Temporomandibular disorders: a survey of dentists' knowledge and beliefs

Knowledge and awareness about temporomandibular disorder among dentists in India: Questionnaire study and review

AIM

Temporomandibular disorders (TMD) comprise ailments involving the jaw joint (temporomandibular joint) and its associated anatomical structures. The complexity involved in TMD is primarily due to its broad spectrum of conditions, clinical signs and symptoms variability, and multifactorial etiology. Considering the above, the present study was performed to help understand the prevailing knowledge and awareness of TMD among Indian dentists in the context of the new specialty "orofacial pain".

SETTINGS AND DESIGN

Questinnaire study and review.

MATERIALS AND METHODS

The questionnaire was distributed using a web-based portal nationwide among Indian dentists. Dentists were invited to participate, clearly stating that the intent and purpose of the questionnaire was to record the existing knowledge and awareness concerning temporomandibular disorders among Indian dentists. The questionnaire was segregated into three sections: pathogenesis, diagnosis, and management of TMDs. The questions were recorded using a Likert three-point scale (1=agree; 2=disagree; 3=not aware). 310 dentists participated in the survey, among which 105 were general dentists (BDS [Bachelor of Dental Surgery] graduates), and 205 were dentists with specialist training (MDS [Masters of Dental Surgery] graduates).

STATISTICAL ANALYSIS USED

The results obtained from the study participants was used to calculate the percentage and frequency, following which tabulations were made based on graduate type and clinical experience. The values obtained from all three sections were recorded, and the responses were analysed using Pearson's Chi-Square test with statistical significance kept at P < 0.05.

RESULTS

Results of the study disclosed that only 58.1% of general dentists and 46.8% of specialists were confident in handling temporomandibular disorder patients. Splint therapy was the preferred treatment modality for general dentists, whereas dentists with specialist training preferred occlusal rehabilitation.

CONCLUSION

The results of the current survey indicate that Indian dentists lack sufficient training in dental schools on all three sections and face difficulty diagnosing and treating TMDs.

Stress-evoked muscle activity in women with and without chronic myofascial face pain

BACKGROUND

Amplified muscle activity in reaction to daily life stressors might explain chronic pain in temporomandibular disorder (TMD).

OBJECTIVES

To assess whether patients with myofascial TMD pain (MFP) react to standardised stressors with greater masticatory muscle activity than demographically matched controls.

METHODS

A total of 124 female MFP patients and 46 demographically matched and pain-free controls rated distress while performing a series of standardised stress-reactivity tasks (viz., cold pressor test, mental arithmetic test, speech stressor test and reaction time/startle response test) as well as a vanilla baseline control task. Blood pressure was measured before and after each task, and electromyographic (EMG) activity was continuously recorded over the jaw-closing muscles and several non-masticatory muscles during each task. Linear mixed model analyses were used to test the hypothesis that case status, stress-reactivity task and muscle recording site influenced EMG activity.

RESULTS

Stress induction was successful, as evidenced by distress ratings and blood pressure measurements that were significantly elevated during performance of the stress tasks. Participants reported that some of the tasks were stressful in a way that resembled stressors experienced in their daily lives. Elevated muscle activity could be confirmed only for the reaction time/startle response task, where mean EMG activity was elevated more in cases than in controls, specifically in the jaw-closing muscles.

CONCLUSION

These data could not provide clear support for the theory that psychological stressors produce a differential increase in masticatory muscle activity in MFP patients than pain-free controls.

The Prevalence of Temporomandibular Disorders and Dental Attrition Levels in Patients with Posterior Crossbite and/or Deep Bite: A Preliminary Prospective Study

Background

The prevalence of various temporomandibular disorders (TMD) and the severity of attrition in patients with either bilateral or unilateral deep bite and/or posterior crossbite has not been established, nor has the effect of one year of orthodontic treatment on TMD.

Methods

Of 310 patients presenting with suspected TMD, 160 were diagnosed with various TMD and 150 were TMD-free. Diagnosis was according to the Axis I of the Diagnostic Criteria for TMD. All participants underwent a dental examination, and 100 patients were reevaluated after one year of orthodontic treatment. Fisher's exact test and the proportion test with Bonferroni's correction were used for the categorical univariate analysis.

Results

There was a significant association (P < 0.001) between deep bite and dental attrition (wear), but not between crossbite and/or deep bite in patients diagnosed with either painful TMD or disc displacement. The risk of sustaining painful TMD when crossbite presented simultaneously on the anterior and the posterior dentition was 2.625-fold greater than when it presented with a normal bite, although this difference was not significant (P=0.286) due to the lack of statistical power. There was no significant sex-related association between the occurrence of either painful TMD or disc displacement. A reduction in TMD findings was demonstrated after one year of treatment, but no statistical power was reached due to the small sample size.

