Gender differences in temporomandibular disorders in adult populational studies: A systematic review and meta-analysis

TET1-mediated epigenetic regulation of tumor necrosis factor-α in trigeminal ganglia contributes to chronic temporomandibular joint pain

Chronic temporomandibular joint (TMJ) pain profoundly affects patients' quality of life. Trigeminal tumor necrosis factor-α (TNFα) plays a pivotal role in mediating TMJ pain in mice, yet the underlying epigenetic mechanisms remain enigmatic. To unravel these epigenetic intricacies, we employed a multifaceted approach. Hydroxymethylated DNA immunoprecipitation (hMeDIP) and chromatin immunoprecipitation (ChIP) followed by qPCR were employed to investigate the demethylation of TNFα gene (Tnfa) and its regulation by ten-eleven translocation methylcytosine dioxygenase 1 (TET1) in a chronic TMJ pain mouse model. The global levels of 5-hydroxymethylcytosine (5hmc) and percentage of 5hmc at the Tnfa promoter region were measured in the trigeminal ganglia (TG) and spinal trigeminal nucleus caudalis (Sp5C) following complete Freund's adjuvant (CFA) or saline treatment. TET1 knockdown and pain behavioral testing were conducted to ascertain the role of TET1-mediated epigenetic regulation of TNFα in the pathogenesis of chronic TMJ pain. Our finding revealed an increase in 5hmc at the Tnfa promoter region in both TG and Sp5C of CFA-treated mice. TET1 was upregulated in the mouse TG, and the ChIP result showed TET1 direct binding to the Tnfa promoter, with higher efficiency in the CFA-treated group. Immunofluorescence revealed the predominant expression of TET1 in trigeminal neurons. TET1 knockdown in the TG significantly reversed CFA-induced TNFα upregulation and alleviated chronic TMJ pain. In conclusion, our study implicates TET1 as a vital epigenetic regulator contributing to chronic inflammatory TMJ pain via trigeminal TNFα signaling. Targeting TET1 holds promise for epigenetic interventions in TMJ pain management.

Does childhood maltreatment play a role in temporomandibular disorders?

The aim of this study was to find out if experiences of maltreatment in childhood have an effect on the occurrence of temporomandibular joint disorders (TMD). The study was conducted on 380 volunteer adults (252 females and 128 males), with a mean (SD) age of 27.63 (9.06) years. The level of TMD was assessed using the Fonseca Anamnestic Index (FAI). Childhood Trauma Questionnaires (CTQ) were completed by the participants and their marital status and educational level were recorded. FAI scores were significantly higher in females than in males. There was no statistically significant difference between gender and total CTQ score. Moreover, there was no statistically significant difference between educational status, marital status, and total CTQ score. FAI scores correlated positively with total CTQ scores in all individuals. Similarly FAI scores correlated positively with total CTQ scores in males and females. Childhood maltreatment is associated with TMDs. Dentists should be aware that possible collaboration with psychiatrists and/or psychologists when treating patients with TMD could increase the success of their treatment.

Occurrence of Temporomandibular Disorders among patients undergoing treatment for Obstructive Sleep Apnoea Syndrome (OSAS) using Mandibular Advancement Device (MAD): A Systematic Review conducted according to PRISMA guidelines and the Cochrane handbook for systematic reviews of interventions

BACKGROUND

Patients undergoing mandibular advancement device (MAD) therapy for obstructive sleep apnea (OSA) may experience changes in jaw position and altered occlusion. This could potentially contribute to the development or exacerbation of TMD symptoms. The literature on the long-term impact of MAD treated for OSA on TMD is scarce. Hence, this review was undertaken to ascertain the occurrence of TMD in MAD users.

METHODS

A comprehensive search protocol was implemented across several online databases using MeSH keywords and Boolean operators. A standardised data extraction form was developed specifically for this review. Two reviewers independently extracted the data. RoB-2 was used to evaluate the methodological quality of the included studies.

RESULTS

A total of 13 clinical studies were selected for this review. Some studies reported a significant reduction in the severity and frequency of TMD symptoms following MAD treatment. However, other studies did not observe significant changes in TMD symptoms or TMJ-related parameters from baseline to follow-up intervals. Temporary increases in TMJ-related pain or symptoms at the beginning of the follow-up period, which later subsided, were reported in some studies. Overall, MAD was not discontinued in any OSA patient due to TMDs.

CONCLUSION

The findings reveal that different outcomes associated with TMD are affected differently by MAD treatment for OSAS. According to a few studies, MAD therapy significantly reduced the severity and frequency of TMD symptoms. Other research, however, found no appreciable modifications in TMD symptoms or TMJ-related indicators. Although the overall results point to no significant effect of MAD treatment on TMD symptoms, the disparity in results between studies highlights the need for additional studies using standardised approaches.

Psychological characteristics of young adults with temporomandibular disorders, somatization and combined conditions: A multidimensional evaluation

BACKGROUND

Temporomandibular disorders and somatization have shown interrelation in many studies. The physical and psychological factors which contributed to the occurrence and relation of both conditions are yet to be determined.

OBJECTIVES

The personality traits, coping styles and psychological distress of young adults with temporomandibular disorder (TMD) and somatic symptoms were characterized together with the determination of psychological risk factors for TMDs, somatization and combined conditions.

METHODS

Participants were recruited from university-attending young adults. TMD and somatic symptoms were appraised with the short-form Fonseca Anamnestic Index and Patient Health Questionnaire-15. Psychological variables were assessed with the Big Five Personality Inventory-10, Brief-COPE Inventory and Depression, Anxiety, and Stress Scales-21. Data were evaluated using chi-squared/non-parametric tests and logistic regression analyses (α = .05).

RESULTS

Among the 507 participants (mean age 22.2 ± 1.5 years), 46.4% reported no TMD/somatic symptoms (NS) while 7.5%, 34.5% and 11.6% had TMDs only (TS), somatization only (SS) and combined TMDs-somatization (CS), respectively. Significant differences in conscientiousness (NS > SS), agreeableness (NS, TS > CS; NS > SS), dysfunctional coping, general distress, depression, anxiety and stress (CS ≥ SS > NS) were discerned. Multivariate analyses indicated that the odds of TS were increased by anxiety (OR = 1.10; 95% CI = 1.01-1.21), while the odds of SS/CS were affected by anxiety (OR = 1.15; 95% CI = 1.06-1.25/OR = 1.34; 95% CI = 0.19-1.52) and problem-focused coping (OR = 0.71; 95% CI = 0.56-0.89/OR = 0.55; 95% CI = 0.39-0.78).

CONCLUSION

Though individuals with TMDs and somatization have dissimilar psychological profiles, anxiety constantly increased their likelihood. Problem-focused coping strategies may help alleviate psychosocial and physical stressors associated with TMDs and somatization.

Prevalence of temporomandibular disorders in the Brazilian population: A systematic review and meta-analysis

This systematic review aimed to assess the prevalence of temporomandibular disorders (TMD) in the Brazilian population, with studies that used the RDC/TMD or DC/TMD as diagnostic tools. A total of 6365 people from 11 studies were included. Sample mean age ranged from 12 to 69.5 years. The pooled prevalence of TMD was 33.6% (95% CI 31.5-35.8; I2 = 37.2). Prevalence of TMD was higher in females (37.0%) than in males (29.3%). Our results indicate that TMD is a prevalent condition across Brazil's territories. The results from this meta-analysis can help calculate more accurate sample sizes for future studies.

Gender differences in lateral pterygoid muscle in patients with anterior disk displacement

OBJECTIVE

To use quantitative MRI to assess gender differences in lateral pterygoid muscle (LPM) characteristics in patients with anterior disk displacement (ADD).

METHODS

Lateral pterygoid muscle of 51 patients diagnosed with temporomandibular joint disorders (TMD) who underwent T1-weighted Dixon and T1-mapping sequences were retrospectively analyzed. There were 34 female patients (10 with bilateral normal position disk [NP]; 24 with bilateral ADD) and 17 male patients (eight with bilateral NP; nine with bilateral ADD) among them. After controlling for age, differences in fat fraction, T1 value, volume and histogram features related to gender and disk status were tested with 2-way ANCOVA or Quade ANCOVA with Bonferroni correction.

RESULTS

Volume of LPM in NP was significantly smaller than that of ADD (p < 0.001). Fat fraction of LPM in females with NP was significantly higher than males with NP (p < 0.05). Females with ADD showed a significantly higher T1 value (p < 0.05), and higher intramuscular heterogeneity than males with ADD.

CONCLUSIONS

Lateral pterygoid muscle in female TMD patients presented more fatty infiltration in the NP stage and might present more fibrosis in the ADD stage compared with males. Together, this leads to more serious intramuscular heterogeneity during the pathogenesis of ADD in females.

Combination of hyperlipidemia and 17β-Estradiol induces TMJOA-like pathological changes in rats

OBJECTIVE

We explored whether hyperlipidemia or combination of hyperlipidemia and E2 could induce TMJOA.

