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Temporomandibular joint dysfunction in infancy
International Journal of Pediatric Otorhinolao'ngologv, 12 (1986) 99-104 Elsevier
99
POR 00397
Temporomandibular joint dysfunction in infancy Daniel J. Franklin 1 Richard J.H. Smith l, Francis I. Catlin l, John F. Helfrick 2 and James H. Foster 2 t Department of Otola~.ngologv and Communicatioe Sciences, Bavlor College of Medicine, Houston, TX 77030 (U.S.A.), and 2 Department of Oral Surge~. Unit,ersity of Texas Dental School Houston, TX (U.S.A.) (Received 23 April 1986) (Revised version received 6 August 1986) (Accepted 8 August 1986)
Key words: Temporomandibular joint dysfunction; Occlusal disharmony; Articular disorder; Blastema
Summary Temporomandibular joint (TMJ) dysfunction describes a pain-dysfunction phenomenon that usually afflicts persons in their 4th or 5th decade. The syndrome can be produced by a variety of etiologic factors including occlusal disharmony, articular disorders, and muscle imbalance. It may cause severe otalgia and refer pain to the temple, occiput, nape of neck, and shoulders. Often, associated joint clicking or popping, aural fullness, vertigo, tinnitus, subjective hypoacusis, and nausea occur. As it has not been previously reported in infants, we would like to describe our experience with this disorder in an ll-month-old boy who was referred to our clinic with a presumed diagnosis of otitis media. The embryology of the temporomandibular joint is reviewed and appropriate treatment with anti-inflammatory analgesics, warm compresses, orthodontics, and external brace appliances is discussed. Because of referral patterns in the infant age group, the pediatric otolaryngologist should be similar with this entity and its presentation in children.
Introduction
Over the past decade, there has been an active interest in temporo mandibular joint (TMJ) disorders. Dental practitioners are inundated with pamphlets describing TMJ continuing education programs and 3 professional societies focus primarily on Correspondence: R.J.H. Smith, Department of Otolaryngology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, U.S.A.
100 the clinical aspects of TMJ dysfunction. To cater to this interest, a journal was established in 1984 devoted exclusively to the management of TMJ problems [13]. And yet, paradoxically, TMJ dysfunction is an illness without clearly definable features. It is a potpourri of disorders affecting various aspects of the masticatory system. Problems range from uncommon severe internal joint derangements to extremely common minor muscle aches and pains. A multitude of symptoms and signs occur, some so vague and commonplace as to make TMJ dysfunction an epidemic in the adolescent and adult populations. It remains, however, extremely rare in children and has not been previously reported in infants. We would therefore like to describe a case of TMJ dysfunction affecting an l l - m o n t h - o l d boy. It is incumbent on the pediatric otolaryngologist to be familiar with this problem as it pertains to infants because typical referral patterns do not generally call for dental or oral surgery consultation in this age group.
Case Report An ll-month-old boy was referred to Texas Children's Hospital Otolaryngology Clinic with a history of recurrent severe bilateral otalgia of one month's duration. The child was noted by his mother to suddenly cry out in excrutiating pain and pull his ears for 5-30 rain 3 - 6 times per day. Several episodes would awaken the child each night. Feeding was impaired and the mother said that bilateral TMJ clicking occurred while her son was breast-fed. There was no history of trauma, infection, arthritis, connective tissue disease, or congenital anomalies.
Fig. 1. External appliance worn by patient.
101 Prior to referral, the child received two courses of antibiotic drops for presumed bilateral otitis externa; however, when we examined him, both external canals and tympanic membranes were normal. Pertinent physical findings were restricted to the TMJs and masticatory muscles. The TMJs would repeatedly sublux and produce pain and associated muscle spasm and, on palpation, tenderness was present over the lateral ptyergoid and temporalis muscles. Plain films were unremarkable and initial therapy was therefore limited to NSAID and local heat. Failure to respond to this treatment prompted us to consult the Oral Surgery Department. An external fixation device was fashioned and the discomfort and symptoms resolved over a 6-week period. One year later, the symptoms had not recurred. (Fig. 1).
