A dynamic model of etiology in temporomandibular disorders

Exercise therapy in postoperative patients with temporomandibular joint internal derangement: A systematic review

OBJECTIVE

Postoperative patients with temporomandibular joint internal derangement (ID) often have problems such as limited mouth opening and pain. Exercise therapy can be advantageous for improving the recovery of patients following surgery. However, there is continuing discussion on the precise aspects of the exercise program, including the optimal timing, length, intensity, and use of assistive equipment. Hence, this study aimed to incorporate pre-existing exercise treatment regimens and investigate their impact.

METHODS

Publications that detailed the clinical treatment of patients with temporomandibular joint ID who received postoperative exercise therapy interventions were included. Nine databases were searched until October 1st, 2023. The JBI critical appraisal tools were used to assess the methodological quality of the included studies.

RESULTS

Five studies were finally included for subsequent analysis; two were randomised controlled studies, and three were quasi-experimental. Exercises suitable for such patients encompass vertical, transverse, and horizontal stretching, among which vertical stretch can be divided into active and passive movements. The start time ranged from the first to the fifth week after surgery, with a duration of 1-6 months. Although the data in the studies could not be integrated and further analysed, preliminary results showed that maximum mouth opening and pain in patients improved significantly. The therapeutic effect of combining three exercise methods was best and was related to patient compliance.

CONCLUSION

Exercise therapy positively affects postoperative rehabilitation in patients with temporomandibular joint ID. It is proposed that targeted, comprehensive studies be conducted to provide a basis for designing more sophisticated exercise therapy regimens and further confirm its curative effect.

Effects of Chronic and Experimental Acute Masseter Pain on Precision Biting Behavior in Humans

Chronic pain in the orofacial region is common worldwide. Pain seems to affect the jaw motor control. Hence, temporomandibular disorders (TMD) are often accompanied by pain upon chewing, restricted mouth opening and impaired maximal bite forces. However, little is known on the effects of pain, in particular the effects of chronic jaw muscle pain on precision biting. The aim of the study was to investigate the effect of chronic and acute jaw muscle pain on oral motor control during precision biting in humans. Eighteen patients with chronic masseter muscle pain and 18 healthy participants completed the experiment. All participants were examined according to the Diagnostic Criteria for TMD. Experimental acute pain was induced by bilateral, simultaneous sterile hypertonic saline infusions into the healthy masseter muscles. A standardized hold and split biting task was used to assess the precision biting. The data was analyzed with non-parametric statistical tests. The results showed no significant differences in the hold forces, split forces, durations of split or peak split rates within or between the pain and pain-free conditions. The mean split rate increased significantly compared to baseline values both in the chronic patients and the pain-free condition. However, this increase was not evident in the experimental acute pain condition. Further, there were no significant differences in the mean split rates between the conditions. The data suggest that jaw muscle pain does not seem to alter precision biting in humans, however, the possibility that a nociceptive modulation of spindle afferent activity might have occurred but compensated for cannot be ruled out.

Changes in the temporomandibular joint disc and temporal and masseter muscles secondary to bruxism in Turkish patients

Objectives:

To analyze the relationships between temporalis and masseter muscle hypertrophy and temporomandibular joint (TMJ) disc displacement in patients with severe bruxism using magnetic resonance imaging (MRI).

Methods:

This retrospective study included 100 patients with severe bruxism, referred to the Department of Oral and Maxillofacial Surgery, University of Marmara and Istanbul Medipol University, Istanbul, Turkey, between January 2015 and December 2016. Patients underwent TMJ MRI with a 1.5-T system in open and closed mouth positions. The masseter and temporalis muscles were measured in the axial plane when the patient’s mouth was closed.

Results:

At its thinnest, the disc averaged was 1.11±0.24 mm. At their thickest, the masseter averaged was 13.65±2.19 mm and temporalis muscles was 12.98±2.4 mm. Of the discs, 24% were positioned normally, 74% were positioned anteriorly, and 2% were positioned posteriorly. The temporalis muscle was significantly thicker in patients with normally positioned discs than in those with anteriorly positioned discs (p=0.035).

Conclusions:

The temporalis muscle was significantly thicker in patients with normally positioned discs than in those with anteriorly positioned discs (p=0.035). Additional studies should be conducted to evaluate the relationships between all masticatory and surrounding muscles and disc movements in patients with bruxism.

Association of temporomandibular disorder and high frequency of suicide ideation in Korean adolescents: a cross-sectional survey

BACKGROUND

This study investigated the association between psychological factors and temporomandibular disorder (TMD) in a representative sample using data from the Korean nationwide survey.

METHODS

The study included 1337 adolescents. Participants provided demographic, socio-economic and behavioural information, and responses to questionnaires assessing their mental health status including perceived stress, depressed mood and suicidal ideation in the presence of TMD. In univariate analysis, t-test was used to test the association between TMD and risk factors by gender in a complex sampling design. Multivariate logistic regression analyses were used to examine the association between TMD and psychological factors.

RESULTS

Male adolescents with TMD were highly engaged with depressed mood and suicidal ideation (p = .0006, p = .0223), however, no psychological factors were significant in female adolescents (p < .05). Male adolescents with both depressed mood and suicidal ideation had significantly high rates of TMD (p = .0024). The risks for experiencing depressed mood (OR: 3.07) and suicidal ideation (OR: 2.564) were significantly associated with TMD in male adolescents after adjusting confounders.

CONCLUSIONS

The results provide evidence that the depressed mood and suicidal ideation were associated with TMD in male adolescents. This study has important implications for enhanced screening and evaluation of mental health among patients with TMD according to gender.

Temporomandibular clinical exploration in Italian adolescents

OBJECTIVE

This study investigated the prevalence of the signs and symptoms of temporomandibular disorders (TMD) among Italian adolescents.

METHODS

The data were recorded from 567 subjects (246 males and 321 females; age range 11-19 years), grouped according to age and molar class relationship.

