Temporomandibular disorders and mandibular function in relation to Class II malocclusion and orthodontic treatment. A controlled, prospective and longitudinal study

The relationship between orthodontic treatment and symptoms and signs of temporomandibular disorders (TMD) was studied prospectively and longitudinally in 65 adolescent girls with Class II malocclusion. The subjects received orthodontic fixed appliance treatment with the straight-wire technique combined with or without extractions and were examined for symptoms and signs of TMD before, during, after, and finally one year post-treatment. Both symptoms and signs of TMD showed considerable fluctuations over the three-year period within the individuals. The general tendency was a decreased prevalence of symptoms of TMD over the three years. The prevalence of pain on mandibular movement and tenderness to palpation of the masticatory muscles was significantly less common during and after orthodontic treatment than before. Clinically registered TMJ clicking increased slightly over the three year period. One orthodontic treatment effect when normalizing Class II malocclusions with fixed appliances was a decreased prevalence of functional occlusal interferences. We concluded that the orthodontic treatment either with or without tooth extractions did not increase the risk for TMD or worsen pre-existing signs of TMD. Subjects with Class II malocclusion and pre-treatment signs of TMD of muscular origin seemed rather to benefit functionally from orthodontic treatment in a three-year perspective.

[Temporomandibular disorders in pediatric age]

In this work the authors consider TMJ disorders in children, evaluating the epidemiological, etiopathogenetic and diagnostic aspects compared to the TMJ pathology in adults and with reference to recent literature. In order to achieve a better understanding of TMJ disorders in children and to promote an appropriate prevention and therapeutic approach, four questions are raised: 1) What are the signs and the symptoms of TMJ disorders during the growth? 2) What factors are associated with TMJ disorders? 3) What is the prognostic meaning of the signs and the symptoms? 4) What is the importance of TMJ disorders in a protocol which considers treatment needs and priority?

From bite to mind: TMD--a personal and literature review

PURPOSE

The purpose of this study was to present a personal view of the development of prevailing opinions about temporomandibular disorders (TMD) during the last half century from a mechanistic to a psychosomatic concept. It also presents some hypotheses concerning: (1) the role of stress in the etiology of human oral parafunctions and its relationship to oral stereotypies in domestic animals; and (2) the pathogenetic mechanisms of masticatory muscle pain.

MATERIALS AND METHODS

The basis for this article was a review of personal experiences derived from clinical and research work with TMD patients. Studies of both older and more recent literature on TMD and related disorders--especially in the fields of stress research, psychosocial medicine, occupational medicine, and etiology--were also used.

RESULTS

A clear line is found in the development of the ideas on etiology, pathogenesis, and therapy of TMD, from the mechanistic attitude of Costen syndrome through the introduction of psychologic and psychophysical theories by the Columbia and Chicago schools to the now increasingly accepted biopsychosocial concept and the view of refractory TMD as a chronic pain condition.

CONCLUSION

The formerly dominant bite-centered therapies--including intraoral appliances, the effects of which still are unexplained--appear to be increasingly banished to the domain of placebo Hence, to an ever-increasing extent occlusal treatments are replaced by physiotherapy and cognitive behavior therapy. The presented hypotheses may have implications for the understanding of the origin of oral parafunction and masticatory muscle pain.

The effect of vertical dimension and mandibular position on isometric strength of the cervical flexors

This study compared the peak isometric strength of the cervical flexors in deep bite temporomandibular dysfunction (TMD) patients while biting in four bite positions: habitual occlusion, edge-to-edge, lateral shift and retruded. These values were then compared to those of the same subjects' bite positions elevated to a functional criterion (maximum isometric strength of the deltoid muscles). The mean height increase was 2.4 mm with a range of 1.5-3.8 mm. Fifteen of eighteen deep bite subjects met an inclusionary criterion, at least 13.3 Newtons (N) stronger cervical muscle strength with mandible relaxed open than habitual bite. Peak strength biting edge-to-edge was significantly greater than biting in habitual occlusion. Strength was found to increase significantly when biting in each of four mandibular positions when the bite was elevated to the functional criterion. The greatest strength was obtained from elevated habitual and edge-to-edge positions. The findings are of clinical significance, suggesting that cervical muscle isometric strength is affected by bite position and vertical dimension of occlusion. The results suggest that when biting, individuals with deep bite may be functioning at about 60% of their potential cervical flexor, isometric strength. The interaction between occlusal position, vertical dimension and cervical muscle function suggests a craniomandibular-cervical masticatory system.