Embwolo~ A review of the embryology is apposite to illustrate the complex interrelationship of the TMJ to the ear and masticatory muscles. The development of the TMJ and its relationship to these structures have been the subject of much controversy [10]. The major points in this controversy center on establishing which structures are involved in joint formation and their relative degrees of contribution. While it is generally accepted that the TMJ develops from two blastemas, influence of the masticatory muscles on this development is uncertain. Both blastemas arise after the development of the muscles of mastication: the condylar blastema, lateral to the lateral pterygoid; and the temporal blastema, between the temporalis and masseter muscles. The condylar blastema, which appears first, is connected to Meckle's cartilage by a sheet of condensed mesenchymal cells. These cell undergo further differentiation and form fibers superior to the condylar blastema which connect the lateral pterygoid muscle to the malleus. This connection may function in initiating the histodifferentiation of the TMJ and thus may play a pivotal role in joint development. Movement in the joint region is also necessary for development and cavitation. In the absence of muscular activity, it has been observed that the joint will fail to cavitate. In the normal situation, cavitation in the inferior compartment occurs first, followed by cavitation in the superior compartment. This order reflects the order of periosteal differentiation in the condyle and the mesenchymal head inferior to the temporal bone. In both compartments, cavitation seems to be initiated by mechanical factors that arise because of the ligamentous attachment of the lateral pterygoid muscle to the malleus. This attachment is also ultimately responsible for formation of the joint disk. In this complex and asynchronous fashion, by the 4th fetal month, all articular elements of the joint are well differentiated.
Discussion
Temporomandibular joint dysfunction is a complex symptom that can be caused by a number of different disease processes. It is usually defined by the identification
102 of one or more of the following signs or symptoms: (1) limited mandibular movement, (2) masticatory muscle pain, (3) TMJ pain, (4) TMJ clicking or crepitus, (5) pain on mastication and (6) deviation on opening. Headaches and TMJ problems also seem to be related according to the work of Magnussen and Carlsson [6,7] and Reik and Hale [12]. Epidemiological surveys are difficult to interpret because different combinations of the preceding signs or symptoms have been used to diagnose TMJ dysfunction. Using such liberal criteria, 28-86% of the general population have, or have had, TMJ problems. Agerberg and Carlsson's [1] cross-sectional questionnaire of every 35th person in Umea, Sweden, indicated that about 50% of all 15-44 year olds had at least one symptom of dysfunction. In the edentulous population, Heloe and Heloe [4] found that 25% of 65-79 year olds have some clinical signs of a TMJ disorder. However, when compared to the general medical health in this population, the TMJ problems pale in significance. Greene and Laskin [3] and Mejersjo and Carlsson [8] have presented data to suggest that despite this "epidemic" of TMJ disorders, most are transient, selflimited, and often without long-term side effects. Although there are only a few longitudinal studies, it appears that bothersome symptoms eventually disappear and, thereafter, although a little joint noise is not uncommon, there is little if any pain or functional disability [11]. These facts, in turn, make it very difficult to provide precise estimates of treatment needs. Osterberg and Carlsson [9] reported that in only 4% of 384 70-year-olds was chewing ability impaired. And yet, 86% had signs or symptoms of TMJ dysfunction. In a similar study done by Solberg et al. [14], although 76% of 739 university students had TMJ dysfunction, less than 5% were candidates for some form of treatment. It appears, therefore, that in spite of the high prevalence of signs or symptoms which may reflect TMJ problems, only a small percentage of the population will seek, or require, medical care. Studies of TMJ dysfunction in children are less numerous but also suggest that while the problem is quite common, the need for treatment is not. Belfer and Kaban [2] studied 40 children ranging in age from 10 to 16 years and found two distinct groups: one with severe organic joint disease; and another with myofacial pain associated with TMJ crepitus and restricted joint motion. The latter group was much larger and included 14 children suffering from acute reactive depression leading the authors to suggest that TMJ dysfunction is a somatic depressive equivalent in children. Katzberg et al. [5] studied 31 patients ranging from 8 to 16 years in age and demonstrated internal joint derangements in 29 and degenerative arthritis in 13. In 12, TMJ dysfunction could be traced to a jaw injury, and in 7, to bruxism. A predisposing cause could not be established in the remaining 12. Diagnostic studies were not initiated, on average, until nearly two years after pain and dysfunction first developed, suggesting that doctors do not frequently consider TMJ disorders to be a problem in children (Fig. 2). Recognition of TMJ dysfunction in infancy is lacking. The remitting and variable course of TMJ dysfunction, coupled with the abundance of true ear pathology in
103
r ''~' "3?' ~..