RESULTS

Forty-four point one percent of subjects showed at least one sign or symptom of TMD, which were significantly more frequent in the 16-19 year-old group (52.9%) in respect to the 11-15 year-old group (39.8%) (χ ² = 8.78; p = 0.003). Signs and/or symptoms were about 1.6 times more frequent in subjects with Class II/1 malocclusion (χ ² = 13.3, p = 0.0003), mostly for TMJ sounds (χ ² = 1.444; p = 0.036). Myalgia was more frequent in females than in males (χ ² = 3.882; p = 0.049).

CONCLUSION

TMD signs and/or symptoms among Italian adolescents seem diffused (44.1%). Therefore, all adolescents should be screened thorough medical history and clinical examination.

Association of temporomandibular disorder with occupational visual display terminal use

Increased visual display terminal (VDT) use has raised the prevalence of VDT-related adverse conditions, such as dry eye disease, and musculoskeletal and psychopathological symptoms, in office workers, including temporomandibular disorder (TMD). Many factors contributing to TMD have been identified, such as parafunctional habit (bruxism and teeth clenching), trauma, mental disorders, lifestyle, poor health, and nutrition, as well as hormonal factors (i.e., estrogen). It is likely that various contributing factors overlap in TMD development in individuals who routinely use a VDT for work. However, the relationship between TMD and VDT use has not been fully elucidated. In this mini-review, findings of recent studies of TMD in relation to occupational VDT use in Japan are discussed, as well as characteristic features and prevention strategies.

[Focus on the occlusal failure]

The success is evidenced by the longevity of aesthetic and functional therapeutic result. The occlusal «postorthodontic» failure could result in dental instability, functional discomfort, dental or musculo-articular complaint. Analysis of the occlusion research potential occlusal pathogenic dysfunction listed in stabilizing (shimming), centering and guiding anomalies. The large capacity of tolerance of the masticatory system makes it difficult to define the border between physiology and pathology but it is necessary to have benchmarks that can be summarized as follows: - shimming: occlusal contact of mesio-lingual cusp of the first maxillary molars (in Class I, II or III) and occlusal contacts between the canines antagonists; - centering: no transversal deflected occlusion between maximal Intercuspation (ICP) and occlusion in Centric Relation (RCP); - guiding: absence of posterior interference, absence of anterior interference (locking).

The Role of Transcutaneous Electrical Nerve Stimulation in the Management of Temporomandibular Joint Disorder

Temporomandibular joint disorders (TMD) constitutes of a group of diseases that functionally affect the masticatory system, including the muscles of mastication and temporomandibular joint (TMJ). A number of etiologies with specific treatment have been identified, including the transcutaneous electrical nerve stimulation (TENS). The current paper presents a literature review on the use of TENS in the management of TMD patients. Temporomandibular joint disorder is very common disorder with approximately 75% of people showing some signs, while more than quarter (33%) having at least one symptom. An attempt to treat the pain should be made whenever possible. However, in cases with no defined etiology, starting with less intrusive and reversible techniques is prescribed. Transcutaneous electrical nerve stimulation is one such treatment modality, i.e. useful in the management of TMD. It comprises of controlled exposure of electrical current to the surface of skin, causing hyperactive muscles relaxation and decrease pain. Although the value of TENS to manage chronic pain in TMD patients is still controversial, its role in utilization for masticatory muscle pain is significant. However, an accurate diagnosis is essential to minimize its insufficient use. Well-controlled randomized trials are needed to determine the utilization of TENS in the management of TMD patients.

Full-Mouth Rehabilitation Following Treatment of Temporomandibular Disorders and Teeth-Related Signs and Symptoms

The literature is replete with theories regarding temporomandibular disorders (TMD). However, there is a paucity of information concerning perceived malocclusion and other teeth-related signs and symptoms after full-mouth rehabilitation. This clinical study was designed to evaluate the perception of TMD patients concerning perceived malocclusion and other teeth-related signs and symptoms after full-mouth rehabilitation guided by the Mental Analog Scale (MAS). Among 38 patients referred for full-mouth rehabilitation, 20 were diagnosed as having TMD after reviewing a questionnaire, recording the major complaints and symptoms, in addition to performing comprehensive clinical examination. Nonsurgical therapy was performed, including fabricating an anterior programming device, a centric relation occlusal device and finally full-mouth rehabilitation by means of placing crowns on all upper and/or lower teeth. All full-mouth rehabilitation procedures were performed using a fully adjustable articulator and mandibular movements were recorded following pantographic tracings. After full-mouth rehabilitation, the patients were followed up at 1, 2, 4, 6, 9, and 12-month intervals, and the major signs and symptoms were recorded along with adjunctive teeth-related signs and symptoms. Fisher exact probability tests were applied to analyze the results (P<.05). Statistical comparisons of the MAS responses before and after treatment (at 1-month recall) showed significant improvement (P<.05) for all teeth-related signs and symptoms except for bruxism (P=.0699). Further improvement was noted at the 4-month recall period. However, these improvements were not statistically significant for all teeth-related signs and symptoms. No further change was noted after the 4-month recall period. There was a marked reduction in perceived malocclusion and adjunctive teeth-related signs and symptoms during function, only after performing occlusal equilibration of the final restorations.

Assessment of thickness and function of masticatory and cervical muscles in adults with and without temporomandibular disorders

OBJECTIVE

The aim of this study was to evaluate the maximal bite force (MBF), electromyographic (EMG) activity and thickness of the masseter, anterior part of the temporalis and sternocleidomastoid (SCM) muscles in a group of young adults with and without temporomandibular disorders (TMDs).

DESIGN

Nineteen individuals comprised the TMD group (6 males/13 females, aged 25.4±3.8 years), classified based on the Research Diagnostic Criteria for TMD (RDC/TMD), and 19 comprised the control group (6 males/13 females, aged 24.1±3.6 years). The MBF was determined with a transducer placed between the dental arches at the first molars level (N). The muscles were evaluated bilaterally at rest and during maximal voluntary clenching (MVC) by assessing EMG activity and performing ultrasonography (USG). The mean values of these measures for both sides of the mouth were used. The normality of the distributions was assessed by the Shapiro-Wilks test. Variables between groups and genders were compared using two-way factorial ANOVA test and correlated using the Spearman coefficient (α=0.05). Unpaired t test was used to compare variables between TMD subgroups. Logistic regression analysis was used to identify the variables associated with the presence of TMD.