MATERIALS AND METHODS

Four groups of female rats were treated with normal diet, normal diet with E2, high-fat diet, and high-fat diet with E2 (HFD/E2), respectively, to induce TMJOA till 8 weeks. Another three groups were then used for COX2 inhibitor celecoxib to block the induction of TMJOA. Primary condylar chondrocytes were treated with combination of E2, ox-LDL, and corresponding inhibitors for evaluating expressions of related molecules.

RESULTS

Condylar cartilage proliferation with plenty of chondrocyte apoptosis and increased staining for LOX1, nuclear NF-κB, IL-1β, and COX2 at 4 weeks and decreased condylar cartilage and increased subchondral bone density at 8 weeks were observed only in the HFD/E2 group. Celecoxib significantly alleviated the cartilage proliferation and apoptosis in the HFD/E2 group. Serum ox-LDL increased in both high-fat diet groups, while serum IL-1β increased only in the HFD/E2 group. Combination of E2 and ox-LDL synergistically induced expressions of LOX1, phosphorylated NF-κB, IL-1β, and COX2, while LOX1 inhibitor blocked the induction of phosphorylated NF-κB, and NF-κB inhibitor the induction of IL-1β, and IL-1β inhibitor the induction of COX2.

CONCLUSION

Combination of hyperlipidemia and E2-induced TMJOA-like pathological changes through LOX1/NF-κB/IL-1β/COX2-signaling pathway.

Temporomandibular joint disorders in seronegative spondyloarthritis: what a rheumatologist needs to know?

Temporomandibular joint (TMJ) can be affected in the context of spondyloarthritis (SpA) with detrimental impact on individuals' quality of life. Intra-articular inflammation, synovitis, enthesitis, disc displacement and cervical vertebrae malalignment are some of the pathophysiological phenomena involved. Temporomandibular joint disorders (TMD) incidence appears to be higher in patients with ankylosing spondylitis and psoriatic arthritis, especially when clinical evaluation includes not only imaging but relevant history, TMJ examination and diagnostic criteria for TMD. The Visual Analogue Scale (VAS) pain score and Health Assessment Questionnaire Disability Index (HAQ) quality of life score could be useful tools. Panoramic radiographs and ultrasound can be used for screening but in symptomatic patients magnetic resonance imaging (MRI) is preferable. Conservative management and early pharmacological treatment can prevent permanent joint impairment. For refractory cases, early referral to Legislation for Oral and Maxillofacial Surgery (OMFS) specialists is indicated. The aim of this narrative review is to address the involvement of TMJ in SpA and to encourage clinicians to incorporate TMJ assessment in their physical examination and basic screening.

DC/TMD axis I subtyping: generational and gender variations among East Asian TMD patients

OBJECTIVES

This study examined the generational-gender distinctions in Diagnostic Criteria for Temporomandibular disorders (DC/TMD) subtypes among East Asian patients.

METHODS

Consecutive "first-visit" TMD patients presenting at two university-based TMD/orofacial pain clinics in China and South Korea were enlisted. Demographic information along with symptom history was gathered and clinical examinations were performed according to the DC/TMD methodology. Axis I physical diagnoses were rendered with the DC/TMD algorithms and categorized into painful and non-painful TMDs. Patients were categorized into three birth cohorts, specifically Gen X, Y, and Z (born 1965-1980, 1981-1999, and 2000-2012 respectively) and the two genders. Data were evaluated using Chi-square/Kruskal-Wallis plus post-hoc tests and logistic regression analyses (α = 0.05).

RESULTS

Gen X, Y, and Z formed 17.2%, 62.1%, and 20.7% of the 1717 eligible patients examined (mean age 29.7 ± 10.6 years; 75.7% women). Significant differences in prevalences of arthralgia, myalgia, headache (Gen X ≥ Y > Z), and disc displacements (Gen Z > Y > X) were observed among the three generations. Gen Z had substantially fewer pain-related and more intra-articular conditions than the other generations. Women presented a significantly greater frequency of degenerative joint disease and number of intra-articular conditions than men. After controlling for generation-gender interactions, multivariate analyses showed that "being Gen X" and female increased the risk of painful TMDs (OR = 2.20) and reduced the odds of non-painful TMDs (OR = 0.46).

CONCLUSIONS

Generational-gender diversities in DC/TMD subtypes exist and are important for guiding TMD care and future research endeavors.

Correlates between temporomandibular disorder severity, emotional distress, and eudaimonic well-being among young adults

OBJECTIVES

This study examined the correlates between severity of temporomandibular disorders (TMDs), emotional distress, and eudaimonic well-being.

SUBJECTS AND METHODS

TMD severity, negative emotions, and eudaimonia were assessed with the Fonseca Anamnestic Index (FAI), Depression, Anxiety, Stress Scales-21 (DASS-21), and Psychological Well-being Scale-18 (PWBS-18) in a cohort of community young adults. Statistical evaluations were done with non-parametric tests/correlation and multivariate regression analyses (α = 0.05).

RESULTS

Amongst the 873 participants (mean age 19.8 ± 1.66 years), 40.7%, 49.0%, and 10.3% had no (NT), mild (MT), and moderate-to-severe (ST) TMD, respectively. Significant differences in total-DASS, depression, anxiety, and stress were ST ≥ MT > NT. Significant variances in total-PWSB and self-acceptance were NT > MT > ST while that for environmental mastery, positive relations, and purpose in life were NT > MT, ST. An inverse relationship was discerned between total-DASS and total-PWBS (correlation coefficient = -0.54). The prospect of ST was increased by anxiety but reduced by positive relations and self-acceptance.

CONCLUSIONS

Young adults with mild and moderate-to-severe TMD experienced substantially higher emotional distress and lower eudaimonia than those with no TMD. As emotional distress and eudaimonic well-being are interrelated, positive psychological interventions may be beneficial for managing TMD-related psychosocial disabilities.

Painful temporomandibular disorders in Confucian-heritage cultures: Their inter-relationship with bodily pain, psychological well-being and distress

BACKGROUND

Temporomandibular disorders (TMDs) are common and affect individuals negatively.

OBJECTIVES

This study investigated the inter-relationship of painful TMDs with bodily pain, psychological well-being and distress in young people from a Confucian-heritage culture (CHC).

METHODS

Adolescents/young adults were recruited from a polytechnic in Singapore. While the presence/severity of painful TMDs and bodily pain were established with the DC/TMD Pain Screener (TPS) and Maciel's Pain Inventory, psychological well-being and distress were evaluated with the Scales of Psychological Well-being-18 (SPWB-18) and Patient Health Questionnaire-4 (PHQ-4). Statistical explorations were conducted using chi-square/Mann-Whitney U tests, Spearman's correlation and logistic regression analyses (α = .05).

RESULTS

Among the 225 participants (mean age 20.1 ± 3.9 years) examined, 11.6% had painful TMDs and 68.9% experienced multisite bodily pain. Though painful TMDs were accompanied by a higher occurrence of multisite bodily pain, the overall/discrete number of bodily pain sites did not differ substantially between the 'no TMD pain' (NT) and 'with TMD pain' (WT) groups. Besides ear pain, differences in overall/discrete bodily pain scores were also insignificant. However, significant differences in environmental mastery, overall psychological distress, depression and anxiety subscale scores were discerned between the NT and WT groups. Psychological well-being and distress were moderately and negatively correlated (rs  = -.56). Multivariate analysis indicated that ear pain and psychological distress increased the prospect of painful TMDs.

CONCLUSION

The prevalence of multi-site bodily pain was high in young people from CHCs irrespective of the painful TMDs' presence of painful TMDs. Enhancing environmental mastery and relieving depression/anxiety may help manage TMD pain.

TMJ degenerative joint disease: relationships between CBCT findings, clinical symptoms, and signs

OBJECTIVES

The relationships between cone-beam computed tomography (CBCT) findings, Temporomandibular disorder (TMD) symptoms, and signs were investigated in patients with TMJ degenerative joint disease (DJD).

MATERIAL AND METHODS

Adult patients with Diagnostic Criteria for TMDs (DC/TMD)-defined intra-articular conditions were enrolled and subjected to CBCT assessment. The participants were organized into three groups, namely no (NT), early (ET), and late (LT) TMJ DJD based on radiographic findings. TMD symptoms/signs were appraised using the DC/TMD methodology. Statistical analyses were performed using Chi-square/non-parametric tests and Kappa statistics (α = 0.05).

RESULTS

The mean age of the participants (n = 877) was 30.60 ± 11.50 years (86.6% women). NT, ET, and LT were observed in 39.7%, 17.0%, and 43.3% of the study sample. Significant differences in the prevalence of TMD symptoms (TMD pain, TMJ sounds, opening, and closing difficulty) and signs (TMD/TMJ pain, TMJ clicking/crepitus, and opening limitation) were discerned among the three groups (p ≤ .001). TMD/TMJ pain and opening difficulty/limitation were more prevalent in early rather than late degenerative changes. While moderate agreements between symptoms and signs were observed for TMD pain/opening limitation, the concurrence for TMJ sounds was fair.

CONCLUSIONS

Young adults with TMJ sounds and pain should be examined with CBCT to establish the extent/progress of osseous changes.

