Joint Vibration Analysis in Routine Restorative Dentistry

[Anonymous]

Fortunately, we currently are in a new place of discussion regarding the diagnosis and possible therapies for occlusal, masticatory, and temporomandibular care. With an objective test for TMJ condition, better treatment plans can be devised for occlusal disease.
      This new place where we are is directly related to the development and usage of biometric technology that gives the doctor objective data from which to make decisions and measured documented treatment results.
     The past attempts to record and/or measure the condylar position and condition included axiopath recordings of joint position and border movements, transcranial and tomographic radiography with objective and subjective interpretation, comparison of condylar position on articulators with multiple jaw position “bite” recordings, magnetic resonance imaging (MRI) and functional MRI scans, computed tomography (CT) and cone beam CT scans, contrast arthrography, computerized mandibular positions based on transcutaneous electrical nerve stimulation pulsed muscle contractions irrespective of the condylar position, face-bow mounted casts on various articulators referenced to numerous closure paths from speech to swallowing, from controlled manipulation to deprogrammed patient closure. At best, these methods were expensive and time consuming; and at worst, these techniques were dependent on the clinician’s experience and subjective analysis.
     The current biometric standard with the Joint Vibration Analysis (JVA), a system of equipment and software manufactured by BioRESEARCH (bioresearchinc.com), allows the dentist to easily and objectively measure the condition of the condyles quickly, affordably, and irrespective of treatment “philosophy.” The mandate from the ADA, as stated in 1990 and 1992, calls upon the dentist “to document, assess, note, describe, evaluate, and record the presence, location, loudness, timing, consistency, and quality” of joint vibrations. This mandate then encourages us to consider biometrics that will accomplish this effectively and affordably with high levels of sensitivity and specificity. The JVA system achieves this standard and creates a 21st-century documentation of objective information that will afford the treating dentist the ability to diagnose the patient’s condition and monitor the patient throughout preventive or therapeutic care. By establishing objective measurements of the condylar condition, the dentist can evaluate the effect of future events such as injury, accident, or therapy. The doctor can also begin to correlate the condylar condition with other data, such as bite force analysis (with T-Scan) and/or electromyography (BioPAK [BioRESEARCH]) measurements of the muscles of mastication. In addition this JVA system can be overlaid on data regarding mastication analysis (BioPAK), range of motion, and mandibular position. CASE REPORT
A patient presented to our office with severe occlusal-related disease. Examination revealed abfractions, anterior wear into the dentin, and periodontal attachment loss. The patient desired a long-term restorative solution that would include aesthetic enhancement of the smile (Figure 1).
     The case was designed with a mock-up of the anterior smile zone, followed by a determination that the envelope of function would be well controlled without having to restore the vertical dimension. The development of the anterior envelope of function was accomplished by first deprogramming the avoidance pattern muscle engrams with an anterior contact (only) appliance. In the deprogrammed patient, the mandibular position is determined by an anterior contact composite ball bite (open-bite centric). This open-bite registration is then tested with the JVA and compared to the preoperative JVA. By testing the stability of the TMJs at the time of bite registration, we can be confident that our diagnostic wax-up will be designed not only to the desired aesthetic result, but also that the provisionals and final restoration will be accomplished with the condyles in a more smooth and stable position (Figures 2 and 3).
The patient’s preoperative casts and mock-up casts were mounted, and cross mounted, at the most stable condylar position allowing for the desired smile design and functional anterior zone. This mounting with the apex of force centric open-bite registration can then be studied on the articulator for a comparison of the condylar position with the condylar position that is associated with the preoperative MIP interdigitation (Figure 4).
     Commonly, the cases that have avoidance-related anterior wear and muscle engrams also show a condylar position discrepancy between the MIP condylar position and the stabilized mandibular restorative position. These small dislocations of the condyle in the MIP are frequently associated with disc movement and subtle changes in the morphology of the posterior band of the meniscus. This increases the frequency of inflammation in the joint and the likelihood that the patient will suffer a partial- or full-disc displacement, along with the associated popping and possible retrodiscal impingement and pain (Figures 5a and 5b).
     The condyle position discrepancy between stable/normal and the MIP dislocation can be in almost any direction and position. The clinical manifestation of this discrepancy is usually referred to as a “slide,” or as a “closure” interference. Rarely does this dental “slide” actually show up as the condyle being on the disc and downward and forward on the eminence. Rather, the abnormal MIP condyle is pulled downward and away from the disc and eminence, thus destabilizing the disc and allowing for the disc movement that is observed on the JVA.