Conclusions

Deep bite may be related to dental wear but not to pain from TMD and/or disc displacement. Only crossbite that presents simultaneously on the anterior and the posterior dentition (mixed X-bite) may have some effect on the level of pain in TMD, but not on in the prevalence of disc displacement. Confirmation of these conclusions by well-designed studies on larger patient groups is warranted. There was a clinically significant improvement in TMD findings after one year of treatment.

Temporomandibular Disorders: Fundamental Questions and Answers

This review aimed to present the current evidence-based answers to a questionnaire which was developed to evaluate the beliefs and knowledge of dental professionals concerning temporomandibular disorder (TMD). A literature review was conducted using the PubMed/Medical Literature Analysis and Retrieval System Online (MEDLINE), Cochrane, Google Scholar, and Scopus search engines from January 1980 to June 2020 corresponding to TMD diagnosis, causes, management, and consequences. A total of 50 articles were considered relevant and selected for full review. The etiology of TMD is multifactorial and complicated and involves several direct and indirect factors. Orthodontic treatment does not appear to either prevent or relieve TMD to a great degree. Nevertheless, condylar and occlusal stability reduces the risk of TMD development. As a result, an assessment of the function of masticatory system prior to beginning orthodontic therapy is fundamental. If signs and symptoms of TMD are significantly present, they should be managed before any orthodontic intervention. Moreover, psychological disorders are strongly associated with joint and facial pain. Thus, professionals who work with chronic TMD patients need to be aware of the psychological aspects of chronic pain and refer the patient for psychological evaluation when warranted. Future research elucidating a cause-effect relationship and neurobehavioral processes underlining chronic pain should be performed.

Exacerbation of chronic myofascial pain during COVID-19

Objective

The COVID-19 pandemic-related restrictions on the public have led to changes in occupation status and societal behavior which may be linked with adverse effects on mental health. We hypothesized that elevated personal stress induced by COVID-19 may underlie pain exacerbation among individuals with chronic myofascial pain.

Methods

Comprehensive myofascial pain questionnaire among 319 patients registered in our pain clinic. In total, 78 patients with TMD-associated pain responded and 113 patients with pain in other orofacial regions responded.

Results

Patients with chronic TMD pain reported a higher self-rated stress level, which correlated with significantly increased pain intensity, and analgesic consumption. In contrast, patients experiencing non-TMD pain did not report of any increase pain, regardless of their stress levels.

Conclusion

Significant correlation between self-perceived psychosocial stress levels and chronic myofascial pain exacerbation. Patients may benefit from early education and conservative intervention, and avoid uncontrolled increases in consumption of pain relief medication.

Self-Perceived Dentists' Knowledge of Temporomandibular Disorders in Krakow: A Pilot Study

Introduction

The most common nondental orofacial pain conditions are temporomandibular disorders (TMDs). TMD basic examination and clinical management are included in a curriculum of each dentistry programme taught in Poland, but it is not clear how the dentists cope with diagnosis and possible treatment in their routine dental practices. The objective of the present study was to assess a level of self-perceived knowledge of TMD amongst dentists in Poland. Materials and methods. The participants, of whom all studied and graduated from a Polish university, were randomly selected from dental offices in Krakow (Poland). The selected dentists were administered an anonymous questionnaire, which contained questions measuring self-assessment of knowledge of TMD diagnosis and therapy and assessing knowledge of ethology and TMD symptoms.

Results

Only 6.5% of the participants identified their TMD knowledge as very good, 32.3% assessed it as good, 39.3% thought it was sufficient, 20.4% as insufficient, and 1.49% considered it as poor. 9.4% of all participants have attempted to diagnose and treat TMD patients very often, 26.4% declared performing it often, 45.8% rarely, and 18.4% had never made such an attempt. There was a significant relationship between the dentists' knowledge and their attempts at diagnosing and treating TMD patients (p < 0.05).

Conclusion

The level of TMD knowledge amongst the Polish dentists is still insufficient. Raising its level would considerably help the dentists to refer their patients to right specialists for a diagnosis and TMD treatment and/or interdisciplinary management of TMD patients.

The prevalence of posterior crossbite, deep bite, and sleep or awake bruxism in temporomandibular disorder (TMD) patients compared to a non-TMD population: A retrospective study

Objective: To assess the prevalence of posterior crossbite and/or deep bite among patients diagnosed with temporomandibular disorders (TMD) compared to a non-TMD population.Methods: Four hundred ninety-four patients were enrolled: 345 with TMD according to the diagnostic criteria for TMD and 149 without TMD (control group). The chi-square test was used for statistical analysis.Results: A statistically significant association was found between sleep and awake bruxism and painful TMDs (p < .001 for both), but not with disc displacement. There was no association between posterior crossbite and/or deep bite with either painful TMD or disc displacement.Conclusion: Within the study limitations, sleep bruxism and awake bruxism may be related to pain in the TMD, and the severity of a deep overbite and presence of a unilateral or bilateral posterior crossbite should not be considered risk factors or as having any effect on the pain associated with TMD and/or disc displacement.

