Ultrasonographic examination of masticatory muscles in patients with TMJ arthralgia and headache attributed to temporomandibular disorders.

This study used ultrasonography to compare the thickness and cross-sectional area of the masticatory muscles in patients with temporomandibular joint arthralgia and investigated the differences according to sex and the co-occurrence of headache attributed to temporomandibular disorders (HATMD). The observational study comprised 100 consecutive patients with TMJ arthralgia (71 females and 29 males; mean age, 40.01 ± 17.67 years) divided into two groups: Group 1, including 86 patients with arthralgia alone (60 females; 41.15 ± 17.65 years); and Group 2, including 14 patients with concurrent arthralgia and HATMD (11 females; 33.00 ± 16.72 years). The diagnosis of TMJ arthralgia was based on the diagnostic criteria for temporomandibular disorders. The parameters of the masticatory muscles examined by ultrasonography were subjected to statistical analysis. The pain area (2.23 ± 1.75 vs. 5.79 ± 2.39, p-value = 0.002) and visual analog scale (VAS) score (3.41 ± 1.82 vs. 5.57 ± 12.14, p-value = 0.002) were significantly higher in Group 2 than in Group 1. Muscle thickness (12.58 ± 4.24 mm) and cross-sectional area (4.46 ± 2.57 cm2) were larger in the masseter muscle than in the other three masticatory muscles (p-value < 0.001). When examining sex-based differences, the thickness and area of the masseter and lower temporalis muscles were significantly larger in males (all p-value < 0.05). The area of the masseter muscle (4.67 ± 2.69 vs. 3.18 ± 0.92, p-value = 0.004) and lower temporalis muscle (3.76 ± 0.95 vs. 3.21 ± 1.02, p-value = 0.049) was significantly smaller in Group 2 than in Group 1. An increase in VAS was significantly negatively correlated with the thickness of the masseter (r = - 0.268) and lower temporalis (r = - 0.215), and the cross-sectional area of the masseter (r = - 0.329) and lower temporalis (r = - 0.293). The masseter and lower temporalis muscles were significantly thinner in females than in males, and their volumes were smaller in patients with TMJ arthralgia and HATMD than in those with TMJ arthralgia alone. HATMD and decreased masseter and lower temporalis muscle volume were associated with increased pain intensity.

Bidirectional association between eating disorder and temporomandibular joint disorder: A retrospective longitudinal nationwide population-based cohort study.

Background/purpose: An increasing body of evidence indicates correlations between the symptoms of temporomandibular disorder and those of eating disorder (ED). However, further investigation is required to elucidate the temporal and causal relationships between the aforementioned disorders. Materials and methods: This retrospective cohort study was conducted using data from the Taiwan National Health Insurance Research Database. Temporomandibular joint disorder (TMJD) was analyzed both as the cause and consequence of ED. We collected the data (from January 1, 1998, to December 31, 2011) of patients with antecedent TMJD (N = 15,059) or ED (N = 1219) and their respective controls (1:10), matched by age, sex, income level, residential location, and comorbidities. This study included patients who had received a new diagnosis of an ED or a TMJD between January 1, 1998, and December 31, 2013. Cox regression models were used to assess the risk of ED or TMJD development in patients with antecedent TMJD or ED. Results: TMJD patients had an approximately 3.70-fold (95 % confidence interval [CI]: 1.93-7.10) risk of ED development. Similarly, patients with ED had an approximately 4.78-fold (95 % CI: 2.52-9.09) risk of TMJD development. Subgroup analyses based on ED subtypes indicated antecedent TMJD and bulimia nervosa as the predictors of increased bulimia nervosa and TMJD risks (hazard ratios: 6.41 [95 % CI: 2.91 to 14.11] and 5.84 [95 % CI: 2.75 to 12.41]), respectively. Conclusion: Previous TMJD and ED are associated with increased risks of subsequent ED and TMJD; these findings suggest the presence of a bidirectional temporal association between TMJD and ED.

Platelet-Rich Plasma in the Management of Temporomandibular Joint Pain in Young Adults With Temporomandibular Disorder.