41t Fig. 2. Bone scan showing increased uptake in the area of the right TMJ. Patient suffered minor trauma to the jaw 6 months earlier.
this age group may account for this. The syndrome is frequently referred to our dental and oral surgery colleges but referral patterns and patient needs generally do not call for dental or oral surgery consultation in infants. The pediatric otolaryngologist, however, frequently examines children with persistent otalgia unresponsive to topical and systemic therapy. Recognition of TMJ dysfunction is suggested for consideration in those children who present with otalgia for which otologic evaluation is negative. Any therapeutic intervention must reflect the fact that development of the TMJ and masticatory apparatus progresses until age 16 in females and 18 in males. Surgical intervention may involve injection of sclerosing agents into the joint space, excision of the lateral pterygoid mandibular attachments to prevent the gliding function of the joint, Mersilene sling supports from the arch to the condylar neck, and down grafting or excision of the articular eminence. Because all have irreversible effects on joint junction and growth, conservative treatment in children is the rule. Local heat and anti-inflammatory analgesics may be all that is required but if dysfunction persists, external brace appliances can be fashioned. The one used in this case was made from acrylic and attached by elastics to a leather cap. This form of conservative external fixation is simple to fashion and easily accepted by parent and child. It is preferrable to surgery during the development of the masticatory system.
Conclusion
TMJ dysfunction represents a pain-dysfunction phenomenon which is infrequently diagnosed in the pediatric population despite its widespread recognition in
104
adults. Consideration of this disorder is suggested in an otherwise healthy infant complaining of persistent otalgia. If the otologic examination is normal, multiple courses of antibiotics can be avoided and proper therapy can be instituted. Initial treatment is of necessity conservative and, as the mandible and masticatory muscles continue to develop, dysfunction may resolve. More agressive treatment should be planned only with oral surgery consultation.
References 1 Agerberg, G. and Carlsson, G.E., Functional disorders of the masticatory system. Distribution of symptoms according to age and sex as judged from investigation by questionnaire, Acta Odontol. Scand., 30 (1972) 597. 2 Belfer, M.L. and Kaban, L.B., Temporomandibular joint dysfunction with facial pain in children, Pediatrics, 69 (1982) 564-567. 3 Greene, C.S. and Laskin, D.M., Long term evaluation of treatment for myofascial jaw-dysfunction syndrome: a comparative analysis, JADA, 107 (1983) 235-238. 4 Heloe, B. and Heloe, L.A., The occurrence of TMJ-disorders in an elderly population as evaluated by recording of "subjective" and "objective" symptoms, Acta Odontol. Scand., 36 (1978) 3-9. 5 Katzberg, R.W. Tallerts, R.H., Hayakawa, K., Miller, T.L., Goske, M.J. and Wood, B.P., Internal derangements of the temporomandibular joint: finding in the pediatric age group, Radiology, 154 (1985) 125-127. 6 Magnusson, T. and Carlsson, G.E., Comparison between two groups of patients in respect to headache and mandibular dysfunction, Swed. Dent. J., 2 (1978) 85-92. 7 Magnusson, T. and Carlsson, G.E., Recurrent headache in relation to temporomandibular joint jaw-dysfunction, Acta Odontol. Scand., 36 (1978) 333-338. 8 Mejersjo, C. and Carlsson, G.E., Long term results of treatment for temporomandibular jaw-dysfunction, J. Prosthet. Dent., 49 (1983) 809-815. 90sterberg, T. and Carlsson, G.E., Symptoms and signs of mandibular dysfunction in 70-year-old men and women in Gothenburg, Sweden, Comm. Dent. Oral Epidermiol., 7 (1979) 315-321. 10 Perry, H.T., Yinghua, X. and Forbes, D.P., The embryology of the temporomandibular joint, J. Craniomandib. Pract., 3 (1985) 126-132. 11 Rasmussen, O.C., Description of population and progress of symptoms in a longitudinal study of temporomandibular arthropathy, Scand. J. Dent. Res., 89 (1981) 196-203. 12 Reik, L. Jr. and Hale, M., The temporomandibular joint jaw-dysfunction syndrome: a frequent cause of headache, Headache, 21 (1981) 151-156. 13 Pugh, J.D. and Solberg, W.K., Oral health status in the United States: temporomandibular disorders, J. Dent. Educ., 49 (1985) 398-405. 14 Solberg, W.K., Woo, M.W. and Houston, J.B., Prevalence of mandibular dysfunction in young adults, JADA, 98 (1979) 25-34.