Condylar axis position, as determined by the occlusion and measured by the CPI instrument, and signs and symptoms of temporomandibular dysfunction

The importance of occlusion as an etiologic factor in signs and symptoms of TMD has been a source of controversy. Very few studies have examined occlusion-dictated condylar position using instrumentation, and none has compared an ideal sample against an untreated control. The purpose of this study was to determine if there is a relationship between condylar axis position as determined by the occlusion and signs and symptoms of TMD, using the condylar position indicator (CPI). A sample of subjects with ideal occlusions, defined as centric relation approximating centric occlusion, was compared with a control sample of untreated subjects. The comparison was based on written patient histories, clinical exams, and CPI measurements. The ideal sample of 30 subjects was selected from a population that had undergone full-mouth reconstruction using gnathologic principles that included centric relation (CR) being coincident with centric occlusion (CO). The control group consisted of 30 untreated subjects from the general population and was matched with the ideal sample with regard to sex. A duplicate written exam was given to the subjects in the ideal sample to assess symptoms prior to treatment. The CR bite registration technique developed by Roth was used. When the pre- and posttreatment examination scores of the ideal sample were compared, an 84% reduction in symptoms was found after treatment. A high correlation (p<.001) between signs and symptoms of TMD and CPI values was documented. Since condylar axis position is dictated upon closure of the dentition into maximum intercuspation and since condylar axis position was shown in this study to be strongly correlated with TMD symptomatology, it can be concluded that a statistically significant relationship exists between occlusion-dictated condylar position and symptoms of TMD.

Stomatognathic function in juvenile rheumatoid arthritis and in developmental open-bite subjects

Patients affected with juvenile rheumatoid arthritis present clear radiological alterations of the condyles of the temporomandibular joint (TMJ) due to the inflammatory process, with a prevalence ranging from 17 percent to 63 percent. This work is a comparison between a group of subjects with juvenile rheumatoid arthritis presenting signs and symptoms of TMT dysfunction and a group of the same age not suffering from any rheumatic morbidity, but presenting an open bite > 3 mm. The aim is to verify whether the open bite can induce an alteration in mandibular function comparable to that observed in juvenile rheumatoid arthritis. Statistically significant difference is found in the juvenile rheumatoid arthritis group only regarding spontaneous and provoked muscle pain and the lateral opening deviations of the mouth, but mostly the two groups seem alike and present the same stomatognathic pattern.

Masticatory myofascial pain: an explanatory model integrating clinical, epidemiological and basic science research

Masticatory myofascial pain (MMP) is a regional muscle pain disorder characterized by localized muscle tenderness in taut bands of skeletal muscles and pain and is one of the most common causes of persistent regional pain. The affected muscles may also display an increased fatigability, stiffness, subjective weakness, pain in movement, and slight restricted ROM that is unrelated to joint restriction. Although the exact etiology of MMP is unclear, recent research has improved our understanding of factors that contribute to the development and progression of MMP. Understanding these factors can help to validate an explanatory model for etiology and treatment of MMP. This model includes peripheral mechanisms from local biomechanical strain leading to the onset of early cases of MMP while central mechanisms associated with psychosocial factors lead to increased chronicity of MMP. As MP persists, chronic pain characteristics often precede or follow it's development. Management of the syndrome naturally follows from this model with therapy to rehabilitate the trigger points (TrPs) while focusing effort on reducing all contributing factors.

Temporomandibular treatment outcomes within five diagnostic categories

This study of temporomandibular disorder (TMD) treatment outcomes examines 274 consecutive patients in five diagnostic categories and a 25 patient comparison group to determine relative levels of symptom improvement. Employing a psychometric outcome measure, the TMJ Scale, it was found that patients receiving active TMD treatments manifest statistically significant symptom improvements. Untreated patients reported minor and statistically insignificant symptom variations. Patients with intracapsular TM joint dysfunctions exhibited higher levels of improvement in pain and other TMD symptoms than patients presenting with primarily muscle symptoms. This research supports the hypothesis that TMDs are not self-limiting and require active treatment interventions. It is suggested that some studies cited to show that TMDs are self-limiting have major methodological limitations, relying upon unvalidated and subjective assessments of symptom levels. This research also outlines a procedure for TMD practitioners to measure treatment efficacy and the relative effectiveness of differing treatment modalities in a valid, consistent and unbiased manner.

