Risk factors for diagnostic subgroups of painful temporomandibular disorders (TMD)

Temporomandibular Disorders (TMD) encompass several entities, which may have differing etiologies. To test this hypothesis, we investigated risk factors for three diagnostic subgroups of painful TMD. Ninety-seven subjects with myofascial pain only, 20 with arthralgia only, 157 with both myofascial pain and arthralgia, and 195 controls without TMD pain met criteria for study eligibility. Investigated risk factors included both physical and psychological variables. Adjusted odds ratios were calculated by multiple logistic regression analyses. Myofascial pain occurring alone was significantly associated with trauma (Odds Ratio [OR] = 2.0), clenching (OR = 4.8), third molar removal (OR = 3.2), somatization (OR = 3.7), and female gender (OR = 4.2). Myofascial pain with arthralgia was significantly associated with trauma (OR = 2.1), clenching (OR = 3.3), third molar removal (OR = 4.0), somatization (OR = 5.1), and female gender (OR = 4.7). No significant associations were found for the small-arthralgia-only group.     

Relationship between self‐reported sleep bruxism and pain in patients with temporomandibular disorders

The aim of this study was to evaluate the association between self‐reported sleep bruxism and the age, gender, clinical subtypes of temporomandibular disorders (TMD), pain intensity and grade of chronic pain in patients previously diagnosed with TMD. Thousand two‐hundred and twenty patients of the Andalusian Health Service were examined using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) questionnaire. The inclusion and exclusion criteria were those included in the RDC/TMD criteria. The bruxism diagnosis was drawn from the question, ‘Have you been told, or do you notice that you grind your teeth or clench your jaw while sleeping at night?’ in the anamnestic portion of the questionnaire. A bivariate analysis was conducted, comparing the presence of perceived parafunctional activity with age (over age 60 and under age 60), gender, different subtypes of TMD, pain intensity, grade of chronic pain and presence of self‐perceived locked joints. The overall prevalence of self‐reported sleep bruxism (SB) was 54·51%. A statistically significant association was found between the presence of SB and patients under age 60, women, greater pain intensity, greater pain interference with activities of daily living, and the axis‐I groups affected by both muscular and articular pathology. There is a statistically significant association between self‐reported sleep bruxism and women under age 60 who have painful symptoms of TMD. There is also a positive association between this parafunctional habit and the presence of chronic pain. However, more studies that cover larger samples and differentiate between sleep bruxism and awake bruxism are needed.     

低年级大学生颞下颌关节紊乱病咬合异常因素的logistic回归分析

目的探讨低年级大学生咬合异常因素对颞下颌关节紊乱病(temporomandibular disorders,TMD)发病的影响,以期为TMD的防治提供病因学基础。方法对遵义医科大学珠海校区低年级学生754名(男性354名,女性400名)进行颞下颌关节检查、牙列与咬合关系检查、问卷调查,采用多因素非条件logistic回归分析与哑变量单因素非条件logistic回归分析咬合功能异常、错畸形以及口腔副功能运动等咬合异常因素与颞下颌关节紊乱病的关系。结果颞下颌关节紊乱病的患病率为31.7%,多因素非条件logistic回归分析结果显示夜磨牙(OR=2.070)、日间紧咬牙(OR=2.553)、无意识空嚼(OR=2.642)和前牙覆关系(OR=1.228),与TMD的发病均有影响(P<0.05)。对不同程度前牙深覆设置哑变量采用单因素非条件logistic回归分析显示深覆程度越重,TMD的发病风险越高[轻度(OR=1.558)、中度(OR=2.189)、重度(OR=3.236),P<0.05]。结论前牙覆关系、夜磨牙、日间紧咬牙、无意识空嚼均是低年级大学生TMD发病的危险因素,前牙深覆程度越重,TMD发病风险越高。     

The relationship between jaw injury, third molar removal, and orthodontic treatment and TMD symptoms in university students in Japan

