The use of the Myo-monitor in clinical dentistry dates from 1969, the mandibular kinesiograph from 1975, and the clinical EMG-1 from 1980. The scientific literature documenting the rationale for use of these modalities has been outlined previously in this report.
Additionally, clinical modalities that have been in use successfully for many years develop a body of anecdotal, case history, or protocol literature. Although by definition they are not controlled studies, these articles develop a rich resource for the practicing clinician. Following are some of the clinical articles published in professional journals regarding clinical experience with the Myo-monitor (low frequency TENS), mandibular tracking, and electromyography.
The American Dental Association directive “Programs of the Council on Dental Materials, instruments and Equipment” states, “Extended clinical experience when appropriate may be utilized as a basis for evaluation of the product.” Following is a partial listing of such articles as they pertain to the modalities covered by this review.
ARTICLES REVIEWED IN THIS PUBLICATION
STUDIES THAT DOCUMENT THE USE OF THE MYO-MONITOR, MANDIBULAR TRACKING AND SURFACE ELECTROMYOGRAPHY IN CLINICAL DENTISTRY.
1. Jankelson, B. Modern diagnosis and management of musculoskeletal dysfunctions of the head and neck. Diseases of the Temporomandibular Apparatus. 2nd Ed., C.V. Mosby Co., St. Louis, pp 59 1-199, 1982. See abstract page 196.
2. Jankelson, B. Neuromuscular aspects of occlusion: Effects of occlusal position on the physiology and dysfunction of the mandibular musculature. Dental Clinics of North America. Vol. 23, No. 2, April 1979. See abstract page 197.
3. Jankelson, B. Research endings and resultant management of craniomandibular (TMJ) symptom cluster syndrome. Proceedings of the Second International Prosthodontic Congress. C.V. Mosby, St. Louis, pp 291-194, 1979. See abstract page 198.
4. Jankelson, B. The Myo-monitor: Its use and abuse (I & II). Quintessence International, Vol. 9, Report 1601, No. 2, pp 1-11, 1978. See abstract page 199.
5. Jankelson, B. Three dimensional orthodontic diagnosis and treatment: A neuromuscular approach. J. of Clinical Orthodontics. Vol XVIII, No. 9, Sept. 1984. See abstract page 201.
6. Dinham, G.A. Myocentric: A clinical appraisal. The Angle Orthodontist. Vol. 54, No. 3, July 1984. See abstract page 201.
7. Callendar, J.M. Orthodontic application of the mandibular kinesiograph: Part I. J. of Clinical Orthodontics. Vol XVIII, No. 10. pp 710-718, Oct. 1984. See abstract page 204.
8. Callendar, J.M. Orthodontic application of the mandibular kinesiograph: Part II. J. of Clinical Orthodontics. Vol XVIII, No. 11. pp 791-805, Nov. 1984. See abstract page 205.
9. Dinham, R. Treatment of tic douloureux with Jankelson Myo monitor. J. Hawaii Dent. Assoc. Vol. III, No. 3, July 1970. See abstract page 206.
10. Vesanen, E. and Vesanen, R. The Jankelson Myo-monitor and its clinical use. Proc. Finn. Dent. Soc. 69:244-247, 1973. See abstract page 206.
11. Rogers, J.L. Patient?s facial pain treated by Myo-monitor and dentures. Dental Survey. Vol. 56, p. 54, May 1979. See abstract page 208.
12. Lerian, H.J. Instructive 16-year case report. Dental Survey. pp 87- 90, Sept. 1974. See abstract page 209.
13. Konzelman, J.L. Glossodynia: A case report. J. of Craniomandibular Practice. Vol. 3, No. 1, Dec. 1984-Feb. 1985, pp 82-83. See abstract page 211.
14. Karlson, R. Relief of TMJ syndrome: A typical case history. Dental Survey. p. 54, Sept. 1975. See abstract page 211.
15. Jach, E.T. Relief of myo-facial pain: Treatment of 5 patients. Dental Survey. pp 44-50, June 1975. See abstract page 212.
16. Keller, D.C. An anterior appliance for treating TMJ dysfunction. J. of Craniomandibular Practice. Vol. 3, No. 3, pp 251-266, 1985. See abstract page 212.
17. Haze, J.J. Overview of sleep disorders and the implication on dental practice. J. of Funct. Ortho. Vol. 4, No. 5, pp 15-17, 1987. See abstract page 213.
18. Hawkins, R. and Jackson, J. Mandibular physiologic neuromuscular position:, The neglected essential. J. Sleep Research. ed. Chase, McGinty, Crane; Univ. of Cal., Los Angeles, 1986. See abstract page 213.
19. Haze, J.J. Treatment of obstructive sleep apnea with the equalizer appliance. J. New Jersey Dent Assoc. pp 34-36, 1987. See abstract page 213.
20. Jach, E.T. The Jankelson Myo-monitor. Chicago Dent. Soc. DCS Review. pp 20-22, Jan. 1974. See abstract page 215.
21. Attanasio, R. A neuromuscular final impression technique for complete dentures. Comp Coutin Educ Dent. Vol. IX, No. 8, pp 641- 644, 1988. See abstract page 216.
22. Cooper, B. Myofascial pain dysfunction: A case report. J. of Craniomandibular Pract. Vol. 6, No. 4, Oct. 1988. See abstract page 217.
Jankelson, B. Modern diagnosis and management of musculoskeletal dysfunctions of the head and neck. Diseases of the Temporomandibular Apparatus. 2nd Ed., C.V. Mosby Co., St. Louis, pp 591-199, 1982.
The Myo-monitor, specifically designed to accomplish relaxation of the mandibular musculature by stimulation of the fifth and seventh nerves (Jankelson and Sparks et al, 1975; Jankelson and Swaim et al, 1975), simultaneously relaxes the various mandibular muscles to their resting lengths. The resulting physiological rest position provides the indispensable reference from which to attain a neuromuscular (myocentric) occlusal position (George and Boone, 1979; Jankelson, 1973; Jankelson, Dent Clin 1979; Jankelson, Proceed Prosth Cong-”Dentures” 1979; Jankelson, Proceed Prosth Cong- “Cluster” 1979; Jankelson and Radke 1978).
USES OF THE MYO-MONITOR
To propel the mandible from rest position through the interocclusal (freeway) space to the position of myocentric occlusion. At intervals of 1 1/2 seconds, in response to the Myo-monitor stimulus, the muscles contract and propel the mandible on a relaxed isotonic trajectory through the freeway space to the position at which occlusion would be most favorable to be perpetuation of a relaxed neuromusculature (Jankelson, 1973; Jankelson, Dent Clin 1979). Propelling the mandible from rest position to occlusion under the influence of balanced, programmed stimuli bypasses the disruptive influence of proprioception that is present in central nervous system- -directed closure and eliminates variables induced by manipulation imposed on the mandible by the practitioner. The resulting myocentric occlusal position is a result of decisions made by the relaxed musculature itself.
To relieve facial pain. Transcutaneous electrical neural stimulation (TENS) is being increasingly used in various areas of the body for relief from pain. A rationale for this procedure was suggested by the gate control theory of Meizak and Wall (Jankelson, Dent Clin 1979) and now by the data regarding the excretion of endorphins- -large polypeptide opiate molecules- – which appear in the bloodstream following electrical stimulation. The Myomonitor is being used effectively as a palliative modality and an adjunct to the overall treatment of atypical facial neuralgia, headache, earache, ticlike pain, and tic douloureux (Jankelson, Proceed Prosth Cong-”Dentures” 1979).
To record skeletal relation at various degrees of mouth opening. The Mandibular Kinesiograph (MKG) (George and Boone, 1979; Jankelson, 1973; Jankelson, Dent Clin 1979; Jankelson, Proceed Prosth Cong-”Dentures” 1979; Jankelson, Proceed Prosth Cong. “Cluster” 1979; Jankelson, “Manual” 1980; Jankelson, Prosth Dent 1980; Jankelson and Swaim et al, 1975) was developed to electronically track mandibular movement and to record the skeletal relation of the mandible to the skull in three spatial dimensions, plus the fourth dimension of time. The additional capability to track vertical velocity of the mandible during opening and closing movements (Jankelson, Prosth Dent 1980; Jankelson, Unpubi 1981; Jankelson and Radke, 1978; Jankelson and Sparks et al, 1975; Jankelson and Swaim et al, 1975) not only provides an overall assessment of the functional status of the musculature but also diagnostically records and displays the presence of joint dysfunction, which occurs as interarticular disc displacement that interferes with untrammeled muscle movement (Farrar et al, 1979).
CLUSTER SYMPTOMS OF MUSCULOSKELETAL DYSFUNCTION OF THE HEAD AND NECK
In the past decade it has become generally recognized that the syndrome is not only a dysfunction of the TMJ complex but also that a cluster of symptoms going beyond that of joint pain and dysfunction characterize the condition. In addition to TMJ involvement, other manifestations of the syndrome might include acute and chronic tension headaches, neck and shoulder stiffness, earache, eustachian tube dysfunction and ear stuffiness, tinnitus, vertigo, atypical facial neuralgia, tic douloureux and ticlike pain (Dinham, 1970).
Any of these symptoms may exist alone or in combination with any of the others. Because of the varied and often opposing concepts of diagnosis and treatment, mandibular dysfunction is commonly regarded as a disturbance with multiple causes (Laskin, 1969; Lupton, 1969; Schwartz, 1955; Schwartz, 1959; Sutcher, 1966). Now, however, modern electronic computer science has uncovered a common cause for this cluster of symptoms, establishing them as variations of response to a common underlying factor.
NATURE OF THE MUSCULOSKELETAL HEAD AND NECK SYNDROME
The data clearly identify a classifiable disease entity and establish two basic aspects of the disease:
1. There is a skeletal malrelation of the mandible to the skull, mandated by proprioceptive dictation that the muscles hold the mandible on a distorted trajectory to accomplish closure to a malpositioned occlusion. The resulting distorted position of the mandible, held by the muscles under tension now malposes the condyles in the joint space (Jankelson, Unpubl 1981).