BACKGROUND: Temporomandibular disorder (TMD) encompasses a range of conditions affecting the temporomandibular joint (TMJ) and associated structures, with TMJ pain being a prevalent symptom. Conventional management strategies have limitations, which require the exploration of innovative interventions. Platelet-rich plasma (PRP), known for its regenerative properties, presents a potential therapeutic avenue. This study aims to investigate the effectiveness of PRP in reducing the pain associated with mild TMJ in young adults. METHODOLOGY: Participants (n = 128) aged 18 to 35 years with mild TMD were evenly randomized into PRP treatment and placebo control groups. PRP was prepared using a standardized protocol, and intra-articular injections were administered. Placebo injections mimic PRP. Follow-up evaluations were carried out at four and eight weeks after the intervention. RESULTS: The study successfully randomized comparable groups, and the PRP treatment group experienced a significant reduction in TMJ pain (visual analog scale [VAS] score: 6.8 ± 1.2 to 2.1 ± 1.0 at eight weeks, P < 0.001). The PRP treatment also increased the largest opening of the mouth (from 38.2 ± 2.5 to 43.5 ± 3.1, P < 0.001) and the number of lateral movements (12.3 ± 1.5 to 14.9 ± 2.0, P < 0.001), while the placebo group had very few changes. Positive patient-reported outcomes on daily activities were observed, with no serious complications reported in either group. CONCLUSIONS: This study provides evidence supporting the efficacy of PRP in reducing TMJ pain, improving jaw function, and improving quality of life in young adults with mild TMD. The results underscore the potential of PRP as a minimally invasive intervention for TMJ disorders.

Neurodevelopmental disorders as a risk factor for temporomandibular disorder: evidence from Mendelian randomization studies.

Objective: This study aims to clarify the incidence rate of temporomandibular joint disease in patients with mental disorders. Methods: Data extracted from the Psychiatric Genomics Consortium and FinnGen databases employed the Mendelian Randomization (MR) method to assess the associations of three neurodevelopmental disorders (NDDs)-Attention-Deficit/Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD), and Tourette's Disorder (TD)-as exposure factors with Temporomandibular Disorder (TMD). The analysis used a two-sample MR design, employing the Inverse Variance Weighted (IVW) method to evaluate the relationships between these disorders and Temporomandibular Disorder. Sensitivity analysis and heterogeneity assessments were conducted. Potential confounding factors like low birth weight, childhood obesity, and body mass index were controlled for. Results: The study found that ADHD significantly increased the risks for TMD (OR = 1.2342, 95%CI (1.1448-1.3307), p < 0.00001), TMD (including avohilmo) (OR = 1.1244, 95%CI (1.0643-1.1880), p = 0.00003), TMD-related pain (OR = 1.1590, 95%CI (1.0964-1.2252), p < 0.00001), and TMD-related muscular pain associated with fibromyalgia (OR = 1.1815, 95%CI (1.1133-1.2538), p < 0.00001), while other disorders did not show significant causal relationships. Conclusion: This study reveals the elevated risk of various TMD aspects due to ADHD. Furthermore, we discuss the link between low vitamin D levels ADHD and TMD. Future research should address these limitations and delve further into the complex interactions between ADHD, ASD, TD, and TMD.

Clinical and MRI-Based Assessment of Patients with Temporomandibular Disorders Treated by Controlled Mandibular Repositioning.

BACKGROUND: Occlusal splints and anterior repositioning splints (ARSs) are widely accepted treatments for temporomandibular disorders (TMDs). However, there is uncertainty with regard to the most suitable amount of mandibular repositioning. The aim of this study is to evaluate the clinical and functional effects of the therapeutic position (ThP) established based on the Controlled Mandibular Repositioning (CMR) method. METHODS: In this clinical trial, 20 subjects with 37 joints with disc displacement with reduction were recruited. The initial standard functional diagnostic protocol, MRI, and digital condylography were performed, and ThP was calculated with the CMR method. After a 6-month follow-up, the standard diagnostic protocol was repeated. The change in disc position was evaluated by means of MRI after 6 months of CMR therapy. RESULTS: The MRI findings in the parasagittal plane demonstrated that out of the 37 joints presenting disc displacement, 36 discs were successfully repositioned; thus, the condyle-disc-fossa relationship was re-established. Therefore, the success rate of this pilot study was 97.3%. The mean position of the displaced discs was at 10:30 o'clock of the TMJ joint and at 12:00 o'clock after CMR therapy. CONCLUSIONS: The ThP determined using the CMR approach reduced all of the anteriorly displaced discs (except one). The CMR method allowed to define an optimum ThP of the mandible thus supporting patients' effective adaptation to treatment position.