AIMS: To determine the association between temporomandibular disorders (TMD) and experiences of jaw injury, third molar removal, and orthodontic treatment, controlling for confounding factors such as age, sex, emotional stress, and oral parafunction. METHODS: First-year university students (n = 2,374) were instructed to answer a questionnaire regarding symptoms of TMD, jaw injury, third molar removal, orthodontic treatment, stress, and parafunctional habits. All subjects were classified according to the level of TMD symptoms. Logistic regression was applied to assess the associations of experiences of jaw injury, third molar removal, and orthodontic treatment with presence of TMD symptoms after controlling for age, sex, stress, and parafunctional habits. RESULTS: Of the 2,374 students, 715 students were TMD symptom-positive. They were classified into 7 groups consisting of those with only clicking (group 1), only pain in the temporomandibular joint (group 2), only difficulty in mouth opening (group 3), clicking and pain (group 4), clicking and difficulty in mouth opening (group 5), difficulty in mouth opening and pain (group 6), and all 3 symptoms (group 7). TMD symptoms were significantly associated with jaw injury. Odds ratios were 2.25, 2.47, 3.38, and 2.01 for groups 2, 3, 6, and 7, respectively. Experience of third molar removal was significantly associated with TMD (odds ratio = 1.81 for group 1). No association was found between orthodontic experience and TMD. CONCLUSION: Experiences of jaw injury and third molar removal might be cumulative and precipitating events in TMD.     

A study of the influence of occlusal factors and parafunctional habits on the prevalence of signs and symptoms of TMD

PURPOSE: The purpose of this study was to investigate the prevalence of the clinical signs and symptoms of temporomandibular disorders (TMD) and the relationship between occlusal factors, parafunctional habits, and TMD in a young adult nonpatient population. MATERIALS AND METHODS: A questionnaire including data from a history and clinical functional examination was used in the study. All 230 subjects were male recruits, from 19 to 28 years of age (mean 21.3 years). RESULTS: Thirty-eight percent of the subjects reported at least one symptom, while in 45% of the subjects at least one sign of TMD was recorded. Temporomandibular joint clicking (40%) and pain on palpation (34%) were the most commonly recorded signs. Multivariate logistic regression analysis showed several weak but statistically significant correlations between the occlusal factors, parafunctional habits, and TMD in this nonpatient population. TMD signs were thus weakly correlated with malocclusion traits (angle Classes II/1, II/2, III, and cross bite), interferences in retruded contact position, midline discrepancy > or = 2 mm, < or = 10 contacts during maximal biting pressure, nonworking-side interferences, horizontal overlap > or = 5 mm, and parafunctional habits (teeth clenching and teeth grinding). CONCLUSION: Some association between occlusal factors and TMD signs was found. However, this association cannot be considered unique or dominant in defining subjects with TMD in the population.     

Factors associated with temporomandibular disorders pain in adolescents

To gain a better understanding of temporomandibular disorders (TMD) pain in adolescents, it is important to study the factors associated with its presence. Therefore, the aim of this study was to investigate potential predictors for TMD pain in adolescents, thereby including a diversity of factors from the biopsychosocial model to determine the strongest predictors. The sample of this cross‐sectional study consisted of 1094 adolescents. The presence of TMD pain was assessed using the RDC/TMD, Axis I. Apart from demographical characteristics, the roles of parafunctional habits, psychosocial aspects, menarche and other bodily pain complaints were evaluated. Single and multiple logistic regression models were used to identify associations between the predictor variables and TMD pain. Painful TMD had a prevalence of 25·5%. Logistic regression analyses showed that TMD pain was associated with sleep bruxism (OR = 1·8 95% CI = 1·34–2·34), awake bruxism (OR = 2·1 95% CI = 1·56–2·83), other parafunctional habits (OR = 2·2 95% CI = 1·17–4·08) and bodily pain complaints (OR = 5·0 95% CI = 3·48–7·28). Parafunctional habits and other bodily pain complaints may play an important role in the presence of TMD pain in adolescents. Of course, it remains unclear whether the observed associations between the investigated factors and the adolescent's TMD pain have a true causal linkage.     

