Reciprocal influence on the incidence of symptoms in trigeminally and spinally innervated areas

Prevalence of Painful Temporomandibular Disorders and Overlapping Primary Headaches Among Young Adults

BACKGROUND

Large population-based estimates of the prevalence of painful temporomandibular disorders (p-TMD) utilising standardised screening tools are scarce and have not investigated the prevalence of overlapping primary headaches. We aimed to estimate the prevalence of p-TMD in a large population of young adults (18 to 23 years) and to estimate the co-occurrence of p-TMD and two primary headaches, migraine and tension-type headache (TTH). The study also aimed to examine the extent of psychological (PHQ-4) and physical (PHQ-15) comorbidities and report prevalence across three gender categories (women, men and other).

METHODS

Survey data from the Danish National Birth Cohort were collected (n = 11,982), in a cross-sectional observational design. A sensitivity analysis was conducted to address participation bias, revealing minimal impact on the estimates.

RESULTS

The overall prevalence of p-TMD was 26.4% with gender-specific prevalence of women: 31.5%, other: 39.2% and men: 16.8%. Among those with p-TMD, 80.5% reported headaches at least once a month, and 13.8% over 15 days monthly. For the p-TMD individuals with a medical headache diagnosis, 31.9% experienced TTH and 10.9% migraine. The study also identified a higher proportion of moderate/severe psychological distress and physical symptoms in the p-TMD group compared to the non-p-TMD group. Logistic regression revealed a positive association between PHQ-4 and p-TMD, modified by gender (p = 0.016).

CONCLUSIONS

High overall prevalence of p-TMD and overlapping primary headaches was found in young adults. In addition, the study reports gender-specific associations between p-TMD, psychological distress and physical comorbidities indicating that this association is stronger for men than for women.

SIGNIFICANCE STATEMENT

This study found a higher-than-expected prevalence of painful temporomandibular disorders in young adults. It is based on a large population cohort and used standardised and validated screening tools. The study also reported common co-occurrence of primary headaches and explored gender differences. The study raises awareness for a possibly underestimated health burden in young individuals, particularly among individuals experiencing psychological distress and multiple physical symptoms.

Risk factors for temporomandibular disorders: a systematic review of cohort studies

OBJECTIVE

A systematic review was performed to synthesize and identify risk factors involved in TMD onset.

STUDY DESIGN

Electronic searches were conducted in PubMed, Web of Science, Scopus, Embase, PsyInfo and Lilacs databases, as well as in three gray literature databases (Google Scholar, ProQuest and Open grey). The studies were blindly assessed by two reviewers and selected by a pre-defined eligibility criterion. Risk of bias of included studies was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Cohort Studies. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was evaluated for most related factors.

RESULTS

Twenty-one cohort studies were included. Significant factors were female gender, symptoms of depression and anxiety, perceived stress, sleep quality, symptoms of obstructive sleep apnea and presence of any comorbidity, such as Irritable Bowel Syndrome, lower back pain, headache frequency, tension-type headache, migraine and mixed headache. Moreover, high estrogen and low testosterone levels in utero, greater pain perception, jaw mobility pain, pain during palpation, orofacial anomalies, as well as extrinsic and intrinsic injuries were also significant.

CONCLUSIONS

Several factors seems to be involved in TMD onset, however, more studies with standardized methodology are necessary to confirm these findings.

Calcitonin Gene-Related Peptide-Mediated Trigeminal Ganglionitis: The Biomolecular Link between Temporomandibular Disorders and Chronic Headaches

A bidirectional causal relationship has been established between temporomandibular disorders (TMDs) and chronic headaches. Recent advances in the neurobiology of chronic pain offer a framework for understanding the comorbidity between these two conditions that might reside in the shared biomolecular mechanisms of peripheral and central sensitization. The initiation of these processes is inflammatory in nature and is most likely mediated by key molecules, including calcitonin gene-related peptide (CGRP). This scoping review proposes that CGRP-mediated neuroinflammation in the trigeminal ganglion may partly explain the biomolecular bidirectional link between TMDs and chronic headaches. Finally, clinical implications of this neuropathologic process are briefly discussed.

Pain in the temple? Headache, muscle pain or both: A retrospective analysis

AIM

Headache attributed to temporomandibular disorders and myalgia are two diagnoses included in the diagnostic criteria for temporomandibular disorders (DC/TMD). However, it is not clear if these two diagnoses are different clinical entities given their similar presentation and way in which they are diagnosed, when the myalgia is within the temporalis muscle. The purpose of this retrospective study was to assess the overlap between headache attributed to temporomandibular disorders and myalgia of the temporalis muscle.

METHODS

The charts of 671 patients seeking treatment at the Section of Orofacial Pain and Jaw Function, Aarhus University, Denmark, between January 2015 and February 2020 were screened for a diagnosis of headache attributed to temporomandibular disorders, myalgia of the temporalis muscle, or both.

