Onset Of Temporomandibular Disorders Research Articles

Causal effects of educational attainment on temporomandibular disorders and the mediating pathways: A Mendelian randomization study.

As one of the most important indicators of socioeconomic status, educational attainment (EA) exhibits a strong association with temporomandibular disorders (TMDs). Despite this link, there is a lack of evidence regarding the causal role of EA in either facilitating or preventing TMDs. This study aimed to investigate the causal effect of education on TMDs and explore potential mediating pathways. Utilizing summary statistics from genome-wide association studies on years of schooling (N = 766 345) and TMDs (N = 211 023), we conducted Mendelian randomization (MR) to assess the overall effect of education. Additionally, a two-step MR approach was employed to evaluate 30 potential mediators and calculate the mediation proportions in the association. Comprehensive sensitivity analyses were used to verify the robustness, heterogeneity, and pleiotropy. Univariable MR analyses revealed a causal effect of lower EA on an increased risk of TMDs (OR: 0.53, 95% CI: 0.43-0.66, p < .001). Five out of 30 modifiable factors were identified as causal mediators in the associations of EA with TMDs, including feeling nervous (mediation proportion: 11.6%), feeling tense (10.2%), depression (9.6%), feeling worry (7.6%) and daily smoking (8.9%). Meanwhile, no pleiotropy was detected in the analyses (p > .05). Our findings supported that higher EA has a protective effect on the onset of TMDs, with partial mediation by psychological disorders and daily smoking. Interventions on these factors thus have the potential of substantially reducing the burden of TMDs attributed to low education.

Age and sex differences in comorbidities in adult temporomandibular disorders: A cross-sectional study using Korea National Health and Nutrition Examination Survey (KNHANES).

To investigate the relationship between Temporomandibular disorder (TMD) and associated comorbidities in groups matched according to age and sex. Using data from the cross-sectional fifth Korea National Health and Nutrition Examination Survey (KNHANES). Of the 25,534 eligible KNHANES, 17,762 adults aged ≥19 years who responded to survey questionnaire on TMD and comorbidities. Subjects were classified into eight groups according to age and sex. Logistic regression analyses were performed to evaluate the association between TMD and comorbidities according to age and sex. Of the enrolled participants, 2,107 (11.86%) complained of ≥1 TMD symptoms. In all groups, odds ratios (ORs) for prevalence of TMD were >1 in those with tinnitus. Rhinitis was closely associated with TMD in 6 groups. ORs for TMD with comorbidities according to age and sex were as follows: hypertension, men aged 50-64 years (OR 0.62; CI 0.41-0.94); ischemic heart disease, men aged 35-49 years (4.38; 1.54-12.47); osteoarthritis, women aged 50-64 years (1.38; 1.03-1.86); diabetes mellitus, men aged 35-49 years (0.21; 0.05-0.88); depression, men aged 50-64 years (1.68; 1.00-2.83), women aged 35-49 years (1.39; 1.05-1.85) and women aged 65-80 years (2.01; 1.46-2.77); migraine, men aged 50-64 years (1.60; 1.14-2.25), women aged d35-49 years (1.44; 1.14-1.81) and women aged 35-49 years (1.43; 1.07-1.90); cold hypersensitivity in the hands and feet, men aged 19-34 years (1.64; 1.05-2.58), men aged 35-49 years (1.68; 1.04-2.70), men aged 65-80 years (1.74; 1.09-2.75) and women aged 35-49 years (1.45; 1.15-1.84); olfaction disorder, men aged 50-64 years (2.49; 1.39-4.43); voice disorder, men aged 50-64 years (2.25; 1.28-3.96) and women aged 65-80 years (1.69; 1.09-2.63). This study confirmed that the types and effects of comorbidities related to prevalence of TMD may differ according to the patient's age and sex and this result will increase the predictability of the onset of TMD.

Is low back pain a risk/prognostic factor for the development and/or progression of temporomandibular disorders? A systematic review with meta-analysis.