Comparison of ultrasonography-based masticatory muscle thickness between temporomandibular disorders bruxers and temporomandibular disorders non-bruxers.

To compare masticatory muscle thickness in patients with temporomandibular disorders (TMDs) during rest and clenching, and by body position, using ultrasonography. This prospective study included 96 patients with TMD (67 females, 29 males; mean age: 40.41 ± 17.88 years): group 1, comprising 66 patients with TMD without bruxism (TMD_nonbruxer), and group 2, comprising 30 patients with concurrent TMD and bruxism (TMD_bruxer). In patients with TMD, bruxism was correlated with the presence of tinnitus, muscle stiffness, sleep problems, psychological stress, and restricted mouth opening. The masseter muscle significantly thickened during clenching (11.16 ± 3.03 mm vs 14.04 ± 3.47 mm, p < 0.001), whereas the temporalis muscle showed no significant increase in thickness from resting to clenching in an upright position (7.91 ± 1.98 vs 8.39 ± 2.08, p = 0.103). Similarly, during clenching in the supine position, the masseter muscle was significantly thicker compared with rest (11.24 ± 2.42 vs 13.49 ± 3.09, p < 0.001), but no significant difference was observed in temporal muscle thickness (8.21 ± 2.16 vs 8.43 ± 1.94, p = 0.464). In comparison between two groups, the average thickness of the masseter muscle was greater among TMD_bruxers than among TMD_nonbruxers in both the upright and supine positions (all p < 0.05). In the generalized lineal model, female sex (B = - 1.018, 95% confidence interval [CI] - 1.855 to - 0.181, p = 0.017) and bruxism (B = 0.868, 95% CI 0.567 to 1.169, p = 0.048) significantly predicted changes in masseter muscle thickness. Female sex (B = - 0.201, 95% CI - 0.299 to - 0.103, p = 0.011), increased age (B = - 0.003, 95% CI - 0.005 to 0.000, p = 0.038), and muscle stiffness (B = - 1.373, 95% CI - 2.369 to - 0.376, p = 0.007) were linked to decreased temporal muscle thickness. Comparing TMD nonbruxer and bruxer muscle thicknesses in upright and supine positions revealed significant increased thickness in the masseter muscle during clenching but not in the temporalis muscle. Masseter muscle thickness varied significantly by sex, body position, and resting/clenching, notably influenced by bruxism. These findings emphasize the relevance of these factors in clinical examinations of patients with TMD.

Validity and reliability of the Turkish version of the 20-item jaw functional limitation scale.

PURPOSE: This study aimed to translate the 20-item Jaw Functional Limitation Scale (JFLS-20) into Turkish (JFLS-20-TR) and investigate the psychometric properties of the JFLS-20-TR. METHODS: This study included 232 patients with temporomandibular disorder (TMD) and 130 individuals without TMD. Structural (with confirmatory factor analysis [CFA]), convergent (with pain intensity, Fonseca Anamnestic Index [FAI], and Oral Health Impact Profile [OHIP-14]), discriminant (with maximum mouth opening [MMO]) and known-group validity were investigated to assess the construct validity. Cronbach's alpha for internal consistency and the intraclass correlation coefficient (ICC2,1) for test-retest reliability were calculated. Additionally, content and face validity, smallest detectable change (SDC95), and floor/ceiling effects were evaluated. RESULTS: According to CFA, the model fit indices were acceptable for JFLS-20-TR, confirming structural validity. Strong correlations were found between the global and subdomain scores of the JFLS-20-TR and pain intensity (r ≥ 0.80), FAI (r ≥ 0.83), OHIP-14 (r ≥ 0.76), and MMO (r ≥ -0.79) scores, confirmed the convergent and discriminant validity of the JFLS-20-TR. In addition, JFLS-20-TR differentiated between patients with TMD and individuals without TMD (p < .05). Internal consistency (Cronbach's alpha values: 0.91-0.93) was excellent, and test-retest reliability (ICC2,1 values: 0.91-0.95) was high. Content and face validity were satisfactory. The SDC95 values ranged from 0.79 to 1.43. No floor or ceiling effects were observed. CONCLUSION: The JFLS-20-TR is a valid, reliable, and useful tool for assessing jaw functional limitations in Turkish-speaking patients with TMD.

The effectiveness of cervical rehabilitation interventions for pain in adults with myogenic temporomandibular disorders: A systematic review and meta-analysis.