RESULTS

A total of 89 patients fulfilled the DC/TMD criteria for either headache attributed to TMD, myalgia of the temporalis or both. Of these, two had a diagnosis of headache attributed to TMD, 16 of myalgia of the temporalis, and 71 were diagnosed with both. In 97.3% of the times that headache attributed to temporomandibular disorders was diagnosed, the patient was also diagnosed with myalgia of the temporalis. The Jaccard index was 0.8, indicating a substantial overlap between the two diagnoses. Finally, the overlap of pain location between the two diagnoses was substantial, with a Jaccard index of 0.9.

CONCLUSIONS

In the present study, headache attributed to temporomandibular disorders was almost exclusively diagnosed together with myalgia of the temporalis. Therefore, we propose that headache attributed to temporomandibular disorders and myalgia of the temporalis muscle have more clinical similarities than differences and as such could be considered one single clinical entity. Further studies will be needed to address the clinical consequences of this proposal.

Clinical, psychological, and sensory characteristics associated with headache attributed to temporomandibular disorder in people with chronic myogenous temporomandibular disorder and primary headaches

Background

Headache attributed to Temporomandibular Disorder (HATMD) is a secondary headache that may have features resulting in diagnostic overlap with primary headaches, namely, tension-type (TTH) or migraine. This cross-sectional study of people with both chronic myogenous TMD and primary headaches evaluated characteristics associated with HATMD.

Methods

From a clinical trial of adults, baseline data were used from a subset with diagnoses of both TMD myalgia according to the Diagnostic Criteria for TMD (DC/TMD) and TTH or migraine according to the International Classification of Headache Disorders, 3rd edition. HATMD was classified based on the DC/TMD. Questionnaires and examinations evaluated 42 characteristics of facial pain, headache, general health, psychological distress, and experimental pain sensitivity. Univariate regression models quantified the associations of each characteristic with HATMD (present versus absent), headache type (TTH versus migraine), and their interaction in a factorial design. Multivariable lasso regression identified the most important predictors of HATMD.

Results

Of 185 participants, 114 (61.6%) had HATMD, while the numbers with TTH (n = 98, 53.0%) and migraine (n = 87, 47.0%) were similar. HATMD was more likely among migraineurs (61/87 = 70.1%) than participants with TTH (53/98 = 54.1%; odds ratio = 2.0; 95%CL = 1.1, 3.7). In univariate analyses, characteristics associated with HATMD included pain-free jaw opening and examination-evoked pain in masticatory muscles and temporomandibular joints (TMJ) as well as frequency and impact of headache, but not frequency or impact of facial pain. Lowered blood pressure but not psychological or sensory characteristics was associated with HATMD. Multiple characteristics of facial pain, headache, general health, and psychological distress differed between TTH or migraine groups. Few interactions were observed, demonstrating that most characteristics’ associations with HATMD were consistent in TTH and migraine groups. The lasso model identified headache frequency and examination-evoked muscle pain as the most important predictors of HATMD.

Conclusions

HATMD is highly prevalent among patients with chronic myogenous TMD and headaches and often presents as migraine. In contrast to primary headaches, HATMD is associated with higher headache frequency and examination-evoked masticatory muscle pain, but with surprisingly few measures of facial pain, general health, and psychological distress. A better understanding of HATMD is necessary for developing targeted strategies for its management.

Trial identification and registration

SOPPRANO; NCT02437383. Registered May 7, 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01255-1.

Dentists working conditions - factors associated with perceived workload

BACKGROUND

Dentists are often exposed to occupational health hazards such as stress, high workload, and ergonomic and mental strain. However, there are limited studies focussing on occupational health and factors associated with working conditions. The aim of this study was to identify possible gender differences and factors associated with a high workload.

METHOD

The study population comprised of 187 dentists (123 women and 64 men) who had been working between 5 and 12 years. All participants completed a questionnaire regarding perceived workload and different working conditions. In the logistic regression analyses, gender and employment (employee or employer/manger), influence over work, social support, ergonomics, and working hours were used as independent covariates.

RESULTS

Poor satisfaction with ergonomic conditions and low influence on the work situation were reported by 40 and 47% of the participants, respectively. Female dentists were more often employees, reported lower influence over work situation, and more often worked part-time compared to male dentists. Those who reported a high workload significantly more often experienced that they had low influence over work, low levels of social support, and were not satisfied with ergonomic working conditions.

CONCLUSION

Dentists with low influence over work, low levels of social support, and who were unsatisfied with the ergonomic conditions reported higher levels of workload. The dentists experienced a similar workload, regardless of employment and gender. Preventive actions at the workplace in order to maintain a moderate workload promote both individual and organizational measures, to minimize the risk of poor occupational health.

Prevalence of temporomandibular disorder in adult patients with chronic pain

Objectives

Chronic pain patients often suffer in multiple locations. In health care, examinations of bodily pain usually do not include questions about temporomandibular disorders (TMD); hence TMD symptoms and potential comorbidities are not regularly assessed. Therefore, the primary aim was to evaluate the prevalence of TMD in patients referred to a pain rehabilitation clinic, and the secondary aim was to evaluate possible factors associated with TMD symptoms.