To evaluate the association between low back pain (LBP) and painful temporomandibular disorders (TMDs). Systematic review of observational studies. Searches were conducted using OVID MEDLINE, CINHAL, Web of Science and PUBMED databases up to 21 October 2022. Qualitative and quantitative analyses were performed. Risk of bias (RoB) was assessed using the Quality in Prognosis Studies tool (QUIPS). Eight studies were included in the present review with meta-analysis. The first onset of TMDs was more likely in patients with previous chronic LBP (hazard ratio (HR) 1.53 [95% confidence interval (CI): 1.28; 1.83, p < .00001]). In addition, patients with chronic LBP had 3.25 times the odds (OR) [95% CI: 1.94; 5.43, p < .00001] of having chronic TMDs than those who did not have chronic LBP. In addition, the higher the exposure to chronic LBP, the higher the risk of developing a first onset of TMDs. Chronic LBP can be considered a risk/contributing factor for painful TMDs. Although there is a high certainty in the evidence linking chronic LBP with the risk of a first onset of TMDs, there are insufficient studies to draw definitive conclusions. Furthermore, while an association between chronic LBP and chronic TMDs and a dose-effect was observed between these two conditions, a limited number of studies and evidence exist to support these findings. Future studies are needed to increase the body of evidence.

EPA Consensus Project Paper: The Relationship Between Prosthodontic Rehabilitations and Temporomandibular Disorders.

The aim of this systematic review is to evaluate the relationship between prosthodontic treatment and temporomandibular disorders (TMD). Two clinical questions have been raised. Can prosthodontic treatment be used as a strategy to manage temporomandibular disorders? Is there any causal relationship between prosthodontic rehabilitation and the onset of TMD? A systematic search was performed in four medical databases to identify Clinical Trials (CT) and Randomized Clinical Trials (RCT) that could answer the two clinical questions. Any articles fulfilling the inclusion criteria were found. Therefore, the best available evidence on TMD management and aetiology is discussed in a scoping review with focus on the relationship with prosthodontic treatment. Based on current scientific evidence, prosthetic rehabilitation cannot be proposed as a treatment option for TMD patients, based on the effectiveness of other more conservative options as well as the absence of association between features of dental occlusion and TMD. Thanks to the high neuro plastic adaptation skills of the stomatognathic system, prosthodontic rehabilitation cannot be identified as a direct cause of TMD, but clinicians should pay caution when performing relevant occlusal modifications.

Temporomandibular Disorders as a Risk Factor for Suicidal Behavior: A Systematic Review.

Temporomandibular disorders (TMD) are a group of common musculoskeletal dysfunctions that affect the temporomandibular joint or masticatory muscles and related structures or are expressed as a clinical combination of these two factors. The etiology of TMD is multifactorial and features related to anxiety, depression and mental disorders can contribute to the predisposition, onset and progression of TMD. The ability to adapt and develop coping attitudes was reduced in patients presenting with chronic pain, while suicidal behavior (suicidal ideation, suicide attempts, and suicide completion) was increased. The objective of this review was therefore to investigate suicidal behavior in relation to TMD. The review was performed according to the PRISMA 2020 guidelines. Six databases (PubMed, MEDLINE, EMBASE, Scopus, Ovid, and Google Scholar) were consulted through the use of keywords related to the review topic. The study is registered on PROSPERO (CRD42022320828). The preliminary systematic search of the literature yielded 267 records. Excluding duplicates, 15 were considered potentially relevant and kept for title and abstract analysis. Only six articles were considered admissible reporting a single exposure factor, TMD and a single outcome, suicidal behavior, although these were evaluated through different assessment tools. We found a low association of TMD with suicidal behavior in observational studies, with estimates partly provided [prevalence ratio (PR) from 1.26 to 1.35, 95% confidence intervals (CI) from 1.15 to 1.19 (lower) and from 1.37 to 1.54 (higher); and odds ratios (OR) from 1.54 to 2.56, 95% CI from 1.014 to 1.157 (lower) and 2.051 to 6.484 (higher)], a relevant sample size (n = 44,645), but a few studies included (n = 6). The results of the included studies showed that the prevalence data of suicidal behavior were more present in young adults with TMD, with a controversial association with gender. Suicidal behavior was also correlated and aggravated by the intensity of pain.