Dentist's distress in the management of chronic pain control: The example of TMD pain in a dental practice-based research network

We aimed to obtain greater understanding of dentists' distress when they diagnose and treat patients with temporomandibular disorders (TMD), and to explore ways in which TMD can be better treated.We conducted a cross-sectional study based on a questionnaire survey of dentists (n = 148). Dentists were queried using an open-ended questionnaire about distress they experienced when treating patients with TMD. Survey responses were analyzed using mixed methods. Associations between specific dentist and patient characteristics and types of distress were analyzed by one way analysis of variance and residual analysis.One hundred thirteen clinicians responded to the questionnaire, giving a 76% response rate. Thematic analysis identified 6 major themes: difficulty in predicting therapeutic effect and prognosis; difficulty in diagnosis; difficulty in the decision about whether to do occlusal adjustment; difficulty in specifying a cause; difficulty in communicating with patients and mental factors; and health insurance system barriers. Clinicians who reported difficulty in deciding whether to do occlusal adjustment saw significantly more patients who experienced shoulder stiffness and headache (P = .008 and P = .022, respectively). Dentists' knowledge of TMD guidelines was associated with a lower percentage of difficulty in predicting therapeutic effect and prognosis (residual analysis; P = .010).These findings provide important insights into clinician's perception of difficulties with patients experiencing TMD-related pain. Knowledge of the existence of TMD clinical practice guidelines may lower dentist distress, particularly with regard to prognosis. Further studies are needed to decrease dentist's distress and to overcome the evidence-practice gap in TMD treatment.

Knowledge and competence in temporomandibular disorders among Swedish general dental practitioners and dental hygienists

OBJECTIVE

The aim of this study was to investigate knowledge and competence in temporomandibular disorders (TMD) among dentists and dental hygienists working in the public dental service (PDS) in Sweden.

MATERIALS AND METHODS

The study population comprised all general dentists (n = 110) and dental hygienists (n = 80) working in the PDS in two Swedish counties: Kronoberg (K) and Blekinge (B). The participants filled out a questionnaire comprised of 15 questions.

RESULTS

The results of these questions are presented. The overall response rate for the general dentists was 87%, while the rate for the dental hygienists was 71%. Statistically significant differences between the general dentists in the two counties were found regarding the following: education in the field of TMD over the last 5 years (K: 37%, B: 73%), evaluation of occlusion when examining patients with suspected TMD ('always': K: 61%, B: 82%), and a desire for consultation of the OFP (orofacial pain)/TMD specialist by telephone (K: 71%, B: 44%). Regarding the dental hygienists, there was a statistically significant difference concerning the use of the treatment modality 'reassurance' (K: 41%, B: 7%).

CONCLUSIONS

The majority of the dental care providers in both counties - irrespective of professional category - had a positive attitude towards patients with TMD. Knowledge and competence in the field are sparse and require postgraduate education. There is a great need of an OFP/TMD specialist for more complicated patients and a need to implement updated knowledge and competence in the PDS in these two counties.

Overbite and Overjet are not Related to Self-report of Temporomandibular Disorder Symptoms

Overbite and overjet, especially high or low values, have been found in some studies to be associated with temporomandibular disorders (TMD). This study evaluates the relationship between overbite/overjet and three TMD self-report measures (pain, joint noises, limited mouth-opening). Subjects were from two population-based cross-sectional studies (3033 subjects). After adjustment for age and gender, high or low values of overbite were not associated with an increased risk of self-reported TMD pain as compared with a reference category of a normal overbite of 2 to 3 mm (-8 to -1 mm, odds ratio = 0.36, 95% confidence interval = 0.05-2.76; 6 to 15 mm, odds ratio = 1.08, 95% confidence interval = 0.68-1.72). Similar non-significant results were found for overjet and TMD pain, and for the association of overjet/overbite and joint noises or limited mouth-opening. This study provides the strongest evidence to date that there is no association between overbite or overjet and self-reported TMD.

Treatment of temporomandibular disorders - knowledge, attitudes and clinical experience among general practising dentists in Sweden

OBJECTIVE

The aim of the study was to investigate the self-perceived level of knowledge, attitudes and clinical experience in treatment of temporomandibular disorders (TMD) among general practising dentists (GPDs).

MATERIAL AND METHODS

A web-based questionnaire was sent to all GPDs in the public dental health service in the County of Uppsala in 2010 (n = 128) and 2014 (n = 113). The GPDs were asked to answer questions in the following categories: Demographic information, Quality assurance, Clinical experience and treatment, Need for specialist resources in the field of TMD and Attitudes. Between the two questionnaires, the GPDs were offered TMD education and an examination template including three TMD questions was introduced in the computer case files. The results were also compared with a previous questionnaire from 2001.

RESULTS

The response rate was 71% (2010) and 73% (2014). The majority of the GPDs were women (70% in 2010 and 72% in 2014). The reported frequency of taking a case history of facial pain and headache increased between 2010 and 2014. In 2014, the GPDs were more secure and reported higher frequency of good clinical routines in treatment with jaw exercises and pharmacological intervention compared to 2001. Interocclusal appliance was the treatment with which most dentists felt confident and reported good clinical routines.

