Prevalence and associated factors for temporomandibular disorders in Chinese civilian pilots

Prevalence of temporomandibular disorders and their associated factors in Confucian heritage cultures: A systematic review and meta-analysis

BACKGROUND

Temporomandibular disorders (TMDs) may be an 'idiom' of psychological distress in Confucian heritage cultures (CHCs).

OBJECTIVES

This systematic review/meta-analysis estimated the prevalence of TMDs in CHCs and compared the differences in TMD occurrence between time periods and age groups. Additionally, the associated biopsychosocial risk factors were also examined.

METHODS

The study protocol was developed a priori following the PRISMA guidelines and Joanna Briggs Institute systematic review methodology (CRD42021245526). Electronic searches of seven databases were conducted from January 2002 to Dec 2021. Reference lists of identified studies were hand-searched for additional articles. Study selection, quality assessment, and data extraction were done. Meta-analysis was performed using the RevMan 5.4 software.

RESULTS

Forty-eight articles were included in the systematic review. Overall prevalences were: TMDs-15% (95% CI: 15-16%); TMD pain-8% (95% CI: 7-9%); TMJ sounds-24% (95% CI: 21-27%); and TMJ locking-7% (95% CI: 1-13%). While TMD prevalence appeared to have declined from 2002 to 2011 to 2012-2021, the occurrence of TMD pain, TMJ sounds, and locking increased marginally or remained constant. TMD prevalence in children/adolescents was 18% (95% CI: 14-22%) and 17% (95% CI: 16-18%) among adults. Significant associations between TMDs and bruxism/psychological distress/education levels were specified by 73%/90%/88% of the relevant studies.

CONCLUSIONS

TMDs are prevalent in CHCs and a slight increase in TMD pain (2%) and TMJ sounds (8%) were discerned over the past two decades. TMDs are related to a myriad of biopsychosocial variables, particularly psychological distress, and these factors must be addressed within the cultural context of patients.

Temporomandibular disorder symptoms, sleep quality, and burnout syndrome in teachers

OBJECTIVE

The aim of this study was to assess the association between the symptoms of temporomandibular disorder (TMD), sleep quality, and indicators of burnout syndrome in teachers.

METHODS

This cross-sectional study included 330 teachers with an average age of 43 years. The Diagnostic Criteria for Temporomandibular Disorders, Pittsburgh Sleep Quality Index, and the questionnaire to assess burnout syndrome - teachers' version were used for data collection. Simple and multiple logistic regression models were applied to analyze the independent variables at a 5% significance level.

RESULTS

Teachers with poor sleep quality, indicators of burnout syndrome, female sex, and impact on the domains of psychological exhaustion and guilt were, respectively, 1.91,1.92, 2.66, 1.97, and 2.60 times more likely to present at least one TMD symptom (p < 0.05).

CONCLUSION

Teachers with indicators of burnout syndrome and impaired sleep quality were more likely to present with at least one TMD symptom.

Low income is associated with impaired jaw function via anxiety and depression in patients with temporomandibular disorders

OBJECTIVE

The association between jaw function and income in patients with temporomandibular disorders (TMDs) remain unclear. The aim of this study was to explore this association and its relationship with anxiety and depression.

SUBJECTS AND METHODS

A total of 451 TMD patients, including 361 males and 90 females, participated in this study. The sociodemographic information of patients and their questionnaires including the Generalised Anxiety Disorder 7-item (GAD-7), Patient Health Questionnaire 9-item (PHQ-9), and Jaw Functional Limitation Scale-8 (JFLS-8) were collected. Patients were divided into the high-income and low-income groups based on a household per capita income of 6000 RMB per month. Multiple regression and mediation analysis were used to explore the association between variables. The bootstrap method was applied to estimate confidence intervals (CIs).