Sex hormones associated with temporomandibular pain on palpation in male adolescents-Results of the epidemiologic LIFE child study

OBJECTIVE

This study aimed to investigate whether the sex steroid precursor hormone dehydroepiandrosterone sulphate (DHEA-S), sex hormone-binding globulin (SHBG) and testosterone (TT) are associated with temporomandibular (TM) pain on palpation in male adolescents.

METHODS

Out of the LIFE Child study dataset containing 1022 children and adolescents aged 10-18 years (496 males, 48.5%), we used a subsample of 273 male adolescents (mean age: 13.8 ± 2.3 years) in advanced pubertal development (PD) to analyse the association between hormones and TM pain. The Tanner scale was applied to describe the stage of PD. Pain on palpation of the temporalis and masseter muscles and the TM joints (palpation pain) was assessed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Serum levels of sex hormones (DHEA-S, SHBG and TT) were determined using standardised laboratory analyses. Free TT was estimated from the ratio between TT and SHBG (free androgen index[FAI]). We calculated the risk of perceived positive palpation pain for male participants as a function of hormone levels (DHEA-S, FAI) taking into account age and body mass index (BMI).

RESULTS

Among more developed (Tanner stage 4-5) male adolescents, 22.7% (n = 62) reported palpation pain in the TM region. In these participants, FAI levels were approximately half that of individuals without such pain (p < .01). DHEA-S levels were about 30% lower in the pain group (p < .01). In multivariable regression analyses, the odds ratio (OR) for pain on palpation decreased to 0.75 (95% confidence interval [CI]: 0.57-0.98) per 10 units of FAI level compared to those without pain, after controlling for the effects of age and adjusted BMI. We observed the same effect for this subgroup per unit of DHEA-S serum level (OR = 0.71; 95% CI: 0.53-0.94).

CONCLUSION

At subclinical lower levels of serum free TT and DHEA-S, male adolescents are more likely to report pain on standardised palpation of the masticatory muscles and/or TM joints. This finding supports the hypothesis that sex hormones may influence pain reporting.

Personality, psychosocial and oral behavioural risk factors for temporomandibular disorder symptoms in Asian young adults

BACKGROUND

The relation between personality, psychosocial factors, somatisation, andoral behaviours as risk factors to temporomandibular disorder symptoms have notbeen well established.

OBJECTIVES

This study examined the association of temporomandibular disorder (TMD) symptoms with personality traits, psychological distress, somatisation and oral behaviours. The psychosocial and oral behavioural risk factors for TMD symptoms were also established in Asian young adults.

METHODS

Participants were recruited from a large private University. Based on the quintessential five TMD symptoms (5Ts) of the DC/TMD, the participants were stratified into those with no (NT), painful (PT), dysfunctional (DT) and mixed (MT) TMD symptoms. Personality traits, psychological distress, somatisation and oral behaviours were evaluated with the Big Five Inventory-10 (BFI-10), Depression, Anxiety, Stress Scales-21 (DASS-21), Patient Health Questionnaire-15 (PHQ-15) and Oral Behaviours Checklist (OBC) accordingly. Data were examined using Kruskal-Wallis/Mann-Whitney U and Chi-squared tests, as well as multivariate logistic regression analysis (α = .05).

RESULTS

Of the 420 young adults (mean age 22.7 ± 1.1 years) evaluated, 41.4% had no TMD symptoms, while 17.4%, 20.0% and 21.2% reported PT, DT and MT, respectively. Though personality traits did not vary notably, participants with MT and PT had significantly higher levels of negative affectivity, anxiety and stress than the NT group. Moreover, those with MT and PT presented significantly greater somatisation and more oral behaviours than the DT and NT groups. Multivariate regression analyses indicated that anxiety, somatisation, sleep-related and waking-state nonfunctional oral activities were associated with painful and/or dysfunctional TMD symptoms.

CONCLUSIONS

Except for sleep-related oral activity, psychosocial and oral behavioural risk factors differed for painful, dysfunctional and mixed TMD symptoms in Asian young adults.

Effectiveness of Dry Needling versus Manual Therapy in Myofascial Temporomandibular Disorders: A Single-Blind Randomized Controlled Trial

Dry needling (DN) is an invasive physiotherapy technique employed for reducing myofascial pain. To compare the effectiveness of dry needling (DN) versus manual therapy (MT) in improving pain, active maximal mouth opening (AMMO) and cervical disability in patients with myofascial pain from temporomandibular disorders (TMDs) were investigated against these treatments. A single-blind, randomized controlled trial was carried out. Individuals (n = 50) with TMDs were randomly allocated in a 1:1 ratio to the DN (n = 25) or MT group (n = 25). Each group received three sessions, separated by 4 days, of either DN or MT. Outcomes were assessed according to pain intensity (Numeric Pain Rating Scale), AMMO (cm), disability (Neck Disability Index), and pressure-pain threshold (PPT) (digital algometry) from the active myofascial trigger points. In both groups, pain and neck disability were significantly lower at the end of treatment compared with those measured at baseline (pain: -2.52 with 95% CI: -3.43 to -1.60 for DN group; pain: -2.92 with 95% CI: -3.77 to -2.07 for MT group; disability: -3.2 with 95% CI: -4.31 to -2.09 for DN group; disability: -2.68 with 95% CI: -3.56 to -1.79 for MT group), but not were not lower after the first session, without differences between the groups. AMMO was significantly higher after the first session (0.16 with 95% CI: 0.03 to 0.29 for DN group; 0.30 with 95% CI: 0.20 to 0.41 for MT group) and at the end of treatment in both groups (0.27 with 95% CI: 0.14 to 0.41 for DN group; 0.37 with 95% CI: 0.22 to 0.52 for MT group) compared with the baseline measurements. Finally, PPT results for the masseter and pterygoid muscles were significantly higher at the end of treatment in both groups (without statistically significant differences between groups), but not after the first session. The assessed therapies, DN and MT, are equally effective in improving pain, AMMO, cervical disability, and PPT in the muscles directly involved in the temporomandibular joint biomechanics of patients with myofascial TMDs.

Trigger point dry needling increases masseter muscle oxygenation in patients with temporomandibular disorder

BACKGROUND

Temporomandibular disorder (TMD) is an umbrella term encompassing various clinical complaints involving the temporomandibular joints, masticatory muscles, and/or associated orofacial structures. Myogenous TMDs are the most frequent cause of chronic orofacial pain. Musculoskeletal pain is commonly associated with myofascial trigger points (MTPs), for which dry needling (DN) is a routine treatment.

OBJECTIVE

To investigate muscle oxygenation and pain immediately after DN application on an MTP in the masseter muscle of patients with myogenous TMDs.

METHODOLOGY

Masseter muscle oxygen tissue saturation indices (TSI%) were assessed by near-infrared spectroscopy (NIRS) pre- and post-interventions by a randomized, controlled, double-blind, crossover DN/Sham clinical trial (primary outcome). Pain was investigated by the visual analog scale (VAS). In total, 32 individuals aged from 18 to 37 years who were diagnosed with myogenous TMD and myofascial trigger points in their masseter muscles participated in this study. Relative deltas for the studied variables were calculated. Data normality was tested using the Shapiro-Wilk test. According to their distribution, data were analyzed by two-way ANOVA and the Student's t-, and Mann-Whitney tests. Statistical analyses were performed using Prism® 5.0 (GraphPad, USA).

RESULTS

We found a significant difference (2,108% vs. 0,142%) between masseter muscle TSI% deltas after the DN and Sham interventions, respectively (n=24). We only evaluated women since men refused to follow NIRS procedures. Pain increased immediately after DN (n=32, 8 men), in comparison to Sham delta VAS.

CONCLUSION

These findings show an increase in tissue oxygen saturation in the evaluated sample immediately after the DN intervention on the MTP of patients' masseter muscle. Pain may have increased immediately after DN due to the needling procedure.

Sex-dependent differences in the genomic profile of lingual sensory neurons in naïve and tongue-tumor bearing mice

Mechanisms of sex-dependent orofacial pain are widely understudied. A significant gap in knowledge exists about comprehensive regulation of tissue-specific trigeminal sensory neurons in diseased state of both sexes. Using RNA sequencing of FACS sorted retro-labeled sensory neurons innervating tongue tissue, we determined changes in transcriptomic profiles in males and female mice under naïve as well as tongue-tumor bearing conditions Our data revealed the following interesting findings: (1) FACS sorting obtained higher number of neurons from female trigeminal ganglia (TG) compared to males; (2) Naïve female neurons innervating the tongue expressed immune cell markers such as Csf1R, C1qa and others, that weren't expressed in males. This was validated by Immunohistochemistry. (3) Accordingly, immune cell markers such as Csf1 exclusively sensitized TRPV1 responses in female TG neurons. (4) Male neurons were more tightly regulated than female neurons upon tumor growth and very few differentially expressed genes (DEGs) overlapped between the sexes, (5) Male DEGs contained higher number of transcription factors whereas female DEGs contained higher number of enzymes, cytokines and chemokines. Collectively, this is the first study to characterize the effect of sex as well as of tongue-tumor on global gene expression, pathways and molecular function of tongue-innervating sensory neurons.