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

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

Oral habits among adolescent girls and their association with symptoms of temporomandibular disorders

AIM: To evaluate the contribution of certain parafunctional activities to the presence of temporomandibular disorder (TMD) symptoms among teenage girls, with special emphasis to gum chewing and jaw play. METHODS: A total of 323 girls, aged 15-16 years, were randomly selected from a religious junior high school. The girls responded to a questionnaire on oral habits and TMD symptoms. RESULTS: Gum chewing was a very prevalent habit (62.4%), performed daily (mean chewing time 3.95 h day-1). Girls who chewed intensively (more than 4 h day-1) showed associations with pain in the ear area during function and at rest, as well as with joint noises. Jaw play, although reported by only 14.3%, was significantly associated with pain in the ear area during function and at rest, feeling of tiredness of the jaw while chewing, joint noises, catch and lock. All oral parafunctions, except chewing gum, were associated with jaw play and with each other. CONCLUSIONS: Jaw play was the most detrimental habit in TMD; intensive gum chewing was a potentially contributing factor for joint noises and pain. Oral parafunctions (except chewing gum) were significantly associated between themselves and suggest a behavioural pattern of "jaw hyperactivity".     

Occlusal risk factors for temporomandibular disorders

OBJECTIVE: To determine the role of occlusal variables (overbite; overjet; number of anterior and posterior teeth; bilateral canine guidance on lateral and protrusive movements; anterior centric slide; Angle Classes I, II, and III malocclusion) as risk indicators for the development of temporomandibular disorders (TMDs). MATERIALS AND METHODS: Seventy-two TMD patients with myofascial pain, with or without limited opening and arthralgia, as well as 30 age- and gender-matched pain-free concurrent controls were included. The association (critical odds ratio [OR] = 2.0) between the significant occlusal variables and TMD was calculated. Confounders were controlled in the inclusion-exclusion criteria as well as in the analysis stage (unconditional logistic regression) by variation in the OR (15%). RESULTS: Angle Class II malocclusion (crude OR = 8.0, confidence interval [CI] = 2.2 to 29.3) and the absence of bilateral canine guidance on lateral excursion (crude OR = 3.9, CI = 1.6 to 9.7) were statistically more common in patients than in controls. Spontaneous pain as well as pain on palpation (Class II or higher) were also statistically worse in TMD patients. Significant confounders (ie, employment, age, cigarette and alcohol consumption) acted as effect modifiers not changing the critical OR (adjusted OR Angle Class II and bilateral canine guidance = 8.3 to 12.4 and 2.2 to 4.1, respectively). CONCLUSIONS: Absence of bilateral canine guidance on lateral excursion and particularly Angle Class II malocclusion were considered important risk indicators for the development of TMD in this investigation, even when some sociodemographic factors were considered as effect modifiers.     

Association between waking‐state oral parafunctional behaviours and bio‐psychosocial characteristics

The term ‘oral parafunctional behaviours’ encompasses behaviours that are different from those required for, or associated with, physiological functional needs such as mastication, communication, swallowing or breathing. Previous reports have associated waking‐state oral parafunctional behaviours with biopsychosocial characteristics such as female gender, presence of psychological symptoms, intensity of pain and pain‐related temporomandibular disorders (TMD) diagnosis. However, the findings have been inconsistent, possibly due to methodological limitations and differences. In the present investigation, we aim to determine whether any association is present between waking‐state oral parafunctional behaviours and biopsychosocial characteristics. All participants were investigated using a set of standardised and validated self‐reporting questionnaires and diagnostic criteria for temporomandibular disorders (DC/TMD) examination protocol for clinical characterisation. Univariate analysis found that self‐reported waking‐state oral parafunctional behaviours were statistically significantly associated with presence of anxiety, depression and physical symptoms, pain intensity and TMD diagnosis. However, forward model multiple linear regression analysis indicated that only self‐reported presence of physical and depression symptoms could explain statistically significant portions of the variance in self‐reported waking‐state oral parafunctional behaviours.     