RESULTS

MBF, EMG and USG data were similar among clinical groups and among TMD subgroups. The thickness of masseter and SCM muscles in the relaxed and clenching states were significantly higher in males than females. On the other hand, the EMG of the temporalis muscle in the rest state was significantly higher in females than males. Additionally, the MBF was positively correlated with the USG characteristics of masseter and SCM muscles, as well as with the EMG activity of masseter and temporalis muscles in the TMD group. In this group, there was also a positive correlation between the thickness of the masseter muscle and its activity. On the other hand, the thickness of the SCM muscle was negatively correlated with its activity. A lower MBF was independently associated with the presence of TMD.

CONCLUSIONS

Subjects with TMD exhibited similar values of MBF, thickness and electrical activity of masticatory and cervical muscles when compared with controls; positive correlations observed between these variables may suggest a muscular alteration in TMD patients and a co-activation of masticatory and cervical muscles during mandibular movement. This fact may also be confirmed by the negative association between bite forces and presence of TMD.

Temporomandibular joint disorders in children

A child's difficulty in verbalizing the precise location and nature of facial pain and jaw dysfunction often results in a nondefinitive history, increasing the importance of the dentist's awareness of the early signs and symptoms of temporomandibular joint disorders (TMD). A focused examination of the masticatory musculature, the temporomandibular joints, and associated capsular and ligamentous structures can reveal if a patient's symptoms are TMD in origin. An accurate differential diagnosis enables timely referral to appropriate health care providers and minimizes the use of diagnostic imaging.

Etiological factors of temporomandibular joint disorders

The temporomandibular joint receives its name from the two bones that enter into its formation, namely the temporal bone and the mandible. This complex synovial system is composed of two temporomandibular joints together with their articulating ligaments and masticatory muscles. This articulation affects other synovial joints that relate specifically to masticatory function. The causes of temporomandibular disorders are complex and multifactorial. There are numerous factors that can contribute to temporomandibular disorders. In some instances a single factor may serve one or all of these roles. Iatrogenic injuries can act as both initiating as well as predisposing factors. The term craniomandibular disorder is used synonymously with the term temporomandibular disorders and is considered a major cause of nondental pain in the orofacial pain region. The successful management of temporomandibular disorders is dependent on identifying and controlling the contributing factors. The temporomandibular disorders are more common in females, the reason is not clearly known. The following article provides detailed information regarding temporomandibular joint disorders.

The value of magnetic resonance arthrography of the temporomandibular joint in imaging disc adhesions and perforations

OBJECTIVES

This study attempted to validate MR arthrography (MRAr) of the temporomandibular joint (TMJ) in detecting the position, integrity and relations of the articular disc and retrodiscal tissue.

METHODS

A total of 20 TMJs from 10 patients with severe TMJ dysfunction underwent MRI and MRAr. A paramagnetic contrast medium was injected into the upper joint compartment to observe possible adhesions and/or leakage into the lower compartment. 15 TMJs were surgically or arthroscopically explored and restored.

RESULTS

MRAr was approximately in the same diagnostic value as MRI when locating position, but superior in detecting disc perforations (eight TMJs) and adhesions (seven TMJs) appearing together in four cases. Surgery confirmed radiological findings in all but one case, where arthroscopy and surgery failed to confirm a disc perforation indicated by MRAr.

CONCLUSIONS

TMJ MRAr may simultaneously reveal adhesions and perforations. Sensitivity and the probability of false-positive results require further study.

Ortodontia como fator de risco para disfunções temporomandibulares: uma revisão sistemática

INTRODUÇÃO: nos últimos anos, a inter-relação entre a Ortodontia e as disfunções temporomandibulares (DTMs) tem despertado interesse crescente na classe odontológica, sendo tema de discussões e controvérsias. Em um passado recente, a oclusão era considerada como principal fator etiológico das DTMs, sendo o tratamento ortodôntico uma medida terapêutica primária para um restabelecimento fisiológico do sistema estomatognático. Assim, passou-se a investigar o papel da Ortodontia na prevenção, desencadeamento e tratamento das DTMs. Com a realização de estudos científicos com metodologias mais rigorosas e precisas, a relação entre o tratamento ortodôntico e as DTMs pôde ser avaliada e questionada dentro de um contexto baseado em evidências científicas. OBJETIVO: o presente trabalho, através de uma revisão sistemática de literatura, teve como objetivo analisar a inter-relação entre a Ortodontia e as DTMs, verificando se o tratamento ortodôntico é fator contribuinte para o desenvolvimento de DTM. MÉTODOS: foi realizado um levantamento em bases de pesquisa (Medline, Cochrane, Embase, Pubmed, Lilacs e BBO) entre os anos de 1966 e 2009, com enfoque em estudos clínicos randomizados, estudos longitudinais prospectivos não randomizados, revisões sistemáticas e meta-análises. RESULTADOS: após a aplicação dos critérios de inclusão, chegou-se a 18 artigos, sendo que 12 eram estudos longitudinais prospectivos não randomizados, 4 revisões sistemáticas, 1 estudo clínico randomizado e uma meta-análise, os quais avaliaram a relação entre tratamento ortodôntico e DTM. CONCLUSÕES: pela análise da literatura, conclui-se que o tratamento ortodôntico não pode ser considerado fator contribuinte para o desenvolvimento de disfunções temporomandibulares.

Correlation between centric relation&#x2013;maximum intercuspation discrepancy and temporomandibular joint dysfunction

OBJECTIVE

To investigate the relationship between centric relation-maximum intercuspation (CR-MI) discrepancy and temporomandibular joint dysfunction (TMD) in pre-treated orthodontic patients.