RESULTS

Higher JFLS-8 scores were significantly correlated with higher GAD-7 scores (r = 0.361, p < .001), PHQ-9 scores (r = 0.339, p < .001). Females and patients with low income had statistically higher JFLS-8 scores (p < .01, p < .001). Mediation analysis with 10 000 bootstrap simulations revealed a significant direct association between JFLS-8 scores and income (-2.920, 95% CI [-4.757, -1.044], p = .002). A significant indirect association of JFLS-8 scores with income via GAD-7 scores and PHQ-9 scores was also observed (-0.889, 95% CI [-1.728, -0.164], p = .025), accounting for 23.3% of the total association.

CONCLUSIONS

Low income is associated with impaired jaw function via anxiety and depression in patients with TMD. Clinicians may need to pay more attention to the psychological status of low-income TMD patients in clinical practice.

Research progress in effect of chewing-side preference on temporomandibular joint and its relationship with temporo-mandibular disorders

Chewing-side preference is one of the risk factors for temporomandibular disorders (TMD), and people with chewing-side preference is more prone to have short and displaced condyles, increased articular eminence inclination and glenoid fossa depth. The proportion of TMD patients with chewing-side preference is often higher than that of the normal subjects. Clinical studies have shown a strong correlation between chewing-side preference and TMD symptoms and signs; and animal studies have shown that chewing-side preference can affect the growth, development, damage and repair of the mandible. After long-term unilateral mastication, changes in the stress within the joint cause the imbalance of temporomandibular joint (TMJ) structural reconstruction, the transformation and even destruction of the fiber structure of masticatory muscle, resulting in uncoordinated movement of bilateral muscles. The joint neurogenic diseases caused by the increase of neuropeptide substance P and calcitonin-gene-related-peptide (CGRP) released locally by TMJ may be the mechanism of TMD. This article reviews the research progress of the influence of chewing-side preference on the structure of TMJ, the relationship between chewing-side preference and TMD, and the related mechanisms.

Cone-beam computed tomographic characteristics in degenerative temporomandibular joint disease patients with chewing side preference

OBJECTIVES

This study is aimed at assessing the Cone-beam computed tomographic (CBCT) characteristics of temporomandibular joints (TMJ) in degenerative temporomandibular joint disease (DJD) patients with chewing side preference (CSP).

MATERIALS AND METHODS

CBCT images of 98 patients with DJD (67 with CSP and 31 without CSP) and 22 asymptomatic participants without DJD were measured retrospectively to compare the osteoarthritic changes and the morphology of TMJ. Quantitative analysis of the TMJ radiographic images was performed to present a comparison between the three inter-group groups and between the two sides of the joints.

RESULTS

The frequencies of the articular flattening and surface erosion occur more often in the preferred side joints of DJD patients with CSP than the contralateral side. In addition, the horizontal angle of condyle, the depth of glenoid fossa (DGF), and the inclination of articular eminence (IAE) were larger in DJD patients with CSP than that in asymptomatic participants (p<0.05). Also, the condylar anteroposterior dimension of preferred side joints was significantly less than that of non-preferred side (p=0.026), while the width of condyles (p=0.041) and IAE (p=0.045) was greater.

CONCLUSIONS

DJD patients with CSP appear to have a higher prevalence of osteoarthritic changes, with the morphological changes such as flat condyle, deep glenoid fossa, and steep articular eminence, which might be considered the characteristic imaging features.

CLINICAL RELEVANCE

This study found that CSP is a predisposing factor for the development of DJD, and attention should be paid to the existence of CSP in DJD patients during the clinical practice.