OBJECTIVE: Little evidence exists for the most effective conservative treatment approach for adults with myogenic temporomandibular disorders (MTMD). We aim to assess the effectiveness of cervical rehabilitation interventions on pain intensity and sensitivity in adults with MTMD compared to comparison intervention such as placebo, sham treatment, education or no intervention. METHODS: For this systematic review and meta-analysis, we searched PubMed, EMBASE, Medline, PEDro databases, forward and backward citations and grey literature studies through PROSPERO, clinical trials and data registries without language or date restrictions between inception and 1 December 2021. We selected randomised controlled trials (RCTs) based on adult populations with MTMD who had a cervical rehabilitation intervention which was defined as any conservative intervention targeting the anatomical structures of the cervical spine. The primary outcome measures for pain were self-reported pain intensity and pain sensitivity through the pressure pain threshold (PPT) of the masseter and temporalis muscles. Secondary outcome measures of maximal mouth opening (on MMO) were included. Included studies were assessed for bias with the Cochrane risk of bias tool for randomised trials. Evidence from RCTs was synthesised to determine treatment effect size as differences between standardised mean difference (SMD) for changes in pain intensity, PPT and MMO comparing adults with MTMD who were treated with cervical rehabilitation interventions compared to a control group. This study is registered on Prospero, number CRD 42021289299. RESULTS: Our general search yielded 2647 studies where seven RCTs met eligibility criteria with low to some concerns in their risk of bias. Pain intensity (five studies, n = 223, SMD -0.98, 95% CI -1.67 to -0.28, I2 = 79%), PPT of the masseter muscle (six studies, n = 395, SMD 0.64, 95% CI 0.43 to 0.86, I2 = 90%) and the temporalis muscles (five studies, n = 295, SMD 0.76, 95% CI 0.07 to 1.45, I2 = 84%) showed large treatment effect estimates favouring cervical rehabilitation interventions compared to no treatment, sham cervical treatment, patient education or non-cervical neuromuscular techniques. Compared to control interventions, one type of cervical rehabilitation intervention, cervical manual therapy alone or in combination with a neck exercise program was associated with statistically significant, large treatment effect estimates on pain intensity (four studies, n = 203, SMD -1.52, 95% CI -2.50 to -0.55). CONCLUSIONS: This review found that in the short-term, cervical rehabilitation interventions especially upper cervical MT alone or in combination with a neck exercise program are effective in improving multiple pain outcomes in adults with MTMD. However, further research is needed to measure the long-term effects of this type of intervention.

Analysis of risk factors and interactions for pain in temporomandibular disorder: A cross-sectional study.

BACKGROUND: Risk factors for temporomandibular disorder (TMD) pain remain unclear. OBJECTIVES: This study aimed to identify risk factors for TMD pain using a biopsychosocial model and to investigate interactions between potential risk factors-oral behaviours (OBs), psychological factors and sleep quality-and their direct and indirect effects on TMD pain. METHODS: This was a cross-sectional study of 488 patients with TMDs (422 women; 30.8 ± 9.4 years). Pain was assessed using the Numerical Rating Scale. Demographic, behavioural, psychological and biomedical data were collected through clinical examination, face-to-face interviews and questionnaires. Multiple linear regression analysis was used to identify factors associated with TMD pain. Mediation and moderation analysis were used to evaluate interactions between variables. Significant mediation ('0' not included in the 95% confidence interval (CI)) and moderation (p < .05) effects on TMD pain were identified. RESULTS: Marital status, diagnosis subgroup, previous medication use, depression and sleep quality were significant risk factors for TMD pain (p < .05). Significant mediation effects were observed as follows: depression and sleep quality mediated the association between OBs and pain; sleep quality mediated the association between somatization, depression, anxiety and pain; and depression mediated the association between sleep quality and pain (all 95% CI did not contain '0'). CONCLUSIONS: (1) Marital status, diagnosis subgroup, previous medication use, depression and sleep quality were associated with TMD pain. (2) OBs can exacerbate pain by promoting depression and reducing sleep quality. Psychological factors and sleep quality can interact to exacerbate pain.

Glossopharyngeal neuralgia due to vertebrobasilar dolichoectasia: a case report.