99
POR 00397
Temporomandibular joint dysfunction in infancy Daniel J. Franklin 1 Richard J.H. Smith l, Francis I. Catlin l, John F. Helfrick 2 and James H. Foster 2 t Department of Otola~.ngologv and Communicatioe Sciences, Bavlor College of Medicine, Houston, TX 77030 (U.S.A.), and 2 Department of Oral Surge~. Unit,ersity of Texas Dental School Houston, TX (U.S.A.) (Received 23 April 1986) (Revised version received 6 August 1986) (Accepted 8 August 1986)
Key words: Temporomandibular joint dysfunction; Occlusal disharmony; Articular disorder; Blastema
Summary Temporomandibular joint (TMJ) dysfunction describes a pain-dysfunction phenomenon that usually afflicts persons in their 4th or 5th decade. The syndrome can be produced by a variety of etiologic factors including occlusal disharmony, articular disorders, and muscle imbalance. It may cause severe otalgia and refer pain to the temple, occiput, nape of neck, and shoulders. Often, associated joint clicking or popping, aural fullness, vertigo, tinnitus, subjective hypoacusis, and nausea occur. As it has not been previously reported in infants, we would like to describe our experience with this disorder in an ll-month-old boy who was referred to our clinic with a presumed diagnosis of otitis media. The embryology of the temporomandibular joint is reviewed and appropriate treatment with anti-inflammatory analgesics, warm compresses, orthodontics, and external brace appliances is discussed. Because of referral patterns in the infant age group, the pediatric otolaryngologist should be similar with this entity and its presentation in children.
Introduction
Over the past decade, there has been an active interest in temporo mandibular joint (TMJ) disorders. Dental practitioners are inundated with pamphlets describing TMJ continuing education programs and 3 professional societies focus primarily on Correspondence: R.J.H. Smith, Department of Otolaryngology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, U.S.A.
100 the clinical aspects of TMJ dysfunction. To cater to this interest, a journal was established in 1984 devoted exclusively to the management of TMJ problems [13]. And yet, paradoxically, TMJ dysfunction is an illness without clearly definable features. It is a potpourri of disorders affecting various aspects of the masticatory system. Problems range from uncommon severe internal joint derangements to extremely common minor muscle aches and pains. A multitude of symptoms and signs occur, some so vague and commonplace as to make TMJ dysfunction an epidemic in the adolescent and adult populations. It remains, however, extremely rare in children and has not been previously reported in infants. We would therefore like to describe a case of TMJ dysfunction affecting an l l - m o n t h - o l d boy. It is incumbent on the pediatric otolaryngologist to be familiar with this problem as it pertains to infants because typical referral patterns do not generally call for dental or oral surgery consultation in this age group.
Case Report An ll-month-old boy was referred to Texas Children's Hospital Otolaryngology Clinic with a history of recurrent severe bilateral otalgia of one month's duration. The child was noted by his mother to suddenly cry out in excrutiating pain and pull his ears for 5-30 rain 3 - 6 times per day. Several episodes would awaken the child each night. Feeding was impaired and the mother said that bilateral TMJ clicking occurred while her son was breast-fed. There was no history of trauma, infection, arthritis, connective tissue disease, or congenital anomalies.
Fig. 1. External appliance worn by patient.
101 Prior to referral, the child received two courses of antibiotic drops for presumed bilateral otitis externa; however, when we examined him, both external canals and tympanic membranes were normal. Pertinent physical findings were restricted to the TMJs and masticatory muscles. The TMJs would repeatedly sublux and produce pain and associated muscle spasm and, on palpation, tenderness was present over the lateral ptyergoid and temporalis muscles. Plain films were unremarkable and initial therapy was therefore limited to NSAID and local heat. Failure to respond to this treatment prompted us to consult the Oral Surgery Department. An external fixation device was fashioned and the discomfort and symptoms resolved over a 6-week period. One year later, the symptoms had not recurred. (Fig. 1).
