CAD/CAM crowns made using a CEREC machine can be much more convenient than crowns made in a traditional lab. We are happy to be at the forefront of digital dentistry in our use of this technique. While it isn’t right for everyone, we have seen it work for many patients and are proud to offer it.
And we’re also happy to see that a recent study confirms that these crowns tend to stand up well under the stress of constant wear.
Testing Different Types of Crowns
For this study, researchers mostly wanted to show that composite crowns could stand up to the same level of wear and tear that ceramic crowns did. Ceramic crowns are made of a solid material that’s fired. Ceramics have the benefit of being extremely strong. Their weakness is that they don’t flex. In situations where they have to flex, they are more likely to fracture. Composite materials combine both plastics and ceramics, with the goal of adding the strength of ceramics to the flexibility of plastic. Hopefully, this should improve the overall durability of the dental crown. In this study, at least, that seems to be the case.
Researchers took 16 individual crowns of five different types–two different ceramic types, and three different composite types–and bonded them to extracted wisdom teeth that were properly prepared and then fitted using the CAD/CAM system.
Once the dental crowns were bonded to the teeth, they were put in a press where they were subjected to 500 Newtons force (about 2300 pounds) for a million cycles. This is higher than the normal maximum bite force of an adult, which is usually 300-350 Newtons. On the other hand, a million cycles is not as many as it seems. Through some complicated estimates (too complicated to go into here), we may bite down as many as 1.5 million times a year, so we’re looking at about a year’s worth of stress fatigue. Potentially more, because higher stress can significantly speed wear on dental crowns.
The study showed that none of the crowns broke under the wear conditions. However, to look for stress on the crowns, researchers used dye to reveal tiny stress fractures in the crowns. They found that the composite crowns seemed to be holding up better than the ceramic ones. The composite crowns had more areas without stress cracking. However, the study didn’t have a good method for performing a full statistical analysis of the amount of cracking, so it wasn’t able to make a definitive statement on that. However, it could say that, in the parameters of this test, the composite crowns seemed to be performing just as well as the ceramic crowns.
Durable Dental Crowns
If you are looking for durable dental crowns in the Columbus, OH area, CEREC crowns fit the bill. This study didn’t really test the longevity of CEREC crowns, but we have that data from other studies, which show that they tend to last 10-15 years, which fits with our experience, though we have seen some last much longer. Not bad for a crown that you get in a single visit.