Methods

Consecutive chronic pain patients referred to the Pain Rehabilitation Clinic at the Umeå University Hospital in Sweden were included. TMD symptoms were assessed using three valid screening questions – 3Q/TMD. Pain sites, emotional distress, kinesiophobia, and demographics were obtained from the Swedish Quality Registry for Pain Rehabilitation.

Results

In total, 188 (144 women) chronic pain patients (mean age 41.8 years) were included. Of these, 123 (96 women) answered affirmatively to at least one of the 3Q/TMD. The relative risk of TMD symptoms among the patients with chronic pain, in comparison to the general population, was 7.1 (95% CI 5.9–8.4). Age was the only independent variable associated with TMD among the patients (p = 0.018).

Conclusions

The prevalence of TMD symptoms was higher in a chronic pain population compared to the general population. The 3Q/TMD questionnaire could be a suitable screening tool at pain rehabilitation clinics to identify patients for further examination of involvement of pain in the trigeminal region. Our results reinforce the clinical importance of paying attention to concurrent widespread pain and local TMD symptoms.

Increased Risk of Migraine in Patients with Temporomandibular Disorder: A Longitudinal Follow-Up Study Using a National Health Screening Cohort

Background: The aim of this study was to investigate the association between temporomandibular disorder (TMD) and migraine through a longitudinal follow-up study using population data from a national health screening cohort. Methods: This cohort study used data from the Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2015. Of the 514,866 participants, 3884 TMD patients were matched at a 1:4 ratio with 15,536 control participants. Crude models and models adjusted for obesity, smoking, alcohol consumption, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, and Charlson Comorbidity Index (CCI) scores were calculated. Chi-squared test, Kaplan–Meier analysis, and two-tailed log-rank test were used for statistical analysis. Stratified Cox proportional hazard models were used to assess hazard ratios (HR) and 95% confidence intervals (CIs) for migraine in both control groups. Results: The adjusted HR for migraine was 2.10 (95% CI: 1.81–2.44) in the TMD group compared to the control group, which was consistent in subgroup analyses according to age, sex, and Kaplan–Meier analysis. Conclusions: This study demonstrated that TMD patients have a higher risk of migraine. These results suggest that dentists can decrease the risk of migraine in TMD patients by managing TMD properly.

Work ability and productivity among dentists: associations with musculoskeletal pain, stress, and sleep

Purpose

Work ability can be measured by the work ability index (WAI), and work-related questions measuring productivity loss in terms of quality and quantity of work. Dentists have high occupational risk of musculoskeletal pain and the exposure of ergonomic strain is already high during dental education. The aim was to evaluate work ability and productivity among dentists, and to identify gender differences and associations with sleep, stress, and reported frequent pain.

Methods

The study population comprised 187 dentists (123 women and 64 men) who had been working as dentists between 5 and 12 years. Participants completed a questionnaire regarding sleep, stress, presence of pain at different sites, work ability assessed by WAI, and productivity in terms of quality and quantity of work.

Results

Poor sleep quality and high level of stress were reported by 31% and 48.1% of participants, respectively, with no gender differences and no association with age. The prevalence of frequent pain ranged 6.4–46.5% with shoulders being the most prevalent site. Thirty-three percent reported reduced work ability. Poor sleep, high amount of stress, and multi-site pain were associated with decreased work ability.

Conclusions

A high prevalence of pain was shown among dentists. Decreased work ability in terms of productivity loss was associated with poor sleep quality, high amount of stress, and multi-site pain. Preventive actions at the workplace should promote good musculoskeletal health, and measures taken, both individual and organizational, to minimize the risk of high, persistent stress and work-related pain.

Patients' experiences of supervised jaw-neck exercise among patients with localized TMD pain or TMD pain associated with generalized pain

Objective: To evaluate temporomandibular disorder (TMD) patients' experiences of a supervised jaw-neck exercise programme. Materials and methods: The study used a mixed method design. All patients were diagnosed with myalgia according to the Research Diagnostic Criteria for TMD and divided into local myalgia (n = 50; 38 women, mean age 43 yrs, SD 14), and myalgia with generalized pain (n = 28; 27 women, mean age 43 yrs, SD 13). Patients participated in a ten-session supervised exercise programme that included relaxation, coordination and resistance training of the jaw, neck and shoulders. After the 10 sessions an evaluation form was filled out including both open- and closed-ended questions. The quantitative analysis was based on closed-ended questions concerned experience, adaptation and side-effects from the exercise programme. The qualitative analysis was employing inductive content analysis of open-ended questions. Results: Patients reported similar positive overall experiences of exercise regardless of diagnosis, although more individuals in the general pain group experienced pain during training (57%) compared to the local pain group (26%; p = .015). Patients in both groups shared similar experiences and acknowledged the possibility to participate in an individualized and demanding exercise programme. They expressed feelings of being noticed, taken seriously and respectful care management to be key factors for successful treatment outcome. The exercise programme was acknowledged as a valuable part of treatment. Conclusion: The hypothesis generated was that individualized and gradually demanding exercise in the rehabilitation process of TMD stimulates self-efficacy and confidence in chronic TMD patients regardless of whether the pain was localized or combined with wide-spread pain.