Embwolo~ A review of the embryology is apposite to illustrate the complex interrelationship of the TMJ to the ear and masticatory muscles. The development of the TMJ and its relationship to these structures have been the subject of much controversy [10]. The major points in this controversy center on establishing which structures are involved in joint formation and their relative degrees of contribution. While it is generally accepted that the TMJ develops from two blastemas, influence of the masticatory muscles on this development is uncertain. Both blastemas arise after the development of the muscles of mastication: the condylar blastema, lateral to the lateral pterygoid; and the temporal blastema, between the temporalis and masseter muscles. The condylar blastema, which appears first, is connected to Meckle's cartilage by a sheet of condensed mesenchymal cells. These cell undergo further differentiation and form fibers superior to the condylar blastema which connect the lateral pterygoid muscle to the malleus. This connection may function in initiating the histodifferentiation of the TMJ and thus may play a pivotal role in joint development. Movement in the joint region is also necessary for development and cavitation. In the absence of muscular activity, it has been observed that the joint will fail to cavitate. In the normal situation, cavitation in the inferior compartment occurs first, followed by cavitation in the superior compartment. This order reflects the order of periosteal differentiation in the condyle and the mesenchymal head inferior to the temporal bone. In both compartments, cavitation seems to be initiated by mechanical factors that arise because of the ligamentous attachment of the lateral pterygoid muscle to the malleus. This attachment is also ultimately responsible for formation of the joint disk. In this complex and asynchronous fashion, by the 4th fetal month, all articular elements of the joint are well differentiated.
Discussion
Temporomandibular joint dysfunction is a complex symptom that can be caused by a number of different disease processes. It is usually defined by the identification
102 of one or more of the following signs or symptoms: (1) limited mandibular movement, (2) masticatory muscle pain, (3) TMJ pain, (4) TMJ clicking or crepitus, (5) pain on mastication and (6) deviation on opening. Headaches and TMJ problems also seem to be related according to the work of Magnussen and Carlsson [6,7] and Reik and Hale [12]. Epidemiological surveys are difficult to interpret because different combinations of the preceding signs or symptoms have been used to diagnose TMJ dysfunction. Using such liberal criteria, 28-86% of the general population have, or have had, TMJ problems. Agerberg and Carlsson's [1] cross-sectional questionnaire of every 35th person in Umea, Sweden, indicated that about 50% of all 15-44 year olds had at least one symptom of dysfunction. In the edentulous population, Heloe and Heloe [4] found that 25% of 65-79 year olds have some clinical signs of a TMJ disorder. However, when compared to the general medical health in this population, the TMJ problems pale in significance. Greene and Laskin [3] and Mejersjo and Carlsson [8] have presented data to suggest that despite this "epidemic" of TMJ disorders, most are transient, selflimited, and often without long-term side effects. Although there are only a few longitudinal studies, it appears that bothersome symptoms eventually disappear and, thereafter, although a little joint noise is not uncommon, there is little if any pain or functional disability [11]. These facts, in turn, make it very difficult to provide precise estimates of treatment needs. Osterberg and Carlsson [9] reported that in only 4% of 384 70-year-olds was chewing ability impaired. And yet, 86% had signs or symptoms of TMJ dysfunction. In a similar study done by Solberg et al. [14], although 76% of 739 university students had TMJ dysfunction, less than 5% were candidates for some form of treatment. It appears, therefore, that in spite of the high prevalence of signs or symptoms which may reflect TMJ problems, only a small percentage of the population will seek, or require, medical care. Studies of TMJ dysfunction in children are less numerous but also suggest that while the problem is quite common, the need for treatment is not. Belfer and Kaban [2] studied 40 children ranging in age from 10 to 16 years and found two distinct groups: one with severe organic joint disease; and another with myofacial pain associated with TMJ crepitus and restricted joint motion. The latter group was much larger and included 14 children suffering from acute reactive depression leading the authors to suggest that TMJ dysfunction is a somatic depressive equivalent in children. Katzberg et al. [5] studied 31 patients ranging from 8 to 16 years in age and demonstrated internal joint derangements in 29 and degenerative arthritis in 13. In 12, TMJ dysfunction could be traced to a jaw injury, and in 7, to bruxism. A predisposing cause could not be established in the remaining 12. Diagnostic studies were not initiated, on average, until nearly two years after pain and dysfunction first developed, suggesting that doctors do not frequently consider TMJ disorders to be a problem in children (Fig. 2). Recognition of TMJ dysfunction in infancy is lacking. The remitting and variable course of TMJ dysfunction, coupled with the abundance of true ear pathology in
103
r ''~' "3?' ~..