CONCLUSIONS

The GPDs felt more insecure concerning TMD diagnostics, therapy decisions and treatment in children/adolescents compared to adults. There is a high need for orofacial pain/TMD specialists and a majority of the GPDs wants the specialists to offer continuing education in TMD.

Achieved competences in temporomandibular disorders/orofacial pain: a comparison between two dental schools in Europe

AIMS

The aim was to study achieved competences in temporomandibular disorders (TMD)/orofacial pain (OP) at two universities by comparing student's knowledge and understanding, satisfaction with their education and confidence in their clinical competences of TMD/OP.

METHODS

The study was conducted in collaboration between Malmö University, Sweden—which uses problem-based learning—and the University of Naples Federico II, Italy—which uses traditional educational methods. Final-semester dental students responded to a self-report questionnaire regarding their knowledge and understanding, interpretation of cases histories, clinical experience, satisfaction and confidence in clinical examination, management and treatment evaluation.

RESULTS

No significant difference was found between the students regarding knowledge and understanding. Eighty-seven per cent of the Malmö students and 96% of the Naples students met the criterion on achieved competence. Malmö students had a higher per cent of correct diagnoses than Naples students in the interpretation of case histories. Overall, Malmö students reported most clinical experience and higher confidence than Naple students.

CONCLUSIONS

The main findings were that students from Malmö and Naples were, similar in knowledge and understanding of TMD/OP and in satisfaction with their clinical competences. However, Malmö students perceived more confidence in clinical management of patients with TMD/OP. This may reflect that, besides the theoretical part of the programme, a sufficient level of clinical exposure to patients with TMD/OP is essential to gain competences in TMD/OP.

Validity of self-reported sleep bruxism among myofascial temporomandibular disorder patients and controls

Sleep bruxism (SB), primarily involving rhythmic grinding of the teeth during sleep, has been advanced as a causal or maintenance factor for a variety of oro-facial problems, including temporomandibular disorders (TMD). As laboratory polysomnographic (PSG) assessment is extremely expensive and time-consuming, most research testing this belief has relied on patient self-report of SB. The current case-control study examined the accuracy of those self-reports relative to laboratory-based PSG assessment of SB in a large sample of women suffering from chronic myofascial TMD (n = 124) and a demographically matched control group without TMD (n = 46). A clinical research coordinator administered a structured questionnaire to assess self-reported SB. Participants then spent two consecutive nights in a sleep laboratory. Audiovisual and electromyographic data from the second night were scored to assess whether participants met criteria for the presence of 2 or more (2+) rhythmic masticatory muscle activity episodes accompanied by grinding sounds, moderate SB, or severe SB, using previously validated research scoring standards. Contingency tables were constructed to assess positive and negative predictive values, sensitivity and specificity, and 95% confidence intervals surrounding the point estimates. Results showed that self-report significantly predicted 2+ grinding sounds during sleep for TMD cases. However, self-reported SB failed to significantly predict the presence or absence of either moderate or severe SB as assessed by PSG, for both cases and controls. These data show that self-report of tooth grinding awareness is highly unlikely to be a valid indicator of true SB. Studies relying on self-report to assess SB must be viewed with extreme caution.

Impact of dentists' years since graduation on management of temporomandibular disorders

OBJECTIVES

The aims were to assess the impact of the number of years since dentists' graduation on appraisement of diagnostic needs and utilization of treatment options for temporomandibular disorders (TMD) and to investigate whether increased knowledge in TMD is sufficiently considered in today's dentist's undergraduate curricula and, therefore, represented in more evidence-based TMD management in dentists with less years since graduation.

MATERIAL AND METHODS

A questionnaire regarding knowledge and management of TMD was developed and was subsequently applied in a random sample of 400 dentists in a region in Northern Germany.

RESULTS

Of the 222 dentists (response rate 55.6 %), participating in the study, the frequency of TMD treatment need in the general population was estimated at 21.5 %, with lower values in dentists with more years passed since graduation. Measures regarding utilization of standardized examination forms, perceptions of insufficient specialization, and referrals of patients to TMD specialists indicated a lower quality and certainty in TMD management in participants with less time since graduation. While the provision of splints was a well-established treatment option in initial TMD management of all participants, additional TMD treatment options were mentioned less often, with lower proportions of participants making use of these options within the first decade since graduation.

CONCLUSIONS

Evidence-based TMD management is not fully represented in dental practitioners in Germany. This might be due to an insufficient consideration of TMD management in the dentist's undergraduate curricula.

CLINICAL RELEVANCE

Effective interventions to increase dentists' knowledge and to change dentists' practices in TMD management are required.