Relationship between Oral Parafunctional and Postural Habits and the Symptoms of Temporomandibular Disorders: A Survey-Based Cross-Sectional Cohort Study Using Propensity Score Matching Analysis.

Temporomandibular disorders (TMDs) are a multifactorial joint disease of the masticatory system. The possible etiological factors involved in the onset and progression of TMDs include oral parafunctional habits (OPFHs) and postural habits (PHs). However, little information is available on the association between OPFHs and PHs and a predisposition to TMDs. Thus, to investigate whether the presence of OPFH and PH predisposes individuals to TMDs, a survey-based cross-sectional cohort study of self-reported TMD was performed. A total of 2292 patients with TMD were recruited for the survey. Through one-to-one propensity score matching, 166 patients with and without sleep bruxism (SB) were selected. The SB group had a significantly higher risk of masticatory muscular pain or fatigue than the non-SB group (p = 0.018). Furthermore, the SB group without other OFPHs and PHs did not show a significantly higher risk of TMD symptoms than the non-SB group. Diurnal clenching and bad posture also affect the stomatognathic system, causing pain or fatigue; however, it did not result in TMDs in patients without any OPFHs and PHs. This implies that OPFHs and PHs may increase the risk of TMD symptoms in coexistence with other habits.

Psychological Profiles and Their Relevance with Temporomandibular Disorder Symptoms in Preorthodontic Patients.

Background Temporomandibular disorders (TMDs) refer to a group of heterogenous musculoskeletal diseases with diverse clinical symptoms and an undetermined aetiology. The psychological profiles were closely related to the onset and treatment outcomes of TMDs. Objective To examine the relevance between psychological profiles and different symptoms of TMDs in preorthodontic patients. Methods The study was conducted among 570 preorthodontic patients. TMDs symptoms were recorded by the Diagnostic Criteria for TMD (DC/TMD) symptom questionnaire. The seven-item Generalized Anxiety Disorder Scale (GAD-7), the nine-item Patient Health Questionnaire (PHQ-9), and the Pain Catastrophizing Scale (PCS) were used for the evaluation of anxiety, depression, and pain catastrophizing levels. The relevance of three psychological profiles with TMDs and subtypes was evaluated with Spearman's rank correlation test and logistic regression analysis (P < 0.05). Results 34.56% of the enrolled preorthodontic patients were diagnosed with TMDs. Scores of GAD-7, PHQ-9, and PCS were significantly higher in the TMDs group than in the non-TMDs group. Participants with anxiety, depression, or high pain catastrophizing had a higher prevalence of both pain-related TMDs symptoms and intra-articular TMDs symptoms. The correlations among pain-related TMDs, intra-articular TMDs, and scores on the psychological scales were significant (P < 0.05). The adjusted logistic regression model revealed that anxiety, depression, and high pain catastrophizing were significant risk factors for TMDs with an odds ratio (OR) of 2.196, 1.741, and 1.601, respectively. Depression was associated with higher pain-related TMDs prevalence (OR = 2.136), while anxiety and depression were associated with higher intra-articular TMDs prevalence (OR = 2.341 and 1.473). Conclusion Anxiety, depression, and high pain catastrophizing were comorbid psychological conditions of TMDs. Depression was the top risk factor for pain-related TMDs, while anxiety rendered the highest risk for intra-articular TMDs. Inclusion of psychological assessments in preorthodontic evaluation might yield great benefits in TMDs screening.

Influência da qualidade das próteses totais na prevalência de disfunção temporomandibular

Abstract Introduction Temporomandibular disorder (TMD) involves the mastication and temporomandibular articulation muscles. Completely toothless patients with prostheses should be thoroughly assessed since edentulism causes damage that can lead to TMD onset. Objective This study aims to assess the effect of the technical quality of total prostheses (TPs) on TMD occurrence in patients with bimaxillary TPs. Material and method 154 patients responded to a questionnaire to obtain personal data, information regarding prostheses, anamnestic index for TMD, and the prosthesis quality index. Result Of the 154 patients examined, 64 (41.6%) had no TMD, 61 (39.6%) had mild TMD, 23 (14.9%) moderate, and only 6 (3.9%) showed severe TMD. As for the quality of total prosthesis, 78 (50.6%) completely toothless individuals had satisfactory TPs while 76 (49.4) presented unsatisfactory prostheses. Regarding the time using total prosthesis, around 50% of individuals with up to 10 years use presented some degree of TMD and 70% of individuals with over 10 years presented TMD. Conclusion Considering the methodology used and the population studied, we conclude that the quality of the TPs did not influence the incidence of TMD.

