get the best quality, but if we work together to improve this industry, communicate properly and give patients the best quality care and products we will be successful and you will have patients that are happy to work with you and your office.
If you are ordering zirconia (or Bruxzir), Emax or any other ceramic material you need to do a shoulder prep. This will allow us to create a strong natural looking crown for your patients and they shouldn’t have any issues with the crown, obviously materials wear out over time crowns may break but there is a better chance for crowns to last longer if you use a shoulder prep.
If you have any questions about how you should prep for your cases feel free to contact us via email or call us on the phone – (801)-484-1750
Here is a chart you can use for reference: