Uses and Benefits of the TMJ Tutor

The comprehensive examination is critical for the evaluation and diagnosis of dental conditions and concerns. It is imperative that we relate the patients’ esthetic appearance and presentation to the functional disharmonies and occlusal relationships that may be contributing factors to tooth pain, appearance, muscle soreness, parafunctional habits or Tempromandibular Joint Disease. Equally important is to provide explanations and understanding of these factors so that patients can make educated decisions regarding treatment and correction.

In the case of esthetic tooth appearance, a diagnostic wax-up conveys to the patient an appreciation of tooth contour or proportion alteration. There is a dramatic difference between a pre-treatment stone cast of debilitated anterior teeth and a correctly contoured and corrected diagnostic wax-up. The patients easily grasp both need and benefit of esthetic improvements.

However, it is a different story when patient conversations require discussions surrounding “occlusal or bite interferences,” “muscle tightness and coordination” and “centric relation occlusion.” The words and the concepts are challenging for patients to wrap their heads around.

The “deer in the headlight” response is very common when attempting to discuss these concepts with patients. This is frustrating for both the dentist and the patient. “Functional” discussions are difficult for patients to comprehend. Using static images from brochures does not provide a “dynamic” representation to which patients are able to relate. Facebow-mounted casts on an articulator are an improvement, but patients are challenged with correlating the instrument with their own jaw function.

The TMJ Tutor provides a dynamic visual tool that patients can more easily relate to. The “magnet board,” which is how our office refers to the Tutor, is simply designed to provide patients with the “visual” for dynamic function, centric relation position and occlusal or bite interdigitation.

In using the Tutor for explanation, virtually all patients respond by stating that the ”magnet board really explains how the jaw works!”

How to incorporate the TMJ Tutor into the comprehensive exam

At the beginning of my comprehensive examination with the patient, I will explain that I will be evaluating not only their teeth, but also the relationship between the teeth, the jaw muscles and the jaw joint. I indicate to them that is it the coordination of these three components of the masticatory system (“mouth”) that determines the health and stability of their oral condition.

If one or more components are defective or not functioning to par, there will be effects on the other part(s) and their oral health and condition in general. I typically use the Tutor following my examination of the patient to help explain the functional relationship of the teeth, muscles and jaw joint. The patients are very receptive and appreciative of this explanation and the use of the Tutor. I believe an explanation of how I typically use the TMJ Tutor in my daily practice may be helpful for incorporating into your own examination, evaluation and patient education.

The TMJ Tutor is an educational device that is sold by various companies - Great Lakes Orthodontics and Kilgore Company are two that may be familiar. They are similar in design and may be used in the same manner.

The device is magnetic so that the individual “cut-outs” may be “swapped out” for various explanation purposes as needed. There is an “ideal” occlusal tooth cutout as well as both anterior and posterior interference cutouts. The anterior interference cutout will deflect the mandible anteriorly upon closure from the interference. The posterior cutout deflects the mandible in a posterior direction. Also included are the corrected cutouts for anterior and posterior interferences.

The upper jaw component is rigidly fixed to the magnet board. This component includes the articular eminence and outline of the upper anterior and posterior teeth. The “center-point” of the articulating fossa is marked with a red line. This represents “centric relation position” within the articular housing.

The mandible and condyle are attached to the upper member by three springs. These springs allow the lower condylar member to move in anatomic or non-anatomic pathways. The design of the “spring system” is to “center” the condylar head within the articulating housing (that is, always returning the condyle to centric relation position) when the “ideal tooth cut-out” is in place.

The red line on the condyle of the mandibular member corresponds to the center of the joint (centric relation). The layout design of the spring system mimics the attachments of the masseter, temporalis and the medial pterygoid muscles. I explain to the patient that these muscles are directly involved in the movement of the jaw and that when the “red center marks” line up, the muscles (springs) are relaxed, and there is no tension or tightness.

Without tooth interferences (bite disharmony), the jaw and muscle system remains comfortable and stable. A stable bite allows the muscles to clench and squeeze with significant force because the jaw is centered within the jaw joint and remains stable. The patients relate to this “tightness” explanation very well.

Using the TMJ Tutor for patient education

As I demonstrate for the patient the stability of the system with the “ideal” cutout in place, I tell them to observe that the muscles (springs) are relaxed, with no tension, and the condyle (jaw) is centered within the fossa (joint), just as a knee, elbow or hip.

It is common for many patients to have occlusal interferences that prevent condylar access to centric relation position. The bite interferences create an anterior or posterior directional slide from first point of contact to intercuspal position. Most patients are unaware this occurs. The TMJ Tutor provides a visual representation of the tooth contacts and the slide that follows. To demonstrate this, the appropriate cutout may be inserted and the occlusal interference may be replicated for patient visualization and understanding.

Occluding the Tutor teeth together will give a representation to the bite interference and subsequent slide to maximum occlusal contact. It also indicates the “strain or tension” developed in the muscles (springs). Additionally, the condyle is no longer centered within the articulating fossa (shown in the disparity in center lines on the Tutor). This visual helps patients comprehend the dynamic nature of occlusion and the detrimental effects that occur with dysfunction and uncoordinated muscle relationships.

The TMJ Tutors include cutouts that correct the anterior or posterior bite interferences. These corrective inserts demonstrate that if the occlusal interferences are corrected, the centered and stable relationship of the teeth, muscles and joints is returned. The stability that is diagrammed helps explain the importance of splint therapy and occlusal equilibration.

Occlusion, function and temporomandibular disorders are challenging topics for patients to comprehend. The dynamic nature of these entities creates difficult conversations and explanations. Using the TMJ Tutor provides visual representation of the important anatomical parts involved and the relationships that exist between them. It is not only easy to use, but it simplifies a complex entity into an understandable discussion.

Jeff Bonk, D.D.S., P.C., Spear Faculty and Contributing Author - http://jeffreybonkdds.com

(Click this link for more dentistry articles by Dr. Jeff Bonk.)