2. Neuromuscular hyperfunction, spasm, and myostatic contracture induced by the proprioceptive dictation hold the mandible on a deflected, muscularly unbalanced trajectory to accomplish intercuspation to a three-dimensionally malpositioned occlusion.
In summary, in the syndrome of musculoskeletal dysfunctions of the head and neck: (1) the soft tissue disturbance lies primarily in the neuromusculature, ligaments, and tendons of the area, and (2) the bony, skeletal malrelationships, stemming from neuromuscular adaptation to malpositioned dental occlusion, change the relationships of the temporomandibular joints and their articular components.
The diagnosis and treatment of musculoskeletal dysfunctions of the head and neck enter a new phase with the availability of high-technology electronic instrumentation. It enables the practitioner to derive objective, electronically measured data on which to base the diagnosis and by which to monitor progress of treatment. The data shed new light on the nature of the disturbance.
The new findings establish the nature and the specificity of the craniomandibular TMJ syndrome. The skeletal malrelationships here described affect the articular components, consisting of the occlusion and the temporomandibular joints. The soft tissue disturbance lies primarily in the neuromusculature.
Jankelson, B. Neuromuscular aspects of occlusion: Effects of occlusal position on the physiology and dysfunction of the mandibular musculature. Dental Clinics of North America. Vol 23, No. 2, April 1979.
In the past the common criterion for evaluating the desirability of an occlusal position has been the mechanical repetitiveness with which the position can be registered. The concern for this criterion is understandable when one considers the problem that faces the clinician when he must decide on an occlusal position for the patient who has become edentulous on one or both arches, or who has had the crowns reduced for reconstruction, or who has an existing occlusion that is giving him problems of dysfunction and discomfort.
However, an even more important criterion for evaluating the desirability of an occlusal position is its effect on the neuromuscular apparatus.
To develop an occlusion that is compatible with relaxed neuromusculature, it is necessary to first develop modalities to relax, normalize, and control the musculature of the jaw. Transcutaneous electrical neural stimulation (TENS) is firmly established in physical medicine as a most effective, physiologically rational means of relaxing specific areas of the musculature.
The Myo-monitor (Jankelson and Radke, 1978) was designed to adapt TENS specifically to the requirements for the relaxation and control of the complex of muscles involved in mandibular function. This is accomplished by the application of mile, timespaced programmed stimuli through the fifth and seventh nerves. Extensive laboratory measurement and clinical testing established that the Myo-monitor stimuli are indeed neurally conducted and are effective in relaxing mandibular musculature that is in a state of fatigue, excitement, tension, or spasm (Jankelson and Sparks et al, 1975).
In addition, transcutaneous electrical neural stimulation has the essential ability not only to relax the musculature, but also to initiate controlled isotonic muscle contraction to propel the mandible from rest position on an isotonic trajectory through the interocclusal space to a neuromuscularly oriented occlusal position in space
Centric occlusion can be described as the existing position of intercuspation. In no case in our investigation did it coincide with centric relation. The data also established that centric occlusion may coincide with the neuromuscularly balanced position, but in a large proportion of cases, centric occlusion showed some deviation in one or more dimensions from the neuromuscular position. In those cases where centric occlusion was not compatible with neuromuscular relaxation, the degree of muscle tension was always further increased by retrusion.
The data show that centric occlusion, apparently by feedback to proprioceptors, is the dictator and controller of the posture and the skeletal relationship of the mandible to the skull. When centric occlusion does not coincide with the neuromuscular position, proprioceptive feedback from the malpositioned centric occlusion dictates and maintains strained muscle accommodation, and an accommodative trajectory of closure. The result is mandible dysfunction characteristic of craniomandibular (TMJ) syndrome.
Rest Position is the clinical reference point from which myocentric occlusion is registered. Myocentric occlusion is that terminal point in space at which, with the mandible in rest position, subsequent isotonic muscle contraction raises the mandible through the interocclusal space along the myocentric (muscle balanced) trajectory. Myocentric occlusion often coincides with centric occlusion, but in no instance was myocentric occlusion found to coincide with centric relation. The registration of myocentric occlusion can only be performed by balanced, relaxed neuromusculature. Myocentric occlusion cannot be registered in the presence of interfering clutches, protruding members, a pantograph apparatus, or manipulation or guidance by the dentist.
Centric Relaxation: Muscle strain and tension are required to achieve retrusion to centric relation. The data show that the conventional gnathologic armamentarium and procedures used to achieve a mechanical occlusion based on a retruded border position program tension into the musculature. The procedures are incompatible with maintenance of a relaxed musculature.
An existing centric occlusion that appears mechanically satisfactory when the teeth are in occlusion may be incompatible with a relaxed musculature. When such a centric occlusion was repositioned and corrected to the myocentric (neuromuscular) position, myocentric occlusion instantly became the patient?s centric occlusion.
Myocentric (Neuromuscular) Occlusion: Registration of myocentric occlusion is achieved by isotonic muscle contraction that originates from rest position. Rest position becomes the launch pad from which subsequent isotonic muscle contractions lift the mandible on a relaxed trajectory through the interocclusal space to the position of myocentric occlusion. Achievement of this physiologic goal in every day clinical practice has now become a reality with the availability of appropriate instrumentation and development of practical clinical techniques.
Jankelson, B. Research findings and resultant management of craniomandibular (TMJ) symptom cluster syndrome. Proceedings of the Second International Prosthodontic Congress. C.V. Mosby, St. Louis, pp 291- 194, 1979.
Breakthroughs in understanding, diagnosing, and treating dysfunction of various parts of human body have always had to await the development of sensitive instrumentation capable of measuring minute body responses. The development and availability of the Mandibular Kinesiograph (MKG) has now brought to the dentist the capability provided by electronic instrumentation for retrieving, recording, and measuring data reflecting mandibular dysfunction. The capability to measure mandibular dysfunction and obtain objective data is now analogous to the capability of the cardiologist to measure cardiac dysfunction with an ECG, the neurologist to measure neurologic dysfunction with the EEG, or the myologist to measure and monitor muscle dysfunction with an EMG.
The data derived from these advanced diagnostic instruments have, in every field, led to the development of treatment instruments. Examples are the cardiac pacemaker and the various stimulators for muscle relaxation and, in neurology, for pain control. Similarly, a highly specialized stimulator, the Myo-monitor, has been designed to fulfill the unique requirements for simultaneous bilateral mandibular stimulation. The instrument uses transcutaneous electrical neural stimulation (TENS) through the fifth and seventh nerves, which control the complex of muscles involved in the function of the mandible. Extensive laboratory measurement and clinical use have established that the instrument is effective in relaxing muscle that is in a state of fatigue, excitement, tension, or spasm.
In a study of 100 consecutive craniomandibular (TMJ) patients monitored on the MKG, the data showed a common dysfunctional etiology for an associated cluster of symptoms. The patients typically complained of unilateral or bilateral facial pain, clicking, or crepitus in the temporomandibular joints, tension, soreness and stiffness of the associated musculature, and restricted, deviated mouth opening. (Headache, earache, ear stuffiness, tinnitus, and stiff neck are commonly associated symptoms which are often not reported to the dentist, except under specific questioning, because they are not commonly associated in the patient?s mind as being connected to his immediate problem of mandibular dysfunction.)
In a 6-year study of over 400 people, the trace patterns on a Kinesiograph demonstrated the remarkable repetitiveness with which the mandibular muscles close the mouth to the intercuspal position of the teeth. The obvious interpretation of this consistent phenomenon is feedback from the occlusion into the craniomandibular proprioceptors and muscle spindles, with which a recent investigation showed this musculature to be richly endowed.
OCCLUSAL POSITION DICTATES THE ADAPTIVE HOLDING POSITION
One might assume that the muscles would relax to their resting position between closures. The MKG patterns, however, establish that this does not occur. Even after the muscles have been relaxed, a single closure to a malpositioned occlusion is sufficient to program the musculature to hold the jaw on or near a trajectory that is dictated by the necessities of entry into the malpositioned occlusion.
The data show conclusively that not only is the musculature unbalanced by the skeletal malrelationship (distortion) in the closed position, but also that when the mouth is open (at the adaptive holding position), the mandibular musculature remains in a programmed state of residual tension as dictated by the position of the occlusion. It is now apparent that there is a distinct physical basis in the form of muscle tension and skeletal malrelation without surcease, whether the mouth is open or closed. This accounts for what appeared to be excessive complaint, attributed to generalized, disturbed emotional states. While generalized emotional tension can be a significant contributing factor, it can also be a result of feedback to the reticular formation in the brain stem from the specific mandibular musculoskeletal disturbance. The administration of ataractic drugs for general, overall relaxation is a helpful adjunct in treatment to decrease systemic tension.
However, their effect on the mandibular musculature specifically is offset by the proprioceptive reintroduction of tension that occurs each time the patient closes the mouth to occlusion.
The basic treatment is to provide an occlusion situated on a relaxed, isotonic trajectory of closure from rest position to occlusion. The correction involved all dimensions; vertical, anteroposterior, and lateral.
Two primary factors determine the preferable mode of treatment: (1) whether, after the muscles have been relaxed, the interocclusal space exceeds 1.5 mm and (2) whether the degree of horizontal malpositioning would require excessive mutilation of the teeth by grinding.
A specific underlying etiology for the craniomandibular syndrome is now emerging. It is characterized by muscle tension, spasm, and myostatic contracture induced by noxious proprioceptive feedback from a malpositioned occlusion. The articular component of the syndrome can be explained on the basis of resultant impingement of the condyles as they are pulled, by the imbalanced musculature, against the walls of the joint cavity, where nerve receptors are located. The ability to measure and control maxillomandibular relationships is essential to accurate diagnosis and consistent, successful treatment of the syndrome.
Jankelson, B. The Myo-monitor: Its use and abuse (I & II). Quintessence International Vol. 9, Report 1601, No. 2, pp 1-11, 1978.