Relationship between oral tori and temporomandibular disorders

The aim of the study was to compare the presence of oral tori and parafunctional activity (clenching, grinding teeth and/or bruxism) between temporomandibular disorder (TMD) patients and control subjects. Fifty-nine TMD and 353 control subjects were included. The groups were similar in sex and age distribution. There was no significant difference in prevalence of torus palatinus (TP) between TMD and control group (P = 0.2), while torus mandibularis (TM) was more common in TMD than in control group (P < 0.0005). Parafunctional habit was more common in TMD patients than in the control group (P < 0.0005). There was no significant association between size of TM and Helkimo's dysfunction index (P = 0.4). The results show that the prevalence of TM and parafunctional activity was higher in TMD than control patients. TM might be useful as an indicator of increased risk of TMD in some patients.     

Association of oral parafunctional habits with anxiety and the Big-Five Personality Traits in the Saudi adult population

BackgroundOral parafunctional habits are related to any abnormal hyperactivity of the oromandibular system. They are prevalent in all societies in varying intensity and have potential physical and psychological implications. The aim of this study was twofold: (1) to determine the prevalence of various types of oral parafunctional habits in the Saudi adult population, and (2) to examine their association with and the level of anxiety and personality factors.MethodsThis cross-sectional study was conducted with an electronic data collection form distributed to the public through social media. The questionnaire comprised of the following: (a) demographic information, (b) the Hamilton Anxiety Rating Scale (HAM-A), (c) the Ten-Item of Big-Five Personality Traits, (d) a list of oral parafunctional habits. Data were analysed using a Pearson’s Chi square and binary logistic regression.ResultsThe participants reported several parafunctional habits including daily gum chewing (86%), lip/object biting (59%), clenching (45%), nail biting (36%) and grinding (32%). Males were 3 [2.3–3.7] times and younger age groups were 1.5 [1.1–2.0] times more likely to be associated with nail biting compared to their counter groups (adj.P < 0.001 and adj.P = 0.007). Lip/object biting was significantly 1.3 [1.1–1.7] times more prevalent in males (adj.P = 0.015). Participants who reported being extroverts were more likely to be associated with clenching (46.4%) (P = 0.024). An emotionally stable person was significantly less likely to be associated with nail biting (28.4%), grinding (24.9%), clenching (35.8%), and lip/object biting (48.4%) (P < 0.001each). Participants who reported conscientiousness and emotional stability were significantly less associated with TMD (P = 0.007, P < 0.001).ConclusionOral parafunctional habits are highly prevalent in the Saudi adult population in varying degrees. Possible risk factors include males, younger age groups, single people, and being financially constrained.     

Oral parafunctions and association with symptoms of temporomandibular disorders in Japanese university students

We examined whether oral parafunctions are associated with symptoms of temporomandibular disorders (TMD) in 3557 Japanese university students, aged between 18 and 26 years. Participants completed a questionnaire regarding various oral parafunctions and subjective symptoms related to TMD, and underwent a dental examination. The prevalence of temporomandibular joint (TMJ) noise, TMJ pain and impaired mouth opening was 41.7, 16.0 and 16.3%, respectively. The most prevalent parafunction was sleeping on one side (60.2%), followed by supporting the jaw by leaning on the palm of the hand (44.8%). Mean age, decayed, missing and filled teeth, and number of teeth were not significantly different between TMD positive and negative groups according to unpaired t-test. The chi-squared test revealed that the ratio of females was significantly higher among students with TMD than without TMD. Multiple logistic regression models adjusted for age and gender demonstrated that chewing on one side caused an increased risk of TMJ noise [odds ratio (OR) = 1.52, P < 0.001], TMJ pain (OR = 1.54, P < 0.001), and impaired mouth opening (OR = 2.00, P < 0.001). Tooth clenching also increased the risk of TMJ noise (OR = 1.86, P < 0.001), TMJ pain (OR = 1.79, P = 0.001) and impaired mouth opening (OR = 1.88, P < 0.001). Further prospective cohort studies, including other potential risk factors, are required to clarify these relationships.     