Whiplash and temporomandibular disorders: a critical review

Some authors have hypothesized a relationship between rear-impact motor vehicle collisions and subsequent symptoms of neck pain and temporomandibular disorders, or TMD, despite no facial impact. This article examines the TMD aspect in terms of the physiological basis and cultural factors influencing the reporting of such symptoms.

Treatment outcome in patients with craniomandibular disorders of muscular origin: a 7-year follow-up

The outcome of different treatment modalities after 7 years was investigated in a selected group of 50 patients with craniomandibular disorders of muscular origin. To minimize the possible effects of selection on the clinical material, the selected treatment group was compared to a consecutive group of patients in terms of age, gender, intensity/duration of pain, and socioeconomic profile. Both groups were comparable in most respects, but the selected group had a longer duration and a higher intensity of pain at baseline. There were more men in the consecutive group than in the selected group. A combined treatment approach resulted in a better outcome than single treatments. Sixty-five percent of all patients in the selected group reported improvement at the 7-year follow-up. All of the 19 patients who received counseling combined with different occlusal treatments improved. Forty-three percent of the patients treated otherwise showed improvement. Patients who were aware of stress responded better to treatment.

Effects of major Class II occlusal corrections on temporomandibular signs and symptoms

This study explored the relationship between malocclusion and signs and symptoms of temporomandibular disorders (TMD) in 124 patients with severe Class II malocclusion, before and 2 years after bilateral sagittal split osteotomy (BSSO). Patients were evaluated with the Craniomandibular Index (CMI), the Peer Assessment Rating Index (PAR Index, to assess gross changes in the occlusion), and symptom questionnaires. The results showed a significant improvement in occlusion; PAR Index scores dropped from a mean of 18.1 before surgery to a mean of 6.1 at 2 years postsurgery (P < 0.001). The CMI and masticatory index (MI) for muscle pain indicated clinically small but statistically significant improvement (P = 0.0001) from before surgery (mean CMI = 0.14, mean MI = 0.15) to after surgery (mean CMI = 0.10, mean MI = 0.08). The number of patients with clicking upon opening decreased significantly from 33 (26.6%) to 13 (10.5%) (P = 0.001). However, the number of patients with fine crepitus increased from 5 (4.0%) before surgery to 16 (12.9%) at 2 years postsurgery (P = 0.005). Significant reductions in subjective pain and discomfort were also found 2 years after surgery. The magnitude of change in muscular pain was not related to the severity of the pretreatment malocclusion, a finding that suggests that factors other than malocclusion may be responsible for the change in TMD.

The relationship between temporomandibular disorders and stress-associated syndromes

OBJECTIVES

The purpose of this study was to determine the comorbidity of temporomandibular disorders and other stress-associated conditions in patients with chronic fatigue syndrome and fibromyalgia.

STUDY DESIGN

Of 92 patients who fulfilled the criteria for chronic fatigue syndrome or fibromyalgia (or both), 39 (42%) reported a prior diagnosis of temporomandibular disorder. Further questionnaires were sent to the members of this group, and 30 patients responded.

RESULTS

Of the original 92 patients, of whom 42% reported temporomandibular disorders, 46% had histories of irritable bowel syndrome, 42% of premenstrual syndrome, and 19% of interstitial cystitis. Of the patients with temporomandibular disorders, the great majority reported an onset of generalized symptoms before the onset of facial pain. Despite this, 75% had been treated exclusively for temporomandibular disorders, usually with bite splints.

CONCLUSIONS

Patients appearing for treatment with chronic facial pain show a high comorbidity with other stress-associated syndromes. The clinical overlap between these conditions may reflect a shared underlying pathophysiologic basis involving dysregulation of the hypothalamic-pituitary-adrenal stress hormone axis in predisposed individuals. A multidisciplinary clinical approach to temporomandibular disorders would improve diagnosis and treatment outcomes for this group of patients.