BACKGROUND: Glossopharyngeal neuralgia due to vertebrobasilar dolichoectasia is a rare form of neuropathic pain and presents with diagnostic and therapeutic challenges. CLINICAL PRESENTATION: A 67-year-old man presented with severe burning pain in the left oral cavity, with no explanatory findings during dental and ENT evaluations. TMJ examination revealed tenderness, and panoramic radiographs showed a non-contributory periapical radiolucency. MRI/MRA revealed abnormally tortuous vertebral arteries compressing the glossopharyngeal nerves and the brainstem. Topical lidocaine reduced pain, confirming glossopharyngeal neuralgia (GPN). Carbamazepine was initially ineffective, but at 200 mg pain reduced from 90 to 20 on the visual analog scale. The patient requested and underwent microvascular decompression (MVD) surgery, which eliminated his pain. CONCLUSION: When the vertebral artery compresses the glossopharyngeal nerve, the pain is more intense, attributed to its thicker vascular structure. Local anesthetic testing aids in identifying GPN. Dentists must be skilled in diagnostics and possess anatomical knowledge for accurate evaluation and referral of throat and ear pain.

Hybrid treatment of varied orthodontic appliances for a patient with skeletal class II and temporomandibular joint disorders: A case report and review of literature.

BACKGROUND: The relation between orthodontic treatment and temporomandibular disorders (TMDs) is under debate; the management of TMD during orthodontic treatment has always been a challenge. If TMD symptoms occur during orthodontic treatment, an immediate pause of orthodontic adjustments is recommended; the treatment can resume when the symptoms are managed and stabilized. CASE SUMMARY: This case report presents a patient (26-year-old, female) with angle class I, skeletal class II and TMDs. The treatment was a hybrid of clear aligners, fixed appliances and temporary anchorage devices (TADs). After 3 mo resting and treatment on her TMD, the patient's TMD symptom alleviated, but her anterior occlusion displayed deep overbite. Therefore, the fixed appliances with TAD were used to correct the anterior deep-bite and level maxillary and mandibular deep curves. After the levelling, the patient showed dual bite with centric relation and maximum intercuspation discrepancy on her occlusion. After careful examination of temporomandibular joints (TMJ) position, the stable bite splint and Invisible Mandibular Advancement appliance were used to reconstruct her occlusion. Eventually, the improved facial appearance and relatively stable occlusion were achieved. The 1-year follow-up records showed there was no obvious change in TMJ morphology, and her occlusion was stable. CONCLUSION: TMD screening and monitoring is of great clinical importance in the TMD susceptible patients. Hybrid treatment with clear aligners and fixed appliances and TADs is an effective treatment modality for the complex cases.

Laser acupuncture to reduce temporomandibular disorder (TMD) symptoms: systematic review and meta-analysis.

The application of low-level laser therapy (LLLT) to acupuncture points may produce effects similar to that of needle stimulation in patients with temporomandibular disorders (TMD). This systematic review was conducted according to the Cochrane Collaboration guidelines and aimed to address clinical questions using the following strategy: Patient/Problem, Intervention, Comparison, and Outcome (PICO). A comprehensive literature search was performed upto April 26, 2023, across nine electronic databases (BVS, PubMed, Scopus, Embase, Web of Science, ScienceDirect, Cochrane Library, Latin American and Caribbean Health Sciences Literature (LILACS), and Google Scholar) supplemented with gray literature. The risk of bias in randomized and nonrandomized clinical trials was assessed using two tools: risk-of-bias (RoB) 2 and Risk Of Bias In Non-randomised Studies-of Interventions (ROBINS-I). Meta-analysis involved the extraction of mean and standard deviation values for spontaneous pain and mouth opening levels. Seven studies were included in this review, all of which used LLLT. The applied wavelengths ranged from 690 to 810 nm without significant variations in light emission patterns. LLLT demonstrated a significant reduction in instantaneous pain levels (standard mean difference [SMD] = 3.85; 95% confidence interval [CI] = 2.09, 5.62; p < 0.003) and an improvement in instantaneous mouth opening ability (mean difference [SMD] = -7.15; 95% CI = -11.73, -2.58; p < 0.002), with low certainty of evidence. LLLT may alleviate symptoms in patients with TMD; however, caution should be exercised when interpreting the results because of protocol variations among studies and the limited number of studies included in the meta-analysis.

Trismus in head and neck cancer: translation and validation of the Chinese version of the Gothenburg Trismus Questionnaire-2 (C-GTQ-2).