Neuroimmune interactions in painful TMD: Mechanisms and treatment implications.

The underlying mechanisms and treatment of painful temporomandibular disorders (TMDs) are important but understudied topics in craniofacial research. As a group of musculoskeletal diseases, the onset of painful TMD is proved to be a result of disturbance of multiple systems. Recently, emerging evidence has revealed the involvement of neuroimmune interactions in painful TMD. Inflammatory factors play an important role in peripheral sensitization of temporomandibular joint (TMJ), and neurogenic inflammation in turn enhances TMJs dysfunction in TMD. Furthermore, centralized neuroimmune communications contribute to neuron excitability amplification, leading to pain sensitization, and is also responsible for chronic TMD pain and other CNS symptoms. Therapeutics targeting neuroimmune interactions may shed light on new approaches for treating TMD. In this review, we will discuss the role of neuroimmune interactions in the onset of painful TMD from the peripheral and centralized perspectives, and how understanding this mechanism could provide new treatment options. Insights into the neuroimmune interactions within TMJs and painful TMD would broaden the knowledge of mechanisms and treatments of this multifactorial disease.

Association of Hormonal Contraceptive Use with Headache and Temporomandibular Pain: The OPPERA Study.

To determine the relationship between hormonal contraceptive (HC) use and painful symptoms, particularly those associated with headache and painful temporomandibular disorders (TMD). Data from the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) prospective cohort study were used. During the 2.5-year median follow-up period, quarterly health update (QHU) questionnaires were completed by 1,475 women aged 18 to 44 years who did not have TMD, menopause, hysterectomy, or hormone replacement therapy use at baseline. QHU questionnaires evaluated HC use, symptoms of headache and TMD, and pain of ≥ 1 day duration in 12 body regions. Participants who developed TMD symptoms were examined to classify clinical TMD. Headache symptoms were classified based on the International Classification of Headache Disorders 3 (ICHD-3). Associations between HC use and pain symptoms were analyzed using generalized estimating equations and Cox models. HC use, endorsed in 33.7% of QHU questionnaires, was significantly associated with concurrent symptoms of TMD (odds ratio [OR]: 1.20, 95% CI: 1.06 to 1.35) and headache (OR: 1.26, 95% CI: 1.11 to 1.43). HC use was also significantly associated with concurrent pain of ≥ 1 day duration in the head (OR: 1.38, 95% CI: 1.16 to 1.63), face (OR: 1.44, 95% CI: 1.13 to 1.83), and legs (OR: 1.22, 95% CI: 1.01 to 1.47), but not elsewhere. Initiation of HC use was associated with increased odds of subsequent TMD symptoms (OR: 1.37, 95% CI: 1.13 to 1.66) and pain of ≥ 1 day in the head (OR: 1.37, 95% CI: 1.01 to 1.85). Discontinuing HC use was associated with lower odds of subsequent headache (OR: 0.82, 95% CI: 0.67 to 0.99). HC use was not significantly associated with subsequent onset of examiner-classified TMD. These findings imply that HC influences craniofacial pain, and that this pain diminishes after cessation of HC use.

Editorial: The Co-Occurrence of Diseases

Editorial: The Co-Occurrence of Diseases

The perception of COVID-19 among Italian dental patients: an orthodontic point of view