MATERIAL AND METHODS

The study involved an experimental group of 107 pre-treated orthodontic patients with signs and symptoms of TMD aged 18-32 years, and a control group of 70 students with no signs and symptoms of TMD aged 20-30 years. The psychological condition of subjects was evaluated using two standard questionnaires, and a clinical examination performed to assess masticatory musculature and temporomandibular joint (TMJ) function, and to establish the presence or absence of TMD. Helkimo indices, the anamnestic dysfunction index (Ai) and the clinical dysfunction index (Di), were determined. Dental casts were mounted on a semi-adjustable articulator in CR using a CR bite record taken by bilateral manipulation and verified by load testing and face bow records. Differences in condylar position between CR and MI in the three planes of space were determined using the condyle position indicator.

RESULTS

A positive CR-MI discrepancy, defined as a discrepancy exceeding 1 mm in the vertical or horizontal planes or 0.5 mm in the transverse plane, was found in 72.9% of the experimental and 11.4% of the control group. Comparison of the groups showed a significant difference (χ² = 22.67, P < 0.001). CR-MI discrepancy was significantly correlated with Di and Ai in all subjects (P < 0.01).

CONCLUSIONS

There was CR-MI discrepancy in most of the pre-treated patients with signs and symptoms of TMD. This discrepancy may be a contributory factor to the development of TMD in these patients.

Factors of importance for the functional outcome in orthognathic surgery patients: a prospective study of 118 patients

PURPOSE

The aim of this study was to assess the influence of orthognathic surgery on patients' stomatognathic function and, further, to evaluate how post-treatment function relates to satisfaction.

PATIENTS AND METHODS

A total of 118 adult patients (51 men and 67 women) who were treated with orthognathic surgery were examined before and a minimum of 12 months after the surgical intervention. The stomatognathic function was evaluated with Helkimo's Anamnestic and Clinical Dysfunction index. The former was also used to assess a control group of 47 individuals with the same age and gender distribution and with no history of or present need for orthodontic treatment.

RESULTS

A total of 76 patients (64.4%) reported severe dysfunction at the beginning of the treatment, and 24 patients (20.3%) reported severe dysfunction at the end of the treatment. Clinical assessment showed that 36 patients (30.5%) had severe dysfunction symptoms upon inclusion versus only 5 (4.2%) at the final examination. However, 3 patients (2.5%) without clinical dysfunction at the time of inclusion developed mild dysfunction during treatment, and 8 patients (6.8%) developed increased dysfunction during treatment. The patients' functional status after treatment and their degree of satisfaction with the treatment were positively correlated. Although a general improvement was verified, the functional status of those who were treated never reached that of the control group.

CONCLUSION

This study indicates that orthognathic surgery improves patients' stomatognathic function in most cases, and that patients' satisfaction correlated with perceived, reported, and measured function at the end of the treatment.

The relationship between temporomandibular joint pathosis and muscle tenderness in the orofacial and neck/shoulder region

OBJECTIVE

The objective of this study was to investigate the association between TMJ pain/disk pathosis and the muscle tenderness pattern in the orofacial and neck/shoulder region.

STUDY DESIGN

One hundred seventy-one TMD patients were divided into 4 groups, including group 1: patients with painful unilateral TMJ disk displacement (DD); group 2: patients with painless unilateral TMJ DD; group 3: patients with painless bilateral TMJ DD; and group 4: patients with a bilateral normal TMJ disk position (n = 41). Each subject underwent muscle palpation and the side-by-side number of muscle tenderness points was combined as the number of muscle tenderness points on each side. Within each group, DD with and without reduction subjects were separated into subgroups and then were analyzed.

RESULTS

In group 1, the median muscle tenderness points on the side with painful TMJ DD without reduction was significantly higher than on the normal side (P = .019), whereas the palpation scores for painless DD patients showed no significant difference between the DD and normal sides.

CONCLUSIONS

These results indicated painful disk displacement to possibly be correlated with ipsilateral muscle tenderness.

Postural evaluation of patients with temporomandibular disorders under use of occlusal splints

Objectives:

Alterations in the temporomandibular complex can reflect in adaptations of the individual's entire muscular system, intervening with the head position and scapular waist, developing postural alterations and modifying all corporal biomechanics. The aim of this study was to evaluate the head position (HP) and head postural alterations before and after installation of occlusal splints.

Material and Methods:

Twenty patients with temporomandibular disorders (TMD) underwent clinical and postural examination, before the installation of an occlusal splint, and after 1 week and 1 month of use.

Results:

There were statistically differences for HP, between the initial values and after 1 week of use of the occlusal device (p= 0.048) and also between 1 week and 1 month of evaluation (p= 0.001). Decrease of the painful symptomatology and maintenance of the rectification were also observed.

Conclusions:

The individual's postural position can suffer biomechanical alterations due to stomatognathic alterations, causing clinically visible changes in dysfunctional individuals and affecting the performance of the involved structures.

Sinais e sintomas da disfunção temporomandibular nas diferentes regiões brasileiras

O objetivo deste estudo foi avaliar a prevalência da severidade de sinais e sintomas de disfunção temporomandibular (DTM) em não-pacientes nas diferentes regiões do país. Questionários foram aplicados a 2.396 universitários, dos quais 73,7% mulheres (21±5 anos) e 26,3% homens (22±4 anos). Determinado o nível de severidade dos sinais e sintomas da DTM, os dados foram tratados estatisticamente, com nível de significância de 5%. Maior prevalência de sinais e sintomas de DTM foi constatada para o sexo feminino (73,03%). Na região Centro-Oeste não foi observada diferença significante entre estudantes com sinais e sintomas de DTM moderada e severa; mas aí há mais probabilidade de encontrar universitários com sinais e sintomas severos do que nas demais regiões. A região Sul apresentou maior porcentagem de estudantes com sinais e sintomas, porém com menor severidade que nas demais regiões. No Nordeste e no Sul, é mais provável encontrar universitários sem sinais e sintomas que universitárias. Pode-se concluir que a porcentagem de universitários não-pacientes portadores de algum nível de severidade de sinais e sintomas da DTM foi maior que a de não-portadores, em todas as regiões. Diferentes regiões apresentam diferentes probabilidades de se encontrarem universitários com algum sinal ou sintoma de DTM.