Reference Values for Cervical Muscle Strength in Healthy Women Using a Hand-Held Dynamometer and the Association with Age and Anthropometric Variables

Knowledge of reference values for cervical muscle strength is a key tool for clinicians to use as a clinical reference measure and to establish goals during rehabilitation. The objective was to establish reference values for the maximal strength of cervical muscles in healthy women using a handheld dynamometer and verify the association of cervical muscle strength with age and anthropometric measurements. A hundred women were classified into four groups (n = 25) according to age: 18-29 years, 30-39 years, 40-49 years, and 50-60 years. Maximal muscle strength of the cervical spine was measured using a Lafayette® handheld dynamometer for flexion, extension, and bilateral lateral flexion. No differences in cervical muscle strength were observed among the groups (p > 0.05). However, the 18-29-year-old group took less time to reach the peak of force for flexion than the 50-60-year-old group. Moderate correlations were observed between cervical flexor strength and weight, body mass index, and neck circumference, and between cervical extensor strength and weight and body mass index (r = 0.43-0.55; p < 0.05). Reference values for cervical muscle strength in healthy women were established using a handheld dynamometer, and the association between muscle strength and anthropometric data was moderate.

Malocclusion Complexity in Patients with Disc Displacement Disorders: A Case-Control Study

This study aimed to determine the possible association between disc displacement (DD) disorders and malocclusion complexity. This cross-sectional study was carried out using a case-control design. The Research Diagnosis Criteria for Temporomandibular Disorders were used to identify cases and controls. The Index of Complexity, Outcome, and Need (ICON) was used to quantify malocclusion complexity as easy, mild, moderate, difficult, or very difficult. A total of 310 subjects were included: 130 cases and 180 controls. A binary logistic regression (p < 0.05) was used to identify associations. The odds ratio (OR) was also calculated. DD was associated with sex, age, and malocclusion complexity (p < 0.05). The malocclusion complexity comparison showed that 89.3% of the controls fell within the easy-moderate levels of the ICON, whereas 85.4% of the cases were in the moderate-very difficult levels (p ≤ 0.001). Difficult and very difficult malocclusions had high ORs (9.801 and 9.689, respectively) compared to the easy cases. In conclusion, patients with malocclusion complexity levels classified as difficult or very difficult have greater odds of presenting DD.

DC/TMD Axis I diagnostic subtypes in TMD patients from Confucian heritage cultures: a stratified reporting framework

OBJECTIVES

This study proposed a conceptual framework for reporting Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) Axis I conditions and investigated the prevalence of TMD subtypes/categories in patients from Confucian heritage cultures. Variances in gender, age, and TMD chronicity between Chinese (CN) and Korean (KR) patients were also explored.

MATERIALS AND METHODS

Subjects were recruited from consecutive patients seeking care at two University-based centers in Beijing and Seoul. Eligible patients completed a demographic survey as well as the DC/TMD Symptom Questionnaire and were clinically examined according to the DC/TMD methodology. Axis I diagnoses were subsequently rendered with the DC/TMD algorithms and documented using the stratified reporting framework. Statistical evaluations were performed with chi-square, Mann-Whitney U tests, and logistic regression analysis (α = 0.05).

RESULTS

Data of 2008 TMD patients (mean age 34.8 ± 16.2 years) were appraised. Substantial differences in female-to-male ratio (CN > KR), age (KR > CN), and TMD duration (KR > CN) were observed. Ranked frequencies of the most common Axis I diagnoses were: CN - disc displacements (69.7%) > arthralgia (39.9%) > degenerative joint disease (36.7%); KR - disc displacements (81.0%) > myalgia (60.2%) > arthralgia (56.1%). Concerning TMD categories, notable differences in the prevalence of intra-articular (CN 55.1% > KR 15.4%) and combined (KR 71.8% > CN 33.4%) TMDs were discerned.

CONCLUSIONS

Though culturally similar, the two countries require disparate TMD care planning/prioritization. While TMJ disorders in children/adolescents and young adults should be emphasized in China, the focus in Korea would be on TMD pain in young and middle-aged adults.

CLINICAL RELEVANCE

Besides culture, other variables including socioeconomic, environmental, and psychosocial factors can influence the clinical presentation of TMDs. Chinese and Korean TMD patients exhibited significantly more intra-articular and combined TMDs respectively.

Comparison of painful temporomandibular disorders, psychological characteristics, sleep quality, and oral health-related quality of life of patients seeking care before and during the Covid-19 pandemic

BACKGROUND

Literature concerning Temporomandibular disorders (TMDs) and the Covid-19 pandemic is limited and disparate findings related to TMD frequencies, psychological distress, and quality of life were presented. This study investigated the prevalence of painful Temporomandibular disorders (TMDs) and compared the psychological, sleep, and oral health-related quality of life profiles of patients seeking TMD care before and during the Covid-19 pandemic.

METHODS

Data were accrued from consecutive adult patients 12 months before (BC; control) and during (DC; case group) the Covid-19 pandemic. The Diagnostic Criteria for TMDs (DC/TMD), Depression, Anxiety, Stress Scales (DASS)-21, Pittsburgh Sleep Quality Index (PSQI), and Oral Health Impact Profile (OHIP)-TMDs were utilized and statistical analysis was performed using Chi-square/non-parametric tests (α = 0.05).

RESULTS

The prevalence of painful TMDs was 50.8% before and 46.3% during the pandemic. Significant differences in PSQI and OHIP component scores were discerned between the BC and DC groups contingent on TMD pain. Total-DASS was moderately correlated to total-PSQI/OHIP (rs = 0.41-0.63).

CONCLUSION

The covid-19 pandemic did not appear to exacerbate psychological distress but affected sleep and increased unease over TMD dysfunction.

Clinical outcomes of the discopexy using suture anchors for repositioning disc displacement in temporomandibular joints: Systematic review and meta-analysis

The present study evaluated the literature regarding the clinical outcomes after discopexy using suture bone anchors for repositioning disc displacement. A systematic review was conducted according to the PRISMA statement and applied for the PROSPERO platform. The database searches were performed in the PubMed, Scopus, Web of Science, EMBASE, The Cochrane Library, and LILACS for full articles published from no restrictions of the initial period time to April 2022. Selection criteria included clinical studies in humans comparing maximal inter-incisal opening (MIO), pain by visual analogue scale (VAS), and protrusive and lateral excursions before and after discopexy. The screening process was performed by two independent reviewers, and if they did not agree with each other, a third reviewer was consulted before proceeding. The meta-analysis was carried out by Comprehensive Meta-Analysis software. Eleven studies met the inclusion criteria. A total of 327 patients were diagnosed with disc displacement, and 142 patients were refractory to conservative and minimally surgical therapies. Preauricular and endaural approaches were performed to place suture bone anchors on the posterior area of the condyle. A significant difference was found in MIO, which ranged from 15.5 mm pre-opeatively to 41.6 mm post-operatively (p = 0.001). Pain scores using the VAS ranged from 7.42 to 0.28 indicating improvement post-operatively (p = 0.001). Mandibular excursions were underestimated. The available results have shown that discopexy using suture anchors seemed to decrease pain and improve mouth opening. Clinical studies are required in a larger sample and lower variability of follow-up time to predict actual benefits.

The relation of temporomandibular disorders with oral health-related quality of life in the Northern Finland Birth Cohort 1966

OBJECTIVE

This study aimed to evaluate the association between temporomandibular disorders (TMD) and oral health-related quality of life (OHRQoL) in an adult population.

METHODS

The data included 1,768 adults 46 years of age in the Northern Finland Birth Cohort 1966 (NFBC1966) study. The symptoms, signs and diagnoses of TMD were assessed using a modified protocol of the Diagnostic Criteria for TMD (DC/TMD) and validated questionnaires. OHRQoL was measured using the Oral Health Impact Profile (OHIP-14). Associations of TMD and OHRQoL were evaluated with χ2 -test and Fisher's exact test.

RESULTS

In females, pain-related TMD signs and diagnoses associated significantly with prevalence of OHIP total and all dimensions, whereas in joint-related TMD, psychological dimensions showed the strongest association. Males with pain- or joint-related TMD, the most impaired dimension was physical pain.

CONCLUSION

Pain-related TMD seems to associate more strongly with lower OHRQoL than joint-related TMD especially in females.

Chocolate intake and muscle pain sensation: A randomized experimental study

BACKGROUND

Chocolate, as a cocoa-derived product rich in flavanols, has been used for medical and anti-inflammatory purposes. Therefore, the aim of this study was to investigate if the ingestion of different percentages of cocoa products affects the experimentally induced pain caused by intramuscular hypertonic saline injections in the masseter muscle of healthy men and women.

METHODS

This experimental randomized, double-blind, and controlled study included 15 young, healthy, and pain-free men and 15 age-matched women and involved three visits with at least a 1-week washout. Pain was induced twice at each visit with intramuscular injections of 0.2 mL hypertonic saline (5%), before and after intake of one of the different chocolate types: white (30% cocoa content), milk (34% cocoa content), and dark (70% cocoa content). Pain duration, pain area, peak pain, and pressure pain threshold (PPT) were assessed every fifth minute after each injection, up until 30 min after the initial injection. Descriptive and inferential statistics were performed using IBM® SPSS (Version 27); significance level was set to p<0.05.