41t Fig. 2. Bone scan showing increased uptake in the area of the right TMJ. Patient suffered minor trauma to the jaw 6 months earlier.
this age group may account for this. The syndrome is frequently referred to our dental and oral surgery colleges but referral patterns and patient needs generally do not call for dental or oral surgery consultation in infants. The pediatric otolaryngologist, however, frequently examines children with persistent otalgia unresponsive to topical and systemic therapy. Recognition of TMJ dysfunction is suggested for consideration in those children who present with otalgia for which otologic evaluation is negative. Any therapeutic intervention must reflect the fact that development of the TMJ and masticatory apparatus progresses until age 16 in females and 18 in males. Surgical intervention may involve injection of sclerosing agents into the joint space, excision of the lateral pterygoid mandibular attachments to prevent the gliding function of the joint, Mersilene sling supports from the arch to the condylar neck, and down grafting or excision of the articular eminence. Because all have irreversible effects on joint junction and growth, conservative treatment in children is the rule. Local heat and anti-inflammatory analgesics may be all that is required but if dysfunction persists, external brace appliances can be fashioned. The one used in this case was made from acrylic and attached by elastics to a leather cap. This form of conservative external fixation is simple to fashion and easily accepted by parent and child. It is preferrable to surgery during the development of the masticatory system.
Conclusion
TMJ dysfunction represents a pain-dysfunction phenomenon which is infrequently diagnosed in the pediatric population despite its widespread recognition in
104
adults. Consideration of this disorder is suggested in an otherwise healthy infant complaining of persistent otalgia. If the otologic examination is normal, multiple courses of antibiotics can be avoided and proper therapy can be instituted. Initial treatment is of necessity conservative and, as the mandible and masticatory muscles continue to develop, dysfunction may resolve. More agressive treatment should be planned only with oral surgery consultation.
References 1 Agerberg, G. and Carlsson, G.E., Functional disorders of the masticatory system. Distribution of symptoms according to age and sex as judged from investigation by questionnaire, Acta Odontol. Scand., 30 (1972) 597. 2 Belfer, M.L. and Kaban, L.B., Temporomandibular joint dysfunction with facial pain in children, Pediatrics, 69 (1982) 564-567. 3 Greene, C.S. and Laskin, D.M., Long term evaluation of treatment for myofascial jaw-dysfunction syndrome: a comparative analysis, JADA, 107 (1983) 235-238. 4 Heloe, B. and Heloe, L.A., The occurrence of TMJ-disorders in an elderly population as evaluated by recording of "subjective" and "objective" symptoms, Acta Odontol. Scand., 36 (1978) 3-9. 5 Katzberg, R.W. Tallerts, R.H., Hayakawa, K., Miller, T.L., Goske, M.J. and Wood, B.P., Internal derangements of the temporomandibular joint: finding in the pediatric age group, Radiology, 154 (1985) 125-127. 6 Magnusson, T. and Carlsson, G.E., Comparison between two groups of patients in respect to headache and mandibular dysfunction, Swed. Dent. J., 2 (1978) 85-92. 7 Magnusson, T. and Carlsson, G.E., Recurrent headache in relation to temporomandibular joint jaw-dysfunction, Acta Odontol. Scand., 36 (1978) 333-338. 8 Mejersjo, C. and Carlsson, G.E., Long term results of treatment for temporomandibular jaw-dysfunction, J. Prosthet. Dent., 49 (1983) 809-815. 90sterberg, T. and Carlsson, G.E., Symptoms and signs of mandibular dysfunction in 70-year-old men and women in Gothenburg, Sweden, Comm. Dent. Oral Epidermiol., 7 (1979) 315-321. 10 Perry, H.T., Yinghua, X. and Forbes, D.P., The embryology of the temporomandibular joint, J. Craniomandib. Pract., 3 (1985) 126-132. 11 Rasmussen, O.C., Description of population and progress of symptoms in a longitudinal study of temporomandibular arthropathy, Scand. J. Dent. Res., 89 (1981) 196-203. 12 Reik, L. Jr. and Hale, M., The temporomandibular joint jaw-dysfunction syndrome: a frequent cause of headache, Headache, 21 (1981) 151-156. 13 Pugh, J.D. and Solberg, W.K., Oral health status in the United States: temporomandibular disorders, J. Dent. Educ., 49 (1985) 398-405. 14 Solberg, W.K., Woo, M.W. and Houston, J.B., Prevalence of mandibular dysfunction in young adults, JADA, 98 (1979) 25-34.