Membrane binding of a lipidated N-Ras protein studied in lipid monolayers

The adsorption of doubly lipidated full-length N-Ras protein on 1,2-dipalmitoyl-sn-phosphatidylcholine (DPPC) monolayers was studied by lateral pressure analysis, grazing incidence X-ray diffraction (GIXD), and specular reflectivity (XR). N-Ras protein adsorbs to the DPPC monolayer (lateral pressure of 20 mN/m) from the subphase thereby increasing the lateral pressure in the monolayer by 4 mN/m. The protein insertion does not alter the tilt angle and structure of the lipid molecules at the air/water interface but influences the electron density profile of the monolayer. Further, electron density differences into the subphase were observed. The Fresnel normalized reflectivity could be reconstructed in the analysis using box models yielding electron density profiles of the DPPC monolayer in the absence and in the presence of N-Ras protein. The electron density profiles of the DPPC monolayer in the presence of Ras showed clear intensity variations in the headgroup/glycerol/upper chain region, the so-called interface region where previous bilayer studies had confirmed Ras binding.

Prevalence and associated factors for temporomandibular disorders in a group of Mexican adolescents and youth adults

The objective of the study was to determine the prevalence and associated factors for temporomandibular disorders (TMD) in a university sample of Campeche, Mexico. A cross-sectional study was carried out in 506 subjects aged 14-25 years. The subjects were requested to answer questionnaires concerning sociodemographic variables, history of stress, lifestyle, and anxiety. The Research Diagnostic Criteria for TMD (RDC/TMD) was used as TMD diagnostic system by four examiners capacitated and standardized. Data were analyzed using binary logistic regression in STATA. The results showed that 46.1% of the subjects exhibited some grade of TMD. Logistic regression analysis with TMD as the dependent variable identified sex (women odds ratio [OR]=1.7), bruxism (OR=1.5), anxiety (OR=1.6), unilateral chewing (OR=1.5), and an interaction between number of tooth loss and stress as the most significant associated variables, thus (1) the effect of having high levels of stress in the group of subjects without tooth loss (OR=1.2; 95% confidence interval [CI]=0.7-1.8) and (2) the effect of having high levels of stress in the group of subjects with at least one tooth lost (OR=2.4; 95% CI=1.01-5.9). The variables associated with diagnosis of pain were principally psychosocial (stress and anxiety), whereas for the non-pain diagnosis group, the variables were clinical, such as bruxism, chewing site preference, and restorations in mouth. We found associations among variables that were similar to findings in other studies, such as bruxism, tooth loss, stress, and anxiety. The final model explains that the effect of stress on TMD depends of the tooth loss, controlling for sex, bruxism, unilateral chewing, and anxiety. Finally, it can be concluded that the variables associated with pain and non-pain diagnosis were of distinct nature.

Facial arthralgia and myalgia: can they be differentiated by trigeminal sensory assessment?

Heat and electrical detection thresholds were assessed in 72 patients suffering from painful temporomandibular disorder. Employing widely accepted criteria, 44 patients were classified as suffering from temporomandibular joint (TMJ) arthralgia (i.e. pain originating from the TMJ) and 28 from myalgia (i.e. pain originating from the muscles of mastication). Electrical stimulation was employed to assess thresholds in large myelinated nerve fibers (Abeta) and heat application to assess thresholds in unmyelinated nerve fibers (C). The sensory tests were performed bilaterally in three trigeminal nerve sites: the auriculotemporal nerve territory (AUT), buccal nerve territory (BUC) and the mental nerve territory (MNT). In addition, 22 healthy asymptomatic controls were examined. A subset of ten arthralgia patients underwent arthrocentesis and electrical detection thresholds were additionally assessed following the procedure. Electrical detection threshold ratios were calculated by dividing the affected side by the control side, thus reduced ratios indicate hypersensitivity of the affected side. In control patients, ratios obtained at all sites did not vary significantly from the expected value of 'one' (mean with 95% confidence intervals; AUT, 1:0.95-1.06; BUC, 1.01:0.93-1.11; MNT, 0.97:0.88-1.05, all areas one sample analysis P>0.05). In arthralgia patients mean ratios (+/-SEM) obtained for the AUT territory (0.63+/-0.03) were significantly lower compared to ratios for the MNT (1.02+/-0.03) and BUC (0.96+/-0.04) territories (repeated measures analysis of variance (RANOVA), P<0.0001) and compared to the AUT ratios in myalgia (1.27+/-0.09) and control subjects (1+/-0.06, ANOVA, P<0.0001). In the myalgia group the electrical detection threshold ratios in the AUT territory were significantly elevated compared to the AUT ratios in control subjects (Dunnett test, P<0.05), but only approached statistical significance compared to the MNT (1.07+/-0.04) and BUC (1.11+/-0.06) territories (RANOVA, F(2,27)=3.12, P=0.052). There were no significant differences between and within the groups for electrical detection threshold ratios in the BUC and MNT nerve territories, and for the heat detection thresholds in all tested sites. Following arthrocentesis, mean electrical detection threshold ratios in the AUT territory were significantly elevated from 0.64+/-0.06 to 0.99+/-0.04 indicating resolution of the hypersensitivity (paired t-test, P=0.001). In conclusion, large myelinated fiber hypersensitivity is found in the skin overlying TMJs with clinical pain and pathology but is not found in controls. In patients with muscle-related facial pain there was significant elevation of the electrical detection threshold in the AUT region.

The influence of war stress on the prevalence of signs and symptoms of temporomandibular disorders

The aim of this study was to determine the prevalence of signs and symptoms of temporomandibular disorders in patients with post-traumatic stress disorder (PTSD) occurring as a consequence of exposure to war stress. The examined group consisted of 100 male subjects, aged from 25 to 50 years, who had taken part in the War in Croatia, and in whom PTSD had previously been diagnosed. The control group comprised 100 subjects, without PTSD, of the same sex and age group, who had not taken part in the War. A functional evaluation of the stomatognathic system was performed using the Helkimo Anamnestic and Clinical Dysfunction Index. Eighty-two per cent of the group with PTSD had at least one symptom, and 98% at least one sign of dysfunction. Eight per cent reported mild symptoms and 74% severe symptoms. Twenty-eight per cent showed mild clinical signs, 22% had signs of moderate, and 48% of severe dysfunction. Twenty-four per cent of the control group of subjects had at least one symptom, and 52% at least one clinical sign of dysfunction. Twenty-two per cent reported mild and 2% severe symptoms. Mild clinical signs of dysfunction were found in 50% of subjects in the control group, moderate in 2% and none exhibited severe clinical signs. It is concluded that correlation exists between war stress and temporomandibular disorders.