Prevalence and occupational risk factors of musculoskeletal diseases and pain among dental professionals in Western countries: A systematic literature review and meta-analysis

Background

This review aimed at examining the prevalence of musculoskeletal diseases and pain among dental professionals in Western countries. Furthermore, possible occupational risk factors were analyzed.

Methods

The literature search was conducted from June to July 2016, with an update in December 2017 using the databases MEDLINE, CINAHL, LIVIVO, Science Direct, PubMed, and Web of Science. The quality assessment was performed with a standardized instrument consisting of 10 items. A meta-analysis was carried out to compute pooled prevalence rates for musculoskeletal diseases and pain.

Results

A total of 41 studies were included in this review; 30 studies met the criteria for the meta-analysis. Prevalence rates of musculoskeletal diseases and pain among dental professionals ranged from 10.8% to 97.9%. The neck was the body region affected most often (58.5%, 95% CI = 46.0–71.0) followed by the lower back (56.4%, 95% CI = 46.1–66.8), the shoulder (43.1%, 95% CI = 30.7–55.5) and the upper back (41.1%, 95% CI = 32.3–49.9). Potential occupational risk factors included an awkward working posture, high number of treated patients, administrative work, vibration, and repetition.

Conclusions

Musculoskeletal diseases and pain are a significant health burden for dental professionals. This study showed high prevalence rates for several body regions. Therefore, suitable interventions for preventing musculoskeletal diseases and pain among dental professionals are needed.

Temporomandibular disorder and comorbid neck pain: facts and hypotheses regarding pain-induced and rehabilitation-induced motor activity changes

According to the "pain adaptation model", temporomandibular disorder (TMD)-related pain induces a paradoxical activity of masticatory muscles: an agonistic hypoactivity during jaw closing and an antagonistic activity during jaw opening (agonist/antagonist co-activation). However, this model suffers several weaknesses; notably, it does not explain all types of neck muscle activities in neck pain (NP), which is a very prevalent TMD comorbid condition. In NP, neck muscle antagonistic activity is increased, and agonistic activity is decreased as postulated by the pain adaptation model. However, synergistic and compensatory activity may occur and agonistic activity may be unchanged or even increased as postulated within the "vicious cycle theory". Thus, both theories would apply partly as outlined currently in musculoskeletal disorders (MSD). Besides pain, psychological stress may also induce motor dysfunction in TMD and NP. In NP, rehabilitation may increase agonistic activity and decrease compensatory activity and antagonistic activity, thus inducing a switch from agonist/antagonist co-activation towards reciprocal inhibition. Thus, rehabilitation-induced motor activity changes constitute a new research field that should improve MSD therapeutics. Additionally, immature tongue function (so-called infantile swallow) might be connected to TMD where low agonistic activity of masticatory muscles would be compensated by facial muscle hyperactivity during oropharyngeal phase of deglutition.

Similar treatment outcome in myofascial TMD patients with localized and widespread pain

OBJECTIVE

To study the outcome of oral appliance treatment in myofascial Temporomandibular disorder (TMD) patients with and without comorbid pain using pain site drawings.

MATERIAL AND METHODS

This randomized, controlled multicentre study comprised 65 myofascial TMD patients diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders. Pain-site drawings were filled in at the baseline examination. The patients were treated with oral appliances. Treatment outcome was followed up for 1 year and analysed according to the recommendations by the Initiative on Methods, Measurement and Pain assessment in Clinical Trials (IMMPACT) on an intent-to-treat basis. The data were analysed for two pain profiles, localized pain (face and head, n = 26) versus widespread pain group (pain sites outside the face and head, n = 39).

RESULTS

Statistically significant improvement was registered within both groups for all outcome variables (characteristic pain intensity, 30% pain reduction of worst reported pain, graded chronic pain, depression, and somatization scores) during the follow-up with only small differences between the groups.

CONCLUSIONS

Oral appliance treatment had a positive effect on all outcome measures during the 1-year follow-up in patients suffering from myofascial TMD pain, regardless of whether the pain was localized or widespread. Multiple pain sites seemed to have surprisingly little influence on the outcome variables. However, some indications of more challenges when treating patients with widespread pain compared to local pain could be observed. Pain-site drawings seem to be useful in the clinical situation and could support the clinicians in decision-making regarding treatment planning.