THE MYO-MONITOR: ITS USE AND ABUSE (I)
In recent years the dental profession has become clearly divided into two general concepts for determining the correct mandible to skull relationship at maximum intercuspation. The condylar theory, more commonly referred to as the gnathologic approach, espouses the retruded, “terminal hinge & position (centric) relation and certain manipulated border movements as the determinants of occlusion, reproducibility being the only justification. No consideration is given to the tension and stress applied to the neuromuscular elements of the stomatognathic system by this approach. The neuromuscular theory, in direct opposition, states that muscle relaxation is prerequisite to obtaining an occlusal position that will in turn sustain a relaxed musculature, and that the level of residual tension within a voluntarily inactive musculature is inversely proportional to the overall health and functional efficiency of the entire system.
New advances in science have always had to await the development and availability of appropriate instrumentation. The advance of dentistry into neuromuscular occlusion is no exception.
The Myo-monitor was originally developed as a means of applying the neuromuscular approach to occlusion. The impetuses for development were: 1. the complete lack of any evidence that function or parafunction occurs at centric relation or along border pathways, 2. a realization that the T.M.J., like any other joint, does not originate but merely accommodates movement, and 3. an acceptance of the uniqueness of a given patient and the need for a technique capable of registering that uniqueness, Thus the Myo-monitor technique is an intra-systemic approach to occlusal positioning using the patient?s own musculature and eliminating ambiguous, universal, and arbitrary criteria.
The objectives of this article are: 1. to clarify for the reader the physical characteristics of the Myo-monitor, 2. to review the various clinical diagnostic and treatment procedures that may be realized through its use, and 3. to reveal its susceptibility to abuse by persons untrained in its use.
THE NEURAL STIMULATION
The Myo – monitor is a digital, electronic pulse generator specifically optimized for bilateral transcutaneous electrical neural stimulation (TENS) of the stomatognathic system (Jankelson and Sparks et al, 1975). The mechanism through which it functions is universally known to the physiologist but has only partially captured the awareness of the dental profession (Jankelson and Swaim, 1972).
The stimuli of the present model J-3 Myo-monitor are 500 microseconds in duration and continuously variable in amplitude from 0 to 25 milliamps maximum. A balance control allows the operator to adjust the relative strengths of the stimuli to the right and left sides for a balanced response. The stimuli are biphasic with a cathodic (negative) initial stimulating phase followed by an anodic (positive) discharge phase and occur at a fixed rate of 40 pulses per minute.
The Myo-monitor has been optimized for stimulation of the motor branches of the Vth and VIIth cranial nerves, bilaterally, using surface electrodes (Choi and Mitani, 1973). While some previous authors (DeBoever and McCall, 1972; Bessett and Quinlivan, 1973) reported failure in their attempts to record E.M.G. evidence of Myo-monitor-induced masticatory muscle contractions, except in the masseter, the more advanced E.M.G. recording techniques of Fujii and Mitani (Fujii and Mitani, 1973) have shows clearly the neural mediation of the stimuli, as have subsequent intensity-duration tests (Jankelson and Sparks et al, 1975). Thus, the muscle responding to the Myo-monitor stimuli include all of the muscles of mastication and facial expression.
THE MYO-MONITOR: ITS USE AND ABUSE (II)
RELAXATION OF THE NEUROMUSCULATURE
The most crucial technical error in utilizing the Myo-monitor is attempting to register myocentric position without first adequately relaxing the musculature by pulsing just above threshold amplitude for at least 30 minutes (Myo-monitor Instruction Manuals 1971, 1974, 1977).
In studies comparing repetitiveness of the gnathological centric relation position and the myocentric position, the sequence of the registrations becomes crucial. The registration of centric relation, even briefly done, excites the musculature. The excitement induced by the retrusion to centric relation then makes it impossible to register a myocentric position. Subsequent reduction of tension and relaxation of the musculature as shown in the Mandibular Kinesiograph (MKG) recording requires 30 to 40 minutes of subsequent Myo-monitor pulsing before proceeding with myocentric registration.
The ability of the Myo-monitor to produce repetitively accurate myocentric closure depends upon first achieving a relaxed muscular state. Investigators who did not include this requirement in the stated conditions of their experiments reported they were unable to obtain consistent results.
EDUCATION IN MYO-TRONIC TECHNOLOGY
With the advent of Myo-tronics, dentistry is being introduced to a new, advanced electronic system that provides improved capability for the management of mandibular function and dysfunction. A change of such significance requires that the researcher and the practitioner become proficient with the new methodology through education and by working in the field.
Jankelson, B. Three dimensional orthodontic diagnosis and treatment: A neuromuscular approach. J. of Clinical Orthodontics. Vol XVIII, No. 9, Sept. 1984.
The use of electronically derived measurements and objective, quantitative data to diagnose the functional status of the musculoskeletal system of the head and neck is a significant step forward in the evolution of orthodontics into a major orthopedic specialty.
Musculoskeletal dysfunction of the head and neck is often the primary etiology of a diverse group of symptoms such as TMJ dysfunction, headaches, myalgia, otalgia, cervicalgia, and neuralgias. (Cooper and Rabuzzi, 1984; Jankelson, Dent Clinics 1979; Jankelson, mt Prosth Cong “Cluster” 1979; Jankelson, 1972; Principato, 1982; DeBaisi and Neironi, 1982; Dinham, 1970; Gernet et al, 1980; Vesanen and Vesanen, 1973; Weiss, 1976; Wessbert et al, 1981; Bazzoti, 1983; Choi and Mitani, 1973; Schwartz, 1955; Thompson, 1971; Carlsson, 1981; Reik and Hale, 1981; Farrar, 1979; Gelb et al, 1978; DeSteno, 1977; Laskin, 1969; Mikhail and Rosen, 1980; Burton, 1969). Before beginning treatment, the orthodontist should consider musculoskeletal dysfunction as a possible cause of one or more of these symptoms or as a presymptomatic potential for future dysfunction (Cooper and Rabuzzi, 1984; Jankelson, 1982). Today?s superior diagnostic capabilities can uncover and intercept presymptomatic musculoskeletal disease that could become acute and symptomatic under the added stress of orthodontic procedures.
Measurement for the diagnosis of existing musculoskeletal dysfunction in the orthodontic patient provides a needed additional functional diagnosis to complement the conventional use of cephalometric and TMJ x-rays. The electromyograph (EM2) and mandibular kinesiograph (MKG) respectively measure electrical activity of the muscles and the skeletal relation of the mandible to the skull. These data are essential for initial diagnosis, monitoring of treatment progress, and verification that a relaxed neuromuscular environment- – which is the goal of functional orthodontic treatment has been obtained for the finished case.
Improvement of appearance is a primary motivation for patients seeking orthodontic treatment. However, every orthodontic patient is also a neuromuscular patient. Alleviation of the head and neck pain of musculoskeletal dysfunction must become an equally strong motivation for orthodontic care, as health-care professionals and the public become increasingly aware of its effectiveness and availability.
It is essential in the diagnosis of every patient, before instituting therapy, to derive precise, quantitative data that reveal whether the skeletal relation of the mandible to the skull is distorted or not, and document the extent of musculoskeletal dysfunction of the head and neck stemming from an existing malpositioned occlusion.
Structural diagnosis based on cephalometric and other x-rays gains in significance when supported by functional data of musculoskeletal status. The increasing emphasis on the orthopedic correction of skeletal malrelation of the mandible to the skull inevitably expands the scope and changes the image of orthodontic practice. As EMG and MKG data show, the significance of the orthopedic capability of orthodontics extends beyond the jaws along to the entire musculoskeletal system of the head and neck; and, as functional considerations become paramount, the orthodontist becomes the primary orthopedic specialist in treatment of head and neck pain.
Dinham, G.A. Myocentric: A clinical appraisal. The Angle Orthodontist. Vol 54, No. 3, July 1984.
With the development of the Myo-monitor by Jankelson (1975) about ten years ago, transcutaneous electrical neural stimulation (TENS) of the motor branches of the 5th and 7th cranial nerves became clinically usable. The objective of TENS was first to decondition or relax the mandibular and facial musculature in order to establish and identify the true mandibular rest position. Then, after the musculature was deconditioned or relaxed, the continuing impulses of the Myo-monitor could stimulate the musculature to raise the mandible from rest position through the interocclusal clearance (freeway space) to its correct vertical functional position.
A Postulate may be – defined as an essential presupposition, condition, or premise. The following postulates are offered as a basis for a rationale for the concept of myocentric relationship.
1. The mandibular musculature is the dominant factor in mandibular positioning.
2. Free mandibular movements start from and return to rest position.
3. The rest position of the mandible is a resultant of a physiologic neuromuscular state which is unique for each individual.
4. The rest position of the mandible is the most reliable starting point from which to evaluate mandibular movements.
5. The true relaxed rest position of the mandible may be different from the apparent rest position.
6. The mandibular musculature must be relaxed before a true rest position can be established.
7. The mandibular musculature can be relaxed by electrical transcutaneous neural stimulation to establish a true rest position.
8. Transcutaneous electrical neural stimulation can also be used to stimulate the relaxed mandibular musculature to raise the mandible from its true resting position through the interocclusal space to the myocentric position of the mandible.
9. The myocentric position of the mandible is the optimum neuromuscular relationship of the mandible to the skull with teeth in contact.
Most orthodontic casts are related by means of a tooth-guided wax bite registration. The patient is instructed to bite into a wax wafer which is used to orient the case for trimming. The resultant static tooth-guided relationship is based on voluntary action by the patient, with or without mandibular guidance or manipulation by the orthodontist.
Such a relationship may or may not show the truly relaxed relationship of the mandible to the maxilla, depending on whether the mandible deviated from a normal path of closure to avoid tooth interferences in its closing path.
Some orthodontists feel that unmounted orthodontic casts can be inadequate or even misleading. Wood (1977) asked “What do these diagnostic tools tell us concerning the relationship of the mandible to the maxilla? Is this a true occlusal relationship? Could there be a more meaningful way to achieve the information necessary to make an accurate and functional diagnosis…?” Roth (1973) stated that “It is obvious that currently used orthodontic diagnostic armamentarium do not relate the dentition to joint movement patterns on closure or during eccentric excursions.” Graber (1961) has said “To relate cases in so-called centric occlusion is purely a static maneuver, arbitrarily selecting the terminal phase of the functional cycle because of the mechanical interlocking.” Thompson (1951) has stated “It is now realized that a proper diagnosis is impossible except in the simplest case by merely occluding upper and lower casts in the hand and looking at individual tooth relations. It is generally accepted that the occlusal position of the mandible may not be the desired functional position.”