Histological evaluation of changes in the temporomandibular joint after direct and indirect trauma: an experimental study

Direct or indirect trauma to the temporomandibular joint (TMJ) may cause several injuries such as fibrous adhesion, ankylosis and fracture. The aim of this study was to examine and compare the histological changes of TMJ and adjacent soft tissue after direct or indirect trauma to TMJ. In this study, a total of 35 healthy young adult guinea pigs were exposed to direct and indirect trauma to their TMJ, and histologic evaluation was done after 24 h, 7, 15 and 45 days. Hemorrhage was the most frequent complication, following that enlargement of the disc, adhesion of the disc to the condyle and fracture of the condyle were seen in both groups. There were regenerative changes in adjacent muscles of the TMJ in indirect trauma group when compared to direct trauma group. Regenerative changes were more obvious on days 15 and 45. As a result, it may be suggested that when a trauma comes to the maxillo-mandibular complex, even TMJ is indirectly affected, TMJ and its adjacent soft tissues should also be examined clinically and followed closely.

Use of a habit reversal treatment for temporomandibular pain in a minimal therapist contact format

Previous research has suggested that a habit reversal treatment might be used effectively in a home-based minimal therapist contact (MTC) protocol to facilitate flexibility and increase treatment completion rates. Recent reviews of MTC interventions have found it to be generally efficacious, cost-effective, and generalizable. While MTC has been used for certain health-related disorders (e.g., headache), almost no research has evaluated the effectiveness of a MTC protocol with a population suffering from temporomandibular disorder (TMD). The current study utilized an oral habit reversal treatment in a MTC format in an attempt to reduce attrition and increase treatment flexibility. Twenty females suffering from TMD were randomly assigned to either a treatment (n = 10) or a wait-list control (n = 10) condition. Six individuals in each group used telephone contact while 4 used e-mail for weekly communication with the therapist. Results demonstrated that a habit reversal treatment in a MTC format led to statistically and clinically significant improvements in mean weekly pain ratings, number of pain-free days per week, and highest weekly pain ratings. Also, a significant reduction in maladaptive oral habits occurred from pre- to post-treatment and significant reductions in life stress and pain interference were observed. Results were maintained at follow-up. The implications for the use of MTC for treatment of facial pain are discussed, as are the implications of these findings for the role of oral habits in the etiology of TMD.

Complex orthodontic problems: the orthognathic patient with temporomandibular disorders

The diagnosis and treatment of temporomandibular disorders (TMD) remain controversial despite considerable research and publication in this area. The relationship of these problems to dental and skeletal malocclusion is equally debatable. Recent studies suggest that although malocclusion may have a role, it is a small one. Accordingly, treatment of TMD with occlusion-altering therapy, such as orthodontics and orthognathic surgery, should be limited to specific situations. This report discusses the management of patients with coexisting TMD and skeletal malocclusion. Current concepts in clinical and radiographic diagnosis are discussed, as well as an overview of noninvasive therapy. A case report is used to illustrate an approach to diagnosis and treatment planning in an individual with active TMD and a skeletal malocclusion requiring orthognathic surgery for correction.

Effect of impact and injury characteristics on post-motor vehicle accident temporomandibular disorders

OBJECTIVES

The objective of this study was to assess the potential effects of motor vehicle accident impact and injury characteristics on post-motor vehicle accident temporomandibular disorders in terms of presenting signs and symptoms, diagnoses, treatment regimens, and outcomes.

STUDY DESIGN

A retrospective chart review of 50 patients with post-motor vehicle accident temporomandibular disorders from a private oral medicine practice was undertaken. Various demographic data and data related to temporomandibular disorders and motor vehicle accident impact and injury characteristics were collected. Chi-square and Fisher exact tests and multiple regression analyses were performed.

RESULTS

Patients involved in front-end collisions or motor vehicle accidents resulting in severe vehicle damage reported more direct orofacial injury. However, those in rear-end collisions or accidents resulting in minimal vehicle damage required more treatment. Direct head or orofacial injury was therefore not a prognostic indicator. From multiple regression analyses, indicators of a poorer prognosis were minimal vehicle damage, lack of headrest use, driver position, and settlement of insurance claim.

CONCLUSIONS

In this patients group several prognostic indicators for patients with post-motor vehicle accident temporomandibular disorders were identified; these indicators may influence the management approach for this patient population.

The relationship between signs and symptoms of temporomandibular disorders and bilateral occlusal contact patterns during lateral excursions

The relationship between signs and symptoms of temporomandibular disorders (TMD) and bilateral occlusal contact patterns was investigated in 143 TMD patients (mean age: 34.0 +/- 15.9 years; 38 male and 105 female). In addition to an interview regarding chief complaints and accompanying symptoms, various muscles and the temporomandibular joints were palpated bilaterally and occlusal analyses were made. Only 5 out of 108 paired variables were found to be significantly associated by using the chi-squared test. Medial pterygoid muscle pain on palpation showed significant associations with the occlusal contact pattern (P < 0.005), especially working side contacts (interocclusal tooth contacts on the working side) (P < 0.005), during contralateral excursions; sternocleidomastoid muscle pain on palpation showed a significant association with balancing side contacts (interocclusal tooth contacts on the balancing side) during ipsilateral excursions P < 0.05); shoulder stiffness and pain in the eye showed significant associations with balancing side contacts during contralateral excursions (P < 0.05). The results show only a weak relationship between some TMD symptomatology and bilateral occlusal contact patterns during lateral excursions. The findings suggesting the specific laterality of a few TMD signs and symptoms associated with particular occlusal contacts may deserve closer case-control study.