Study on self-assessment regarding knowledge of temporomandibular disorders in children/adolescents by Swedish and Saudi Arabian dentists

OBJECTIVE

To estimate the degree of self-assessed knowledge among dentists in Sweden and Saudi Arabia regarding temporomandibular disorders (TMD) in children and adolescents using a summative form of assessment and further to investigate the possible factors that may influence the self-assessed knowledge.

MATERIALS AND METHODS

A questionnaire survey covering four domains (Etiology; Diagnosis and classification; Chronic pain and pain behavior; Treatment and prognosis) regarding TMD knowledge was used. Out of 250 questionnaires (125 in each country) a total of 65 (52%) were returned in Sweden and 104 (83%) in Saudi Arabia.

RESULTS

Self-assessed individual knowledge was significantly associated to the level of actual knowledge among the Swedish groups in the domains Etiology; Diagnosis and classification and Treatment and prognosis (p < 0.05). However, in the Saudi Arabian groups a corresponding significant association was only found in the domain Diagnosis and classification (p < 0.05).

CONCLUSIONS

This study showed that there is a difference in the accuracy of self-assessment of own knowledge between the dentists in Sweden and Saudi Arabia. The Swedish dentists have a better ability to assess their level of knowledge compared to Saudi Arabian dentists regarding TMD in children and adolescents. This difference could be related to several factors such as motivation, positive feedback, reflection, psychomotor, and interpersonal skills, which all are more dominant in the Swedish educational tradition.

Masticatory muscle sleep background electromyographic activity is elevated in myofascial temporomandibular disorder patients

Despite theoretical speculation and strong clinical belief, recent research using laboratory polysomnographic (PSG) recording has provided new evidence that frequency of sleep bruxism (SB) masseter muscle events, including grinding or clenching of the teeth during sleep, is not increased for women with chronic myofascial temporomandibular disorder (TMD). The current case-control study compares a large sample of women suffering from chronic myofascial TMD (n = 124) with a demographically matched control group without TMD (n = 46) on sleep background electromyography (EMG) during a laboratory PSG study. Background EMG activity was measured as EMG root mean square (RMS) from the right masseter muscle after lights out. Sleep background EMG activity was defined as EMG RMS remaining after activity attributable to SB, other orofacial activity, other oromotor activity and movement artefacts were removed. Results indicated that median background EMG during these non-SB event periods was significantly higher (P < 0·01) for women with myofascial TMD (median = 3·31 μV and mean = 4·98 μV) than for control women (median = 2·83 μV and mean = 3·88 μV) with median activity in 72% of cases exceeding control activity. Moreover, for TMD cases, background EMG was positively associated and SB event-related EMG was negatively associated with pain intensity ratings (0-10 numerical scale) on post-sleep waking. These data provide the foundation for a new focus on small, but persistent, elevations in sleep EMG activity over the course of the night as a mechanism of pain induction or maintenance.

Effect of contingent electrical stimulation on jaw muscle activity during sleep: a pilot study with a randomized controlled trial design

OBJECTIVE

To determine the effect of contingent electrical stimulation (CES) on jaw muscle activity during sleep in a double-blinded randomized controlled trial (RCT).

MATERIALS AND METHODS

Eleven patients with myofascial TMD (mean age 37 years) and with a clinical diagnosis of bruxism were included. EMG activity (Grindcare®) was recorded from the anterior temporalis muscle during sleep and analyzed online. Jaw muscle activity related to clenching or grinding triggered an electrical square-wave pulse train (450 ms) adjusted to a clear, but non-painful intensity. TMD patients were randomized into two groups: active treatment with CES or no CES (placebo). Number of EMG episodes/hour sleep was the primary outcome parameter. The following variables were assessed as secondary outcome parameters; number of painful muscles, maximum pain-free jaw opening, characteristic pain intensity, depression scores and Oral Health Impact Profile scores. Numerical Rating Scale scores for self-reported pain and muscle tension were registered for at least 4 nights per week during the experiment.

RESULTS

The number of EMG episodes/hour sleep was significantly reduced (52 ± 12%) in the CES group during the sessions with CES (ANOVA: p = 0.021) compared to baseline. There were no significant differences in the secondary outcome parameters (ANOVA: p > 0.513) or pain or muscle tension scores between groups (p = 0.645). The average duration of sleep hours during the nights with and without CES was not significantly different (p = 0.646).

CONCLUSIONS

These results demonstrate a significant inhibitory effect of CES on jaw muscle EMG activity during sleep in a RCT, but with no effects on self-reported pain.

Temporomandibular Disorders: Knowledge, Attitude and Practice among Dentists in Tehran, Iran

Background and aims

Temporomandibular disorders (TMD) account for the most common orofacial pains rising from musculoskeletal origin. The aim of this study was to investigate the level of knowledge, attitudes and practice of dental practitioners regarding TMD in Tehran, Iran.

Materials and methods

A questionnaire, containing 29 questions on etiology, signs and symptoms, diagnosis and treatment of TMD, was given to 200 randomly selected general dental practitioners and specialists as well as 11 TMD ex-perts.

