Joint Vibration Analysis (JVA)

Joint Vibration Analysis (JVA)

Ray M. Becker, DDS, FAGD (International Certifying and Interpretation Instructor of the Total BioPAK System, Private Practice, USA)
DOI: 10.4018/978-1-4666-6587-3.ch006
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Abstract

This chapter describes Joint Vibration Analysis (JVA) technology that assesses pathological changes that can occur within the Temporomandibular joints. Joint Vibration Analysis (JVA) uses tissue accelerometers to objectively capture vibrations given off by structurally compromised internal TM Joint anatomy. The structural breakdown leads to altered mandibular movement patterns during chewing function. Different attributes of representative JVA vibrations have been shown to indicate the presence of various disease states often seen within the Temporomandibular Joint complex. After being recorded, the JVA software displays the various vibration waveforms for clinician analysis to determine the specific internal derangement present. This chapter provides an overview of the various vibratory waveforms that indicate TM Joint pathology and illustrates the utility of Joint Vibration Analysis as a Temporomandibular Joint diagnostic adjunct.
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Introduction

Temporomandibular Joint (TMJ) Anatomy

The Temporomandibular joint (TMJ) is a ginglymoarthroidial joint, which is also diarthroidal, in that it translates and rotates throughout function. It is comprised of the following components:

  • The posterior slope of the eminentia,

  • The mandibular condyle,

  • The articular disc

  • The synovial tissue

  • The vascular and innervated retrodiscal tissue, which includes the posterior attachment of the articular disc to both the mandible and to the temporal bone

  • The posterior attachment tissue, which is vascular and innervated

The articular disc is a biconcave fibro-cartilaginous capsule that normally rests between the head of the mandibular condyle and the articular eminence of the temporal bone. The disc is attached to the lateral and medial poles of the condyle, while also being elastically attached posteriorly to the temporal bone and the mandible. Anteriorly, the disc is attached to a few fibers of the superior belly of the lateral pterygoid muscle, which assists in translating both the disc and the condyle forward upon excursions of the mandible (Figure 1).

Figure 1.

Lateral cross-sectional view through the right Temporomandibular joint showing: A-posterior slope of eminentia with typical convex contour; B-mandibular condyle; C- biconcave articular disc fitted between a convex eminentia and a convex condylar head; D-synovial tissue; E-retrodiscal tissue including the posterior attachment of articular disc and temporal bone; F-posterior attachment tissue which is innervated and vascular; G-superior belly of lateral pterygoid muscle with fibers attaching to medial aspect of articular disc; H-inferior belly of lateral pterygoid muscle attaching to condyle. (Adapted by Breanna Becker from, Dawson, P.E. (2008). Functional Occlusion: From TMJ to Smile Design, Chapter 5; The Masticatory Musculature., C.V. Mosby, Elsevier. Used with permission.)

Through normal excursive movements of the mandible, the Temporomandibular joint is required to both rotate and translate. A healthy joint will perform this task without giving off any sounds or vibrations throughout its entire range of motion (Ishigaki, Bessette, & Maruyama, 1993).

In a healthy occlusion, during function there exists synergy with the coordination of the firing and relaxation of the opposing elevator and depressor muscles (Higashi, 1989). Masticatory muscle coordination results from the sensory input of the teeth, the muscles themselves, the Periodontal Ligaments, the tongue, and the oral soft tissues. The input from these organs creates a pattern of muscle activity, or muscle engrams, that are founded within a pool of neurons located within the brainstem, that is known as the Central Pattern Generator (CPG) (Lund, 1991; Levy, 2009). If there is any malocclusion it will reduce the coordinated firing of these muscles (Higashi, 1989). This muscle incoordination will cause vectoring of forces upon the posterior aspect of the disc (Radu, Marandici & Hottel, 2004; Wang, Sun, Yu, Liu, Jiao, Wang, Liu, & He, 2012). The degradation of the posterior aspect of the disc eventually diminishes its normal self-centering capability. This begins initially as laxity of the articular disc, which allows the disc to partially displace under function, and then possibly to fully displace, over time. When the articular disk reduces and then displaces during mandibular opening and closing movements, the disc gives off a vibration, which can be audible, and indicates there is a disruption of the normal, smooth motion of the structures within the Temporomandibular joint (Findlay and Kilpatrick, 1960).