Multidisciplinary approach to chronic pain from myofascial pain dysfunction syndrome: a four-year experience at a Brazilian center

Chronic pain is the major complaint of myofascial pain dysfunction syndrome (MPDS) and is a complex problem which involves physical, psychological and social aspects. The etiology of MPDS is multifactorial and the multidisciplinary approach is essential for differential diagnosis and for comprehensive treatment planning. In 1993, the Dental School of Piracicaba-UNICAMP, Brazil, opened a Center for Pain Studies (CPS), staffed by health care providers including, dentists, psychologists, physicians, physiotherapists and phonoaudiologists. The major aims of the CPS are to provide clinical care and to develop basic and applied research. Sixty-two MPDS patients had been admitted to the CPS by 1997. There were 60 females and 2 males, mean age-32.5 years. The mean duration of chronic pain was 48 months. Pain intensity and unpleasantness were measured employing the Visual Analogue Scale. The tendency to develop stress-related diseases was assessed by the Social Readjustment Scale. There was a mean reduction of chronic pain of 69.89% and 71.78% relative to intensity and unpleasantness, respectively. The experience of clinical attendance at a multidisciplinary center showed the relevance of a team consisting of health care providers from different specialties with well-established aims, completely integrated and sensitive enough to understand the painful complaints of MPDS patients.

Cognitive factors associated with facial pain

Most well-accepted etiological models of facial pain (e.g., temporomandibular disorders and headache) implicate emotional distress as an important factor in the development and maintenance of pain. Data exists to support the notion that some facial pain sufferers are more emotionally distressed than no pain controls. However, many of these dependent measures of emotional distress are either lengthy assessment batteries, lack clear cut psychotherapeutic treatment implications, or focus exclusively on pain related sequela. As cognitive-behavioral interventions become more integrated into the treatment of chronic pain conditions, including various facial pain conditions, it becomes more imperative that the tools used to assess psychological functioning provide the clinician with specific cognitive/behavioral targets for change. The purpose of this study was to assess the degree to which symptomatic treatment seeking facial pain sufferers (N = 25), symptomatic non-treatment seeking facial pain sufferers (N = 48), and healthy pain-free controls (N = 70) differed on the Rational Beliefs Inventory (RBI). The RBI is a reliable, valid questionnaire assessing rational beliefs that are operationalized within a Rational Emotive Therapy (RET) framework. RET is a cognitive-behavioral treatment paradigm that focuses on how an individual's maladaptive cognitive errors or distortions exacerbate emotional distress. Group differences were assessed using a oneway Analysis of Covariance (ANCOVA) with the total RBI score serving as the dependent measure, and a Multivariate Analysis of Covariance (MANCOVA) using individual RBI belief subscales as dependent measures. These results indicated that groups differed significantly on the total score and several of the individual belief subscales. These findings indicated that facial pain sufferers generally hold maladaptive beliefs that may be of clinical significance for cognitive/behavioral treatment approaches.

Schedule-induced masseter EMG in facial pain subjects vs. no-pain controls

Empirical reports suggest that oral habits (e.g., teeth clenching) may be behavioral mediators linking stress to muscle hyperreactivity and the development of facial pain. Another report suggests that excessive behavioral adjuncts develop in conjunction with fixed-time stimulus presentation. The present study assessed the extent to which the oral habits exhibited by facial pain patients are schedule-induced. Subjects with Temporomandibular Disorder (TMD) symptomatology (n = 15) and pain-free controls (n = 15) participated in a 4-phase experiment (adaptation, baseline, task, recovery) designed to elicit schedule-induced behaviors. Self-report of oral habits and negative affect were recorded after each phase. Objective measures of oral habits were obtained via behavioral observation and masseter EMG recordings. Results revealed that negative arousal significantly increased during the fixed-time (FT) task and was also associated with increased oral habits among the TMD subjects. Moreover, 40% of the TMD subjects and none of the controls exhibited a pattern of EMG elevations in the early part of the inter-stimulus interval that met a strict criteria for scheduled-induced behavior per se. Taken together, these results suggest that the TMD subjects were engaging in schedule-induced oral habits. The adjunctive behavior literature seems to provide a plausible explanation as to how oral habits develop and are maintained in TMD patients, despite their painful consequences.

Temporomandibular disorder: efficacy of an oral habit reversal treatment program

Little attention has been directed at interventions that directly teach facial pain patients to detect, interrupt, and reverse the maladaptive oral habits and cognitions thought to be associated with muscle hyper-reactivity and pain. The present study tested a seven-session structured-group habit reversal treatment intervention for facial pain patients. Nine facial pain subjects participated in treatment groups and seven qualified subjects who did not participate in treatment served as a comparison group. Pre, post, and follow-up assessments included measures of pain and psychological functioning. Subjects in the treatment group improved on all measures of pain relative to those in the comparison group. These improvements were maintained or augmented at four month follow-up assessments suggesting that habit reversal training, particularly in a group format, may provide a cost-effective intervention for facial pain patients.

Achieving improved visualization of the temporomandibular joint condyle and fossa in the sagittal cephalogram and a pilot study of their relationships in habitual occlusion

Improved glenoid fossa and condyle visualization is achieved by adapting the Denar TMJ Orthoceph Slimline Cassette (Denar Corp., Anaheim, Calif.) to sagittal cephalometry. This cassette contains rare-earth intensifying screens to enhance the temporomandibular joint region. A plastic template of circles of varying diameters is positioned so that the appropriate circle size is tangent to the superior, anterior, and posterior borders of the glenoid fossa seen on the resultant radiograph. The planar geometric center of the glenoid fossa is then identified coincident with the center of the template circle. The condyle planar geometric center is similarly identified. The relationships of these centers with respect to each other is described by using a rectangular coordinate system with the origin at the glenoid fossa geometric center. The condyle center is further described as being in any one of four quadrant locations or concentric with the glenoid fossa geometric center. This method was then applied to 38 patients who were free of temporomandibular joint symptoms in a pilot study relating the condyle quadrant location with the dentition in habitual occlusion. Findings revealed 89% of the condyles were in any one of the four possible quadrants. Fifty-three percent of the condyles were located in a downward and forward position (quadrant IV). Eleven percent of the condyle geometric centers were concentric with the glenoid fossa geometric center.