Association between temporomandibular disorders and anxiety: A systematic review

Temporomandibular Joint Dysfunction (TMD) is an umbrella term that includes musculoskeletal and neuromuscular conditions affecting the temporomandibular joint. The present systematic review aimed to verify whether there is a specific association between TMD and anxiety. The searches were carried out in electronic databases, including PubMed, Scopus, Web of Science, and LILACS, without restrictions on publication date and language. The acronym PECO was used, whose participants (P) were humans exposed to TMD (E), compared to participants without TMD (C) and the presence of anxiety as an outcome (O). After the search retrieval, the duplicates were removed, and the articles were evaluated by title and abstract, following our inclusion and exclusion criteria; then, the papers were read and thoroughly assessed. After selection, the methodological quality was performed using the Newcastle-Ottawa Scale (NOS) for observational studies. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool was used to assess the level of evidence. A total of 710 studies were found, and 33 articles were considered eligible and were included for the qualitative synthesis and the level of evidence assessment. The studies confirmed the association between anxiety and DTM, although there was a low certainty of evidence among the selected studies. Most articles showed a low risk of bias. Although the limitations of this systematic review, it suggested a significant association between anxiety and TMD, as well as highlights possible directions for future research.

A comparative study of condyle position in temporomandibular disorders patients with chewing side preference using cone-beam computed tomography

BACKGROUND

Chewing side preference (CSP) could cause structural and morphological changes of temporomandibular joint (TMJ) and has been suggested as one etiology of temporomandibular disorders (TMDs), but the condylar position in TMD patients with CSP is unknown.

OBJECTIVE

To compare the condylar position in the TMD patients with and without CSP.

METHODS

Ninety TMD patients with unilateral symptom (69 with CSP and 21 without CSP) and 20 asymptomatic participants received cone-beam computed tomography. The condylar position was determined based on the measurements of sagittal joint spaces. Intergroup and intragroup comparisons of the condylar position were performed.

RESULTS

The condyles in asymptomatic participants located nearly randomly in anterior, centric, and posterior positions. Patients without CSP had significantly more posterior condyles than asymptomatic participants (57.1% vs 30.0%, P<0.05). In patients with CSP, 50.7% of the condyles on the preferred chewing side and 42.0% on the unpreferred side located posteriorly, reaching no significant level compared with the asymptomatic participants and patients without CSP (P>0.05). The symptomatic joints and asymptomatic joints in patients with CSP and without CSP showed no significant differences in condylar position. While patients without CSP had significantly more posterior condyles in symptomatic joints than asymptomatic participants (P<0.05), patients with CSP showed a trend towards more posterior condyles in symptomatic joints compared with the asymptomatic participants (53.6% vs 30.0%, P=0.054).

CONCLUSION

Condylar position is not a strong indicator to differentiate CSP-related TMDs from none-CSP-related TMDs. Posterior condyle could not be viewed as one indicator of TMD.

The effects of emotional trait factors on simulated flight performance under an acute psychological stress situation

Objective. Pilots are commonly exposed to some sources of emotional and cognitive stressors, especially for flight cadets, which have an important influence on flight safety. The present study aimed to study the relationship between emotional trait factors, emotional state, mental workload and simulated flight performance (SFP) under an acute psychological stress situation. Methods. Fifty-five undergraduates were included in the study. The Wong and Law emotional intelligence scale (WLEIS), state-trait anxiety inventory (STAI), stress rating questionnaire (SRQ) and National Aeronautics and Space Administration task load index (NASA-TLX) were used as data collection tools. Nine hours of simulated flight training were conducted in a simulator of the Type-6 Primary Trainer (Aviation University Air Force, China). The simulated flight assessment was taken as the acute psychological stressor. Results. SFP was negatively correlated with tensity and state anxiety. Emotional intelligence (EI) indirectly affected the SFP mediated by emotional state and workload, and emotional state had a mediating effect on the relationship between trait anxiety and SFP. Conclusions. The findings indicated that emotional trait factors (EI and trait anxiety) may indirectly affect SFP under an acute psychological stress situation, and emotional state (tensity and state anxiety) and mental workload played an important mediating role.