Multimodal physiotherapy treatment based on a biobehavioral approach for patients with chronic cervico-craniofacial pain: a prospective case series

The purpose of this prospective case series was to observe and describe changes in patients with chronic cervico-craniofacial pain of muscular origin treated with multimodal physiotherapy based on a biobehavioral approach. Nine patients diagnosed with chronic myofascial temporomandibular disorder and neck pain were treated with 6 sessions over the course of 2 weeks including: (1) orthopedic manual physiotherapy (joint mobilizations, neurodynamic mobilization, and dynamic soft tissue mobilizations); (2) therapeutic exercises (motor control and muscular endurance exercises); and (3) patient education. The outcome measures of craniofacial (CF-PDI) and neck disability (NDI), kinesiophobia (TSK-11) and catastrophizing (PCS), and range of cervical and mandibular motion (ROM) and posture were collected at baseline, and at 2 and 14 weeks post-baseline. Compared to baseline, statistically significant (p < 0.01) and clinically meaningful improvements that surpassed the minimal detectable change were observed at 14 weeks in CF-PDI (mean change, 8.11 points; 95% confidence interval (CI): 2.55 to 13.69; d = 1.38), in NDI (mean change, 5 cm; 95% CI: 1.74-8.25; d = 0.98), and in the TSK-11 (mean change, 6.55 cm; 95% CI: 2.79-10.32; d = 1.44). Clinically meaningful improvements in self-reported disability, psychological factors, ROM, and craniocervical posture were observed following a multimodal physiotherapy treatment based on a biobehavioral approach.

The effect of supervised exercise on localized TMD pain and TMD pain associated with generalized pain

OBJECTIVES

To evaluate the effect of a supervised exercise program in patients with localized/regional temporomandibular disorder (TMD) pain and with TMD associated with generalized pain.

MATERIAL AND METHODS

Consecutively referred patients with localized/regional TMD pain (n = 56; 46 women and 10 men, mean age 44 years) and TMD associated with generalized pain (n = 21; 21 women, mean age 41 years) participated. Patients underwent a 10-session structured supervised exercise program over 10-20 weeks that included relaxation, and coordination and resistance training of the jaw and neck/shoulders. The outcomes were jaw pain intensity on the Numerical Rating Scale, endurance time for jaw opening and protrusion against resistance and chewing, and effect of pain on daily activities.

RESULTS

After the exercise program, a reduction in jaw pain was reported by the local (p = .001) and general (p = .011) pain groups. There were no significant differences in jaw pain intensity between the groups, before (p = .062) or after treatment (p = .121). Endurance time increased for both groups for jaw opening/protrusion (both p < .001) and chewing (both p = .002). The effect of jaw pain on daily activities decreased after exercise compared to baseline for both the local (p < .001) and general (p = .008) pain groups.

CONCLUSIONS

Supervised exercise can reduce TMD pain and increase capacity in patients with TMD. The results suggest that activation of the jaw motor system with exercise has a positive effect in patients with localized/regional TMD pain and TMD associated with generalized pain.

Effects on jaw function shortly after whiplash trauma

Normal jaw function involves muscles and joints of both jaw and neck. A whiplash trauma may disturb the integrated jaw-neck sensory-motor function and thereby impair chewing ability; however, it is not known if such impairment is present shortly after a neck trauma or develops over time. The aim was to evaluate jaw function after a recent whiplash trauma. Eighty cases (47 women) were examined within 1 month after a whiplash trauma and compared to 80 controls (47 women) without neck trauma. Participants completed the Jaw disability checklist (JDC) and Neck Disability Index (NDI) questionnaires and performed a 5-minute chewing test. Elicited fatigue and pain during chewing were noted, and group differences were evaluated with Fisher's exact test and Mann-Whitney U-test. Compared to controls, cases had higher JDC (P < .0001) and NDI scores (15% vs 2%, P < .0001), and reported more fatigue (53% vs 31%, P = .006) and pain (30% vs 10%, P = .003) during the chewing test. Cases also had a shorter onset time for fatigue and pain (both P = .001) Furthermore, cases reporting symptoms during chewing had higher JDC and NDI scores compared to cases not reporting symptoms (both P = .01). Symptoms mainly occurred in the trigeminal area for both groups, but also in spinal areas more often for cases than for controls. Taken together, the results indicate that jaw-neck sensory-motor function is impaired already within 1 month after a whiplash trauma. The association between neck disability and jaw impairment underlines the close functional relationship between the regions, and stresses the importance of multidisciplinary assessment.

Pain and Disability in the Jaw and Neck Region following Whiplash Trauma

The relationship between whiplash trauma and chronic orofacial pain is unclear, especially with regard to the time elapsed from trauma to development of orofacial pain. The aim was to analyze prevalence of jaw pain and disability, as well as the relationship between pain and disability in the jaw and neck regions in the early nonchronic stage after whiplash trauma. In this case-control study, 70 individuals (40 women, 30 men, mean age 35.5 y) who visited an emergency department with neck pain following a car accident were examined within 3 wk of trauma (group 1) and compared with 70 individuals (42 women, 28 men, mean age 33.8 y), who declined to attend a clinical examination but agreed to fill in questionnaires (group 2). The 2 case groups were compared with a matched control group of 70 individuals (42 women, 28 men, mean age 37.6 y) without a history of neck trauma. All participants completed questionnaires regarding jaw pain and dysfunction, rating pain intensity in jaw and neck regions on the Numerical Rating Scale, the Neck Disability Index, and Jaw Disability Checklist. Compared with controls, individuals with a recent whiplash trauma reported more jaw pain and dysfunction. Furthermore, there was a moderate positive correlation between jaw and neck pain ratings for group 1 (r = 0.61, P < 0.0001) and group 2 (r = 0.59, P < 0.0001). In the logistic regression analysis, cases showed higher odds ratios (range, 6.1 to 40.8) for jaw and neck pain and disability compared with controls. Taken together, the results show that individuals with a recent whiplash trauma report more jaw pain and disability compared with controls without a history of neck trauma. Furthermore, the correlation between jaw and neck pain intensity implies that intensity of neck pain in the acute stage after whiplash trauma might be a possible risk factor also for development of chronic orofacial pain.