OBJECTIVES: Trismus, marked by restricted mouth opening, significantly affects patients with temporomandibular disorder (TMD) and head and neck cancer (HNC). Despite its prevalence, specialized questionnaires for trismus assessment are scarce. This study aims to fill this gap by translating and validating the Gothenburg Trismus Questionnaire version 2 (GTQ-2) into Chinese (C-GTQ-2), enhancing the evaluation of trismus in HNC and TMD patients. MATERIALS AND METHODS: The study involved 78 HNC patients, 75 TMD patients, and a control group of 150 individuals without trismus symptoms. Participants were asked to complete the C-GTQ-2 and other health-related quality of life (HRQL) instruments. A subset of 30 individuals retook the questionnaire within two weeks to assess test-retest reliability. RESULTS: The C-GTQ-2 demonstrated remarkable reliability, with Cronbach's alpha values exceeding 0.70 in three of the four domains, indicating high internal consistency. The instrument also showcased high intra-class correlations in the test-retest, affirming its reliability. Furthermore, it exhibited strong convergent validity, aligning well with other HRQL instruments, and effectively discriminated between patients with and without trismus, establishing its discriminant validity. CONCLUSIONS: The C-GTQ-2 emerges as a valid and reliable tool for assessing trismus in HNC and TMD patients, promising to significantly enhance both clinical and research approaches to managing trismus-related complications in the Chinese-speaking demographic. CLINICAL RELEVANCE: C-GTQ-2 proves effective for trismus assessment in head and neck cancer and temporomandibular disorder patients, offering enhanced clinical and research utility.

Temporomandibular joint disorders and associated factors in a Turkish pediatric population.

OBJECTIVE: To explore the presence and severity of temporomandibular disorders (TMD) signs and symptoms in a Turkish pediatric population, as well as their relationship to parafunctional behaviors, bruxism, malocclusion, anxiety, and sociodemographic traits. METHODS: A cross-sectional study was conducted with patients between the ages of 5-15. Demographic variables, TMD signs and symptoms, parafunctional habits, bruxism, and malocclusion were evaluated by clinical examination. Fonseca Anamnestic Index (FAI) was used to determine the presence and severity of TMD. State-Trait Anxiety Scale for Children (STAI-C) was used to evaluate the anxiety. Student t, Mann-Whitney U, chi-square tests, and logistic regression were used for statistical analysis. RESULTS: One hundred sixty-two participants (85 girls, 77 boys) with a mean age of 10.03 ± 1.88 years were included. The frequency of the participants who reported signs/symptoms of TMD was 19.7% according to FAI scores. Logistic regression analysis with the associated factors showed a significant relationship between the presence of the signs/symptoms of TMD and parafunctional habits (OR 4.24, 95% CI 1.64-10.93), and the presence of signs/symptoms of anxiety (OR 1.09, 95% CI 1.02-1.16). CONCLUSIONS: Children and adolescents who exhibit parafunctional behaviors and anxiety had a higher likelihood of having TMD signs/symptoms of varying degrees of severity.

Orofacial fascial space abscess disguised as temporomandibular disorder: a report of 3 cases and literature review.

Fascial space abscess is a condition in which infections spread into fascial spaces. It is a severe and life-threatening disease unless treated at an early stage. Due to the similarity of clinical symptoms, fascial space abscesses in the orofacial area are often disguised as other diseases, such as temporomandibular disorder (TMD). In this case series, we report three cases of fascial space abscesses disguised as TMD. In all cases, patients complained of severely limited mouth opening and pain in the temporomandibular joint (TMJ) and masseter muscles, which led clinicians to diagnose them with TMD. After two patients showed facial swelling and the third complained of dyspnea, clinicians realized the possibility of an orofacial fascial space abscess. On further evaluation, all patients showed increased C-reactive protein in blood tests, and the location of the fascial space abscess was confirmed by enhanced computed tomography images. Moreover, all patients had suspicious sources of odontogenic infections in panoramic images, periapical abscess on maxillary molars and periodontal disease on maxillary and mandibular molars, which were not appropriately evaluated at the first visit. This case series emphasizes the need for clinicians to realize the possibility of orofacial fascial space abscesses based on: clinical symptoms of severely limited mouth opening (< 15 mm) with pain in the facial area, including TMJ or masseter muscle, and possible sources of infection such as odontogenic infection, other infectious lesions, trauma, or invasive treatments. These clinical insights will enable the early detection of fascial space abscesses.

