Before fabricating a splint, the relaxed rest position of the mandible must be determined. This article explains how to identify this position and distinguish it from the habitual bite.
Determination of rest position and construction bite versus habitual bite.
Ongoing Diagnosis and Therapy of the Craniomandibular and Musculoskeletal System (TMS/MSS)
The Correct Jaw Position – Why It Matters So Much
In most joints of the body, muscles determine where the joint sits. The temporomandibular joint is different: as soon as the teeth bite firmly together, they dictate – through the occlusion – the final position of the joint.1 If this habitual bite does not match the relaxed, healthy joint position, it can cause problems over time. For any treatment of temporomandibular joint problems, a healthy, relaxed jaw position must first be found. That is exactly what this professional publication is about.
This relaxed position – in technical terms “centric” or physiological jaw position – is not a fixed value, but individually different and can vary slightly depending on muscle tension, posture, and daily condition.2 There is no single “true” measurement method for it; rather, the goal is to find a position that fits the entire jaw and musculoskeletal system. This determination is always preceded by a thorough3 functional analysis.
Centric Bite and Therapeutic Construction Bite
To record the jaw position, a bite registration is taken – in simple terms, a precise impression of the bite position in a wax plate. Two situations are distinguished:
Centric Bite in Healthy Joints
For symptom-free joints, a relatively simple centric bite is sufficient. The warmed wax plate is adapted to the upper jaw, and the patient bites into it in an upright, relaxed posture – entirely without the practitioner guiding the lower jaw. Afterward, the contact points are carefully checked and reduced until a stable, reproducible bite position is achieved.
Therapeutic Construction Bite in Compromised Joints
When symptoms or diseased joints are present, this is not sufficient. Here, a therapeutic construction bite is taken – while simultaneously palpating the joints through the ear canal. This allows precise assessment of mobility, symmetry, and the sensitive area behind the condyle while the correct position is being set. Before taking the bite, the joints are gently mobilized and muscle tension is released; accompanying manual therapy is ideal.4 A particularly hard wax is used that remains dimensionally stable in the mouth and thus allows manual control.
Full-Body Examination
Whether the position found is actually correct is shown not only at the jaw. With the construction bite in place, the patient is asked to swallow once and take a few steps – so the body can reorganize itself. Posture and mobility tests are then repeated.5 If these findings improve significantly with the new bite, this is a strong sign that the jaw position actually fits the body and musculature. This comparison makes the determination more objective and reliable.
From Bite Registration to Appliance
The recorded position is transferred to an articulator using a facebow and the construction bite – a device that accurately replicates jaw movements outside the mouth.6 Only this precise model mounting allows reliable analysis of the occlusion and the fabrication of a precisely fitting occlusal splint. Without this careful transfer, the position would be inaccurate and unusable for both diagnosis and splint fabrication.
A striking case example from the publication shows why this is so important: A patient with severe back pain appeared “unremarkable” at first glance—only the models mounted in the articulator revealed that the lower jaw was being forced into an unfavorable position. Had treatment proceeded here without considering the joint, the entire therapy would have failed. A guiding principle puts it aptly: “Think orthopaedic first—then teeth”—first the joint and function, then the teeth.
Also Suitable for Children
The described procedure can also be applied to children and adolescents, for example when a construction bite is needed for a removable functional orthodontic appliance. Here too, simultaneous palpation of the joints provides valuable additional information.
Diagnosis and Therapy Belong Together
The relaxed, healthy jaw position is the foundation of any treatment for temporomandibular disorders. It cannot simply be “read off” but must be carefully determined and verified throughout the whole body. A conscientiously taken construction bite, combined with manual diagnostics and precise model mounting, creates the basis for an appliance that truly fits—and thus for successful, lasting treatment.
Sources
- Kubein-Meesenburg, D. (Hrsg.). (1985). Die kraniale Grenzfunktion des stomatognathen Systems des Menschen. Hanser.
- Türp, J., Schindler, H. J., Rodiger, O., Smeekens, S., & Marinello, C. P. (2006). Vertikale und horizontale Kieferrelation in der rekonstruktiven Zahnmedizin. Schweizer Monatsschrift für Zahnmedizin, 116, 403–411.
- Meyer, G. (2018). Short clinical screening procedure for initial diagnosis of temporomandibular disorders. Journal of Aligner Orthodontics, 2(2), 91–98.
- Schupp, W., & Marx, G. (2002). Manuelle Behandlung der Kiefergelenke zur Therapie der kraniomandibulären Dysfunktionen. Manuelle Medizin, 40(3), 177–183. https://doi.org/10.1007/s00337-002-0133-8
- Schupp, W., Boisserée, W., Haubrich, J., Hermens, E., Grunert, I., Rottler, A., & Meyer, U. (2015). Diagnostische Verfahren im kraniomandibulären System. Manuelle Medizin, 53(1), 47–59. https://doi.org/10.1007/s00337-014-1174-5
- Meyer, G. (Hrsg.). (1993). Die physiologische Zentrik im Rahmen der instrumentellen Okklusionsdiagnostik. Funktionslehre. Hanser.
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