#177 Everyone on the Planet Has 2 Bites, and the Difference Between the Two Can Cause TMD

Every dentist is taught in dental school that there are two distinct bites.  This is a very important concept for many reasons, not the least of which is that every type of dental treatment, procedure, or device depends on the dentist have a thorough grasp and understanding of this concept.  If you question your dentist about this statement, he or she will say, “Of course, everybody has two bites, that’s basic dental knowledge. But patients have rarely ever heard of it.  In the language of a dentist, these two bites or positions of the teeth as they meet together are called Centric Occlusion, and Centric relation. 

So, lets start at the beginning, and as Voltaire suggests for every successful communication, let’s define our terms. 

 In dentistry, a bite (formally known as occlusion) refers to the way your upper and lower teeth meet when you close your mouth or chew. A healthy bite allows the teeth to align properly, distributing pressure evenly across the jaw and protecting against tooth wear and joint pain. 

Centric occlusion (CO) is the position of your lower jaw (mandible) when your teeth are fully meshed together in their most stable and balanced contact.  

 Centric Relation (CR) is defined as the most anterior-superior position of the mandibular condyles within the glenoid fossa, (jaw joint) where they articulate against the thinnest, avascular portion of their respective articular discs. Crucially, this is a maxillomandibular relationship (jaw-to-jaw) that is independent of tooth contact. It is considered a reproducible, physiological reference point used by dentists to plan complex restorative treatments, dentures, and orthodontic care. (1) 

Everybody on the planet has a measurable difference between CO and CR.  Some people have very small differences of 1 millimeter or less, and some people have a difference approaching 1 inch.  The bigger the difference, the bigger the problem and the problems caused.   

Large differences can become obvious to the observer from across a room, and appear as facial growth problems.  Dr. Urbanek spent a good part of his surgical career managing and correcting facial growth problems in children and adults. The smaller differences may not be obvious to the observer but can create significant damage to the temporomandibular joint by the constant shift between centric occlusion (CO) and centric relation (CR) especially in patients with a habit of clenching and grinding their teeth, (Bruxism).   

A difference of as little as 2 to 3 millimeters can cause significant damage to the temporomandibular joint (TMJ). The difference between CO and CR is a change in position of the entire lower jaw in its relationship with the upper jaw.  In the CR position the teeth do not fit together as usual because the entire lower jaw shifts rearward.  The teeth do not move within the jaw, the entire jaw moves including the teeth embedded in the jaw.   

The healthy position for the temporomandibular joint is CR.  The Urbanek device and Protocol is exceptionally effective in treating the symptoms of TMD because it naturally places the lower jaw at CR.  Now the pain and other symptoms are gone but in about 10% of the patients, there is evident a large enough difference between CR, where the joint is comfortable, and CO where the teeth used to fit comfortably, that a correction to bring CO closer to CR is necessary.  Most of the time this can be done with orthodontic assistance, but in larger differences between CO and CR the treatment required includes orthodontics and surgery on the jaw.  This is called orthognathic surgery, which literally translates as “Straight Jaw Surgery”.  Fortunately, less than 4 percent of patients with Temporomandibular Joint Disorder, (TMD) need Orthognathic Surgery    

A significant difference between CO and CR is one of the three things that damage to the Temporomandibular Joint (TMJ) creating TMD. This is called a functional malocclusion.  Everyone has 2 bites and the difference between the two can cause TMD. 

1.  Dawson Academy