APPRAISAL OF THE PROCEDURE
The questions to be resolved are:
1. Do you find out more about the problem? Does any added information justify the extra time and effort?
2. Does it help to decide whether to extract or not?
3. Should lateral cephalometric radiographs be taken with the mandible in the myocentric position?
1. DO YOU FIND OUT MORE?
In my opinion, using this procedure before treatment can be very valuable. Casts mounted with this procedure are at least as useful as the usual orthodontic cases, and quite possibly much more so. One can more easily see interferences, lateral and anteroposterior shifts, and vertical problems.
2. THE EXTRACTION DECISION
Functional analysis of these cases in the myocentric position before treatment could still be very valuable. If there is a possibility that single- arch extraction such as maxillary first bicuspids only, or closing spaces of missing lateral incisors, could contribute to a myocentric malocclusion, such procedures should be considered carefully.
3. CEPHALOMETRIC RADIOGRAPHS
The possibility of a diagnostic advantage in taking cephalometric radiographs with the mandible in the myocentric position was investigated in 14 cases.
MYOCENTRIC DURING TREATMENT
This procedure is valuable in checking arch correlations, closing deviation, lateral or anteroposterior displacements, dual bites, vertical discrepancies, and overall jaw relationships.
Neuromuscular registrations were also made for 33 patients after active appliance therapy had been completed. Most of these patients were still under retention, but some had been without any appliances for several years. With their casts mounted in articulators at the myocentric position, some degree of myocentric malocclusion could be detected in all of them. Some were very close to the myocentric occlusal position, and others had mild malocclusions which were apparently well tolerated with no TMJ symptoms. These could usually be equilibrated.
There were also some more severe functional malocclusions that required further treatment with splints, bite plates or retaining appliances designed for minor tooth movements. According to the neuromuscular analysis, the teeth in these cases were too far from a myocentric occlusion for effective correction with equilibration alone.
Many of those cases would be considered acceptable as orthodontic results are usually judged. However, when they were subjected to a critical neuromuscular analysis certain functional discrepancies became apparent. Some of the more common discrepancies were:
* Incisal interference causing posterior mandibular displacement
* Excessive interincisal angles, usually associated with insufficient uprighting of incisors
* Excessive anterior vertical overbite
* Insufficient vertical height and lack of vertical support in the posterior areas when the mandible was at the myocentric position
* Poor arch form correlation when the mandible was in the myocentric position
* Various combinations of the above with posterior and/or lateral mandibular displacements
Some of those myocentric malocclusions were probably too minor for identification by examination of the usual orthodontic casts or by examination of the patient. These are often tolerated by the patient. However, when significant myocentric malocclusions are found, they should be treated (orthodontically, if possible) to establish an acceptable functional neuromuscular occlusion.
Callender, J.M. Orthodontic application of the mandibular kinesiograph Part I. J. of Clinical Orthodontics. Vol XVIII, No. 10, pp 710-718, Oct. 1984.
In our office, in addition to standard orthodontic records and tomograms, we do a mandibular kinesiograph (MKG) analysis on patients who present any of the following symptoms:
* Joint noise or encumbered opening and closing of the jaws
* Pain to palpation of the joint capsule and several muscles of mastication
* Chronic ear problems
* Poor rate of opening and closing the jaws
* Diminished range of motion of the jaw (in three dimensions)
* Various crossbites or septal midline asymmetries
* Various tongue – swallow dysfunctions
* Various airway problems
* Apparent skeletal disproportions of the jaws
* Various facial asymmetries
PRETREATMENT FUNCTIONAL ANALYSIS
Pretreatment jaw function is analyzed by recording typical jaw motions on the cathoderay screen. To understand abnormal MKG tracings, it is necessary to know the appearance of normal tracings.
The greatest value of an MKG is that it gives the operator electronically magnified eyes to view the stomatognathic system in function. As the operator gains experience, he can develop hypotheses for resolving dysfunction and observe their validity “live” prior to pursuing irreversible treatment procedures.
The initial analysis of jaw function is made using these photographs together with study casts and pantographic, cephalometric, and tomographic x-rays. Hypotheses can be tested by observing the screen as the patient performs various jaw functions- -swallow, speech sounds, maximum opening and closing, stretch reflex, etc. Plans must be made to eliminate contributors to abnormal jaw function.
We often find it necessary to use a splint to negate proprioceptive influences. Psychic input .that is affecting jaw function can also be evaluated.
In my experience, very few young people have suffered pathologic alteration of the mandibular condyle, meniscus, or temporal fossa. It is common for them to have clicks and pops associated with entrapment of function of the joint parts. These alterations of joint function can be observed and measured on the MKG screen. They often can be correlated with abnormal positions of the condyle in the temporal fossa at centric or during translation of the joint as observed in tomograms. Their resolution should be planned during this analysis.
After carefully analyzing all the factors involved- -joint condition, swallow reflex, airway, occlusion, etc. – -the doctor marks a point on the screen where he wants the jaw to be positioned. A photograph of the screen is made at this point, which reflects the condition of the musculature and the quality of muscle function at the time of registration. The technician then makes the acrylic index of that jaw position, and marks on the photograph the precise point at which the patient was directed during registration.
A point 1.5mm above physiologic rest is chosen to record the bite index. This is to be the eventual myocentric. The index is used for mounting one set of casts to be used during diagnosis. We routinely index within 0.25mm of our chosen point on the screen in all three planes of space. In cases of reciprocal click, it is extremely important that the point of index be on the path of closure at more jaw opening than the point of reciprocal click. We want to be sure the meniscus is recaptured by the condyle, and not displaced. This takes precedence over initially achieving myocentric, and it must be documented in the records to avoid confusion later on.
Information for treatment planning includes the patient?s history, range of motion, and muscle palpation charts that are completed at the initial examination. All x-rays- -including tomograms of the joints- -are arranged for viewing on a large medical viewer so that they may be cross- referenced. Two sets of models are used- -one set oriented to the existing occlusion in the traditional orthodontic manner, and the other mounted on a Galetti articulator, using the MKG indices.
The notes made while observing the patient on the MKG screen and the photographs of the screen are also important, because they document the initial problems and qualify the MKG indices. The initial MKG index does not always represent the myocentric that we are trying to achieve. Although it is taken with the jaws closing on the trajectory dictated by the relaxed musculature, there are sometimes vertical interferences such as division 2 anterior tooth interference, tongue volume, airway demands, and collapsed dental arches with complicated occlusal schemes. The intention is to plan initial treatment with the best jaw position possible.
We use any procedure needed to achieve an unencumbered path of opening and closing of the jaws as demonstrated on the MKG, and we are careful that we have achieved myocentric before final treatment is planned.
Once a trustworthy MKG index is achieved, final treatment planning is undertaken to resolve the orthopedic and orthodontic problems. The concept is to treat to an MKG-defined jaw position and not to an existing centric occlusion. Incipient pathology may already be present in the joints.
Callender, J.M. Orthodontic application of the mandibular kinesiograph Part II. J. of Clinical Orthodontics. Vol XVIII, No. 11, pp 791-805, Nov. 1984.
This series of articles has introduced a concept of treating orthodontic cases in the vertical dimension to a determined rest-to-closure distance, with the occlusion set on a pathway on which the jaws are free to open and close without encumbrance and with relaxed musculature. This position is often at variance with existing dentric occlusion or with a centric relation achieved by the most distal positioning of the condyles. It is a stable post-treatment position, at which the condyles are well centered in the fossae.
This treatment does not discount current orthodontic concepts. It uses an additional diagnostic tool- -the MKG- -which allows visualization of the functioning jaws, and it cross-references this data with that of traditional orthodontic diagnostic techniques.
All the traditional orthodontic treatment modalities, along with the new concepts in functional appliances, are used to resolve functional problems. Functional appliances are fabricated to the jaw position indicated by the MKG. We have been able to create occlusions and jaw functions that are dramatically more free of pathology -producing dysfunction, and that have remained free of dysfunction for a number of years. The MKG is also used post-treatment to assure that functional goals have been achieved. Continued evaluation of completed cases demonstrates that the MKG-dictated resolution of orthodontic problems and TMJ dysfunction is efficient, stable, and economically viable.
Dinham, R. Treatment of tic douloureux with Jankelson Myo-monitor. J. Hawaii Dent. Assoc. Vol III, No. 3, July 1970.
The usefulness of the Myo-monitor in occlusal adjustment, complete prosthesis, reduction of post surgical trismus and swelling, full mouth rehabilitation, diagnosis and treatment of TMJ problems, can be readily understood. Undoubtedly there will be many clinical adaptations as yet not imagined.
Such a one is the case history presented here:
Japanese Female, Age 42 – – June 10, 1969:
Patient referred by endodontist because of limited opening and inaccessibility of upper right molar tooth for treatment.
Has had trifacial neuralgia for ten years (diagnosed by physicians) has had four alcohol injections, sinus surgery and lower third molar removed in September, 1968, empirically. Because of severe pain- -no relief- – referred to neuro-surgeon who injected alcohol in ganglion and diagnosed condition as a “tic.”
Nov. 20, 1989:
Patient came in without appointment with excruciating pain on right side. All of the symptoms of a tic, sensitive to any kind of contact, almost fainting from the pain. I used the Myo-monitor only (no adjusting of occlusion) for one hour. ( I also administered Zactirin.) After thirty minutes patient relaxed and actually fell asleep. At the end of an hour pain was completely gone- -patient was relaxed and comfortable. I continued the Myo-monitor for fifteen minutes more and Nov. 24, 1969 dismissed her.
Dec. 16, 1969:
Patient checked by telephone- -completely comfortable and free of pain.
Heretofore the usual treatment of “tic” facial neuralgia has been by painful injection of alcohol or severing the 5th nerve at the ganglion. If this were a true tic, perhaps this is the first time the Jankelson Myo-monitor has been used in its treatment. It most certainly opens a new avenue of clinical treatment of this most painful of afflictions.
Vesanen, E., and Vesanen, R. The Jankelson Myo-monitor and its clinical use. Proc. Finn. Dent. Soc. 69:244-247, 1973.
