Temporomandibular disorders among medical students in China: prevalence, biological and psychological risk factors

Associations Between Temporomandibular Disorders and Brain Imaging-Derived Phenotypes

OBJECTIVE

Temporomandibular disorders (TMD) affect the temporomandibular joint and associated structures. Despite its prevalence and impact on quality of life, the underlying mechanisms of TMD remain unclear. Magnetic resonance imaging studies suggest brain abnormalities in patients with TMD. However, these lines of evidence are essentially observational and cannot infer a causal relationship. This study employs Mendelian randomisation (MR) to probe causal relationships between TMD and brain changes.

METHODS

Genome-wide association study (GWAS) summary statistics for TMD were collected, along with brain imaging-derived phenotypes (IDPs). Instrumental variables were selected from the GWAS summary statistics and used in bidirectional 2-sample MR analyses. The inverse-variance weighted analysis was chosen as the primary method. In addition, false discovery rate (FDR) correction of P value was used.

RESULTS

Eleven IDPs related to brain imaging alterations showed significant causal associations with TMD (P-FDR < .05), validated through sensitivity analysis. In forward MR, the mean thickness of left caudal middle frontal gyrus (OR, 0.76; 95% CI, 0.67-0.87; P-FDR = 1.15  ×  10-2) and the volume of right superior frontal gyrus (OR, 1.24; 95% CI, 1.10-1.39; P-FDR = 2.26  ×  10-2) exerted significant causal effects on TMD. In the reverse MR analysis, TMD exerted a significant causal effect on 9 IDPs, including the mean thickness of the left medial orbitofrontal cortex (β = -0.10; 95% CI, -0.13 to -0.08; P-FDR = 2.06 × 10-11), the volume of the left magnocellular nucleus (β = -0.15; 95% CI, -0.22 to -0.09; P-FDR = 3.26 × 10-4), the mean intensity of the right inferior-lateral ventricle (β = -0.09; 95% CI, -0.14 to -0.04; P-FDR = 2.23 × 10-2), the volume of grey matter in the anterior division of the left superior temporal gyrus (β = 0.09; 95% CI,  0.04-0.14; P-FDR = 1.69 × 10-2), and so forth.

CONCLUSIONS

This study provides genetic evidence supporting the bidirectional causal associations between TMD and brain IDPs, shedding light on potential neurobiological mechanisms underlying TMD development and its relationship with brain structure.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Analysis of the Effect of Exams on Perceived Stress and Temporomandibular Joint Status in Physiotherapy Students: A Pilot Study

Background and Objectives: Temporomandibular disorders or dysfunction (TMDs) encompass a range of complex conditions that impact the temporomandibular joint (TMJ), chewing muscles, teeth, and/or their supporting tissues. Stress is one of the most associated factors studied as a TMD predictor. The aim is to figure out the influence of stress on TMJ status and salivary cortisol in university students during and before exams. Materials and Methods: The study was non-experimental, employing a longitudinal, analytical, observational cohort design. The study population consisted of students enrolled in the physiotherapy degree program at the Alfonso X El Sabio University (Madrid, Spain). Data were collected during two distinct academic periods: the first period was characterized by low academic stress and no exams, and the second period coincided with the high academic stress of final course exams. The collected results included sociodemographic data, assessment of TMJ status (Fonseca Index), evaluation of muscle evaluation (masseter, upper trapezius, and sternocleidomastoid) using a MOXY Monitor (muscle oxygenation) and Neurotrac® (surface EMG, sEMG), assessment of perceived stress (PSS-14), and measurement of salivary cortisol (enzyme immunoassay with Elisa). The statistical analysis was conducted with a confidence level of 95% (p ≤ 0.05) and asymptotic or bilateral significance. Results: 70 students were analyzed during two different measurement periods. According to the Fonseca Index, initially, 37.14% of the analyzed students showed mild TMDs, 17.14% moderate TMDs, and 45.72% showed no TMDs. In general terms, stress increased with age and is related to female sex, maximum mouth opening decreased with age, oxygen saturation decreased with age and academic stress, and myoglobin concentration was related to age. Furthermore, muscle contraction decreased during higher academic stress and increased with age. For women, age was a risk factor for suffering from TMDs, and stress worsened the transition from having TMDs to having no TMDs in both sexes. Conclusions: Academic stress influences TMJ status and muscle outcomes such as oxygen saturation, myoglobin concentration, and muscle contraction, although more research is needed.