Cone-beam computed tomographic assessment of the inclination of the articular eminence in patients with temporomandibular disorders and chewing side preference

Background

Chewing side preference (CSP) has been proposed as one etiology of temporomandibular disorders (TMDs) as it can induce the structural changes of the temporomandibular joint. But its association with the inclination of the articular eminence (IAE) is unknown. This study aimed to compare IAE between patients with CSP and without CSP.

Methods

Cone-beam computed tomography images of 90 patients with TMD (mean age of 45.6 years, 69 with CSP, 21 without CSP) and 20 participants without TMD and CSP (mean age of 41.3 years) were measured to compare IAE and depth of the glenoid fossa (DGF)

Results

IAE and DGF showed a positive correlation among all the participants. Compared with the participants without TMD and CSP, the TMD patients without CSP presented a similar IAE but with a significantly higher value of DGF (p < 0.05); in contrast, the TMD patients with CSP presented a significantly greater IAE and DGF (p < 0.05). No bilateral differences in IAE and DGF were observed in all the participants. Except the male patients with CSP had a deeper fossa than did the female, no differences in IAE and DGF according to gender were observed.

Conclusions

TMD patients with CSP seem to have a deep glenoid fossa with steep eminence which might be considered one characteristic imaging feature.

Sleep bruxism and temporomandibular disorders: A scoping review of the literature

OBJECTIVE

To provide a scoping review of the literature by assessing all the English-language papers that investigated the relationship between sleep bruxism (SB) and temporomandibular disorders (TMDs).

STUDY DATA AND SOURCES

A search was performed in the National Library of Medicine (PubMed) and Scopus databases, in order to identify all the articles published assessing the relationship between SB and TMDs, by several different approaches. The selected articles were then structurally read and summarized in PICO tables. The articles were selected independently by the two authors.

STUDY SELECTION

Out of 185 references that were initially retrieved, 47 articles met the inclusion criteria and were thus included in the review. The studies were divided into four categories based on the type of SB assessment: 1. questionnaire/self-report (n = 26), 2. clinical examination (n = 7), 3. electromyography (EMG) (n = 5), and 4. polysomnography (PSG) (n = 9).

CONCLUSIONS

Studies based on questionnaire/self-report SB featured a low specificity for SB assessment, and in general they found a positive association with TMD pain. On the contrary, instrumental studies (i.e., electromyography, polysomnography) found a lower level of association or even a negative relationship between SB and TMD pain. Findings from this updated review confirmed the conclusions of a previous review by Manfredini & Lobbezoo, suggesting that literature findings on the relationship between SB and TMDs are dependent on the assessment strategies that are adopted for SB. Future studies should consider SB as a multifaceted motor behavior that must be evaluated in its continuum spectrum, rather than using a simplified dichotomous approach of presence/absence.

Level of work stress and factors associated with bruxism in the military crew of the Peruvian Air Force

BACKGROUND

Military life leads to a great personal sacrifice and labor in the aircrew because they are constantly subjected to innumerable activities which have a great work pressure; therefore, the aim of this study was to determine the level of work stress associated with bruxism in the aircrew of the Peruvian Air Force.

METHODS

This was a cross-sectional study. A total of 204 crew members of the Peruvian Air Force from the Air Group were surveyed, and the stomatological clinical inspection was carried out. Each crew member was evaluated using the validated International Labor Organization-World Health Organization (ILO-WHO) Work Stress Scale, and clinical records were used to diagnose bruxism using the Smith and Knight wear index.

RESULTS

It was found that 93.7% (n = 191) of the crew members were men and 6.3% (n = 13) were women; and the percentage of intermediate-level stress was found to be high in the grade of non-commissioned officers, whereas in the officer grade, the level of stress was low. There was also a statistically significant association between the variables military grade, sex, and age group. The sub-officers presented a higher percentage in the category "with bruxism", while in the rank of officers the category of "non-bruxism" was the most prevalent.

CONCLUSIONS

This study showed a statistically significant association between the variable bruxism and the level of work stress between the military aviators of the Peruvian Air Force (p<0.001).