The Myo-monitor (Jankelson, 1971) is an electronic instrument designed to generate an electric current corresponding to the natural nerve stimulus that produces muscle contraction in the body. It produces controlled current pulses adjustable between zero and 30 milliamperes. Pulses of 2 milliseconds? duration are provided at intervals of 1.5 seconds. The instrument is powered by four 1.5 volt flashlight batteries. The interval between pulses allows the muscles sufficient resting time between contractions, so that they can respond indefinitely without fatigue.
Contact with the patients is established with two electrodes placed symmetrically on the skin of the face, just in front of the tragus of the ears, and with the third opponent electrode placed at the nape of the neck. Through these electrodes the instrument provides simultaneous stimulation to the facial nerve and the trunk of the fifth nerve over the opening of the mandibular notch. After it has emerged from the skull through the foramen ovale. When properly adjusted, the pulse current produces repetitive contraction of all the muscles involved in mandibular movement, and guides mandibular closure to the correct occlusal position dictated by the musculature alone. It is important to understand that the muscles do not contract singly but all act simultaneously. Jaw closure is the result of contraction of a group of muscles.
REPORT OF TWO CASES
The two cases below have been selected from among the patients treated in the writers? private practice.
PATIENT NO. 1, FEMALE, AGED 56
March 10, 1969. The patient came for full dentures. She had had severe pain in the left side of the head for several years, mainly in the maxillary sinus region and behind the ear, with some occasional flow of mucus from the upper part of the throat. She had undergone two maxillary sinus operations, etc., in connection with which the teeth on the left side (upper and lower bicuspids, molars and upper cuspid) had been extracted. No relief of pain had been achieved. The parotid gland and ear had also been examined but nothing was found.
After consultation, it was decided to prepare a full upper immediate denture and lower partial. Bicuspids and molars were extracted from the right side. Impression taking was then postponed until the Myo-monitor was available.
Sept. 26, 1969: Impressions were taken with the aid of the Myomonitor. The patient felt great relief of pain when the instrument was operating and pleaded for longer treatment. She spent an extra 1/2 hour in the Myo-monitor.
Sept. 27, 1969: The patient returned with enthusiasm: the left ear had opened with a crackle on the way home the previous day. The patient had never told that her left ear had been almost deaf for about 2 years. Centric occlusion and vertical height were recorded with the Myo-monitor, and teeth selected.
Oct. 10, 1969: The immediate full upper denture and the lower partial denture were inserted.
During the following two appointments only very minor adjustments were necessary. All symptoms had disappeared and the patient felt happy and satisfied. She was requested to visit for rebasing after 2-3 months.
Nov. 3, 1969: The patient arrived without an appointment asking for Myo-monitor treatment. Trouble in the left ear had returned. She was treated with the Myo-monitor for about 1 hr. and felt relaxed.
Nov. 4, 1969: The patient was treated with the Myo-monitor for about 1 hr.
Jan. 10, 1970: Resorption was so small that only minor rebasing was necessary At her request, the patient was again given Myo-monitor treatment.
Remarks: During the work with the Myo-monitor in Oct. 1969 one of the possible sources of the ear trouble was localized in the Eustachian tube area. Either the muscle tensor veli palatini was in spasm or the Eustachian tube was full of mucus. The patient was sent to an ear-nose-and-throat specialist for further examination. Nothing was found.
We did not hear from the patient for a long time and phoned to her in Jan. 1973. She felt happy and satisfied with the dentures, as before. Because of the ear trouble, she consulted another specialist. Careful examination revealed a small tumor, the size of a pea, at the orifice of the Eustachian tube. The benign tumor was removed.
However, this does not explain all the symptoms. Special attention should also be paid to the fact that of the muscles of the inner ear the stapedius muscle is governed by the facial nerve and the tensor tympani muscle by the trigeminal nerve. Besides, there is a close anatomic connection between the tensor veli palatini and tensor tympani muscles Myrhaug (1970) has shown conclusively that functional disturbances in the biting muscles can be transferred to the muscles of the inner ear and vice versa. The Myo-monitor could be an important instrument for further study of the subject.
The case was reported in Nov. 1969 to Dr. B. Jankelson of Seattle, Wash., USA. It was the first of its kind.
PATIENT NO. 2, FEMALE, AGED 75
Nov. 16, 1972: Temporo-mandibular joint problem. The patient explained that she had difficulty in opening her mouth. The opening between the incisors was only 21 mm, a grating sound was heard from the joint on both sides and there was deviation to the right. There was a deep natural overbite. More vertical height had been lost, possibly after recent extraction of the lower first and second molars from both sides. Almost all the teeth were crowns and bridges, except the upper right second molar, the left first and second molars, and the lower left third molar. Both upper third molars and the lower right had been extracted long ago.
After 45 mm. with the Myo-monitor the opening of the mandible was 27 mm. The occlusion was checked, and bad premature contact was recorded on the left side between the upper second and lower third molars. This was eliminated. Besides, temporary amalgam fillings were made on the acrylic crowns to raise the vertical height about 1/2 mm. The patient felt relaxed.
Nov. 19, 1972: Opening 25 mm. The deviation had been overcome. After 30 mm. in the Myo-monitor the opening was 27 mm; after 45 mm 28 mm; and after 60 mm 30 mm.
Nov. 22, 1972: Opening 29 mm. After 0 mm. in the Myo-monitor 30 mm.
Nov. 23, 1972: Opening 29 mm. After 45 mm. 30 mm. The patient stated that during the treatment she felt thirsty and produced more saliva than usual. She had been suffering from a dry mouth.
Nov. 25, 1972: Opening 30 mm; after 60 mm 30 mm. The patient felt relaxed. The opening was not getting wider, but the result obtained was satisfactory to the patient, who commented that the opening had never been wide. For maintaining the present opening a lower partial denture was planned and made.
Remarks: The trouble had started with the loss of the lower first and second molars. All the crowns were already worn down and could not maintain the vertical height. The bite collapsed and the joints were forced to move backward, which caused muscle spasm. Bad premature contact on the left side developed at the same time. The opening between the maxillary and mandibular incisors became 9 mm wider after Myo-monitor treatment. The total opening between the incisors is still only 30 mm. But, considering that the depth of the overbite is 11 mm, the total opening of the mandible is 41 mm.
The seriousness of the case from the patient?s point of view can be judged from our first consultation. She came with the x-ray diagnosis “ligaments of the styloid muscles are ossifying” and with oral information that nothing could be done.
Rogers, J.L. Patient’s facial pain treated by Myo-monitor and dentures. Dental Survey. Vol 56, p. 54, May 1979.
On the morning of April 13, 1977, a 71-year-old white woman with a diagnosis of tic douloureux presented at my office. Pain, occurring on the right side of the face about four times a day for 30 or 40 minutes, was being triggered by eating, brushing the teeth, sneezing, touching the face, or air movement. Tic, which had begun in summer 1976 and gotten progressively more frequent, longer-lasting, and severe, had become excruciating.
A gynecologist had first diagnosed tic douloureux in September 1976. The patient had then seen an internal medicine specialist, who had confirmed the diagnosis and referred her to a neurologist for facial and skull x-rays. The only treatment mentioned had been to sever the involved fifth nerve, but the neurologist advised living with the pain rather than submitting to such severe surgery.
MYO – MONITOR THERAPY
I treated the patient in my office on April 13 with the Myo-monitor for 1 hour at T=1 (threshold +1). She reported one attack that afternoon, but with lessened severity and with duration of only about 10 minutes.
The following day, April 14, at the patient?s insistence, treatment was for 2 hours at T +2. She reported no attacks that day.
Although I then requested that the patient wait for a further attack before additional treatment (to attempt to ascertain the duration of the relief that treatments were affording), she was so pleased by the pain-free day she had experienced that she requested another treatment the following day, April 15. I relented, and the patient once more received 2 hours of T +2.
There was no more pain reported until 4 days later, April 19, when the patient appeared in my office and reported that pain had “tried to start” that morning. T +2 was used for 2 hours.
Subsequently, a new upper denture and lower partial were constructed to the proper vertical dimension as determined by the Myo-monitor. As of this writing, the patient has been free of pain for over 1 year.
Lerian, H.J. Instructive 16-year case report. Dental Survey. pp 87-90, Sept. 1974.
Day after day we remain within the confines of our offices, practicing the same way we have practiced for years and convinced that our method of doing things is the best way. When we run into problems, we often solve them by trial and error. Nowhere is this approach more apparent than in the interpretation of such terms as centric relation, centric occlusion, rest position, freeway space and vertical dimension.
Within the isolation of his office each practitioner works out his own definitions and applies them in a method of treatment which appears to work most often for him. All is guesswork, and the dentist who guesses best has the fewest failures. He soon develops an innate sense of what is right and what is wrong- – an innate sense based on such intangible factors as sight, touch, intuition and experience.
Is it any wonder, then, that it is so difficult for us to accept the fact that we might be wrong? This becomes even more difficult to accept when an impersonal electronic gadget appears to know more than we do.
The case history described here presents a most unusual set of circumstances occurring over a 16-year period for a single patient. During that time she was treated for severe temporomandibular pain, underwent parotidectomy twice, suffered severe alveolar bone destruction and received complete periodontal treatment. Finally, the patient underwent full mouth reconstruction, during which it developed that she had zero tolerance for TMJ dysfunction; in order to prevent recurrent TMJ pain, perfect occlusion had to be achieved.
The wide-ranging course of diagnosis and treatment proved most instructive, and point up some lessons for all practitioners.
To reestablish her centric and vertical relationships, we used an electronic instrument (Myo-monitor) developed by Dr. Bernard Jankelson. (The underlying principle is that use of this instrument allows the dentist to take control of the muscles of mastication away from the patient in order to achieve accurate occlusal registration. Using electrodes placed on the patient?s face and a low voltage current, the dentist obtains 40 involuntary closures a minute.)
I employed the Myo-monitor again, ground away the occlusal surfaces of the temporary bridge until it was completely out of occlusion, and placed a thin mix of tooth-colored acrylic resin on the occlusal surfaces of this bridge. Rough edges were smoothed, but no attempt was made to alter the fossae or cusps that had been developed by the electronic readings.