BackgroundThe present study aimed to investigate the patients’ perception of the dental practice during the COVID-19 outbreak, and whether the pandemic will affect the attendance of orthodontic patients at the dental practice. An online questionnaire, including the Patient Health Questionnaire-4 (PHQ-4), was submitted to Italian dental patients with items about their perceived risks when going to the dentist, concerns about continuing orthodontic treatment, and the onset of temporomandibular disorders (TMD). Data were analyzed with a chi-square test and logistic regression analysis. The level of significance was set at P < 0.05.ResultsA total of 1566 subjects completed the survey, including 486 who were under orthodontic treatment or who had a child in orthodontic treatment. A total of 866 participants (55.3%) thought the risk of contracting the COVID-19 infection was higher in a dental practice; this perception was associated with gender (women more than man), age (over 60 years old) and high levels of distress (P<0.001). However, 894 patients (57.1%) felt comfortable going back to the dentist. Most of the orthodontic patients (84%) would continue their treatment. After the lockdown, there was a slight increase in the frequency of TMD pain (356 versus 334).ConclusionsMost of the participants believed that the dental practice is a place at greater risk of contracting COVID-19, even if they continue to go to the dentist. Gender, age, and the level of distress were associated with the increase in the fear of going to the dentist due to COVID-19. Because of the pandemic, 16% of patients undergoing orthodontic treatment would not return to the dental practice to continue their orthodontic treatment after the lockdown. The prevalence of TMD pain in the population increased due to the pandemic.

Pain Sensitivity Modifies Risk of Injury-Related Temporomandibular Disorder

This study evaluates contributions of jaw injury and experimental pain sensitivity to risk of developing painful temporomandibular disorder (TMD). Data were from the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) nested case-control study of incident painful TMD. Injury and subsequent onset of painful TMD were monitored prospectively for ≤5 y in a community-based sample of 409 US adults who did not have TMD when enrolled. At baseline, thermal-pressure and pinprick pain sensitivity, as potential effect modifiers, were measured using quantitative sensory testing. During follow-up, jaw injury from any of 9 types of potentially traumatic events was determined using quarterly (3-monthly) health update questionnaires. Study examiners classified incident painful TMD, yielding 233 incident cases and 176 matched controls. Logistic regression models, estimated incidence odds ratios (IORs), and 95% confidence limits (CLs) were used for the association between injury and subsequent onset of painful TMD. During follow-up, 38.2% of incident cases and 13.1% of controls reported 1 or more injuries that were 4 times as likely to be intrinsic (i.e., sustained mouth opening or yawning) as extrinsic (e.g., dental visits, whiplash). Injuries due to extrinsic events (IOR = 7.6; 95% CL, 1.6–36.2), sustained opening (IOR = 5.4; 95% CL, 2.4–12.2), and yawning (IOR = 3.4; 95% CL, 1.6–7.3) were associated with increased TMD incidence. Both a single injury (IOR = 6.0; 95% CL, 2.9–12.4) and multiple injuries (IOR = 9.4; 95% CL, 3.4,25.6) predicted greater incidence of painful TMD than events perceived as noninjurious (IOR = 1.9; 95% CL, 1.1–3.4). Injury-associated risk of painful TMD was elevated in people with high sensitivity to heat pain (IOR = 7.4; 95% CL, 3.1–18.0) compared to people with low sensitivity to heat pain (IOR = 3.9; 95% CL, 1.7–8.4). Jaw injury was strongly associated with elevated painful TMD risk, and the risk was amplified in subjects who had enhanced sensitivity to heat pain at enrollment. Commonly occurring but seemingly innocuous events, such as yawning injury, should not be overlooked when judging prognostic importance of jaw injury.

Orofacial sensorimotor behaviour in unilateral chewing: A comparative analysis in asymptomatic population

The main aim of the present study was to evaluate the presence of differences in motor, somatosensory and laterality recognise variables between individuals with unilateral chewing (UC) versus bilateral chewing (BC). A cross-sectional study with a nonprobabilistic sample was conducted. Seventy asymptomatic individuals were grouped as UC or BC to assess differences in motor, somatosensory, and laterality recognise variables. The recorded variables were range of motion (ROM), electromyographic (EMG) activity, lip grip force, 2-point discrimination (2-PD), pain pressure threshold (PPT), and laterality recognition. Significant differences in EMG activity of the masseter and temporal muscles were found in group*side (p<.005). Significant changes in group*side (p<.005) were found in lip strength and 2-PD in the maxillary and mandibular branch. For laterality, significant between-group differences in accuracy were found (p=.037). Individuals with UC showed unilateral sensorimotor modifications compared with those with BC. Although the relationship between type of mastication and temporomandibular disorder (TMD) cannot be established, neurophysiological changes in UC could affect biomechanics and temporomandibular joint function and could predispose individuals to the onset, development, and maintenance of TMD because patients with TMD usually present an impairment in orofacial motor and sensory functions, with recruitment abnormalities of the masseter and temporal muscles during chewing.