Odontologic survey of referred patients with symptoms allegedly caused by electricity or visual display units

Twenty-eight consecutive patients with symptoms allegedly caused by electricity or visual display units were odontologically investigated according to a specially designed registration form including an anamnestic interview and a clinical protocol. The most common oral and general symptoms reported were burning mouth, craniomandibular dysfunction symptoms, skin complaints, and fatigue. Oral symptoms such as craniomandibular dysfunction and general symptoms such as eye complaints and dizziness scored highest on a visual analog scale regarding mean symptom intensity. The patients reported various numbers of medical diagnoses, such as allergic rhinitis or asthma and hypothyroidism. Various dental diseases were found; the most common were temporomandibular joint and masticatory muscle dysfunctions, lesions in the oral mucosa, and periodontal diseases. Urinary-Hg (U-Hg) analysis showed a mean U-Hg concentration of 8.5 nmol Hg/L urine, and none of the patients exceeded the limit of 50 nmol Hg/L urine. The U-Hg concentration was positively correlated with the number of amalgam fillings (P< 0.01) and craniomandibular disorders (P < 0.05). No or low secretion of the minor mucous glands was found in 43% of the patients. One patient showed hypersensitivity to gold and cobalt. The present study showed that various odontologic factors might be involved in some of these patients' suffering. Thus, it is important that professionals from other disciplines collaborate with dentistry if these patients are to be properly investigated.

Case report KY: functional analysis of a follow-up chin cup patient with TMJ pain

At 19 years 1 month, the patient returned to the clinic for a follow-up screening of chin-cup patients. She was the only TMJ dysfunction patient who agreed to undergo further treatment. Mandibular kinesiograph, computer-aided axiograph, and electromyograph records were gathered to aid in evaluating function. Splint therapy and orthodontic retreatment relieved the TMJ pain associated with balanced muscular activity and helped to achieve more normal movement of the mandible.

[Idiopathic facial pain. Part 2: Treatment and prognosis]

The present paper introduces a new concept in the physiopathology and treatment of the called "temporomandibular disfunction". This paper was divided into two parts, the first explained the definition, etiology and hypothesis of the idiopathic facial pain. In this second part, its treatment, prognosis and recommendations are explained. The treatment consists basically in counselling, and, in a second stage, the use of tricylic antidepressants or similar drugs is used. Occlusal devices are some times used, but have been of less value. Arthroscopy can be used in resistant patients, and surgery is usually not indicated. The present management is based on a working model developed in this department and in other world centres, and is revolutionising the clinical management of the patients with idiopathic facial pain.

[Etiologic factors in temporomandibular joint disorders and pain]

Parallel to the construction of better classifications and the identification of subgroups of temporomandibular disorders, an important development has taken place in research concerning its etiology. The etiological factors implied in muscle problems refer to more generalised disorders as myofascial pain syndrome and fibromyalgia. The role of occlusal and articular factors has been brought down to realistic proportions, indicating a minor contribution. Similarly, doubt has arisen concerning the existence of a vicious cycle of pain/spasm/pain. With regard to internal derangements, emphasis has been put on the high prevalence in an otherwise normal population and the fluctuating character of the symptom. Also here, developments point towards constitutional and systemic factors, more than local influences. Trauma, however, seems to play an increasing role. The development of osteoarthrosis has been studied more in depth revealing local processes of inflammation, neurogenic inflammation and the existence of specific markers which might be important in the future. The relationship between disc derangement and the development of osteoarthrosis remains unclear.

Gadolinium-enhanced MR imaging of temporomandibular disorders: improved lesion detection of the posterior disk attachment on T1-weighted images obtained with fat suppression

OBJECTIVE

The purpose of this study was to assess the potential for improved lesion detection in the posterior disk attachment and its surrounding tissue in temporomandibular disorders when gadolinium-enhanced MR imaging performed with fat suppression is used.

MATERIALS AND METHODS

Forty-five patients underwent MR imaging with conventional T1- and T2-weighted, gadolinium-enhanced T1-weighted, and gadolinium-enhanced fat-suppressed spin-echo imaging sequences. Qualitative and quantitative assessments of the contrast enhancement of each type of imaging were also performed.

RESULTS

The contrast-enhanced fat-suppressed T1-weighted imaging sequence had several advantages over the other imaging techniques in detecting abnormalities of the posterior disk attachment and in detecting bone marrow lesions in the mandibular condyle. The most significant advantage was better enhancement of lesion conspicuity. The diagnostic accuracy of contrast-enhanced fat-suppressed imaging was 77% versus 70% for conventional contrast-enhanced imaging. The kappa value for interobserver agreement was .95 for contrast-enhanced fat-suppressed imaging and .72 for conventional contrast-enhanced imaging.