The patient reported later in the day that all her TMJ symptoms had disappeared and she was quite comfortable.
One week later the patient returned to try on the ten-unit casting. Occlusal registration was taken electronically, the temporary bridge was replaced and the patient was dismissed.
The unit was mounted on an articulator, and processed at a laboratory. I noticed when it was returned that the upper and lower molars on the right side did not occlude completely. Years of experience and intuition had taught me that this could not be correct, so I assumed that the occlusal registration material had prevented the patient from closing completely.
I closed the occlusion a fraction of a millimeter until the molars occluded on the right side, and instructed the laboratory to complete the unit. In view of this patient?s critical TMJ tolerance, I had the laboratory process the unit in plastic in order to simplify any necessary occlusal adjustments. One week later I seated the unit but did not cement it.
The patient called the next day and her TMJ symptoms were back in full bloom once again. I was ready to scream.
The patient came to the office, and she was in true agony. I ground the plastic out of occlusion, flowed a mix of cold-cure acrylic resin over the occlusal surfaces of the bridge, and made electronic readings of her occlusion. I smoothed off the rough edges and sent the patient on her way. The next day she was completely free of pain.
Now I was beginning to believe that the machine knew something I didn?t.
The patient remained free of pain for a week, so I removed the plastic bridge, replaced it with the old temporary bridge, and sent the bridge to the laboratory to duplicate the plastic with porcelain- -and without altering the fossae and cusps developed by the machine.
A week later the bridge was inserted but not cemented. Not a single adjustment was made to the occlusion. When the patient remained completely comfortable for a week, the bridge was demented to place, in May 1972. To date, not one occlusal adjustment has been necessary.
Since this was unheard-of, I satisfied my curiosity by checking the original electronic occlusal registration on the articulator. It fit perfectly.
Because of my refusal to accept the original registration, I had put myself, my patient and my laboratory through a totally unnecessary ordeal.
We as practicing dentists must learn to accept the fact that our preconceived ideas may be wrong and that no procedure is infallible, regardless of how long we have used it.
Konzelman, J.L Glossodynia: A case report. J. of Craniomandibular Practice. Vol 3, No. 1, Dec. 1984-Feb. 1985, pp 82-83.
Diagnostic therapy consisted of one hour of transcutaneous electric neural stimulation (TENS through transcranial leads in the area of the coronoid notches, with a cervical spine ground. (Please note that most conventional TENS units cannot be used transcranially. Two units that can safely be used in this way are the Myo-monitor (Myo-tronics, Inc., Seattle, WA), when used with a cervical spine ground, and the Pain Suppressor, a high frequency TENS.) The purpose of this treatment was to relax the muscles innervated by cranial nerves V and VII, which are accessible through the coronoid notch. The patient experienced complete pain relief which lasted for about 48 hours.
She returned in one week, and I again pulsed her muscles with TENS for one hour. At this visit, she was given a flat intraoral orthotic to disengage dental intercuspation and to permit a more relaxed mandibular muscle movement. Her glossodynia has not returned.
The early difficulty in making a diagnosis in this case may have been due to the presence of two distinct entities affecting the same anatomic area, both of which are relatively common. Benign migratory glossitis occurs in 1.4 to 2.4 percent of all patients examined, according to Shafer (1974). Glossodynia secondary to referred myofascial pain has been known and treated for many years by Funt (Funt, L.A., personal communication).
The current body of knowledge on pain referred from myofascial trigger points can explain some of the poorly understood “idiopathic” pain syndromes. For that contribution we owe considerable gratitude to Dr. Janet Travell (Travell, 1983).
Karlson, K. Relief of TMJ syndrome: A typical case history. Dental Survey, p. 54, Sept 1975.
I would like to share with other readers one of many typical case histories of patients who have been referred to our office by specialists in our area.
A woman complained of severe pain on the left side of her face. For 4 years she had been unable to open her mouth completely without great discomfort. She also had been examined by a neurologist, who suggested the possibility of exploratory surgery. Prior to this she had undergone acupuncture treatment in an effort to relieve the pain, but to no avail.
Since she had most of the systems of severe TMJ syndrome, we decided to use and electronic pulsating occlusal devise (Myo-monitor) which often can relieve such symptoms in 15 to 30 minutes. One of our assistants placed the electrodes in a position mesial to the lobes and applied a minimal threshold of current for 30 minutes.
After 30 minutes of minimal pulsation, I checked the patient?s progress, and asked her to “open wide”. When she did she smiled broadly and exclaimed, “This is the first time I have been able to open my mount without pain in over 4 years.” She even asked if she could take the device home with her.
The device restores normal muscle function in much the same way that normal contractions do, except that the normal function is inhibited by muscular accommodation to pain. The series of physical and chemical events require and exposure of 15 to 30 minutes of electrical stimulation before effects can be readily seen. Increased blood flow to the muscles and the flushing effect on the renewed lymphatic activity are the first steps toward normalizing the learned response to malocclusion and real joint disorders.
Proof of the memory accuracy of the neutralized musculature is demonstrated when taking impressions of lower occlusal registration. The outline maintains its sharpness after being hit over 100 times while paste impression material is setting. …Before using such a device, of course, the operator should obtain thorough instruction in its use.
Jach, E.T. Relief of myo-facial pain: Treatment of 5 patients. Dental Survey. pp 44-50, June 1975.
One method I have found useful in determining the physiologic relationship of a denture involves the use of an electronic pulsating occlusal device that supplies an electrical impulse to the face. When electrodes are properly placed, one on each side of the face in front of the ear and on the posterior surface of the neck, branches of the fifth and seventh nerves are stimulated 40 times per minute, and the associated muscles are brought into function. This frequency produces the least fatigue in the muscles and theoretically can continue indefinitely without ill effects.
Then the instrument is properly adjusted, the mandible will rise from the relaxed open position to the top of the freeway space, in an anteriorprosterior and lateral position that is most compatible with comfortable muscle function. (Vesanen, B., and Vesanen, R, 1973)
When the muscles are healthy and there are no obstructions to muscle action, the instrument can aid in establishing a functional maxillary- mandibular relationship, since the instrument-activated muscles bring the mandible to a specific reproducible position.
The instrument has been used to relieve muscle spasm; to equilibrate both natural occlusion and restorations to achieve muscle-balanced denture impressions, (Jach E.T., 1974) to relieve tic douloureux, (Dinham, R., 1970) trismus and post-surgical swelling; and to establish occlusal relationships in orthodontic therapy. The most satisfying and challenging applications I have found have been those involving myo-facial pain.
The foregoing examples certainly are not typical and the results are not always as quick or dramatic, but they do illustrate the benefits of muscle balanced occlusion. It is a comfort to operate knowing that the muscles have dictated the position of the mandible for optimal function. But as with all instruments, the pulsating instrument is a tool which is useless unless coupled with the knowledge, experience and ability of the dentist.
Keller, D.C. An anterior maxillary appliance for treating TMJ dysfunction. The Journal of Craniomandibular Practice. Vol 3, No. 3; 1985.
The method of treatment described in this article first establishes a physiological mandibular position and then maintains this functional position throughout treatment. (This may involve conventional banded orthodontic techniques or passive eruption.) This system was specifically designed for treating patients who have TMJ dysfunction. The author presents case histories illustrating the corrections of a number of TMJ problems involving different stages of dysfunction. This system provides the practitioner with an option that can be incorporated easily into existing treatment modalities with little additional cost to the practitioner or the patient. It also offers positioning and precision that is not always available in other systems.
ADVANTAGES OF THE SYSTEM
The goal of this system is to properly position the mandible in relation to the maxilla and to approximate the dentition so that the TMJ assembly can function normally, the muscles of mastication have a normal physiologic motion, and the dentition occludes in the proper relationships with adequate lateral and protrusive protections. By establishing the desired end-f-treatment mandibular position first, the teeth can be approximated in harmony with the muscles of mastication. In TMJ dysfunction patients, this system can maintain the final splint position and allow dental approximation orthodontically or orthopedically. In orthodontic patients, the system can help reduce the chances of posttreatment TMJ problems, and it can also be used to intercept and correct potential TMJ problems.
The most important step in this technique is establishing the proper mandibular position. This can be accomplished with equipment such as a Myomonitor. A Mandibular Kinesiograph, or an Electromyograph, or with tomographs, splint therapy, kinesiology, TMJ radiographs, or other means. Once the position is established, the appliance described here will help to maintain it throughout treatment.
This article illustrates a TMJ orthodontic system that can be used to help intercept and correct potential temporomandibular joint problems. It also shows how this system is being used to treat patients with active TMJ problems. This system should not be seen as an end-all cure, but simply as one step in TMJ treatment.
I feel that this system can help to intercept many potential temporomandibular joint problems by establishing the proper end-of- treatment mandibular position and then correcting the occlusion to meet this desired position. The precision that the system offers allows the practitioner to use orthopedic and orthodontic treatments for a greater range of potential problems.
I have found no conclusive evidence that the system described here is potentially better than a combination of other orthopedic and orthodontic systems. However, this system allows a number of various treatment principles to be used simultaneously, which can help decrease the period of therapy while increasing the end-of-treatment precision. It is up to each practitioner to review the information presented in this article and draw his or her own conclusions regarding its values.
Haze, J.J. Overview of sleep disorders and the implication on dental practice. The Functional Orthodontist. Vol 4, No. 5; 1987.
The recognition of the existence of Sleep Disorders has brought about rigorous investigation by medical, dental and allied health professionals. Dental practitioners should be aware of the general signs and symptoms of Sleep Disorders, treatment approaches, relationships to dental care and available treatment for sufferers.
NON-SURGICAL TREATMENT OF OBSTRUCTIVE SLEEP APNEA WITH THE EQUALIZER APPLIANCE.
Equalizer Appliance is constructed by using neuromuscular principles for positioning the mandible. Sophisticated electronic instrumentation (EMZ Computerized Mandibular Scanner, are available from Myotronics Research, Inc.) is utilized in order to, determine the correct position along the trajectory of Isotonic closure of the mandible from physiologic rest through free-way space to fabricate the appliance. The use of this position, as determined by the Computerized Mandibular Scanner, will satisfy the need for providing the proper spatial relationship between anatomic parts by supporting the craniomandibular and pharyngeal musculature, and thus enhancing airway potency. The tongue is discouraged from posterior collapse by the increased tone of the Genioglossus muscle which is effected by mandibular positional change.