RESULTS

This study showed that intake of chocolate, no matter the type, reduced the induced pain intensity significantly more than no intake of chocolate (p<0.05, Tukey test). There were no differences between the chocolate types. Further, men showed a significantly greater pain reduction than women after intake of white chocolate (p<0.05, Tukey test). No other differences between pain characteristics or sexes were revealed.

CONCLUSION

Intake of chocolate before a painful stimulus had a pain-reducing effect no matter the cocoa concentration. The results indicate that perhaps it is not the cocoa concentration (e.g., flavanols) alone that explains the positive effect on pain, but likely a combination of preference and taste-experience. Another possible explanation could be the composition of the chocolate, i.e. the concentration of the other ingredients such as sugar, soy, and vanilla. ClinicalTrials.gov Identifier: NCT05378984.

Sex-dependent Differences in the Genomic Profile of Lingual Sensory Neurons in Naïve and Tongue-Tumor Bearing Mice

Mechanisms of sex-dependent orofacial pain are widely understudied. A significant gap in knowledge exists about comprehensive regulation of tissue-specific trigeminal sensory neurons in diseased state of both sexes. Using RNA sequencing of FACS sorted retro-labeled sensory neurons innervating tongue tissue, we determined changes in transcriptomic profiles in males and female mice under naïve as well as tongue-tumor bearing conditions Our data revealed the following interesting findings: 1) Tongue tissue of female mice was innervated with higher number of trigeminal neurons compared to males; 2) Naïve female neurons innervating the tongue exclusively expressed immune cell markers such as Csf1R, C1qa and others, that weren't expressed in males. This was validated by Immunohistochemistry. 4) Accordingly, immune cell markers such as Csf1 exclusively sensitized TRPV1 responses in female TG neurons. 3) Male neurons were more tightly regulated than female neurons upon tumor growth and very few differentially expressed genes (DEGs) overlapped between the sexes, 5) Male DEGs contained higher number of transcription factors whereas female DEGs contained higher number of enzymes, cytokines and chemokines. Collectively, this is the first study to characterize the effect of sex as well as of tongue-tumor on global gene expression, pathways and molecular function of tongue-innervating sensory neurons.

Temporomandibular disorders in children and adolescents: A review

BACKGROUND

Temporomandibular disorders (TMD) are generally observed in individuals between the ages of 20 and 40 years. TMD have also been described in children and adolescents but are still not widely detected and treated in routine practice. Through a literature review, this work aims to improve the diagnosis and management of TMD in children and adolescents by dentists.

METHODS

This literature review was performed by a computerized search of the database PubMed for published articles on TMD in children and adolescents. Articles evaluating the prevalence, etiologies and risk factors, diagnosis, signs, and symptoms as well as the comorbidities of TMD, published between 2001 and 2022, were included in this review.

RESULTS

A total of 51 articles were included. Most of studies reported a prevalence of over 20%, with a higher prevalence in females. The two most common diagnoses were myofascial pain and disk displacement with reduction. Headaches were often associated with the condition. The management of TMD in children and adolescents has been poorly studied.

CONCLUSION

TMD frequently affect children and adolescents. Therefore, for prevention purposes, an examination of the masticatory system should be included in the dental check-up. Early diagnosis is essential in order to limit effects on their growth, development, and quality of life. TMD management is not currently validated for children and adolescents. Noninvasive and reversible care should be preferred.

The influence of the COVID-19 pandemic, sex, and age on temporomandibular disorders subtypes in East Asian patients: a retrospective observational study

BACKGROUND

Despite its major existential, societal, and health impacts, research concerning the COVID-19 pandemic and Temporomandibular disorders (TMDs) is still limited. This study examined the effect of the pandemic on TMD subtypes and elucidated the influence of the pandemic, sex, and age on the prospect of pain-related (PT) and/or intra-articular (IT) TMDs in East Asian patients.

METHODS

Data were accrued from consecutive new patients attending two university-based TMD/orofacial pain clinics in China and South Korea, 12 months before (BC; Mar 2019-Feb 2020) and during (DC; Mar 2020-Feb 2021) the COVID-19 pandemic. TMD diagnoses were derived from pertinent symptoms, signs, and radiographic findings according to the Diagnostic Criteria for TMDs (DC/TMD) methodology. Patients were subsequently categorized into those with PT, IT, and combined TMDs (CT) and also stratified by attendance period, sex, and age groups (adolescents/young adults [AY] and middle-aged/older adults [MO]) for statistical analyses using Chi-square/Mann-Whitney U tests and logistic regression analyses (α = 0.05).

RESULTS

The BC and DC groups comprised 367 (75.2% females; 82.8% AY) and 471 (74.3% females; 78.3% AY) patients correspondingly. No significant differences in sex and age group distributions were observed. The DC group had significantly more PT/IT conditions with higher prevalence of myalgia, headache, and degenerative joint disease than the BC group. Univariate analyses showed that PT/CT was associated with sex and age, whereas IT was related to the pandemic and age. However, multivariate analyses indicated that the odds of PT were affected by sex (OR = 2.52) and age (OR = 1.04) while the odds of IT (OR = 0.95) and CT (OR = 1.02) were influenced by age only.

CONCLUSIONS

The COVID-19 pandemic, as an impact event, did not influence the prospect of PT and/or IT. Sex and age appeared to play more crucial roles in the development of PT and IT/CT respectively.

Exercise therapy improves pain and mouth opening in temporomandibular disorders: A systematic review with meta-analysis

OBJECTIVE

To analyse the effectiveness of exercise therapy in improving pain and active or passive maximum mouth opening in patients with temporomandibular disorders.

DATA SOURCES

PubMed Medline, Web of Science, Scopus, CINAHL Complete and Physiotherapy Evidence Database, until April 2022, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

REVIEW METHODS

We included randomized controlled trials evaluating the effect of exercise therapy on pain and on active and passive maximum mouth opening in patients with temporomandibular disorders. Effect size was calculated using Cohen's standardized mean difference (SMD) and their 95% confidence interval (95% CI) in a random-effects model.

RESULTS

A total of 16 studies with 812 participants were included. Exercise therapy is effective in reducing pain (SMD: -0.58; 95% CI: -1.01 to -0.12) and increasing the pain pressure threshold (SMD: 0.45; 95% CI: 0.14-0.76), active and passive maximum mouth opening (SMD: 0.43; 95% CI: 0.14-0.71 and SMD: 0.4; 95% CI: 0.06-0.75, respectively). Subgroup analyses showed more effect of exercise therapy more splints versus splints on pain (SMD: -0.5; 95% CI: -0.73 to -0.26), active and passive maximum mouth opening (SMD: 1.14; 95% CI: 0.22-2.07 and SMD: 0.56; 95% CI: 0.06-1.06, respectively). On pain pressure threshold, exercise therapy was better than physiotherapy approach (manual therapy and electrotherapy) (SMD: 0.48; 95% CI: 0.09-0.87).

CONCLUSIONS

Therapeutic exercise is an effective therapy to reduce pain and increase pain pressure threshold and active and passive maximum mouth opening in patients with temporomandibular disorders.

Prevalence of temporomandibular disorders in children and adolescents evaluated with Diagnostic Criteria for Temporomandibular Disorders: A systematic review with meta-analysis

BACKGROUND

The prevalence of temporomandibular disorders (TMDs) in children and adolescents is not well-known. This is partly because TMD is not often diagnosed in children and partly because there is no agreed-upon definition of TMD. There is a growing body of evidence to suggest that there are gender differences in the prevalence and presentation of TMD in adult. The aim was to assess the prevalence of TMDs in subjects aged 8-19 evaluated with Diagnostic Criteria for TMDs (DC/TMD) and to assess gender differences.

METHODS

PubMed, Web of Science and Lilacs were systematically searched until 30 November 2022, to identify studies presenting children and adolescents patients affected by TMDs.

RESULTS

Out of 40 papers, three studies were included. The included subjects in this review were 1914 (1093 female and 821 male). Seven hundred and thirty-six on 1914 patients (38.4%) presented TMD. Among 1093 female, 489 (44.7%) presented TMD, while 247/821 male (30%) experienced TMD. Meta-analysis revealed that the female had a higher TMD prevalence than male (RR 2.10; 95% CI: 1.21-3.65).

CONCLUSION

TMD prevalence in children and adolescence varies between 20% and 60%. Female had a higher prevalence of TMDs compared to male.