CONCLUSION

Contrast-enhanced fat-suppressed T1-weighted spin-echo MR imaging is a valuable technique for visualizing the extent and degree of lesions in the posterior disk attachment and bone marrow lesions in the mandibular condyle.

Temporomandibular joint dysfunction in children: evaluation of treatment

Thirty-eight pediatric patients with temporomandibular joint (TMJ) dysfunction were diagnosed and treated. The etiology for the TMJ dysfunction was trauma in 30 (79%) patients, degenerative joint disease in two (5%) patients, growth disturbances in two (5%) patients and tumor in one (3%) patient. In three (8%) patients the etiology was unclear. The treatment modalities were: non-invasive therapy in 19 (50%) patients, occlusal therapy in 10 (26%) patients and surgical treatment in nine (24%) patients. The reported symptoms of temporomandibular joint dysfunction using the Helkino anamnestic index revealed that, at the initial examination, eight (21%) reported mild symptoms and 30 (79%) severe symptoms. One year later, 33 (87%) reported no symptoms, four (10%) mild symptoms and one (3%) severe symptoms. These differences were significant (P < 0.05-0.01). Maximum mouth opening 1 year after treatment as compared to the initial examination increased (P < 0.05) in all three treatment modalities. Deviation of the mandible on opening, 1 year after treatment as compared to the initial examination, decreased (P < 0.05) in all three treatment modalities. No differences were found between the modalities in both the maximum mouth opening or deviation of the mandible. TMJ dysfunction in children can be effectively treated by non-surgical treatment modalities. Surgery should be considered only when the non-surgical therapies were ineffective.

TMD treatment need in relation to age, gender, stress, and diagnostic subgroup

Associations between treatment need for temporomandibular disorders (TMD) and age, gender, stress, and diagnostic subgroup were analyzed in an adult Finnish population sample of 506 subjects. When analyzed separately, the association between TMD treatment need and all the studied factors was statistically significant. This finding is in accordance with earlier results. When the studied factors were included into an explanatory model, however, the picture changed. The logistic regression analysis revealed that diagnostic subgroup was the strongest predictor for the TMD treatment need. Total stress score significantly added to the explanatory power of the model, but age and gender did not. The commonplace observation that women show more signs and symptoms of TMD seems to be explainable by their higher stress scores and by the type of symptoms.

TMD treatment outcomes: a statistical assessment of the effects of psychological variables

This study analyzes the degree to which pretreatment psychosocial factors (psychological dysfunctions and stress) effect outcome in 269 consecutive temporomandibular disorder (TMD) patients at the completion of treatment. Employing the TMJ Scale, a validated measure of TMD symptoms, it is found that pretreatment TMD pain and overall symptom levels (excluding internal derangement symptoms) are weakly but nevertheless, significantly related to pretreatment psychological dysfunction and stress. However, the latter appeared totally unrelated to four treatment outcome measures. Additionally, the data supports the hypothesis that both initial and post-treatment intrascapular symptoms (TMJ Scale, Joint Dysfunction sub-scale) are unrelated to psychosocial factors. Data from this study call into question the value of categorizing the TMD patients by means of psychosocial "profiling" and "dual-axis" classification methods proposed by some researchers.

Diver's mouth syndrome: a report of two cases and construction of custom-made regulator mouthpieces

Scuba diving is becoming more and more popular and dentists are increasingly likely to encounter patients with diving-related problems. Protruded mandibular positions and the biting forces exercised on the anterior occlusion during diving can cause pain and dysfunction, particularly where a predisposing factor such as bruxism exists. In this article, two cases are reported of patients with diving-exacerbated pain dysfunction syndrome, which improved following the construction of custom-made mouthpieces which distributed the forces more evenly. Laboratory procedures are described for construction of a custom-made scuba regulator mouthpiece that allows more comfortable diving.

