Before a splint is made, the relaxed resting position of the lower jaw must be determined. This article explains how to identify this position and distinguish it from the patient’s habitual bite.
Determination of the resting position and the construction occlusion in relation to the habitual occlusion.
Ongoing diagnostics and therapy of the craniomandibular and musculoskeletal system (TMS/MSS)
The Correct Jaw Position – Why It's So Important
In most of the body’s joints, the muscles determine the joint’s position. The temporomandibular joint is different: as soon as the teeth are firmly clenched together, they—through the bite—determine the joint’s final position. If this habitual bite does not correspond to a relaxed, healthy joint position, it can lead to discomfort over time. For any treatment of temporomandibular joint problems, a healthy, relaxed jaw position must therefore be established first. That is precisely what this professional publication is about.
This relaxed position—known in technical terms as the “centric” or physiological jaw position—is not a fixed value, but varies from person to person and can change slightly depending on muscle tension, posture, and how you’re feeling on a given day. There is no single “correct” measurement method for this; rather, the goal is to find a position that suits the entire jaw and musculoskeletal system. This determination is always preceded by a thorough functional diagnosis.
Centric occlusion and therapeutic occlusion
To record the position of the jaw, a bite registration is taken—in simple terms, a precise impression of the bite position in a wax plate. There are two different situations:
The Centric Bite and Healthy Joints
For joints without symptoms, a relatively simple centric bite is sufficient. The heated wax plate is fitted to the upper jaw, and the patient bites down while sitting upright and relaxed—without the dentist guiding the lower jaw at all. The contact points are then carefully checked and reduced until a stable, reproducible bite position is achieved.
Therapeutic occlusal splints for joint disorders
This is not sufficient for patients with joint pain or joint disorders. In such cases, a therapeutic bite registration is taken—while simultaneously palpating the joints through the ear canal. This allows for a precise assessment of mobility, symmetry, and the sensitive area behind the condyle as the correct position is adjusted. Before taking the bite, the joints are gently mobilized and muscle tension is released; accompanying manual therapy is ideal. A particularly hard wax is used, which retains its shape in the mouth and thus allows for manual control.
Full-body check
Whether the position found is truly correct is not determined by the jaw alone. With the provisional bite in place, the patient is asked to swallow once and take a few steps—this allows the body to readjust. Posture and mobility tests are then repeated. If these findings improve significantly with the new bite, this is a strong indication that the jaw position actually fits the body and musculature. This comparison makes the determination more objective and reliable.
From Bite Registration to a Splint
The position determined is transferred to an articulator using a facebow and the design bite—a device that realistically simulates jaw movements outside the mouth. Only this precise model setup allows for a reliable analysis of the bite and the fabrication of a custom-fit occlusal splint. Without this careful transfer, the position would be inaccurate and unusable for diagnosis or splint fabrication.
An impressive case study from the publication illustrates why this is so important: A patient with severe back pain appeared “unremarkable” at first glance—it was only when the models were mounted in the articulator that it became clear the lower jaw had been forced into an unfavorable position. Had treatment been performed here without considering the joint, the entire therapy would have failed. A guiding principle sums it up aptly: “Think orthopedic first—then teeth”—first the joint and function, then the teeth.
Also suitable for children
The procedure described above can also be used for children and adolescents, for example, when a diagnostic bite is needed for a removable functional orthodontic appliance. Here, too, simultaneous palpation of the joints provides valuable additional information.
Diagnosis and treatment go hand in hand
A relaxed, healthy jaw position is the foundation of any treatment for temporomandibular joint disorders. It cannot simply be “read off a chart,” but must be carefully determined and assessed in relation to the entire body. A meticulously taken diagnostic bite, combined with manual diagnosis and precise model assembly, lays the groundwork for a splint that truly fits—and thus for successful, long-lasting treatment.