Impact of COVID-19 on Portuguese Dental Students: A Cohort Study

Introduction: The goal of this study was to assess the impact of COVID-19 on Portuguese dental students on their depression, anxiety, temporomandibular dysfunction, academic degree, and oral behaviors. Methods: The target of this population study was to enroll third-, fourth-, and fifth-year students of the Integrated Master’s degree in Dental Medicine at the Universidade Católica Portuguesa—Faculty of Dental Medicine (Viseu, Portugal) in the academic year 2021–2022. Temporomandibular disorders (TMD) symptoms, oral behaviors, anxiety, and depression were assessed using validated questionnaires. The variables under study were (a) age, gender, marital status, academic level, academic degree, medication, and any existing pathologies; (b) questions related to taste changes or thoughts that would indicate (or not) worsening psychological conditions (anxiety and depression). After data collection (Google Forms®), data were transferred to an Excel file and entered into SPSS® software. A chi-square test allowed the independence between ordinal or nominal variables. The Spearman correlation test was used to analyze the relationship between variables in the study (significant if p ≤ 0.05). Results: 98.2% of the students answered the questionnaire. TMD had a prevalence of 35%, and anxiety and depression a prevalence of 29% and 24%, respectively. The results showed that the female gender was the most affected by psychological and temporomandibular disorders. Statistically significant correlations were identified between variables, such as gender and anxiety, TDM, and depression (respectively, p = 0.0001, p = 0.014, and p = 0.026); between TDM and anxiety and depression (respectively, p = 0.001 and p < 0.001); and between performing oral behaviors and TMD, anxiety, and depression (respectively, p = 0.0001, p = 0.0001, and p = 0.006). The variables, such as age and academic degree, did not establish a statistically significant relationship with TMD, oral behaviors, and the two psychological conditions. Conclusions: It was possible to conclude that there was a moderate prevalence of TMD, anxiety, and depression in the period studied. Moreover, a statistically significant relationship was found between TMD, anxiety, and depression with gender and frequency of OBs; however, no significant association was found for TMD, anxiety, and depression with the age of students and with the academic degree.

Prevalence and associated factors of myofascial pain in orthognathic patients with skeletal class II malocclusion

Orthognathic patients with skeletal class II malocclusion frequently suffer from myofascial pain (MP).

PURPOSE

This study aimed to evaluate the prevalence and associated factors of MP in these patients.

METHODS

This cross-sectional study was performed in adult patients with skeletal Class II malocclusion requiring orthognathic surgery. They were divided according to the presence or absence of MP. The predictor variables were craniofacial morphology, sex, temporomandibular disorders, chronic pain, depression, and polymorphisms of dopamine receptors DRD2 (rs6275 and rs6276) and ANKK1 (rs1800497) genes. Data were submitted to statistical analyses using the linear regression model and Poisson regression with a significance level of 0.05.

RESULTS

Sixty-five individuals were selected, of which 50 (76.92%) were females. A total of 21 (32.3%) patients had MP. Individuals with MP showed a decrease in the mandible gonial angle (p = 0.042) and an increased risk of having temporomandibular joint (TMJ) disc displacement (p = 0.003), TMJ pain (p = 0.030), chronic pain (p = 0.001), and severe depression (p = 0.015). Additionally, individuals carrying AA and AG genotypes in rs6275, and CC genotype in rs6276, were more likely to have MP (p < 0.05).

CONCLUSION

In this study, 32.3% of skeletal class II orthognathic patients had MP, which was associated with a decreased gonial angle, TMJ disc displacement, TMJ pain, chronic pain, depression, and polymorphisms in the DRD2 gene.

Incidence and Clinical Presentation of Temporo-Mandibular Joint Disorders and their Association with Psychological Distress and Para-Functional Habits in a Non-Patient Population

Purpose

The study aims at finding the incidence of temporo-mandibular joint disorders (TMDs) in a non-patient population and relates their association with psychological distress and parafunctional habits.

Materials and Methods

A DC/TMD questionnaire and DASS-21 scale survey were completed by selected participants followed by clinical examination of TMDs symptoms in sample population.

Results

A study sample of 855 participants revealed 36.65% population with various TMDs symptoms, while 63.5% population had no TMDs symptoms. 50.8% study participants were men, and 49.2% were women. Of all affected population, 16.2% had pain-related TMDs, 12.39% had intra-articular TMDs symptoms, and 8.07% had TMJ pain associated with pain or dysfunction. For all TMDs symptoms groups, the strongest correlations were for depression, while no significant associations were observed with parafunctional habits in all groups.

Conclusions

Overall psychological distress and anxiety increased the prospects of TMDs symptoms. Clinical factors like muscle tenderness, crossbite and deep vertical overlap seem to be significant etiological factors, while angle molar relationship and parafunctional habits do not seem to be significant etiologic factors in TMDs.

Sex effects in the interaction of acute stress and pain perception

ABSTRACT

A reciprocity between the stress and the pain system is recognized; however, the manner by which sex affects this reciprocity is unclear. Understanding the interactions of stress, pain, and sex may shed light on the apparent women's vulnerability to chronic pain, which often coexists with increased distress, and to affective disorders, which often coexist with chronic pain. The study's aim was to examine the effect of acute, validated, psychosocial stress on pain perception and modulation of women and men in a controlled manner. Participants were 82 women and 66 men. Heat-pain threshold, heat-pain tolerance, and pain modulation by temporal summation of pain (TSP), and pain adaptation were measured before and after exposure to the Montreal Imaging Stress Task (MIST) or to a sham task. The stress response was verified by perceived ratings of stress and anxiety, autonomic variables, and salivary cortisol. A significant stress response was obtained by the MIST among both sexes; however, women displayed a greater increase in perceived distress, and men displayed a greater increase in cortisol. Among women, TSP decreased and pain adaptation increased following the MIST, responses that were predicted by perceived distress levels. Among men, TSP increased following the MIST but was not predicted by the stress variables. In conclusion, acute stress manipulation seems to differentially affect both stress and pain responses of women and men: women exhibited stress-induced antinociception and men exhibited stress-induced pronociception. Higher perceived stress levels among women may trigger a temporary increase in pain inhibition mechanisms to serve evolutionary purposes.

Rasch validation of the oral health impact profile for temporomandibular disorders

OBJECTIVES

This study examined the metric properties of the Oral Health Impact Profile for Temporomandibular Disorders (OHIP-TMD) using Factor/Rasch analyses and created a short-form version of the measure.

SUBJECTS AND METHODS

Aggregated OHIP-TMD data were obtained from a cross-sectional study involving 844 TMD patients with diagnostic criteria for TMDs defined conditions. The dimensionality of the OHIP-TMD was first evaluated with exploratory factor analysis. An eigenvalue >1.0 and oblique oblimin rotation were applied for extracting the factors. Rasch analysis was subsequently performed on the primary dimension using the ConQuest software.

RESULTS

Multi-dimensionality of the OHIP-TMD was observed with the primary dimension comprising ten items. Adequate fit to the Rasch model was noted after deleting item 8 with infit/outfit mean-square values ranging from 0.75 to 1.40 logits. Item difficulty ranged from -0.75 to 1.05 logits, while participants' ability to respond varied from -4.55 to 5.19 logits. The respondent spread was slightly skewed and satisfactory item-response targeting was present.

CONCLUSIONS

The 22-item OHIP-TMD demonstrated multi-dimensionality with the primary dimension consisting of nine reliable items with adequate fit to the Rasch model. The 9-item short-form version of the OHIP-TMD (SOHIP-TMD) is a promising tool for evaluating OHRQoL.

Uptight responses between clenching and forearm raising with factors of visual feedback and maintenance effort in healthy young women: An experimental study on factorial design

BACKGROUND

To achieve different central preset force levels requires various fine-tuning efforts and may elicit different uptight responses. The mandibular lever system has a distinct regularity in the fine-tuning function of the upper limbs. The purpose of the present study was to detect whether the uptight responses elicited from motivating clenching differ from those induced by motivating forearm raising at different force levels.

METHODS

Twenty-five healthy females were enrolled in this study. The target was low, medium, and maximum force levels with or without visual feedback and/or maintenance effort. Surface electromyographic (SEMG) activity was recorded from the bilateral anterior temporalis and masseter or left biceps brachii muscle (BicL), and the T-Scan III System synchronously recorded the sensitive force values. The uptight responses and task difficulties were recorded for occlusal and left forearm lifting tasks using a unique visual analogue scale.

RESULTS

The highest uptight response value was achieved at a low clenching force level with visual feedback requiring no maintenance effort but at a maximum forearm-raising force level with visual feedback and maintenance effort. The SEMG activities of both jaw-closing muscles and BicL were associated with the central preset force level (P < 0.001). However, the maintenance effort only increased the jaw-closing muscles' SEMG activity at the maximal force level (P < 0.001).

CONCLUSIONS

Clenching at the central preset lower force level with visual feedback is prone to elicit a higher degree of uptight response. The constant need for a low-intensity bite can have a negative effect on an individual's mood.

Temporomandibular disorder severity and its association with psychosocial and sociodemographic factors in Turkish adults

BACKGROUND

There is a lack of awareness regarding temporomandibular disorder (TMD) and its association with psychological and sociodemographic factors in the Turkish population. This study aimed to evaluate the relationship between signs/symptoms of anxiety-depression, sociodemographic factors, parafunctional habits, bruxism, and the presence and severity of the symptoms of TMD in Turkish adults.

METHODS

The participants completed an online questionnaire consisting of sociodemographic questions, the Fonseca Anamnestic Index, and the Patient Health Questionnaire-4.

RESULTS

The mean age of the 2580 participants was 35.29 ± 12.70 years, and 63.3% were women. The frequency of the participants who showed symptoms of TMD was 69.8%. The severity of TMD symptoms was significantly greater in participants who had signs/symptoms of anxiety and depression (p < 0.05). Sociodemographic and psychological data showed an association between the presence and severity of the symptoms of TMD and sex (OR 1.52, 95% confidence interval (CI) 1.26-1.85), parafunctional habits (OR 2.64, 95% CI 2.36-2.99), bruxism (OR 3.14, 95% CI 1.78-4.90), signs/symptoms of anxiety (OR 2.30, 95% CI 1.76-3.00), and signs/symptoms of depression (OR 1.90, 95% CI 1.48-2.42).