Three-dimensional theoretical model for effectively describing the effect of craniomaxillofacial structural factors on loading situation in the temporomandibular joint.

BACKGROUND: Temporomandibular joint (TMJ) overloading is considered a primary cause of temporomandibular joint disorders (TMD). Accordingly, craniomaxillofacial structural parameters affect the loading situation in the TMJ. However, no effective method exists for quantitatively measuring the loading variation in human TMJs. Clinical statistics, which draws from general rules from large amounts of clinical data, cannot entry for exploring the underlying biomechanical mechanism in craniomaxillofacial system. The finite element method (FEM) is an effective tool for analyze the stress and load on TMJs for several cases in a short period of time; however, it is difficult to generalize general patterns through calculations between different cases due to the different geometric characteristics and occlusal contacts between each case. METHODS: (1) This study included 88 subjects with 176 unilateral data to measure angle (α) of the distance to the plane of occlusion. The bone destruction score was evaluated for clinical statistics. To rule out effects of the potential factors and ensure the generality of the study, one participant with no obvious bone destruction was selected as the standard case for establishing the three-dimensional (3D) theoretical model and FEM. (2) Three groups of forces, including biting, muscles and joint reaction forces on mandible, were adopted to establish a 3D theoretical model. (3) By modifying the sagittal α and coronal three types of deviation angle (φ) of the original model, nine candidate models were obtained for the FEM studies. RESULTS: (1) The static equilibrium equations, were used to establish a 3D theoretical model for describing the loading of the TMJ. The theoretical model was validated by monotonously modifying the structural parameter in comparison to two-dimensional theoretical models reported previously; (2) The force on the TMJ gradually decreased with α, and this trend was validated by both clinic statistics and FEM results; (3) The effects of the three types of deviation angle were different. The results of the case where only rotating biting forces were considered was consistent with clinical statistics, indicating that the side with lower α experiences higher TMJ load. (4) Changing the unilateral proportionality coefficients of biting and muscle force produced opposite effects, wherein the effects of the muscle force were stronger than those of the biting forces. CONCLUSIONS: A negative correlation was observed between the joint load and α. Among the three types of asymmetric deformities, occlusal deviations were the primary factors leading to TMD. Unilateral occlusion can result in a greater load on the ipsilateral joint and should be avoided when using the side corresponding to the TMD. This study provides a theoretical basis for the biomechanical mechanism of TMD and also enables the targeted mitigation and treatment of TMD through structural modification.

Occlusal splint and combined multiwave locked system laser therapy demonstrated differential patient-reported outcomes and clinical parameters: A randomized controlled trial in patients with temporomandibular disorder.

PURPOSE: To evaluate the impact of occlusal splint plus laser therapy (OS + LT) compared with OS alone on the patient-reported outcomes and clinical parameters of patients with temporomandibular disorders (TMDs). METHODS: Twenty-three patients with TMDs were randomly assigned to two treatment approaches: OS and OS + LT (multiwave locked system). The two outcomes were clinical parameters (mouth-opening distances, number of muscles and TMJs with pain) and patient-reported outcomes (pain score and oral health-related quality of life [OHRQoL] determined using the 14-item oral health impact profile [OHIP-14]). The outcomes were measured at four time points: baseline, 2 weeks, 1 and 3 months after treatment. According to DC/TMD Axis I classification, the participants were diagnosed as having pain only and pain with intraarticular joint disorder. Adjusting for age and sex, the outcome changes were analysed using generalized estimating models at a 5% significance level. RESULTS: The pain-free mouth-opening distance of the patients who received OS + LT continuously increased from 2 weeks to 3 months. However, the value was significantly increased at 3 months in patients who received OS alone. The unassisted mouth-opening distance significantly increased after 3 months in both groups. In both treatment approaches, the number of muscles and TMJs with pain, as well as the pain and OHIP-14 scores gradually decreased from baseline to 3 months. CONCLUSIONS: The patients who received OS and OS + LT demonstrated better OHRQoL and clinical parameters during 3 months after treatment. An improvement in the pain-free mouth-opening distance at 2 weeks was found only in OS plus LT group; however, this difference may not be clinically significant.

Relationship between masseter muscle activity during wakefulness and temporomandibular disorder-related symptoms.