Results

An overall response rate of 97% was achieved among participants (mean age: 39 ± 8.2 years old; mean years in practice: 11.5 ± 7.4). The mean score of knowledge of TMD was found to be 10.85± 2.54 (of a total of 23). TMD specialists were significantly more knowledgeable than general dental practitioners (p<0.05). With respect to attitude, there was a significant difference among various age groups, and by increasing age and years in practice, the attitude towards TMD had weakened. However, no significant difference was recorded between general dental practitioners’ attitude and that of TMD experts towards TMD. There was a positive correlation between subjects’ knowledge and attitude (P= 0.007, r=0.138).

Conclusion

According to the results, the level of knowledge and attitude of general dental practitioners of Tehran regarding TMD is not desirable. The majority are not willing to admit and treat TMD patients.

Temporomandibular disorders in German and Chinese adolescents

OBJECTIVE

The etiology of temporomandibular disorders (TMD) remains unclear. The aim of this study was, by comparing the prevalence of TMD between adolescents of different ethnic origin, to examine whether certain genetic factors may play a role in causing TMD.

SUBJECTS AND METHODS

We assessed the prevalence of TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) in 1,058 subjects (561 German, 497 Chinese) aged 13 to 18 years from two general population samples.

RESULTS

In total, the prevalence of RDC/TMD diagnoses was 13.9% (N = 147). The difference between German (13.0%, N = 73) and Chinese adolescents (14.9%, N = 74) was not statistically significant. After controlling for the effects of age, gender and orthodontic treatment using multivariable logistic regression analyses, the prevalence of RDC/TMD group II diagnoses (disc displacement) was lower in China than Germany (odds ratio [OR] = 0.5, 95% confidence interval [CI]: 0.3-0.8), whereas the prevalence of RDC/TMD pain diagnoses (group I, III) was higher in China (OR = 3.3, 95%-CI: 1.7-6.5).

CONCLUSIONS

Our study reveals obvious differences in the prevalence of TMD between adolescents of different ethnic origins (Asians and Europeans). These differences cannot be attributed to cultural differences alone, which implies the involvement of genetic factors in the etiology of TMD.

Living with Uncertainty

Temporomandibular disorders (TMDs) are a common group of chronic illnesses. There is evidence that health professionals find them difficult to diagnose and manage. A consequence of this difficulty in diagnosis might be that sufferers of TMDs have an experience of illness comparable with other chronic illnesses. To explore the sufferers’ experience of TMDs, we conducted a qualitative study with a purposive maximum variation sample of secondary care TMD patients. Semi-structured interviews were conducted with the sample and were recorded and transcribed verbatim. Data collection and analysis continued until data saturation (n = 19). For analysis, we broadly followed the constant comparative method and used frameworks to organize the data. The key finding was that a lack of diagnosis caused uncertainty over the nature of the cause of the sufferer’s complaint. This uncertainty reportedly caused negative impacts on sufferers’ daily lives. Clearly, diagnosis of TMDs needs to be encouraged at the first point of contact.

A survey on German dentists regarding the management of craniomandibular disorders

The purpose of the present investigation was to identify the most frequent therapies and, in particular, the prescription patterns for occlusal splints for the management of craniomandibular disorders (CMDs) used by German general dentists and specialists. Additionally, the knowledge and opinion of the practising dentists were examined. All active members of the statutory dental insurance providers of the German North Rhine (n = 5,500) and the Westphalia-Lippe area (n = 4,984) were surveyed with a questionnaire by mail. Results indicated that occlusal splints were the first-choice therapy followed by physiotherapy and occlusal equilibration. In the preceding year, both general dentists and specialists made 30 occlusal splints on average. With regard to high-quality evidence-based recommendations, some statistically significant discrepancies between general dentists and specialists were detected. On the basis of the present data, it seems useful to consider intensifying the topic of CMDs and orofacial pain in future undergraduate dental curricula and in postgraduate training.

Assessment of bruxism in the clinic

Bruxism is a much-discussed clinical issue in dentistry. Although bruxism is not a life-threatening disorder, it can influence the quality of human life, especially through dental problems, such as tooth wear, frequent fractures of dental restorations and pain in the oro-facial region. Therefore, various clinical methods have been devised to assess bruxism over the last 70 years. This paper reviews the assessment of bruxism, provides information on various assessment methods which are available in clinical situations and discusses their effectiveness and usefulness. Currently, there is no definitive method for assessing bruxism clinically that has reasonable diagnostic and technical validity, affects therapeutic decisions and is cost effective. One future direction is to refine questionnaire items and clinical examination because they are the easiest to apply in everyday practice. Another possible direction is to establish a method that can measure actual bruxism activity directly using a device that can be applied to patients routinely. More clinical studies should examine the clinical impact of bruxism on oral structures, treatment success and the factors influencing the decision-making process in dental treatment.