CONCLUSIONS

The results of the present study suggest that females and those who report bruxism, parafunctional habits, and signs/symptoms of anxiety-depression are more likely to show symptoms of TMD with different severity.

Differences between Maximum Tongue Force in Women Suffering from Chronic and Asymptomatic Temporomandibular Disorders-An Observational Study

Background: Temporomandibular disorders are craniofacial disorders characterized by the presence of chronic pain in masticatory muscles, with higher incidence in the women population. There is little research that has studied tongue force related to temporomandibular disorders, but there are a lot of studies that have demonstrated the impact of tongue force in vital functions, such as chewing, swallowing, phonation, or breathing. According to this, the aim of this study was to compare the maximum force of the tongue between females with chronic temporomandibular disorders and asymptomatic females. We also wanted to establish whether any relationship existed between the pain and fatigue versus the maximum force developed in females with chronic temporomandibular disorders. Material and methods: A cross-sectional study of 67 women between the ages of 18 and 65 years old was performed. The included women were assigned to one of two groups, according to whether they had chronic temporomandibular disorders or not. The procedure was the same for both groups. Outcome measures included the maximum tongue force, intensity of perceived orofacial pain, and intensity of perceived orofacial fatigue. Results: The results showed significant statistical differences for the maximum tongue force measurement between the chronic temporomandibular disorders group and the control group (p < 0.05) for all the movements, except the lip pressure measurement. Furthermore, the analysis revealed significant statistical differences between the intensity of perceived orofacial fatigue between the groups (p < 0.05). Moreover, the data showed no significant correlations between variables. Conclusion: The study found significant differences in maximum tongue force when comparing women with chronic temporomandibular disorders and asymptomatic women (being superior in these). Likewise, we found that the intensity of perceived orofacial fatigue after tongue exercises showed significant differences between groups. However, this study reveals no correlations between the intensity of perceived orofacial pain and fatigue and the maximum tongue force.

Craniofacial Morphology of Temporomandibular Disorder Patients with Different Disc Positions: Stratifying Features Based on Sex and Sagittal Skeletal Pattern

Disc displacement (DD) appears in the majority of temporomandibular disorder (TMD) patients. The correlation between craniofacial morphology and different disc positions has been underlined, while the craniofacial morphological differences based on sex and sagittal skeletal pattern stratification have been insufficiently studied. In this study, 304 patients with TMD complaints were included and classified into normal position, disc displacement with reduction (DDwR) and disc displacement without reduction (DDwoR) groups according to magnetic resonance imaging. A total of 24 cephalometric measurements, covering the cranial base, vertical relationship, sagittal relationship, mandible position and morphology, and dental relationship, were assessed using lateral cephalograms. A stratified analysis was performed based on the sex and sagittal skeletal pattern. Overall, DD patients had distinctive craniofacial morphological features. The posterior cranial base length and mandibular arc angle were statistically different only in females, while the Y-axis angle, occlusal plane angle and sella nasion point A angle (SNA) might be unique features in males. Skeletal class II had the most statistically different measurements compared to the others. Differences in the Frankfort mandibular incisor angle (FMIA) and saddle angle were especially displayed in skeletal class III patients. The sex and skeletal sagittal pattern could affect the morphological differences in TMD patients with different disc positions.

Use of the Depression Anxiety Stress Scale-21 in young people with temporomandibular disorders: Reliability and dimensionality

OBJECTIVE

The reliability and dimensionality of the Depression Anxiety Stress Scale-21 (DASS-21) were explored in adolescents/young adults with temporomandibular disorders (TMDs).

METHODS

TMD presence was established with the Fonseca Anamnestic Index. Reliability of the DASS-21 for participants with (WT) and without (NT) TMDs was assessed by the Cronbach alpha test, while dimensionality was examined using exploratory factor analysis.

RESULTS

Data from 400 participants (mean age 18.8 ± 1.5 years; 52.2% women) comprising 47.0% with and 53.0% without TMDs were evaluated. Total-DASS and the 3 subscales showed acceptable to high internal consistencies for the WT and NT groups, with alphas of 0.78-0.94 and 0.66-0.92, respectively. Although 3 factors contributed to about half the variance for both groups, scalar and item discrepancies in the primary anxiety-stress factor existed.

CONCLUSION

The DASS-21 has good reliability but may comprise only 2 dimensions, specifically anxiety-stress and depression, instead of the 3 originally asserted.

Continued persistent facial pain despite several surgical interventions in the temporomandibular joint

This article describes a woman in her forties who spontaneously developed facial pain 19 years after double-jaw orthognathic surgery. The focus of her pain was the left side of the face, including the temporomandibular joint (TMJ). Conservative treatment was initiated, including several occlusal splints, in addition to injections with local anesthesia, botulinum toxin, and corticosteroids, with limited effects. Surgical treatments with arthroscopy and discectomy, and ultimately a TMJ prosthesis, improved the patient's joint function but did not reduce pain. The question is whether the degenerated joint was due to progression of the original disease process or to multiple surgical procedures.

Temporomandibular disorders: knowledge, competency, and attitudes of predoctoral dental students

OBJECTIVE

To evaluate knowledge, competency, and attitudes related to temporomandibular disorders (TMD) among predoctoral dental students, and to investigate the curricular organization of contents related to TMD and occlusion.

METHODS

Predoctoral dental students (n = 147) answered a questionnaire with topics related to TMD. Another questionnaire evaluated the organization of TMD and occlusion courses.

RESULTS

Contents related to TMD and occlusion were taught in the same course in all dental schools. The students' responses showed low agreement with the current gold standards pertaining to TMD. Most students declared that they did not feel confident to treat patients with TMD (62.6%), were not satisfied with the content pertaining to TMD (55.8%), and considered a lack of clinical practice to be the primary limitation in their training (59.2%).

DISCUSSION

Students' knowledge of basic concepts related to TMD was limited, highlighting the need for readjustment of the dental curriculum to increase clinical experience.

Surgical Treatment of Temporomandibular Joint Derangement: 30-Year Follow-Up of Temporomandibular Joint Discectomy, a Case Report and Literature Review

The improvement in diagnostic accuracy, improvement of the endoscopic equipment, better selection of patients for open TMJ surgery, and increased focus on research and education are promising for the treatment of the group of patients with TMJ derangements. In the future, prospective randomized clinical trials need to be performed to give the clinician guidelines as to which type of intervention should be chosen in a particular patient base on accepted criteria for diagnosis and treatment of TMJ derangement.

The association between problematic smartphone use and the severity of temporomandibular disorders: A cross-sectional study

Objective

To evaluate the prevalence of different types of temporomandibular disorders (TMD) symptoms in young adults and determine their associations with problematic smartphone use (PSU).

Methods

The data of the study were collected from local university students through an online questionnaire survey. Demographic information, Fonseca Anamnestic Index (FAI), Smartphone Addiction Scale-Short Version (SAS-SV), and Patient Health Questionnaire-4 (PHQ-4) responses were gathered electronically and analyzed using multiple logistic regression analysis.

Results

There were 163 male and 307 female respondents were participated in this study. The prevalence of PSU and TMD were 83.6% and 66.4%, respectively. There was a moderate statistical correlation between PSU and TMD among young adults (r = 0.31, p < 0.01). The logistic regression model revealed that the risk of TMD was 1.77 times higher in people with PSU than in those without PSU (OR = 1.77; 95% CI 1.04-3.06). PSU is a risk factor for pain-related TMD (OR = 1.81; 95% CI 1.08-3.04) but not intra-articular TMD.

Conclusion

Subjects showed high prevalence of both TMD and PSU. People with PSU experienced more severe and frequent pain-related rather than intra-articular TMD symptoms than those without PSU. By reducing the problematic smartphone use, the risk factor of TMD might be avoided.

Temporomandibular disorders and associated comorbidities among brazilian dental students during COVID-19

Aim: This study aimed to assess the prevalence of temporomandibular disorders (TMD) and psychosocial comorbidities in undergraduate dental students in a southern Brazilian university, during the COVID-19 pandemic. Also, it aimed to verify the association between psychosocial factors and TMD. Methods: Fonseca Anamnestic Index, Depression Anxiety Stress Scale (DASS-21), a socioeconomic questionnaire, and questions about academic performance and social distancing were applied. Poisson regression analysis was used to assess the association of predictive variables with TMD. Results: The prevalence of TMD was found to be 82.4%, and more than half of the students had some degree of stress, anxiety, and depression. Students who had symptoms of stress (RR 1.11; 95% CI 1.04-1.19), anxiety (RR 1.19; 95% CI 1.12-1.27) and reported academic performance worsening (RR 1.12; 95% CI 1.07-1.19) had higher TMD scores. Conclusion: The findings suggest that TMD was highly prevalent among dental students at a federal university in southern Brazil during the pandemic, being associated with high levels of stress, anxiety, poor academic performance, and greater social distancing.