Hawkins, R., and Jackson, J. Mandibular physiology neuromuscular position: The neglected essential. Sleep Research, Vol 15; Brain Information Service/Brain Research Institute; University of California, Los Angeles; 1986.
To reestablish the physiologic neuromuscular relationship of the mandible to the cranium, nervi Vand VII (trigeminal and facial) are stimulated with low frequency electrical current. In contrast to the existing pathologic position of the mandible, a new position devoid of muscular imbalances is attained. This new position is firmly recorded with an electronically based procedure known as myoregistration. From this myoregistration, an intraoral orthotic may be fabricated to maintain this physiologic position. (Jankelson, B. 1979.)
To advantage the candidate for UPPP with this technology, the following procedure may be followed:
(1) Lateral headfilm with mandible in acquired (habitual) relationship with cranium. Measurements recorded for PAS and Hyoid space.
(2) Lateral headfilm with myoregistration in place intraorally. Measurements recorded for PAS and Hyoid space.
(3) If an augmentation of PAS occurred yielding an excess of 10 mm. of PAS and a diminution of Hyoid space occurred yielding a measurement of less than 20 mm., the candidate has a favorable prognosis.
This study utilized cephalometric roentogenograms of five person. Each person had two headfilms, one with the mandible in habitual relationship and a second with the myoregistration in place. Tracings and measurements were obtained for each roentogenogram to demonstrate the millimetric changes in the posterior air space and the hyoid space.
It was noted that as the distance increases from the mandibular symphysis to the posterior wall of the pharynx, the hyoid is elevated and the tongue is carried forward by its attachment to the superior mental spine via the genioglossus thus concomitantly increasing the posterior air space. These events are routinely observed in the electronic establishment of the mandibular physiologic neuromuscular position, the notable exception being Angle?s classification III which denotes mandibular prognathism.
Haze, J.J. Treatment of obstructive sleep apnea with the equalizer appliance. Journal of the New Jersey Dental Association. 1987.
Three types of sleep apnea are recognized with polysomnography; 1) obstructive upper airway apnea; 2) central apnea, which is secondary to a cessation of respiratory effort; 3) mixed sleep apnea, which is basically a combination of central and obstructive. Many patients show a combination of all three types of apnea; however, by far the most cases of sleep apnea are of the obstructive type.
The Equalizer Appliance is constructed at myocentric occlusion which is determined by using sophisticated Instrumentation developed by Myotronics Research Inc. These Instruments are: the myomonitor, the bioelectric processor and the computerized mandibular scanner. The myomonitor is a transcutaneous eletroneural stimulator, the bioelectric processor is a eletromyographic instrument and the computerized mandibular scanner is a three-dimensional mandibular jaw movement tracking device.
Patient selection is very important for successful treatment with the Equalizer Appliance. The following outline services as and overview of treatment planning aids and factors to consider in case selection:
TREATMENT PLANNING AIDS
A. Patient History
B. Clinical Exam
C. Diagnostic Casts
D. Radiograph: Cephalometric, full Mouth Series, Panorex, Transcanial (six views).
E. Electromyography: 8 channels (Temporalis Anterior and Posterior, Masseter, Digastrics)
F. Computerized Mandibular Scanning
G. Myocentric Bite Registration
H. Muscle Palpation and Temporo-mandibular Joint Ausculation.
I. Polysomnography Report
J. Otolaryngological Evaluation
TREATMENT PLANNING FACTORS
A. Patient?s Psycological Profile
B. Patient?s Motivation, attitude, and Ability to be Compliant
C. Periodontal support and health
D. Cranio Mandibular Functional Assessment
E. Nasal Airway Requirements
F. Skeletal Problems
G. Definitive Treatment Alternatives (Prosthetics, Orthodontics, Orthognathic Surger, etc.) must be considered.
The body of information on sleep disorders is growing rapidly. The impact of dentistry on the complete treatment of these sufferers is only of late being recognize, the future contribution by dental practitioners is being sought out due to the high success rate of treatment utilizing the Equalizer Appliance.
Jach, E.T. The Jankelson Myo-monitor. Miniclinic. ed. Venezia, A., reprinted from CDS Review, pp 20-22; 1974.
Dr. Jach has found the Myo-Monitor and its associated conceptual approach to the establishment of a physiologically balance, musculature- oriented relationship of the maxillary and mandibular arches to be a valuable ancillary to his clinical dental practice. Dr. Jach stresses that the machine is a tool whose value and employment is limited by the operator?s knowledge, talent, and interpretation.
The Jankelson Myo-Monitor is an electronic instrument that has completely changed the method of dental practice for many of us.
It is a conversion from the mechanical-anatomical concept of dental practice which has dominated for some many years to an electronic- physiological approach.
The Myo-Monitor itself is an electronic instrument which stimulated the fifth and seventh nerves and the corresponding muscles. This is accomplished through paste-on electrodes that are applied to the face and relay the electrical stimulus through the skin to the nerves.
A question always arises concerning centric occlusion and centric relation as applied to the Myo-Monitor. The relationship is strictly of historic interest since they are meaningless in this technique which records a dynamic, functional position instead of a static anatomical one. Experience has shown that this position is most comfortable for the muscles of mastication.
Dentures made using the described technique have been the best fitting and least troublesome of any technique I have used. This observation has been common among Myo-Monitor users.
Denture construction is only one of many uses for the concept of Myotronics. Techniques have been developed for full mouth reconstruction, treatment of Myofacial Pain Syndrome (T.M.J.) and occlusal equilibration. Oral Surgeons have reported using the instrument for relief of trismus and reduction of post surgical swelling; Orthodontists have told me they use the “mate Position” as the goal to work toward in their cases, and last but not least case of Tic Douloureux have been successfully treated with the MyoMonitor.
Will all of the foregoing I do not in any way want to give the impression the Myo-Monitor is an Electronic Dentist, and the only talent needed is an educated finger to flick the switch on and off. It is an instrument associated with a philosophy of Dentistry that when combined with the knowledge, training, and talent of the operator can make the practice of Dentistry more enjoyable and less troublesome for the dentist and more comfortable and more comprehensive for the patient.
Attanasio, R. A neuromuscular final impression technique for complete dentures. Compend. Contin. Educ. Dent Vol IX, No. 8.
In essence, the final impressions will be made in two phases. Phase I will be responsible for the initial refinement and muscle trimming of the acrylic custom trays by identifying areas of excessive tray pressure in the denture-bearing areas as will as by identifying the peripheral extension and thickness of the trays. Phase II will be responsible for refining the phase I impressions with a corrective wash.
A low – frequency transcutaneous electrical neural stimulation (TENS) unit, the Myomonitor, is used to muscle-trim involuntarily the impression material in the custom trays to their proper neuromuscular extension and thickness. By placing the myotrode patches over the preauricular sigmoid notch area bilaterally, it is possible to stimulate the facial and trigeminal nerves. (Choi, B., 1973; Williamson, E., 1986) In this way, all of the muscles innervated by these cranial nerves will be stimulated, including the vestibular muscles. This is clinically evident by observing these movements during the stimuli.
Before the impression making, the patient should be pulsed with the low-frequency TENS unit for approximately 15 to 20 minutes at an amplitude that produces a mandibular rise or “kick” of 0.5 mm. to 1.0 mm with each pulse ever 1.5 seconds. the amplitude that results in this mandibular rise is called the clinical threshold-old. (Jankelson, B., 1978) It has been shown that TENS will relax and not fatigue the musculature as long as the frequency is 60 impulses/mm or fewer. (Dixon, H., 1967) The efficacy of neural stimulation of the fifth and seventh cranial nerves using low frequency TENS has been documented. (Jankelson, B., 1975)
For the phase I impressions, the Myoprint is mixed in a ratio of 2.5 parts polymer to 1.0 part monomer. After attaining a smooth consistency, the material is loaded in and around the peripheries of the mandibular custom tray. The tray is inserted into the patient?s mouth and is oriented over the supportive tissues. Light pressure is then placed on the finger guides, and the TENS amplitude is increase to the clinical threshold +50% until the fingertips detect a firm “kick” caused by the mandibular movement of each impulse. For example, a clinical threshold amplitude reading of “2” on the instrument dial will require an impression amplitude of “3”.
By increasing the amplitude, the muscles in the buccal and labial vestibules as well as those in the floor of the mouth will contract with each pulse of the TENS unit, thereby custom muscle-trimming the impression material.
This article has presented a neuromuscular technique for making complete denture final impressions in which the oral tissues are reproduced with all of their muscle attachments in a position of function that would be compatible with comfort for the patient during speech, deglutition, and mastication. By using a low-frequency TENS unit to stimulate both the facial nerve and the mandibular branch of the trigeminal nerve, the clinician uses the contraction of the muscles in the vestibules, across the palate and hamular notches, and in the floor of the mouth to muscle-trim the impression and mold the flange extension and thickness. In this way, the clinician can avoid using any hand-manipulative border-molding methods that would not be representative of a true neuromuscular condition.
“Overtugging” may result in an underextended flange. Also, low-frequency TENS allows the practitioner to muscle trim areas such as the posterior palatal border, the hamular notches, and the buccal fold aspect of the tuberosities since the muscles involved are innervated by the motor branch of the trigeminal nerve.
Cooper, B. Myofascial pain dysfunction: A case report. J. of Craniomandibular Pract Vol 6, No. 4, Oct. 1988.
This article follows the case of a 16-year-old female in whom myofascial pain dysfunction was precipitated by the physical trauma of a bicycle accident, ultimately resulting in a maximum interincisal opening of 8 mm. The practitioner?s therapeutic goal was to fully relax the musculature and reposition the mandible with an anatomically accurate orthotic to maintain optimal muscle function without accommodative function.