Primary headaches interfere with the efficacy of temporomandibular disorders management

OBJECTIVES:

This cross-sectional study aimed to evaluate the influence of Primary Headache (PH) on efficacy of a Temporomandibular Disorders (TMD) conservative therapy and its association with the presence of self-reported parafunctional habits.

SAMPLE AND METHODS:

Sample was composed of 400 medical records, divided into four groups: I) Muscular TMD (n=64); II) Muscular TMD+PH (n=48); III) Muscular TMD+Articular TMD (n=173); IV) Muscular TMD+Articular TMD+PH (n=115). All groups had undergone a TMD therapy for three months with a stabilization appliance and counseling for habits and behavioral changes, with no specific headache management. Current pain intensity and existence or not of self-reported bruxism were assessed. Repeated measures ANOVA and Chi-Square test followed by Odds were used for statistical analysis, with a significance level of 5%.

RESULTS:

results of this study showed that: (1) A conservative therapy with stabilization appliance and counseling for habits and behavioral changes was effective in the TMD pain relief; (2) Groups with an additional diagnosis of PH had worsened the pain improvement significantly; and (3) no association between the presence of self-reported bruxism and PH was found.

CONCLUSIONS:

this study could elucidate the important effect that headache may have on the TMD management.     

Chronic TM Disorder and Non-TM Disorder Pain: A Comparison of Behavioral and Psychological Characteristics

The purpose of this paper is to determine whether patients with chronic temporomandibular disorder (TMD) pain manifest behavioral, experiential, and psychological characteristics similar to patients with other chronic pain illnesses. The Chronic Pain Battery^TM (CPB), a multidimensional assessment tool for chronic pain patients, was used to compare several important variables between 78 TM disorder (TMD) patients and 98 non-TMD chronic pain patients. The study found that chronic TMD patients had lower “usual” pain intensity and suffering levels, fewer vegetative symptoms associated with depression, higher pain tolerance, less impairment of activity, more hope about treatment outcome, lower health care system utilization, but higher reported stress levels than non-TMD chronic pain patients. The two groups manifested no significant differences in use of narcotics, sedatives, and sleeping pills; levels of depression, anxiety, somatization, hostility, or psychoticism; illness behavior reinforcement in their social surroundings; or ratings of problems with work, family, self-esteem, or suicidal impulses.

These findings suggest that chronic TMD pain patients (with a symptom duration of over six months) are behaviorally and psychologically similar to non-TMD chronic pain patients, but that they differ in their perceptions of their disorder, rendering them less handicapped by their problems. Psychological, social, and behavioral treatment methods useful for treating chronic pain syndrome may thus also be applied along with dental therapy for optimal treatment of TMD associated with chronic pain.     

Reduced heart rate variability and increased saliva cortisol in patients with TMD

Temporomandibular disorders (TMD) are the most common source of non-dental pain. The pathogenesis of TMD is multifactorial, involving biological, psychological and behavioral factors. Those factors are involved with alterations of the autonomic nervous system (ANS) and stressful conditions. Heart rate variability (HRV) has been used as a marker of ANS function. Increased cortisol level (a stress indicator), has been found in chronic pain. Therefore, the present study aimed to compare pain intensity, HRV, psychological factors, and salivary cortisol level between TMD patients and a control group. Twenty-one TMD patients and twenty-three healthy control subjects participated in the study. All participants underwent 24-h-Holter monitoring to record HRV. Morning unstimulated saliva samples were collected from each participant for cortisol analysis. The pain intensity was assessed using a visual analog scale. The participants were evaluated for anxiety and depression via the Hospital Anxiety and Depression Scales. We found that pain intensity and psychological distress in the TMD group were significantly greater than those of the control (p < 0.01). Pain intensity showed a positive correlation with psychological distress (p < 0.01). HRV parameters in the TMD group were significantly lower than those in the control, suggesting reduced HRV in TMD patients. Pain intensity was negatively associated with HRV. Salivary cortisol level of the TMD group was greater than that of control. Our findings indicate that reduced HRV with higher psychological distress and increased salivary cortisol levels were observed in the TMD group. Therefore, TMD patients may benefit from interventions that can restore ANS function and stress balance.     