Assessing treatment outcomes in two temporomandibular disorder diagnostic categories employing a validated psychometric test

This study measures the effects of treatment interventions on two classes of temporomandibular disorder (TMD) patients in a dental practice in Ottawa, Canada. Other studies of TMD treatment outcome have employed subjective, largely qualitative and nonquantitative measures of symptom levels to make this type of assessment, rendering such research largely incapable of being replicated. The current study employs the TMJ Scale, a validated and psychometrically-developed symptom inventory, to measure symptom levels before and after treatment. The study first determined the sensitivity (92.1%) and specificity (88.1%) of the TMJ Scale for 219 patients in the practice population. One hundred and eleven consecutive TMD patients completed TMJ Scales prior to treatment, and then were retested after the completion of treatment. Results indicate that patients with symptoms of internal joint derangement reported more symptomatic improvement than those with predominantly muscular symptomology, despite the fact that the latter manifested lower symptom levels initially. Patients with internal derangement symptoms initially presented with lower levels of psychological symptoms than patients with muscular symptoms. Substantial improvements in both groups were noted, employing TMJ Scale percentile rank changes as outcome measures. This study can serve as a model for future research toward establishing baselines for expected TMD symptom improvement.

Negative affectivity, somatic complaints, and symptoms of temporomandibular disorders

This study examined the relationship between trait anxiety, subjective somatic symptoms, and pain associated with temporomandibular disorders (TMD) in a combined cross-sectional and prospective study. Compared with the initial measurements, a significant reduction in anxiety and pain was observed in the follow-up phase (two years after evaluation and therapy). No change in general somatic complaints was found. In both the initial phase and the follow-up phase, a consistent relationship between anxiety, somatic complaints, and TMD-related pain was demonstrated. The results are in agreement with a conceptualization of negative affectivity (e.g., anxiety, distress, tension) as a general dimension of somatopsychic distress. The best predictors of later TMD pain were general somatic complaints, followed by initial pain, and trait anxiety. Significant moderate correlations between anxiety, somatic complaints, and response to muscle palpation (feelings of tenderness) were also found. It is concluded that studies of TMD should incorporate measures of negative affectivity and general somatic complaints because these factors are important predictors of TMD pain, response to treatment, and chronicity.

Informed consent for the prosthodontic patient with temporomandibular disorders. Report of the Committee on Temporomandibular Disorders of the American College of Prosthodontists

The prosthodontic treatment of patients with a history of temporomandibular disorders presents unique risk-management problems because of the varied nature, uncertain prognosis, and frequent recurrence of these disorders. Patients with temporomandibular disorders frequently require managed treatment over extended periods of time and may complicate the delivery and outcome of prosthodontic treatment. Informed consent is needed to protect both the patient and the prosthodontist because it facilitates proper communication, goal setting, and cooperation. The purpose of this article is to discuss the essential elements of informed consent and to present an informed consent program useful in the prosthodontic treatment of patients with temporomandibular disorders.

Effects of splint therapy in TMJ dysfunction: a study using magnetic resonance imaging

This pilot study was undertaken to correlate clinical and MRI diagnoses in seven symptomatic TMJ dysfunction patients and to account, if possible, for the clinical improvement in the signs and symptoms after the use of a maxillary stabilizing splint. The symptomatic TMJs were evaluated by means of MRI prior to splint insertion. Sagittal open/closed, and coronal closed images were obtained with a 0.3 T Fonar MR Scanner. A follow-up MRI was taken after three months of splint therapy for the purposes of a comparative study. All subjects responded positively even at the early phase of splint treatment. By the end of the three month period, six subjects experienced full remission of pain in the TMJ and associated masticatory muscles with one subject experiencing only partial remission following therapy. Baseline MRI study revealed that only three subjects had anterior disc displacement while the other four subjects had normal disc/condyle relationships and morphology. In the follow-up MRI study, there were no signs of recapture of the three anteriorly displaced discs despite there being evidence of improved jaw movement and remission of pain symptoms. The use of MRI in this preliminary study indicates that some but not all TMJ pain dysfunction syndromes are caused by internal derangements of the joint. A larger MRI study using the same clinical parameters is indicated for future research.

Management of orofacial pain in cancer patients

Pain in patients with cancer may arise due to the primary disease, or due to therapy of the malignant disease. Pain may be caused by oral infection, oral mucositis, and by alteration in musculoskeletal and neurological function. The management of orofacial and oropharyngeal pain in patients with cancer is reviewed in this paper.

Mandibular condyle position: comparison of articulator mountings and magnetic resonance imaging

This study evaluated the reliability of jaw positions, the existence of distinct jaw positions, and condyle-disk-fossa relationships in a symptom-free population by using articulator mountings and magnetic resonance imaging (MRI). The subjects examined included 28 men, 22 to 35 years of age, all having Angle Class I molar relationships and no discernible TMJ dysfunction. Records taken included the following: an axiographic face-bow to locate retruded hinge axis position, an interocclusal registration of retruded position (RE), a series of interocclusal registrations for centric occlusion (CO), a leaf gauge-generated centric relation (CR), a series of interocclusal registrations for CR, and MRI. The mandibular position indicator of the SAM articulator (Great Lakes Orthodontics, Ltd., Tonawanda, N.Y.) was used to determine reliability and existence of distinct jaw positions. Magnetic resonance imaging also evaluated jaw positions and anatomic relationships. The results indicate: (1) The articulator analysis of CO and CR is statistically replicable. (2) A distinct jaw position could be demonstrated for CO that was separate from RE and CR. It was not possible to discriminate between RE and CR. (3) Condylar concentricity was observed in half of the sample and remained consistent in RE, CO, and CR. (4) Of the sample 13% demonstrated anteriorly displaced disks that were not influenced by posterior condyle placement. (5) The clinical concept of treating to CR as a preventive measure to improve disk-to-condyle relationships was not supported by this study.