BACKGROUND: Masseter muscle activity during wakefulness may be associated with temporomandibular disorder (TMD)-related symptoms, psychosocial status and pain-related disability; however, this relationship is unclear. OBJECTIVES: This study aimed to determine the relationship between masseter muscle electromyography (EMG) burst/duration during wakefulness and TMD-related symptoms, psychosocial status and pain-related disability. METHODS: Sixty participants were assessed masseter muscle activity during wakefulness using a data-logger-type ultraminiature EMG system and TMD-related symptoms, psychosocial status and pain-related disability through Axis I and II of the diagnostic criteria for TMD (DC/TMD). EMG bursts lasting longer than 0.25 s but less than 2.0 s and those lasting longer than 2.0 s were classified as phasic and tonic bursts, respectively. RESULTS: Participants with palpation-related pain in the temporalis and masseter muscles, as assessed through the DC/TMD examination form in Axis I, had more bursts (number/h) (p = .035 and p = .009, respectively) and longer duration (time/h) (p = .013 and p = .004, respectively) of tonic bursts of the masseter muscle during wakefulness. Participants with palpation-related pain in the masseter muscles had higher oral behaviour scores during wakefulness using Axis II (p = .001), which affected the number and duration of tonic bursts of the masseter muscle activity during wakefulness (p = .011 and p = .007, respectively). CONCLUSION: As tonic bursts mainly reflect clenching, individuals with pain in the masseter muscles by palpation may have a high frequency and longer duration of clenching, as well as a high frequency of oral behaviours during wakefulness.

Comparison of low-level laser therapy and standard treatment for temporomandibular disorders: An assessment of therapeutic and placebo effects.

BACKGROUND: Despite extensive research on the use of low-power lasers for TMD treatment, the extent of their effectiveness remains uncertain. OBJECTIVE: This study aimed to investigate the therapeutic or placebo effect of LLLT for TMD, and to compare it with standard treatment methods. A unique aspect of this study was the inclusion of a control group that received only standard treatment, allowing for an assessment of the placebo effect of LLLT. METHODS: A total of 42 patients with TMD were referred to Kerman Dental School Pain Clinic and were randomly assigned to three groups: group A received LLLT, group B was a placebo group and group C was a control group that received only standard treatment. The laser groups received gallium-aluminium-arsenide laser treatment twice a week for 10 sessions. Patients' jaw movement rate indicators and VAS index were evaluated at the start of treatment, and indicators were re-recorded every week for 5 weeks. SPSS 21 was used for statistical analysis, including ANOVA and Tukey's post hoc tests for inter-group comparisons. The repeated measurement test was used to analyse the data. RESULTS: All groups showed significant improvement in VAS indicators (p = .0001), lateral jaw movements (p = .0001), forward jaw movement (p = .007) but not for maximum mouth opening. No significant difference was observed between the groups at the end of the study (p = .000). CONCLUSION: Our study provides insights into LLLT's effectiveness for TMD, suggesting it cannot replace standard treatment alone. These findings contribute to the literature and emphasise the importance of including a control group in future studies to assess the placebo effect of LLLT.

Survival of temporomandibular total joint replacement: A systematic review and meta-analysis.

BACKGROUND: Prosthetic total joint replacement has been incorporated as a treatment for complex temporomandibular disorder; however, the survival of those devices is unknown. OBJECTIVE: To assess the survival rate of the total temporomandibular joint (TMJ) prothesis and their main causes of failure. METHODS: An electronic search was conducted in eight databases until March 2023. Prospective studies reporting the survival rate of total TMJ prothesis with a minimum follow-up of 12 months were included. Studies with partial TMJ prostheses or those no longer available on the market were excluded. Two reviewers assessed the individual risk of bias using the JBI Systematic Reviews for Quasi-experimental studies tool. Meta-analysis of proportions was conducted to summarise the survival rate, using 95% confidence intervals (CI). The GRADE approach assessed the certainty of the body of evidence. RESULTS: Data from 320 patients were collected from six prospective studies. The number of prothesis losses varied from none to four. All studies presented sources of bias related to follow-up description of the patients. The follow-up time varied from 12 months to 21 years. In most of the studies, prosthesis failure occurred within the first 6 months after surgery due to infection. The overall survival of total TMJ protheses was 97% (95% CI: 95%; 99%), with low heterogeneity (I2 = 29%) and a very low certainty of evidence. CONCLUSION: TMJ total prosthesis apparently is a safe procedure with a high survival rate and the evidence is very uncertain and presents important sources of bias.