The association between wear facets,bruxism, and severity of facial pain in patients with temporomandibular disorders

STATEMENT OF PROBLEM: It is unclear whether patients with temporomandibular disorders (TMD) who report high levels of bruxism have more severe signs and symptoms of TMD and more advanced tooth wear than patients with TMD who report lower levels of bruxism. PURPOSE: The purpose of this study was to determine whether there was a significant association between tooth wear, the parafunctional oral habit of bruxism, temporomandibular joint (TMJ) pain, and muscle pain severity in a TMD population. MATERIAL AND METHODS: A total of 84 subjects previously diagnosed with TMD, according to the Research Diagnostic Criteria for TMD (RDC/TMD) and who met 10 specific inclusion/exclusion criteria underwent a thorough multiaxial examination and classification recommended by the National Institute of Dental and Craniofacial Research (NIDCR). Measurement of tooth wear facets by use of a 4-point scale were graded in 10 zones on mandibular casts. One calibrated examiner performed all scoring. Bruxism was assessed in a standardized pretreatment questionnaire and in the dental history and interview (RDC/TMD) to indicate how frequently (0 = never to 3 = very often) subjects performed a list of oral habits, which included bruxism. The Kappa reliability coefficient (range from: -1.0 to 1.0) was used to correct for chance agreement, and was computed for each of the 10 study sites designated for rating. Subjects were also compared for muscle and joint pain. Muscle pain was a summed measure derived from the dental examination findings (range 0 to 20), calculated from the presence or absence of pain induced by palpation of 20 predetermined muscle sites. Similarly, joint pain was a summed measure of the presence or absence of pain in the TMJs induced by palpation of the joints on the outer surface and in the external auditory canal in 5 different positions of the mandible. A Pearson product-moment correlation was used to compute the summed severity of tooth wear and the subjects' age. Analysis of covariance was used to determine whether the number of wear facets was significantly higher in patients with TMD who reported a history of bruxism, compared with patients with TMD who reported no or minimal bruxism, after controlling for the effect of age. Multivariate analysis of variance was used to determine whether the number of painful muscles of mastication and joint sites on standardized examination were significantly higher in patients with TMD with a history of bruxism (alpha=.05). RESULTS: In the population tested, tooth wear was modestly correlated with age (r =.40, P<.001). Of the 84 subjects studied, 11.9% reported no bruxing activity, 32.1% reported some or occasional bruxing activity, and 47.6% had frequent bruxism activity; the remaining 8.4% were eliminated from analysis because they provided inconsistent responses. Bruxism activity was not correlated with muscle pain on palpation and was inversely associated with TMJ pain on palpation. Tooth wear was not significantly correlated with bruxism, TMJ pain, or muscle pain. CONCLUSIONS: In this TMD population, tooth wear factors did not differentiate patients with bruxism from those without. The amount of bruxism activity was not associated with more severe muscle pain and was associated with less pain in the TMJ on palpation.     