In this case, my patient was a 16-year-old girl pre-disposed to MPD. She had been referred by her pediatrician and otolaryngologist after a bicycle accident precipitated myofascial pain dysfunction. Nine months prior to my examination, the patient had fallen off a bicycle, head first over the handlebars, hitting the left side of her face. She experienced pain in the left side of her face and ear, and several physicians and dentists examined her in the ensuing months0. Treatments included endodontic therapy for a left mandibular molar thought to be the cause of her pain, and eventually extraction of the tooth was followed by extraction of two maxillary molars on the same side.
Electromyography was done on the anterior temporalis, masseter, and diagastric muscles. Results showed moderate above-normal resting levels and poor clenching ability. Pretreatment data show weak functioning levels in both temporalis muscles and no output (Below the instrument?s 16 uV threshold) from the masseters. An electronic three dimensional study of jaw movement was performed on a Mandibular Kinesiograph (MKG). The patient?s velocity before treatment was 25mm/second on opening and closing (normally >250 mm/second) and she opened 8 mm maximum. On the same day, I used transcutaneous electrical neural stimulation for 10 hours to relax her facial muscles. Afterwards, I inserted an orthotic appliance over her lower teeth to maintain temporarily the improved muscle function achieved by TENS and to allow her to function in a neuromuscular occlusion. Maximum opening at that time was 11 mm. In the weeks that followed, the pediatrician treated the patient?s drug dependency while I repeated the TENS therapy and used the orthotic to reduce muscle spasm and pain. ACT scan of the TMJ revealed no evidence of destructive process in the TM joints, demonstrated well-aerated paranasal sinuses, and showed intact middle – ear structures.
During the next five months, I monitored her muscle function and the accuracy of the neuromuscular orthotic electronically. A series of orthotics was made during this period as increasing muscle relaxation permitted greater accuracy in the occlusal position being established. My therapeutic goal was to fully relax the musculature and reposition the mandible with an anatomically accurate orthotic in the neuromuscular occlusal position to maintain optimum muscle function without accommodative function. TENS was used extensively throughout this period.
Major improvement was achieved by the end of the second month, demonstrated by pain reduction and a maximum interincisal opening of 24 mm……
When I examined her at the end of that two weeks, I measured her maximum interincisal opening at 40 mm. Mandibular Kinesiograph testing recorded maximum velocities of mandibular movement in opening and closing of >300 mm/second and documented a healthy maximum opening, as observed clinically. Her occlusal position, established by the orthotic appliance, was on neuromuscular trajectory, with 1 mm vertical freeway space from rest to occlusion, verified by MKG analysis. EMG recorded healthy resting levels for the muscles tested and excellent compressive force on voluntary clenching with the orthotic appliance in place. The patient appeared to be in excellent health. She reported that painful symptoms were gone except for slight discomfort still felt around the left angle of the mandible, which subsequently disappeared.
In order to establish a healthy long-term occlusion, we performed a passive eruption procedure, uncovering the most posterior tooth on each side of the mouth by cutting away the orthotic?s acrylic so that the neuromuscular occlusal position would be maintained by the remainder of the orthotic. When her exposed teeth had erupted into the neuromuscular position, we sequentially uncovered the next ones, bilaterally. This procedure can take two or more years, depending on eruption speed. Orthotic appliances are replaced as they lose essential occlusal accuracy following attrition. Eventually, all the teeth occluded neuromuscularly, eliminated the potential for MPD to recur. The patient has been symptom-free for three years following therapy.
All dental universities in Japan and most medical/dental universities in Italy have pioneered the use of biomedical instrumentation for clinical and research purposes. This instrumentation is used in many other countries abroad in universities as well as in private clinics. Foreign researchers publish a substantial number of articles annually concerning biomedical instrumentation for occlusal evaluation, aids in TMD/MSD diagnosis and treatment, and other research. Many of these articles are published in English in U.S. or international journals and, if so, will be found elsewhere in this collection. The following bibliography is just a sample of some of the articles published in foreign languages.
Arizumi, K., Yamauchi, M., and Kawano, J. Masticatory muscle activity and jaw movement before and after treatment of temporomandibular joint-pain dysfunction – patient with reciprocal clicking and using anterior repositioning splint. The First Department of Prosthodontics, Asahi University, School of Dentistry.
Boschiero, R., Fraccari, F., and Pagnacco, O. Sindrome algico-disfunzionale dell?articolazione temporo-mandibolare. Estratto da Minerva Stomatologica, Vol. 35, No. 4, pp 339-356, April 1986.
Boschiero, R., Fraccari, F., and Pagnacco, O. Analisi dei resultati dell?uso del Myo-monitor in pazienti con ridotta apertura del cavo orale. Estratto da Minerva Stomatologica, Vol. 35, No. , pp 857-864, Sept. 1986.
Castroflorio, T., Talpone, F., Deregibus, A., Piancino, M.G., and Bracco, P. Effects of a functional appliance on masticatory muscles of young adults suffering from muscle-related temporomandibular disorders. J Oral Rehabil. Jun 2004. 31(6):524-9.
Choi, B. On the mandibular position regulated by Myo-monitor stimulation. J. Japanese Prosthetic Dentistry, Vol. 17, pp 73-96, 1973.
Coronelli, E., and Lasagna, M. L?elettromiografia nella pratica odontoiatrica. Suo rulo nella diagnosi e nella terapia. Estratto da Odontostomatobogia & Implantoprotesi, Feb. 1986.
Eble, O.S., Jonas, I.E., and Kappert, H.F. Transcutaneous electrical nerve stimulation (TENS): its short-term and long-term effects on the masticatory muscles. J. Orofac Orthop. Vol. 61. No. 2, 2000
De Biase, S., Neroni, P., and Sesenna, E. Valutazioni kinesiografiche dopo correzione chirurgica di un morso incrociato laterale. Mi Stom., Vol. 35, pp 181-190, 1986.
Fraccari, F., Bogini, A., and Bertele, G.P. Vabutazione dell?equilibrio muscolare pre e post-chirurgico in soggetti affetti da microgenia. Estrattro da Minerva Stomatologica, Vol. 35, No. 3, pp 147-157, March 1986.
Fraccari, F., Mariotto, R., and Bogini, A. Riabilitazaione protesica mediante Guida neuro-muscolare di un raro caso di sindrome di christ-simmens-weech. Estratto da Dental Cadmos, pp 71-77, May 1986.
Fraccari, F., Bogini, A., and Tsamis, J. Bruxismo: riabilitazione e controlbo in base a principi neuro-muscolari. Estratto da Minerva Stomatologica, Vol. 37, No. 4, pp 247-254, April 1988.
Izotani, Y. The clinical significance of the mandibular position regulated by myopulses. J. Japanese Prosthetic Dentistry, Vol. 24, No. 3, 1980.
Kawazoe, T. Effect of Myo-monitor pulsing on jaw opening in patients with trismus. J. Gifu Dent. Assoc., Vol. 15, No. 1, pp 159-169, 1983.
Lasagna, M., and Orland, C. Modificazione dci flussi ematici muscoro-cutanei indotta dalla stimolazione neurale transcutanea-ischemia e dolore della patologia occlusale. Estratto da Odontostomatologia e Implantoprotesi, Jan. 1986.
Losert-Bruggner, B., Dudek, B., and Hülse, M. Wenn Schmerzen nicht schlafen lassen (Articles in German) Teil 1. AZN Jan 2007: 20-25 und Teil 2. AZN Feb 2007: 16-19
Losert-Bruggner, B., Schöttl, R., and Zawadzki, W. Neuromuskulär ausgerichtete Bisslagebestimmung mit Hilfe niedrigfrequenter TENS-Therapie. “Determining the neuromuscular mandibular position by use of low frequency TENS.” (Article in German) GZM – Praxis und Wissenschaft 8. Jg. 1/2003.
Minagi, S., Matsunaga, T., Shibata, T., and Sato, T. An appliance for management of TMJ pain as a complication of Parkinson’s Disease. Jnl of Craniomandibular Practice, January 1998, Vol 16. No.1
Onizaka, K., Ochiai, S., and Kajiyama. The use of Myo-monitor in treating the temporomandibular joint syndrome. J. Kyushi Dental Assoc., pp 55-64, 1984.
Pantaleo, T., Prayer-Galletti, F., Pini Prato, G., and Prayer-Galletti, S. Effects of transcutaneous electrical nerve stimulation and of acrylic splints on jaw muscles activity in patients with myo-facial pain dysfunction syndrome: an electromyographic study. Instituto di Fisiologia, University of Florence, 1986.
Preston, J.D., Blatterfein, L., Smith, F. Glossary of Prosthodontic Terms, Fifth Edition. J. Prosth Dent, 1987, p. 15
Prinz, J.F. Characterization of sounds emanating from the human temporomandibular joints. Arch Oral Biol, Jul 1996 41(7):631-9
Sasaki, H., Suzuki, K., and Doi, Y. The longitudinal inspection of cases finished by neuromuscular prosthetic treatment. Sapporo City.
Tollaro, I., Bergamini, M., Antonini, A., and Vichi, M. La valutazione kinesiografica nella diagnosi ortognatodontica. Estratto da Mondo Ortodontico, May 1984.
Torigoe, N., Yasahira, K., Yamani, T., and Yamashita, A. Analysis of the mandibular movement, Part 3, Normal opening-closing and maximum opening-closing after myopulsing. J. Okayama Dent. Assoc., Vol. 3, No. 1, pp 51-57, 1984.
Yamani, T., Yamashita, A., et al. Analysis of the mandibular movement, Part 4, Mandibular rest position and latercuspal position after myo-pulsing. J. Okayama Dental Assoc., Vol. 3, No. 1, pp 89-95, 1984.
Yainashita, A.., et al. An analysis of the mandibular movement at the incision inferious of toothed adults without complaint of temporomandibular joint dysfunction syndromes. J. Okayama Dent. Assoc., Vol. 1, No. 1, pp 25-31, 1982.
Yamashita, A., et al. Analysis of the mandibular movement, Part 2, Mandibular rest position and intercuspal position. J. of Okayama Dent. Assoc., Vol. 2, No. 1, pp 57-66, 1983.
Unknown. The Glossary of Prosthodontic Terms, Sixth EditionJ Prosth Dent, 1994 Jan, p.59