If the displaced condition deteriorates further over time, it is likely the disc will become permanently displaced, whereby undesirable forces from the condyle will be placed upon the disc’s posterior tissue attachment. This structure is the nutrient supply for the disk and synovial tissue, which is highly vascularized and innervated. Applied pressure from the condyle typically denervates and devascularizes the tissue over time, which then either forms a connective tissue “pseudo-disk”, or the posterior attachment ultimately perforates. A perforation allows the condylar bone and temporal bone to have direct contact (Rohlin, Westesson, & Eriksson, 1985). This bone-to-bone contact will give off a distinctive vibration pattern that repeats each time the mandible opens and closes (Rohlin, Westesson & Eriksson, 1985).

Joint Vibration Analysis (JVA) is capable of detecting a variety of these internal Temporomandibular joint anomalies, by using accelerometers that accurately measure the vibrations made by the disk and condyle during repeated mandibular opening and closing (Figures 2 and 3). Its bilateral accelerometer design can detect how much of a vibration’s energy transfers from the ipsilateral to the contralateral Temporomandibular joint, which reveals to the clinician to which direction the disc is displacing (Radke & Kull, 2012).

Figure 2.

As the patient closes their mandible (A), the articular disc displaces anteriorly (B), which creates a vibration detected by Joint Vibration Analysis (C)

Figure 3.

As the patient opens their mandible (A), the displaced articular disc reduces (B), which creates a compressed high amplitude waveform indicative of Disc Displacement with Reduction (DDR), as detected by JVA (C)

A normal Temporomandibular joint does not create any sizable vibrations when operating under routine function (Mazzetto, Hotta, Carrasco, & Mazzetto, 2008). This generates a JVA trace without appreciable detected vibrations (Ishigaki, Bessette, & Maruyama, 1994). If there is dysfunction present within the TM joint, vibrations will appear within the JVA trace. These detected vibrations have been extensively studied, to determine the companion structural deformity that each vibration represents, such that over the past few decades, these studies indicate that vibration patterns have distinct diagnostic value for the health or pathology of the Temporomandibular joint structures (Huang, Lin, and Li, 2011; Ishigaki, Bessette, & Maruyama, 1993a; Ishigaki, Bessette, & Maruyama, 1993b; Olivieri, Garcia, Paiva, & Stevens, 1999; Goiato, Garcia, dos Santos, & Pesqueira, 2010; Owen, 1996; Christensen & Orloff, 1992).

Key Terms in this Chapter

Ethology: The scientific study and observation of predicting human behavior under various circumstances.

Closed-Locked Disc: A diagnostic term referring to an anteriorly displaced disc in the Temporomandibular joint, which does not reduce upon opening of the mandible.

Stomatognathic System: The interrelated and interdependent structural components of the mouth involved in speech, and in the reception, mastication, and deglutition of food including the teeth, muscles of mastication, and the Temporomandibular joints.

Heuristics: Any process or element that acts as an aid in self-discovery, or self-education to improve overall performance.

Joint Vibration Analysis (JVA): A diagnostic computerized analysis technology that records and measures the vibratory events associated with functionally compromised structures of the Temporomandibular joint.

Temporomandibular Dysfunction (TMD): TMD is a plural descriptive abbreviation, and refers to not one specific disease, but is an umbrella term that includes many complex maladies that affect the entire Stomatognathic system.

Electrognathography (EGN): The computerized, electronic 3-Dimensional tracking in real-time, of mandibular movement in the frontal, sagittal, and horizontal planes.

Standard of Care: The medico-legal term referring to the typical treatment expected to be rendered in a particular area, at a particular time.

Biometrics Model of Occlusion: The use of computerized technology to obtain data from the teeth, muscles, and Temporomandibular joints, as the primary means of diagnosing, treating, and re-evaluating a patient’s occlusion.

Accelerometers: The sensitive and standardized sensors used in the JVA headset, that records the vibratory events associated with the function of the Temporomandibular joint.

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