How can I be sure I am in Centric Relation?
Posted by: Dr. Jeff Scott
Centric Relation is one of the topics that we get many questions about. In fact, in our Examination & Records course, we spend an entire day on what Centric Relation is, why it's important, how you find it, and how you record it. We're going to talk about, "How can I be sure that I'm in CR?" We're going to talk about healthy, intact joints, which brings up another point you need to know, the anatomy of the joint.
Refer to the guides to understand CR first.
You need to be very familiar with the concept of Centric Relation. One of the common problems we find in our Records course is that people need help understanding the general concept of CR. However, once we are in that course we need to train them on the proper technique. I'm going to refer you to the textbook (Functional Occlusion - From TMJ to Smile Design) and to the videos that we have online that can introduce the definition of CR. From there you can start to grasp things like ideal finger position, thumb position, and starting with a very light touch.
The most common mistake is load testing with heavy hands.
The patient is going to have a response to resist you and to engage their muscles and to be more difficult to manipulate. That's exactly the opposite of what we're trying to do. We're really not manipulating, we’re guiding the patient into a physiologic position that we load test. The technique is right, so long as you are following the instructions that we've given you, but then the load test is what verifies that you're in Centric Relation.
Use a Lucia jig to verify.
When you're first learning how to do this, we always recommend that you use a Lucia jig, which is a very easy way to feel confident about that you're in CR, and that is again described in our manuals and online, which is using this flat plane anterior deprogrammer to let the lower teeth guide forward and back. Without putting your hands on the patient at all, the joint will automatically go to Centric Relation if it's healthy and intact and the muscles are not hyperactive. As soon as the patient repeats that same position, protrusion and then retrusion as far back as they can, the muscles will take the joint to its correct position. At that point, when it keeps repeating in that same position, you're going to load test again, and that verifies that you're in centered relation.
Only take a bite record until CR is verified.
If you ever have a question, you can certainly use a Lucia jig if you have a difficult patient or you're even just not quite sure. One thing we don't recommend is taking three bite records and pick the two that match. We want you to be able to dial it in and do it right just one time. You wouldn't be taking a bite record if you weren't able to verify CR. The Lucia jig is going to help you do that.