Occlusal Splint Therapy Combined with Cranio-Temporomandibular Kinesiotherapy in Patients with Temporomandibular Disorders-A CBCT Study

Occlusal splints are used as a non-invasive treatment for patients diagnosed with temporomandibular disorders (TMD). Another non-invasive treatment option for TMD patients is kinesiotherapy, which may be used alone or in conjunction with occlusal splint therapy. The aim of this study was to evaluate the changes in the intra-articular spaces of the temporomandibular joint (TMJ) after occlusal splint therapy combined with cranio-temporomandibular kinesiotherapy in TMD patients. Twenty-four patients (N = 24) diagnosed with TMD according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were included. Cone beam computed tomography (CBCT) images were taken before and after treatment. The anterior, superior, posterior, and medial joint spaces were measured on the CBCT images, and the condylar ratio was calculated using Pullinger and Hollender's formula. Additionally, the thickness of the glenoid fossa (GFT), condylar medio-lateral widths (MLW), and condylar height (HCo) were measured. The condylar ratio was significantly higher after treatment (p = 0.049). The changes in dimensions of the anterior, superior, posterior and medial joint spaces were not statistically significant after treatment. No statistically significant differences were found in the dimensions of the GFT, MLW, and HCo post treatment. The condylar position did not shift anteriorly in a statistically significant way after occlusal splint therapy combined with cranio-temporomandibular kinesiotherapy in TMD patients.

Dimensional and Positional Characteristics of the Temporomandibular Joint of Skeletal Class II Malocclusion with and without Temporomandibular Disorders

AIM

This study sought to evaluate dimensional and positional temporomandibular joint (TMJ) features in three-dimensions in skeletal class II malocclusion with and without temporomandibular disorders (TMDs).

MATERIALS AND METHODS

A total of 91 (182 joints) adult patients were divided into the following two groups: (1) Group I - TMD (n = 56; 112 joints) and (2) group II - non-TMD (n = 35; 70 joints). Dimensional and positional TMJ characteristics including glenoid fossae, mandibular condyles, and joint spaces were assessed using cone-beam computed tomography (CBCT).

RESULTS

The mandibular fossa in the TMD group was significantly more lateral than in the non-TMD group, and the mandibular fossa anterior wall inclination to the horizontal plane showed a significantly more vertically inclined wall in the TMD group compared to the non-TMD group. Significantly vertical mandibular condylar changes in the form of less vertical inclination, more vertical position, and lower vertical dimension (height) in addition to more upward position within the joint space were found. The TMD group showed significantly decreased superior and posterior joint spaces in addition to significantly increased medial joint spaces.

CONCLUSION

Patients with TMDs are associated with laterally positioned mandibular fossa with the more vertically inclined anterior wall. They are characterized by vertical mandibular condylar changes in the form of less vertical inclination, more vertical position, and lower vertical dimension (height) in addition to more upward positioning within the joint space is accompanied by a decrease in superior and posterior and an increase in medial joint spaces.

CLINICAL SIGNIFICANCE

The TMJ characteristics of skeletal class II make it more susceptible to TMDs and any orthodontic and/or surgical interventions in a direction possibly change these characteristics are to be considered.

Development of a new category system for the profile morphology of temporomandibular disorders patients based on cephalograms using cluster analysis

Objective

This study aims to develop a new category scheme for the profile morphology of temporomandibular disorders (TMDs) based on lateral cephalometric morphology.

Methods

Five hundred and one adult patients (91 males and 410 females) with TMD were enrolled in this study. Cluster tendency analysis, principal component analysis and cluster analysis were performed using 36 lateral cephalometric measurements. Classification and regression tree (CART) algorithm was used to construct a binary decision tree based on the clustering results.

Results

Twelve principal components were discovered in the TMD patients and were responsible for 91.2% of the variability. Cluster tendency of cephalometric data from TMD patients were confirmed and three subgroups were revealed by cluster analysis: (a) cluster 1: skeletal class I malocclusion; (b) cluster 2: skeletal class I malocclusion with increased facial height; (c) cluster 3: skeletal class II malocclusion with clockwise rotation of the mandible. Besides, CART model was built and the eight key morphological indicators from the decision tree model were convenient for clinical application, with the prediction accuracy up to 85.4%.

Conclusion

Our study proposed a novel category system for the profile morphology of TMDs with three subgroups according to the cephalometric morphology, which may supplement the morphological understanding of TMD and benefit the management of the categorical treatment of TMD.

Masseter muscle contraction and cervical muscle sensitization by nerve growth factor cause mechanical hyperalgesia in masticatory muscle with activation of the trigemino-lateral parabrachial nucleus system in female rats

OBJECTIVE

To establish a new rat model of craniofacial myalgia, and to clarify which central nervous system pathways are activated in the model.

BACKGROUND

Craniofacial myalgia, represented by myogenous temporomandibular disorder and tension-type headache with pericranial tenderness, is more common in female patients. The pain is thought to be a type of multifactorial disorder with several coexisting causes. To our knowledge, there are no models of craniofacial muscle hyperalgesia caused by multiple types of stimuli.

METHODS

We injected nerve growth factor into the trapezius muscle of female and male rats and repeatedly stimulated the masseter muscle (MM) electrically for 10 days. We determined the mechanical head-withdrawal threshold of MM and extent of phosphorylated extracellular signal-related kinase 1/2 (pERK) immunoreactivity in various regions of the lower brainstem. We conducted retrograde tract-tracing to determine the projection of mechanosensitive MM-innervating secondary neurons to the lateral parabrachial nucleus. Finally, we administered morphine in rats to determine whether increases of pERK immunoreactivity were dependent on noxious inputs.

RESULTS

In female rats, but not male rats, the mechanical head-withdrawal threshold was decreased significantly from days 9 to 12. The number of pERK-immunoreactive neurons in the brainstem was increased significantly in female rats in the group with both stimuli compared to rats in other groups with a single stimulus. Mechanosensitive MM-innervating neurons in the brainstem projected to the parabrachial nucleus. Morphine administration blocked the increase in the number of pERK-immunoreactive neurons in both the brainstem and parabrachial nucleus.

CONCLUSIONS

We established a model of craniofacial myalgia by combining trapezius and MM stimuli in female rats. We found mechanical hyperalgesia of the MM and activation of the pain pathway from the brainstem to parabrachial nucleus. The model reflects the characteristics of patients with craniofacial myalgia and might be helpful to clarify the pathogenic mechanisms underlying these disorders.

Temporomandibular Disorders and Vitamin D Deficiency: What Is the Linkage between These Conditions? A Systematic Review

Although a growing body of literature has been emphasizing the role of vitamin D in oral health, there is still a gap of knowledge regarding the correlation between temporomandibular disorders (TMDs) and vitamin D. Therefore, the aim of this systematic review was to assess the linkage between hypovitaminosis D and TMDs to map the current literature in this field. On 10 September 2022, PubMed, Scopus, and Web of Science databases were systematically searched from the date of their inception to identify the studies that had assessed patients with TMDs. The primary outcome assessed in this review was the relationship between hypovitaminosis D and TMDs. Out of the 329 studies identified, 13 studies met the eligibility criteria and were included in the present work. Seven studies assessed the relationship between vitamin D and TMDs, reporting that vitamin D serum levels are lower in patients with TMDs. Our results suggested that vitamin D receptor (VDR) polymorphisms might have a role in TMDs’ development. However, the quality assessed underlined that only one study did not present a serious risk of bias. Further good-quality studies are needed to clarify the linkage between vitamin D deficiency and TMDs, but the evidence currently available has suggested potential correlations.

Chronic temporomandibular disorders are associated with higher propensity to develop central sensitization: a case-control study

ABSTRACT

Temporomandibular disorders (TMD) include a group of musculoskeletal disorders that may involve increased responsiveness of nociceptive neurons in the central nervous system (ie, central sensitization). To test this hypothesis further, this study examined whether, as compared with healthy subjects, patients with chronic TMD have a greater propensity to develop secondary mechanical hyperalgesia-a phenomenon that can be confidently attributed to central sensitization. In this case-control study, we assessed the area of secondary mechanical hyperalgesia induced experimentally by delivering high-frequency electrical stimulation (HFS) to the volar forearm skin in 20 participants with chronic TMD and 20 matched healthy controls. High-frequency electrical stimulation consisted in 12 trains of constant-current electrical pulses (5 mA) delivered at 42 Hz. The area of secondary mechanical hyperalgesia was evaluated 30 minutes after applying HFS. The area of secondary mechanical hyperalgesia induced by HFS was on average 76% larger in the chronic TMD group (M = 67.7 cm 2 , SD = 28.2) than in the healthy control group (M = 38.4 cm 2 , SD = 14.9; P = 0.0003). Regarding secondary outcomes, there was no group difference in the intensity of secondary mechanical hyperalgesia, but allodynia to cotton after HFS was more frequent in the chronic TMD group. To the best of our knowledge, this is the first study to show that individuals with chronic TMD have an increased propensity to develop secondary hyperalgesia in a site innervated extratrigeminally. Our results contribute to a better understanding of the pathophysiology of chronic TMD.