Chronic orofacial muscle pain: a new approach to diagnosis and management

The initial data from this study indicate that there are clearly identifiable chronic muscle pain conditions in the form of localized pain; myofascial pain or regional pain conditions; and fibromyalgia or generalized pain conditions. A clear difference exists between the prevalence of these conditions in male and female patients, with a higher percentage of female patients suffering generalized pain problems and temporomandibular problems. Generalized or localized pain appears to be an individual variant of a similar problem and pain patients may have a genetically determined vulnerability associated with bacterial toxins, particularly within the genitourinary tract. It appears that in fibromyalgia there is an underlying genetic factor that causes abnormalities in the muscle metabolic cycle, and preliminary data suggest that lipid anomalies predispose to fibromyalgia and possibly chronic fatigue syndrome. Patients report infectious events at/or around onset in more than 60 percent of cases. Seventy percent of fibromyalgic cases report orofacial pain.

A conservative surgical approach of osteochondroma affecting the mandibular condyle

An osteochondroma of the condyle in a 49-year-old venezuelan female patients is reported. Clinical, radiological and histopathological features of the tumor are described. A wide local surgical excision permitted the patient to regain normal function.

Temporo-mandibular joint pain dysfunction syndrome: report of two cases and review of literature

Two cases of TMJ pain dysfunction syndrome were diagnosed and treated between 1990 and 1992. The two cases occurred in females in the 4th decade of life. In the two cases, there was evidence of psychogenic origin but no evidence of organic origin. These cases are being presented because of the common psychogenic origin as aetiological factor in both cases and the quick response to treatment as soon as cause of the disorder was discovered.

Epidemiologic studies reveal trends in temporomandibular pain and dysfunction

Recent epidemiologic investigations have provided novel perspectives concerning the type of patient in whom temporomandibular pain and dysfunction syndrome develops. Information regarding prevalence has challenged current concepts regarding signs and symptoms. Gender, age, ethnic, and socioeconomic data have provided insight into the risk factors, and have led to broader biopsychosocial investigations of the cause of this syndrome.

The changing focus of chronic temporomandibular disorders: management within a hospital-based, multidisciplinary pain centre

Despite evidence to the contrary, many dentists still cling to outdated beliefs and practices regarding the aetiology and management of chronic temporomandibular disorders (TMDs). Chronic pain disorders require a multidisciplinary approach with a strong focus on psychological factors. Treatment failures and relapse are likely if such factors are not considered. Most chronic temporomandibular pain problems are extracapsular and of myofascial origin. Mechanistic or invasive treatments in such cases may be inappropriate and can cause harm. Conservative measures used for other types of chronic muscular pain are generally recommended. All health practitioners who deal with acute and chronic pain should be aware of recent major advances in the understanding of pain mechanisms. Along with psychosocial considerations, these must be emphasised in undergraduate and continuing education programmes.

[The involvement of the temporomandibular joints in multiple myeloma]

Four patients with myeloma disease were examined. The debut was characterized by stubborn strong pain in the temporomandibular joint (TMJ). Involvement of the TMJ presents as arthralgia but not arthritis. A specific feature of the disease is possibility of rather long functioning of the joint and absence of any inflammatory changes. X-Ray examinations show multiple round clearly seen 1 to 5 mm defects in the bone without any destructive or degenerative changes. Myeloma disease is to be differentiated from TMJ involvement in systemic lupus erythematosus, rheumatoid arthritis, Bechterew's disease, in elderly patients or patients with a long disease standing from involution involvement of the TMJ (Costen's syndrome) or osteoarthrosis deformans.

Clinical evaluation of temporomandibular joint disorders (TMD) in patients treated with chin cup

The purpose of this manuscript was twofold: (1) to provide more information on the incidence of temporomandibular joint disorders (TMD) in chin cup-treated patients during and after active treatment; and (2) to evaluate results of functional analysis for one orthodontically treated chin cup patient with temporomandibular joint (TMJ) pain and difficulty of maximum mouth opening. Eighty-six out of a total of 160 chin cup patients responded to our questionnaire and were checked for pain, clicking, and maximum mouth opening. Twenty-eight of the chin cup subjects showed one or more symptom(s) of TMD. Spontaneous pain was found most often during active treatment but clicking (sound) occurred more often during the retention phase. One retreated patient showed remarkable improvement of TMD symptoms.

An appliance for management of TMJ pain as a complication of Parkinson's disease

This is a case report of a 71-year-old female with pain in the right TMJ, who was also suffering from Parkinson's Disease and was treated using a new intraoral occlusal appliance. The new appliance was designed to limit excessive mandibular excursion of the right side by restricting the mediotrusive movement of the left coronoid process. The appliance significantly suppressed involuntary mandibular excursion.