Chronic Neck Pain and Cervico-Craniofacial Pain Patients Express Similar Levels of Neck Pain-Related Disability, Pain Catastrophizing, and Cervical Range of Motion

Background. Neck pain (NP) is strongly associated with cervico-craniofacial pain (CCFP). The primary aim of the present study was to compare the neck pain-related disability, pain catastrophizing, and cervical and mandibular ROM between patients with chronic mechanical NP and patients with CCFP, as well as asymptomatic subjects. Methods. A total of 64 participants formed three groups. All participants underwent a clinical examination evaluating the cervical range of motion and maximum mouth opening, neck disability index (NDI), and psychological factor of Pain Catastrophizing Scale (PCS). Results. There were no statistically significant differences between patients with NP and CCFP for NDI and PCS (P > 0.05). One- way ANOVA revealed significant differences for all ROM measurements. The post hoc analysis showed no statistically significant differences in cervical extension and rotation between the two patient groups (P > 0.05). The Pearson correlation analysis shows a moderate positive association between NDI and the PCS for the group of patients with NP and CCFP. Conclusion. The CCFP and NP patient groups have similar neck disability levels and limitation in cervical ROM in extension and rotation. Both groups had positively correlated the NDI with the PCS.

Risk factors associated with incidence and persistence of frequent headaches

OBJECTIVE

Headaches represent a significant public health problem, but the knowledge of factors specifically related to incidence and persistence of headaches is still limited. The aim of this study was to evaluate whether gender, self-reported bruxism and variations in the dental occlusion contribute to onset and persistence of frequent headaches.

MATERIALS AND METHODS

The study population comprised 280 dental students, examined annually in a 2-year prospective study with a questionnaire and a clinical examination of the jaw function. In the analysis subjects were dichotomized into cases with frequent (once a week or more) or without frequent headaches (controls). The 2-year cumulative incidence was based on subjects without frequent headaches at baseline. Cases with 2-year persistent headaches reported such symptoms at all three examinations. Self-reported bruxism and factors in the dental occlusion at baseline were used as independent variables in logistic regression analyses.

RESULTS

The 2-year cumulative incidence of frequent headaches was 21%. Female gender (OR = 2.6; CI = 1.3-5.4), self-reported bruxism (OR = 2.3; CI = 1.2-4.4) and mandibular instability in intercuspal position (OR = 3.2; CI = 1.4-7.5) were associated with incidence of frequent headaches. Persistent headaches during the observation period were present in 12 individuals (4%) and significantly related to mandibular instability in intercuspal position (OR = 6.1; CI = 1.6-22.6).

CONCLUSIONS

The results indicate that female gender, self-reported bruxism and mandibular instability in intercuspal position are of importance in the development of frequent headaches. In management of these patients a multidisciplinary approach including dentists may be important and, thus, advocated.

Prevalence of signs and symptoms indicative of temporomandibular disorders and headaches in 35-, 50-, 65- and 75-year-olds living in Västerbotten, Sweden

OBJECTIVE

The aim of this study was to analyze and compare prevalence of signs and frequently occurring symptoms indicative of temporomandibular disorder (TMD) and headaches in 35-, 50-, 65- and 75-year-old men and women in Västerbotten County, Sweden.

MATERIALS AND METHODS

From a total target population of 11 324 subjects living in Västerbotten County in the year 2002, 300 individuals in each age group were randomly selected. Of these, 998 (82% response rate) answered and returned a postal questionnaire and 779 (65% response rate) individuals accepted a clinical examination.

RESULTS

The prevalence of frequent TMD symptoms peaked among 50-year-old women and then declined. Women at this age reported significantly higher prevalence compared to men for all TMD symptoms except temporomandibular joint locking. In the 65- and 75-year-olds, the prevalence was practically equal between men and women as well as between these ages. Frequent headaches showed the highest prevalence among 35- and 50-year-old women, with a statistically significant difference between men and women of 50 years of age (p < 0.05). Fifty-year-old women had statistically significantly higher prevalence of muscle pain to palpation (p < 0.001), temporomandibular joint sounds (p < 0.01) and impaired maximal jaw opening capacity (p < 0.01), compared to 50-year-old men.

CONCLUSIONS

The different symptoms indicative of TMD and headaches showed a similar pattern, with higher prevalence among the 35- and 50-year-old, as compared to the 65- and 75-year-old, participants. The pattern may be related to biological, psychosocial or generation-related factors.

Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: recommendations of the International RDC/TMD Consortium Network* and Orofacial Pain Special Interest Group†

AIMS

The original Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I diagnostic algorithms have been demonstrated to be reliable. However, the Validation Project determined that the RDC/TMD Axis I validity was below the target sensitivity of ≥ 0.70 and specificity of ≥ 0.95. Consequently, these empirical results supported the development of revised RDC/TMD Axis I diagnostic algorithms that were subsequently demonstrated to be valid for the most common pain-related TMD and for one temporomandibular joint (TMJ) intra-articular disorder. The original RDC/TMD Axis II instruments were shown to be both reliable and valid. Working from these findings and revisions, two international consensus workshops were convened, from which recommendations were obtained for the finalization of new Axis I diagnostic algorithms and new Axis II instruments.

METHODS

Through a series of workshops and symposia, a panel of clinical and basic science pain experts modified the revised RDC/TMD Axis I algorithms by using comprehensive searches of published TMD diagnostic literature followed by review and consensus via a formal structured process. The panel's recommendations for further revision of the Axis I diagnostic algorithms were assessed for validity by using the Validation Project's data set, and for reliability by using newly collected data from the ongoing TMJ Impact Project-the follow-up study to the Validation Project. New Axis II instruments were identified through a comprehensive search of the literature providing valid instruments that, relative to the RDC/TMD, are shorter in length, are available in the public domain, and currently are being used in medical settings.

RESULTS

The newly recommended Diagnostic Criteria for TMD (DC/TMD) Axis I protocol includes both a valid screener for detecting any pain-related TMD as well as valid diagnostic criteria for differentiating the most common pain-related TMD (sensitivity ≥ 0.86, specificity ≥ 0.98) and for one intra-articular disorder (sensitivity of 0.80 and specificity of 0.97). Diagnostic criteria for other common intra-articular disorders lack adequate validity for clinical diagnoses but can be used for screening purposes. Inter-examiner reliability for the clinical assessment associated with the validated DC/TMD criteria for pain-related TMD is excellent (kappa ≥ 0.85). Finally, a comprehensive classification system that includes both the common and less common TMD is also presented. The Axis II protocol retains selected original RDC/TMD screening instruments augmented with new instruments to assess jaw function as well as behavioral and additional psychosocial factors. The Axis II protocol is divided into screening and comprehensive self report instrument sets. The screening instruments' 41 questions assess pain intensity, pain-related disability, psychological distress, jaw functional limitations, and parafunctional behaviors, and a pain drawing is used to assess locations of pain. The comprehensive instruments, composed of 81 questions, assess in further detail jaw functional limitations and psychological distress as well as additional constructs of anxiety and presence of comorbid pain conditions.

CONCLUSION

The recommended evidence-based new DC/TMD protocol is appropriate for use in both clinical and research settings. More comprehensive instruments augment short and simple screening instruments for Axis I and Axis II. These validated instruments allow for identification of patients with a range of simple to complex TMD presentations.

Widespread pain in temporomandibular disorders

SUMMARY Chronic widespread pain (CWP) represents pain involving several regions of the body. Various psychological and social risk factors such as poor general health status, sleep disturbance, fatigue and high psychological distress have been identified for the development of CWP. Numerous chronic pain conditions are comorbid, resulting in the development of CWP in many of these patients. Temporomandibular disorder is one of the most extensively studied chronic musculoskeletal pain condition in terms of its comorbidity with CWP and fibromyalgia. It has been proposed that these comorbid pain disorders share common denominators, including exposure to certain environmental events, elevated psychological distress, pain amplification and genetic predisposition. Increased awareness of CWP is important for improved diagnoses and more effective pain management. Patients with CWP can be effectively managed in multidisciplinary pain clinics.

Experimental masseter muscle pain alters jaw-neck motor strategy

BACKGROUND

A functional integration between the jaw and neck regions has been demonstrated during normal jaw function. The effect of masseter muscle pain on this integrated motor behaviour in man is unknown. The aim of this study was to investigate the effect of induced masseter muscle pain on jaw-neck movements during a continuous jaw opening-closing task.

METHODS

Sixteen healthy men performed continuous jaw opening-closing movements to a target position, defined as 75% of the maximum jaw opening. Each subject performed two trials without pain (controls) and two trials with masseter muscle pain, induced with hypertonic saline as a single injection. Simultaneous movements of the mandible and the head were registered with a wireless optoelectronic three-dimensional recording system. Differences in movement amplitudes between trials were analysed with Friedman's test and corrected Wilcoxon matched pairs test.

RESULTS

The head movement amplitudes were significantly larger during masseter muscle pain trials compared with control. Jaw movement amplitudes did not differ significantly between any of the trials after corrected Wilcoxon tests. The ratio between head and jaw movement amplitudes was significantly larger during the first pain trial compared with control.

CONCLUSIONS

Experimental masseter muscle pain in humans affected integrated jaw-neck movements by increasing the neck component during continuous jaw opening-closing tasks. The findings indicate that pain can alter the strategy for jaw-neck motor control, which further underlines the functional integration between the jaw and neck regions. This altered strategy may have consequences for development of musculoskeletal pain in the jaw and neck regions.

Diagnostic criteria for headache attributed to temporomandibular disorders

AIMS

We assessed and compared the diagnostic accuracy of two sets of diagnostic criteria for headache secondary to temporomandibular disorders (TMD).