Masseter Deoxygenation in Adults at Risk for Temporomandibular Disorders

Patients with muscular temporomandibular disorder (TMD) present with abnormal oxygenation of the jaw muscles. Nonetheless, the deoxygenation pattern of jaw muscles of healthy subjects with frequent wake-time tooth-clenching episodes, who are at greater risk for TMD, has never been investigated. This case-control study compared the deoxygenation of the masseter during standardized tasks between TMD-free individuals with frequent self-reports of wake-time clenching and those with infrequent self-reports. University students (N = 255) filled out the Oral Behavior Checklist. Fourteen females with high versus low scores—high parafunctional (HP) group (n = 7, ≥80th percentile of score distribution) versus low parafunctional (LP) group (n = 7, ≤20th percentile)—completed 2 sessions during which they clenched at their maximum voluntary contraction (MVC) for 2 min and at 10% to 20% MVC for 20 min. Tissue oxygen saturation (StO2) and changes in oxygenated hemoglobin, deoxygenated hemoglobin, and total hemoglobin of the masseter were measured via near-infrared spectroscopy and analyzed with a generalized mixed effect model. A significant interaction effect (task × study group) was found on all outcome measures, indicating that the deoxygenation pattern of the HP group differed from the LP group (all P < 0.001). MVC of the masseter induced an almost 5-times-greater reduction of StO2 in the HP group as compared with the LP group (P = 0.023). However, the relative increase in StO2 at rest after the MVC was similar between groups (P > 0.05). At the end of the prolonged MVC task (10% to 20%), the blood flow (change in total hemoglobin) was almost 6 times higher in the LP group as compared with baseline. On the contrary, it increased minimally in the HP group (all P < 0.001). Healthy individuals at risk for TMD have abnormalities in masseter deoxygenation. Future prospective studies are needed to test whether this contributes to the onset of muscular TMD.

Prevalence of temporomandibular disorders and oral parafunctions in adolescents from public schools in Southern Italy

ABSTRACT Objective: The aim of this cross-sectional epidemiologic study was to estimate the prevalence of temporomandibular disorders (TMDs) and oral parafunctions in Italian adolescents and to assess the associations between age, gender, oral habits, and TMD. Methods: Three hundred sixty-one adolescents, aged 14–18 years, were examined for TMDs according to the Research Diagnostic Criteria for TMD. Furthermore, oral habits were explored by means of a written questionnaire. Results: Almost one-third of the sample (27.4%) showed at least one TMD diagnosis, with myofascial pain being the most prevalent. Gum chewing was the most prevalent oral habit. The female gender and oral habits were significantly associated with TMD. Conclusion: TMD in adolescents, although lower than in adults, are significantly prevalent. General practitioners should include TMD screening methods in their routine dental examinations of adolescent patients. Adolescents should be instructed on how to avoid incorrect oral behaviors that might predispose them to the onset of TMD.

Malocclusion as a Cause for Temporomandibular Disorders and Orthodontics as a Treatment.

This article explores the long-standing controversy between orthodontics and temporomandibular disorders (TMDs). It reviews the history of this controversy and presents a discussion of the current literature concerning the potential role of malocclusion in the onset of TMDs. It also explores the potential role of orthodontic treatment as a possible cure for TMDs and concludes, based on the most current evidence-based literature, that there is no relationship.

Temporal change in headache and its contribution to the risk of developing first-onset temporomandibular disorder in the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) study.