[The clinical x-ray manifestations of a muscle imbalance in the temporomandibular joint and its treatment]

The causes of dysfunction of the temporomandibular joint are analyzed, their clinical and x-ray symptoms enumerated, diagnosis and treatment described. The main cause of pain in this condition is the imbalance of masticatory muscles.

Basicranial flexion, facial reduction and temporomandibular joint dysfunction

Although dysfunction is the major condition affecting the bilateral temporomandibular joint (TMJ), it has defied previous attempts to explain, predict, or prevent its clinical manifestations. A hypothesis is developed that there is an anatomical predisposition to TMJ dysfunction which should be sought in the phylogenetic flexing of the hominid basicranium. It is argued that the glenoid fossa, caught between an ever-increasing brain size and more ventrally oriented facial apparatus, has become deepened and hence labile to dysfunction.

[The effect of indirect trauma on the goat temporomandibular joint: a histopathologic study]

The aim of this experiment was to study the effect of indirect trauma on the goat temporomandibular joint (TMJ). Trauma to the TMJ was achieved through an impact to the right mandibular angles of 20 goats, their left TMJs were used as a controls. The animals were killed after 2 h, 1 month, 3 months and 6 months. Light microscopic observations revealed that the condyles exhibited an eburnated, eroded surface with osteophytes, the disks were thinned or perforated, and the temporal surfaces were thickened and the lining were separated. These changes were histologically similar to those of the advanced osteoarthritis. This study suggests that the indirect trauma on TMJ lead to osteoarthritis.

[Adverse effects of orthodontic treatment]

The authors reviewed the adverse effects. The main effects are: demineralisation; gingivitis hyperplastica, mucogingival and marginal attachment bone loss, long-term-effects; pulp damage and devitalisation of teeth; apical and marginal root resorption; temporomandibular dysfunction.

Pain and other cardinal TMJ dysfunction symptoms: a longitudinal survey of Japanese female adolescents

Longitudinal data were obtained for 4 years from 361 Japanese high school girls between the ages of 12 and 16. The data were analysed for the occurrence of pain and its associations with the occurrence of other cardinal TMJ dysfunction symptoms and occlusal states. It was determined that even if pain or noise or jaw-deviation symptoms appeared, those symptoms did not necessarily last thereafter. The symptoms were not persistent but rather appeared and disappeared repetitively. Those who exhibited noise during at least one of the surveys of the 4-year survey period showed a significantly higher prevalence of pain than those who did not exhibit noise at all (P < 0.05). Those who exhibited noise by the age of 13 showed a significantly higher prevalence of pain than those who exhibited noise after age 14 (P < 0.1). The temporal occurrence of pain depended upon the appearance of noise and the age at which noise first appeared. On the other hand, the occurrence of pain symptoms was not necessarily related to specific types of malocclusions, which suggests the significance of multifactorial contributions in understanding the aetiology of pain rather than the occlusal factor.

[Post-traumatic temporomandibular pain dysfunction syndrome and the problems raised by its imputation]

Direct, certain and total imputability of trauma as the cause of mandibular joint dysfunction is often difficult to establish. The theoretically obligatory conditions are rarely met, making the expert's opinion quite difficult to establish. The complexity of the pathophysiology involved in mandibular joint dysfunction confirms however the reality of this sequella. By determining the precise lesional or functional origin of the syndrome and the latent or patent nature of the prior status it is possible to ascertain intermediary situations.

[Stomatologic implications of Turner syndrome II. Orthodontic disorders and some characteristics of the temporomandibular joint]

Turner syndrome is a disease belonging to the group of chromosome disorders, which affect sexual chromosomes. The present study aims at analysing and describing orthodontic and TMI joint disorders in patients with Turner's syndrome, and comparing the results with those healthy controls. Data of 24 patients with Turner's syndrome as well as 24 healthy controls were collected and analysed. No significant alteration in TMI was found in any of the two groups. Both groups presented orthodontic anomalies, however, crowding was the most common anomaly in the control group, whereas in the case of patients with Turner's syndrome, other anomalies (protrusion, open bite, cross bite) could also be found more frequently.