Bruxism physiology and pathology: an overview for clinicians

Awake bruxism is defined as the awareness of jaw clenching. Its prevalence is reported to be 20% among the adult population. Awake bruxism is mainly associated with nervous tic and reactions to stress. The physiology and pathology of awake bruxism is unknown, although stress and anxiety are considered to be risk factors. During sleep, awareness of tooth grinding (as noted by sleep partner or family members) is reported by 8% of the population. Sleep bruxism is a behaviour that was recently classified as a 'sleep-related movement disorder'. There is limited evidence to support the role of occlusal factors in the aetiology of sleep bruxism. Recent publications suggest that sleep bruxism is secondary to sleep-related micro-arousals (defined by a rise in autonomic cardiac and respiratory activity that tends to be repeated 8-14 times per hour of sleep). The putative roles of hereditary (genetic) factors and of upper airway resistance in the genesis of rhythmic masticatory muscle activity and of sleep bruxism are under investigation. Moreover, rhythmic masticatory muscle activity in sleep bruxism peaks in the minutes before rapid eye movement sleep, which suggests that some mechanism related to sleep stage transitions exerts an influence on the motor neurons that facilitate the onset of sleep bruxism. Finally, it remains to be clarified when bruxism, as a behaviour found in an otherwise healthy population, becomes a disorder, i.e. associated with consequences (e.g. tooth damage, pain and social/marital conflict) requires intervention by a clinician.

The Role of Tooth-Grinding in the Maintenance of Myofascial Face Pain: A Test of Alternate Models

OBJECTIVE

While mechanisms of myofascial face pain are poorly understood, bruxism has been implicated in the maintenance of this painful disorder. This study evaluates whether evidence of one aspect of bruxism, tooth-grinding, is positively associated with pain severity, as predicted by a psychophysiological model, or negatively associated, as predicted by an adaptation model of face pain.

PATIENTS

Participants were 51 women who met Research Diagnostic Criteria for the myofascial subtype of temporomandibular disorder.

OUTCOME MEASURES

Tooth-grinding was quantified by changes in microwear features of the molar teeth over 2 weeks. Palpated pain severity was quantified on an 11-point scale in response to palpation of the skin overlying the masseter and temporalis muscles bilaterally. Other measures included validated scales of spontaneous pain severity, stress, distress, and psychological symptoms. Association was quantified as Pearson correlation coefficients.

RESULTS

Data showed an inverse correlation (r = -0.37, P < 0.05) between palpated pain severity and the index of tooth wear, supporting the adaptation model. This correlation provided a weighted average of a strong effect (r = -0.80, P < 0.01) seen in those women reporting pain only the right side of their face with an effect that approximated zero in those reporting bilateral pain. Tooth wear measures were negatively associated with ratings of pain severity only over the right masseter.

DISCUSSION

While these data do not address the role of clenching, they cast serious doubt on the theory that myofascial face pain is maintained by tooth-grinding.

'Management is a black art' – professional ideologies with respect to temporomandibular disorders

OBJECTIVE

To gain a deeper understanding of the range of influences on the full range of dental professionals who provide treatment for temporomandibular disorders (TMD).

DESIGN

Qualitative semi-structured interviews.

SETTING

Primary and secondary care in the North and South of the United Kingdom.

SAMPLE AND METHOD

A criterion-based purposive sample was taken of dental practitioners, comprising primary and secondary care practitioners. In-depth interviews were conducted and data collection and analysis occurred concurrently until data saturation was achieved. DATA AND DISCUSSION: There was a reported lack of adequate remuneration for provision of treatment for TMD within primary care. This alongside the primary care practitioners' reported uncertainty in diagnosis of TMD appeared to lead to a propensity for referral to secondary care. Practitioners recognised a poor and scanty evidence base on which to base their care, and this allowed for idiosyncratic practice. Often the outcome measure for treatment was a subjective questioning of the patient focussing mainly on relief of pain.

CONCLUSION

There is a need for better quality evidence on which to base TMD treatment, more continuing professional development and improvement in contracting arrangements to enable primary practitioners to feel confident in managing TMD.

Reliability of clinician judgements of bruxism

Bruxism is considered to be a parafunctional disorder requiring treatment and is viewed as a risk factor for the development of temporomandibular disorders (TMDs). The purpose of this investigation is to examine the reliability of clinician judgements of bruxism severity. Twenty dentists who are faculty members in a dental school examined 29 stone casts and gold-plated models of individual teeth for evidence of bruxism. Ordinal ratings of bruxism severity for the 29 augmented models were made on two occasions, approximately 3 months apart. Inter-rater reliability among all clinicians, evaluated using intraclass correlation coefficients (ICCs), was poor at both time one and time two (i.e. ICC = 0.33 and 0.32, respectively), with somewhat better reliability found among those clinicians with above-average time elapsed since completion of dental training (i.e. ICC = 0.48 and 0.50 for time 1 and time 2, respectively). Three-month test-retest reliabilities were fair (ICC = 0.46) for the full group of raters and were unrelated to clinicians' degree of confidence in their ratings. These results indicate a need to standardize methods for clinical assessment of bruxism. Additionally, they have implications for studies using clinical assessments of bruxism to test the association between bruxism and other conditions such as TMDs.