While cross-sectional studies have demonstrated an association between headache and temporomandibular disorder (TMD), whether headache can predict the onset of TMD is unknown. The aims of this study were to evaluate the contribution of headache to the risk of developing TMD and describe patterns of change in headache types over time. An initially TMD-free cohort of 2410 persons with low frequency of headache completed quarterly questionnaires assessing TMD and headache symptoms over a median 3.0-year follow-up period. First-onset TMD was confirmed by clinical examination in 199 participants. Baseline reports of migraine (hazard ratio [HR] = 1.67, 95% confidence interval [CI]: 1.06-2.62) or mixed headache types (HR = 4.11, 95% CI: 1.47-11.46), or headache frequency (HR = 2.13, 95% CI: 1.31-3.48) predicted increased risk of developing TMD. In addition, headache dynamics across the follow-up period before the TMD onset were evaluated in a nested case-control study where 248 incident TMD cases were matched to 191 TMD-free controls. Both headache prevalence and frequency increased across the observation period among those who developed TMD but not among controls. Patients with TMD were more likely to experience worsening in the headache type compared with that by controls, eg, prevalence of definite migraine among TMD cases increased 10-fold. Among all headache types experienced by patients with TMD before the TMD onset, migraine had the highest odds of progression relative to remission (odds ratio = 2.8, 95% CI: 1.6-4.8), whereas for controls this ratio was significant only for the tension-type headache (odds ratio = 2.1, 95% CI: 1.2-3.9). The important clinical implication of these findings is that adequate treatment of migraine may reduce the risk for developing TMD.

Subjective Sleep Quality Deteriorates Before Development ofPainful Temporomandibular Disorder.

There is good evidence that poor sleep quality increases risk of painful temporomandibular disorder (TMD). However, little is known about the course of sleep quality in the months preceding TMD onset, and whether the relationship is mediated by heightened sensitivity to pain. The Pittsburgh Sleep Quality Index was administered at enrollment into the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) prospective cohort study. Thereafter the Sleep Quality Numeric Rating Scale was administered every 3months to 2,453 participants. Sensitivity to experimental pressure pain and pinprick pain stimuli was measured at baseline and repeated during follow-up of incident TMD cases (n=220) and matched TMD-free controls (n=193). Subjective sleep quality deteriorated progressively, but only in those who subsequently developed TMD. A Cox proportional hazards model showed that risk of TMD was greater among participants whose sleep quality worsened during follow-up (adjusted hazard ratio=1.73, 95% confidence limits=1.29, 2.32). This association was independent of baseline measures of sleep quality, psychological stress, somatic awareness, comorbid conditions, nonpain facial symptoms, and demographic characteristics. Poor baseline sleep quality was not significantly associated with baseline pain sensitivity or with subsequent change in pain sensitivity. Furthermore the relationship between sleep quality and TMD incidence was not mediated via baseline pain sensitivity or change in pain sensitivity. Subjective sleep quality deteriorates progressively before the onset of painful TMD, but sensitivity to experimental pain does not mediate this relationship. Furthermore, the relationship is independent of potential confounders such as psychological stress, somatic awareness, comorbid conditions, nonpain facial symptoms, and various demographic factors.

The Association of Temporomandibular Disorders and Orthognathic Surgery

This retrospective study aimed to determine the prevalence of temporomandibular disorder (TMD) secondary to orthognathic surgery (OGS) in various types of dentofacial deformities, to access the relationship of new onset of TMD in different types of OGS to pain-related TMD and intraarticular TMD, and to evaluate the chronic facial pain, temporomandibular joint (TMJ) function, and masticatory efficiency after OGS. A total of 26 patients who were previously treated with OGS in University Malaya Medical Centre, Kuala Lumpur from January 2005 to June 2015 agreed to participate. The subjects had either undergone bilateral sagittal split ramus osteotomy (BSSRO) or bimaxillary osteotomy (BIMAX). All subjects were assessed using Diagnostic Criteria for Temporomandibular Disorder (DC/TMD). Data collected from patients’ records showed absence of TMD at presurgical stage. The present study showed 42.3% of 26 patients experienced TMD after OGS in various types of dentofacial deformities, 19.2 % of them presented with post-operative facial pain, 30.8 % had limitation in mastication, 19.2 % experienced limitation in mobility of the jaw, and 11.5% of them experienced limitation in verbal and emotional commences. In conclusion, there was no association between prevalence of TMD secondary to OGS in either type of dentofacial deformities or type of surgery involved. We also noted that the minority of the patients suffered chronic facial pain and jaw function limitation after OGS.