Midline mandibular osteotomy: an analysis of functional outcomes

Although the oncologic validity and perioperative complications of midline mandibular osteotomy are well described, little attention has been directed toward the long-term functional problems that may be associated with its use. Thirty-one patients who had undergone this procedure were examined to assess postoperative sensation, temporomandibular joint (TMJ) function, occlusion, and cosmesis. The majority (27 of 31) patients had some sequelae but these were minor in nature. Twenty of 31 patients had abnormal sensation, 24 of 31 noted a changed occlusion, and 15 of 31 had signs or symptoms of TMJ myofascial pain. Although patients should be advised of the potential for functional problems with this procedure, they can be reassured that these are likely to be relatively minor in significance. If technically feasible and if an exact restoration of occlusion is a priority, a prefabricated lingual splint should be used.

The aetiology of temporomandibular disorders: a philosophical overview

Over the last 50 years many theories have been put forward to explain the syndrome currently called 'temporomandibular disorders'. However, it is doubtful whether any single theory fits all the complex features of this condition. The 'multifactorial' explanation also appears flawed. On the assumption that a valid theory should fit the whole evidence, this paper starts by separating the 'predisposing' from the 'initiating' factors, and notes that most existing theories appear to identify the former rather than the latter. The research material is examined in an effort to formulate a theory that is both logical and fits all the known clinical findings.

The role of oxygen free radicals in idiopathic facial pain

Patients with chronic facial pain including those with facial arthromyalgia (TMJ dysfunction syndrome) were investigated for evidence of abnormal systemic and intra-articular free radical activity. Chronic facial pain patients showed significantly raised serum 2,3-dihydroxybenzoic acid after an oral dose of 1.2 g of aspirin which indicates increased systemic free radical activity. This was reflected in the TMJ aspirates of the facial arthromyalgia patients which contained thiobarbituric acid-reactive substance (TBA-RS) which is also a product of free radical activity. The synovial aspirates also contained high levels of the hyperalgesic eicosanoid 15-HETE. However, there was no difference between the painful and symptom-free joints, which suggested that in part the clinical features are probably determined by asymmetrical masticatory function or as yet unknown algesic factors such as local cytokine production.

Prevalence of hyperactive digastric muscles during swallowing as measured by electromyography in patients with myofascial pain dysfunction syndrome

One purpose of this clinical study is to establish a relationship between the hyper activity of the digastric muscles and predisposition of an individual to MPDS (myofacial pain dysfunction syndrome). If a population predisposed to MPD could be identified by an early diagnosis, intervention and treatment could eliminate potential pain in adulthood. Secondly, can the employment of electromyography to aid in the diagnosis of patients with MPD be helpful in establishing a program of prevention and treatment? Thirty-one patients, male and female, were randomly selected from among those routinely diagnosed as having myofascial pain dysfunction syndrome by the dental staff at the Long Island Center for Craniofacial Pain. Eighteen patients who did not experience any symptoms of facial pain comprised the control group in the study. This study demonstrated that the average trace readings which indicate the activity of the digastric muscles, as measured by the electromyogram from patients experiencing facial pain were significantly higher than those from patients without pain symptoms. In every instance, the correlation between facial pain and abnormal swallow patterns which are a cause of hyperactivity of the digastrics was confirmed.

Psychoneuroimmunology and its relationship to the differential diagnosis of temporomandibular disorders

Psychoneuroimmunology (PNI) is a field of medicine which joins immunology and neurobiology. It focuses on the relationship of stress upon the hypothalamic-adrenal-pituitary (HPA) axis. Depletion of hormones and neurotransmitters within the HPA-axis, as a result of stress, can lead to a multitude of diseases and disorders. Therefore, it is necessary for the dentist to be familiar with PNI and the HPA-axis in order to make an accurate diagnosis of TMD.

Special considerations in orofacial pain and headache

The dental profession faces educational, scientific, and ethical challenges in orofacial pain and headache. Past educational deficiencies are being addressed with guidance and recommendations from the AADS, the ADA, and the AAOP. With education and further research, many dental ethical questions in TMD will be resolved. The educational process must continue with a solid foundation in scientific basis provided in university settings. The appropriate use of TMD diagnostic machines, treatment modalities, and management of perpetuating factors such as sleep will evolve with the new knowledge of scientific discovery. These are some of the many challenges of orofacial pain and headache disorders that warrant special consideration.