Is bruxism severity a predictor of oral splint efficacy in patients with myofascial face pain?

Both the efficacy and mechanism of any effect of oral splint therapy for patients with temporomandibular disorders (TMDs) are a matter of controversy. To address these issues, this study tested the hypothesis that oral splints produce the most marked pain relief for those TMD patients with myofascial face pain (MFP) who also brux (i.e. grind or clench) more than other MFP patients. In a 6-week randomized controlled clinical trial, 52 women with MFP were randomly assigned to receive either a full-coverage hard acrylic splint or a palatal-only splint. Bruxism was assessed both by self-report and by an objective assessment of molar microwear changes over a 2-week period prior to the start of the trial. Tested across multiple outcome measures, results indicated that those receiving the full-coverage splint had marginally better improvement on some pain-related measures than those receiving the palatal splint, but severity of bruxism did not moderate the therapeutic effect of the full-coverage splint. These findings strongly argue against the belief that oral splints reduce MFP by reducing bruxism and raise questions about the importance of bruxism in the maintenance of MFP.

Temporomandibular disorders: a review of current understanding

OBJECTIVE

The purpose of this article is to conduct a narrative review of current evidence regarding the understanding, evaluation, management, and treatment of temporomandibular disorders to provide a broad perspective and updated introduction to an important and controversial subject with rapidly changing developments and limited well-designed research.

DATA SOURCES

Studies were identified through a search of MEDLINE for 3 topics (temporomandibular disorder, temporomandibular joint, and chronic pain) over a 10-year period (January 1988 to August 1998) and of bibliographies of identified studies and review articles.

STUDY SELECTION

More than 5000 articles were produced. In-depth review of all of this literature was beyond the scope of the present article, which is intended to provide an overview. The amount and diversity of the literature and the limitations of covering such a broad topic being recognized, the papers selected were those that reviewed limited topics or studied focused areas. This report is not a systematic (qualitative) or meta-analysis (quantitative) review. An acknowledged limitation of this narrative review method lies in the potential for bias in selection. The referenced works do not include all papers reviewed; only pertinent literature and reviews with comprehensive references were selectively included.

CONCLUSIONS

Advances in basic and clinical science have resulted in important changes in the understanding and management of temporomandibular disorders. Many treatments are not supported by research, and the role of dentistry is changing to a more diagnostic and management-based model from the hands-on treatment procedures of the past. The present science-based understand-ing of a biopsychosocial disorder is important in properly and responsibly dealing with patients with temporomandibular disorders.

Medical legal considerations in temporomandibular disorders

Dentists commonly see patients with temporomandibular disorders who are involved in litigation, and dentists are occasionally accused of temporomandibular disorder-related negligence. Rapidly changing scientific knowledge must be reflected in dental practice and in the courtroom, where dentists act as experts. In this article, concepts pertaining to assessments of patients with temporomandibular disorders for impairment and disability and concepts pertaining to legal causation are discussed, especially in relation to motor vehicle accidents. Recommendations for avoiding malpractice suits are presented.

Osteonecrosis of the mandibular condyle. Pathophysiology and core decompression

Deviations of the condylar form are usually ascribed to "degenerative arthritis" or "osteoarthritis." More recently, osteonecrosis has been discussed as a possible cause of condylar degeneration and pain. This article presents a review of the literature on osteonecrosis, emphasizing the spectrum of degenerative osseous disease, which includes osteoarthrosis, condylsis, osteomyelitis, and osteonecrosis. Preliminary results of mandibular core decompression with and without bone grafting are presented suggesting a therapeutic benefit. Further study is recommended to elucidate this process.

Chronic illness of the temporomandibular joints as experienced by support-group members

PURPOSE

For temporomandibular disorders, the clinical situation is one of considerable etiologic, diagnostic, and therapeutic uncertainty. Using interview data, this report describes this condition and the search for care from the perspective of sufferers who are support-group members.

PARTICIPANTS AND METHODS

Thirty-two individuals participated; all were members of a support group for individuals with long-term problems attributed to the temporomandibular joints and/or the surrounding masticatory muscles. Using a structured, open-ended interview format, this study investigated how individuals understand and give meaning to their symptoms, their patterns of care seeking, and the consequences of the illness on their lives. The participants also completed several structured questionnaires.

RESULTS

For these support-group members, symptoms extended beyond the jaw and surrounding area, with extensive musculoskeletal involvement and resulting dysfunctions that have far-reaching consequences for the sufferers' lives. Primary care physicians are often consulted, especially early in the illness history. They also provide ongoing care and are asked for guidance when patients seek specialized treatment. A striking aspect of the findings from the interviews is the complex and costly pattern of health care seeking. This extended search for effective treatment is examined with reference to culturally based understanding, shared by patients and clinicians, about the nature of illness.