METHODS

In 373 headache subjects with TMD, a TMD headache reference standard was defined as: self-reported temple headache, consensus diagnosis of painful TMD and replication of the temple headache using TMD-based provocation tests. Revised diagnostic criteria for Headache attributed to TMD were selected using the RPART (recursive partitioning and regression trees) procedure, and refined in half of the data set. Using the remaining half of the data, the diagnostic accuracy of the revised criteria was compared to that of the International Headache Society's International Classification of Headache Diseases (ICHD)-II criteria A to C for Headache or facial pain attributed to temporomandibular joint (TMJ) disorder.

RESULTS

Relative to the TMD headache reference standard, ICHD-II criteria showed sensitivity of 84% and specificity of 33%. The revised criteria for Headache attributed to TMD had sensitivity of 89% with improved specificity of 87% (p < 0.001). These criteria are (1) temple area headache that is changed with jaw movement, function or parafunction and (2) provocation of that headache by temporalis muscle palpation or jaw movement.

CONCLUSION

Having significantly better specificity than the ICHD-II criteria A to C, the revised criteria are recommended to diagnose headache secondary to TMD.

Prevalence of symptoms indicative of temporomandibular disorders in adults: cross-sectional epidemiological investigations covering two decades

OBJECTIVES

The aims were (1) to study possible secular trends in the prevalence of temporomandibular disorder (TMD) symptoms in adults and (2) to analyse possible associations between TMD symptoms and background factors.

MATERIALS AND METHODS

The investigation has a repeated cross-sectional design. Three independent, randomly selected samples of ∼100 individuals in the age groups of 20, 30, 40, 50, 60 and 70 years, a total of 1704 subjects, participated in the Jönköping studies in 1983, 1993 and 2003. All the subjects were evaluated using a questionnaire and a structured interview relating to the presence of TMD symptoms. Associations between symptoms and the Anamnestic Dysfunction Index (Ai) as dependent variables and each of the independent variables, age group, gender, reported bruxism, trauma (1983), self-perceived health impairment and the year of investigation were analysed in binary logistic regression models.

RESULTS

The prevalence of the separate symptoms, apart from for TMJ clicking, did not vary to any statistically significant degree between the different examination years. However, the prevalence of recurrent headache in 20-year-old subjects rose remarkably in 2003 and an increase in the Ai I and Ai II for the whole population was observed during the 20-year period. Reported bruxism, which increased during the study period, and self-perceived health impairment were associated with most of the TMD symptoms and the Ai.

CONCLUSIONS

An increase in the prevalence of TMD symptoms expressed as Anamnestic Dysfunction Index I and II has been noted over a 20-year period.

Some dogmas related to prosthodontics, temporomandibular disorders and occlusion

It is the aim of this paper to give a few examples of dogmas related to prosthodontics and oral implants and to discuss the controversial role of occlusion in the aetiology of temporomandibular disorders. New knowledge is developing at a rapidly increasing rate in dentistry, as in other areas of society. Our lecturers at university taught us many useful things. But, as time goes by, what is still relevant? Some methods are so well established that they deserve to be called dogmas. It is implied that a dogma is not supported by strong evidence, even though it has existed and been practised for a long time. In the era of evidence-based dentistry it is appropriate to scrutinize such issues. A review of the current literature indicates that conflicting opinions exist concerning a number of common procedures in clinical dentistry, mainly due to a scarcity of good studies with unambiguous results. There is therefore a need for more high-quality clinical research in attempting to reach the goal of evidence-based clinical practice. The dental community should take an active part in this process.

Risk factors associated with incidence and persistence of signs and symptoms of temporomandibular disorders

OBJECTIVE

To analyze whether gender, self-reported bruxism, and variations in dental occlusion predicted incidence and persistence of temporomandibular disorder (TMD) during a 2-year period.

MATERIAL AND METHODS

The study population comprised 280 dental students at Umeå University in Sweden. The study design was that of a case-control study within a 2-year prospective cohort. The investigation comprised a questionnaire and a clinical examination at enrolment and at 12 and 24 months. Cases (incidence) and controls (no incidence) were identified among those without signs and symptoms of TMD at the start of the study. Cases with 2-year persistence of signs and symptoms of TMD were those with such signs and symptoms at all three examinations. Clinical registrations of baseline variables were used as independent variables. Odds ratio estimates and 95% confidence intervals of the relative risks of being a case or control in relation to baseline registrations were calculated using logistic regression analyses.

RESULTS

The analyses revealed that self-reported bruxism and crossbite, respectively increased the risk of the 2-year cumulative incidence and duration of temporomandibular joint (TMJ) signs or symptoms. Female gender was related to an increased risk of developing and maintaining myofascial pain. Signs of mandibular instability increased the risk of maintained TMD signs and symptoms during the observation period.

CONCLUSION

This 2-year prospective observational study indicated that self-reported bruxism and variations in dental occlusion were linked to the incidence and persistence of TMJ signs and symptoms to a higher extent than to myofascial pain.