Reduction in parafunctional activity: a potential mechanism for the effectiveness of splint therapy

Interocclusal splints may be an effective modality in the management of temporomandibular disorders (TMD), but there is little evidence regarding the mechanism by which splints work. This study tested the hypothesis that pain reduction produced by splints is associated with reduction in parafunctional activity. In a two-group, single-blinded randomized clinical trial, patients diagnosed with myofascial pain received full coverage hard maxillary stabilization splints. Patients were instructed to maintain or avoid contact with the splint for the 6 weeks of active treatment. Patients who decreased the intensity of tooth contact were expected to show the greatest alleviation of pain, and those who maintained or increased contact were expected to report lesser reductions in pain. Experience-sampling methodology was used to collect data on pain and parafunctional behaviours at pre-treatment and during the final week of treatment. Patients were reminded approximately every 2 h by pagers to maintain/avoid contact with the splint. The amount of change in intensity of tooth contact accounted for a significant proportion of the variance in pain change scores. Patients who reduced tooth contact intensity the most reported greater relief from pain. Splints may produce therapeutic effects by reducing parafunctional activities associated with TMD pain.     

Association between temporomandibular joint symptoms, signs, and clinical diagnosis using the RDC/TMD and radiographic findings in temporomandibular joint tomograms

AIM: To identify associations between clinical symptoms of temporomandibular joint disorders and radiographic findings. METHODS: Two hundred four adult patients (156 women, 48 men, mean age 40 years) with temporomandibular joint (TMJ) pain/sounds or changes in mandibular motion were examined according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Bilateral sagittal corrected TMJ tomograms in closed and open positions were assessed for the presence of flattening, erosion, osteophytes, and sclerosis in the joint components and the range of mandibular motion. Logistic regression analyses were performed with the radiographic findings as the dependent variables and the following clinical variables as independent variables: opening pattern, maximal jaw opening, TMJ sounds, number of painful muscle/TMJ sites, duration of pain, presence of arthritic disease, depression and somatization scores, graded chronic pain, and age and gender. RESULTS: Coarse crepitus on opening/closing (odds ratio [OR] > or = 3.12), on lateral excursions (odds ratio > or = 4.06), and on protrusion (OR > or = 5.30) was associated with increased risk of degenerative findings in tomograms. A clinical diagnosis of osteoarthritis increased the risk of radiographic findings (OR > or = 2.95) and so did increasing age (OR > or = 1.03 per year) and the female gender (OR > or = 2.36). Maximal assisted opening and maximal opening without pain (< 40 mm) was associated with a posterior condyle-to-articular tubercle position (OR > or = 2.60). No other significant associations were observed. CONCLUSION: Age, gender, and coarse crepitus, but no pain-related variables, were associated with increased risk of degenerative findings in TMJ tomograms. Maximal opening < 40 mm was associated with a posterior condyle-to-articular tubercle relation on opening.     

Waking-state oral parafunctional behaviors: specificity and validity as assessed by electromyography

In contrast to sleep-related oral parafunctional behaviors, little is known about waking oral parafunctional behaviors. The Oral Behaviors Checklist contains terms referring to a variety of non-observable behaviors that are reliable when prompted (e.g. 'clench') but validity data are absent. Our goal was to assess whether (i) each behavioral term is distinct electromyographically, and (ii) temporomandibular disorder (TMD) subjects differ from non-TMD subjects in their performance. Surface electromyographic (EMG) activity was used to measure bilateral masseter, temporalis, and suprahyoid muscles while subjects (27 patients with TMD; 27 healthy controls) performed ten oral behaviors without explanation. Electromyographic data were averaged between bilateral muscles and two trials. A multivariate construct (jaw muscle activity) was analyzed using Wilks lambda within multivariate analysis of variance (manova). Obvious behaviors (e.g. clench, read, tongue press) exhibited expected EMG patterns, and patients and controls produced identical profile plots of the EMG data. Of 10 tested behaviors, nine were found to be associated with significantly differing proportions of amplitudes across muscles and were thus unique. Behaviors with similar terms were associated with different EMG patterns. The present data support the specificity of behavioral terms and performances. Implications include causation related to TMD based on subtle behaviors that occur at a high frequency.