Somatosensory profiles of patients with chronic myogenic temporomandibular disorders in relation to their painDETECT score

BACKGROUND

The purpose of this study was to characterize patients with chronic temporomandibular disorders (TMD) in terms of existing hyperalgesia against cold, heat and pressure.

METHODS

The extent of hyperalgesia for pressure and thermal sensation in TMD patients was determined by the use of the painDETECT questionnaire ("Is cold or heat in this area occasionally painful?" "Does slight pressure in this area, e.g., with a finger, trigger pain?") and experimental somatosensory testing against thermal and pressure stimuli (Quantitative Sensory Testing; QST). In addition, we explored psychological comorbidity among the chronic TMD patients (hospital anxiety and depression scale, HADS-D and coping strategies questionnaire, CSQ).

RESULTS

Nineteen patients with chronic TMD and 38 healthy subjects participated in the study. N = 12 patients had a painDETECT score ≤ 12, n = 3 patients had a painDETECT score of 13-18 and n = 4 patients had a painDETECT score ≥ 19. TMD patients with painDETECT scores ≥19 had moderately, strong or very strong enhancement of thermal and pressure pain perception, whereas patients with painDETECT scores 13-18 and ≤ 12 responded these questions with "never", "hardly noticed" or "slightly painful" (p < 0.05-0.01). With increasing painDETECT scores we found increased hyperalgesia for pressure (p < 0.01) and thermal stimuli (p < 0.05) in QST. The patients with a painDETECT score ≥ 19 showed increased signs of anxiety (p < 0.05), depression (p < 0.01), praying and hoping (p < 0.05).

CONCLUSION

The present study has shown that the PainDETECT questionnaire can be a helpful additional diagnostic tool. Together with QST, the PainDETECT questionnaire detected hyperalgesia for pressure and thermal sensation. Therefore the PainDETECT questionnaire is helpful to decide which TMD patients should undergo QST.

[Alteration of metabolic characteristics on the masseter muscle fiber of unilateral chewing rats and its adenosine monophosphate activated protein kinase regulatory mechanism]

OBJECTIVE

This study aims to determine the influence of unilateral chewing on metabolic characteristics of masseter muscle fibers in rats and the regulatory effect of an adenosine monophosphate activated protein kinase (AMPK) signal pathway on metabolism.

METHODS

Rats were submitted to exodontia of all the right maxillary molars and divided into 2, 4, 6, and 8 weeks groups, and corresponding control groups were set as well. Sections were stained by nicotine adenine dinucleotide tetrazolim reductase(NADH-TRase) to demonstrate the types, proportion, and density of masseter muscle fibers. AMPKα1 and p-AMPK(Thr172) levels in bilateral masseter muscles were detected by Western blot.

RESULTS

In the 2-week group, the percentage of dark fibers augmented in the ipsilateral side, whereas the percentage of intermediary fibers in the contralateral side was increased accompanied by a decrease of light fibers, compared with the control group (P<0.05). The percentage of dark fibers was increased in the bilateral sides, whereas the percentage of dark fiber in the ipsilateral sides surpassed that of the contralateral sides in the 4, 6, and 8-week groups. The percentage of intermediary fibers was decreased in the bilateral sides in the 6 and 8-week groups (P<0.05). The percentage of light fibers was reduced in the ipsilateral sides in the 8-week group, whereas no alteration was observed in contralateral sides (P>0.05). In the ipsilateral sides, p-AMPK (Thr172)/AMPKα1 levels were increased in the 2 and 4-week groups (P<0.05), whereas no change was observed in the contralateral sides in either group (P>0.05).

CONCLUSIONS

Unilateral chewing increases the oxidative metabolic ability in bilateral masseter muscle fibers especially in the non-working side accompanied with change of muscle fiber types. The improvement of aerobic metabolism ability is related to the AMPK signal pathway.
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