Temporomandibular joint stress analysis of patients with different mandibular deformities during unilateral molar occlusion

Mandibular prognathism, retrusion and deviation are common mandibular deformities. They can lead to functional and aesthetic problems due to their important role in the oral system. Different from other occlusions, unilateral molar occlusion often occurs during mastication, which has a deep impact on the functions of temporomandibular joints (TMJs). Therefore, the study of unilateral molar occlusion is of great importance and significance to the daily life of patients with mandibular deformities. A total of 35 individuals were involved in this study, including 11 asymptomatic subjects, 10 patients with mandibular prognathism, 5 patients with mandibular retrusion and 9 patients with mandibular deviation. Finite element (FE) models corresponding to the unilateral molar occlusion were constructed. During unilateral molar occlusion, mandibular deformity increases the pressure on the condyle and articular disc. Compared with mandibular protrusion or retraction, facial asymmetry will significantly increase the stress of TMJ. Chewing on the non-deviated side also will lead to higher stress in the TMJ of patients with mandibular deviation. Therefore, patients with mandibular deviation have the highest risk of temporomandibular disorder (TMD), and it is recommended that patients with mandibular deviation chew bilaterally or with the deviated side.

Is sleep bruxism in obstructive sleep apnea only an oral health related problem?

BACKGROUND

The etiology of sleep bruxism in obstructive sleep apnea (OSA) patients is not yet fully clarified. This prospective clinical study aimed to investigate the connection between probable sleep bruxism, electromyographic muscle tone, and respiratory sleep patterns recorded during polysomnography.

METHODS

106 patients with OSA (74 males, 31 females, mean age: 56.1 ± 11.4 years) were divided into two groups (sleep bruxism: SB; no sleep bruxism: NSB). Probable SB were based on the AASM criteria: self-report of clenching/grinding, orofacial symptoms upon awakening, abnormal tooth wear and hypertrophy of the masseter muscle. Both groups underwent clinical examination for painful muscle symptoms aligned with Temporomandibular Disorders Diagnostic Criteria (DC/TMD), such as myalgia, myofascial pain, and headache attributed to temporomandibular disorder. Additionally, non-complaint positive muscle palpation and orofacial-related limitations (Jaw Functional Limited Scale-20: JFLS-20) were assessed. A one-night polysomnography with electromyographic masseter muscle tone (EMG) measurement was performed. Descriptive data, inter-group comparisons and multivariate logistic regression were calculated.

RESULTS

OSA patients had a 37.1% prevalence of SB. EMG muscle tone (N1-N3, REM; P = 0.001) and the number of hypopneas (P = 0.042) were significantly higher in the sleep bruxism group. While measures like apnea-hypopnea-index (AHI), respiratory-disturbance-index (RDI), apnea index (AI), hypopnea-index (HI), number of arousals, and heart rate (1/min) were elevated in sleep bruxers, the differences were not statistically significant. There was no difference in sleep efficiency (SE; P = 0.403). Non-complaint masseter muscle palpation (61.5%; P = 0.015) and myalgia (41%; P = 0.010) were significant higher in SB patients. Multivariate logistic regression showed a significant contribution of EMG muscle tone and JFLS-20 to bruxism risk.

CONCLUSION

Increased EMG muscle tone and orofacial limitations can predict sleep bruxism in OSA patients. Besides, SB patients suffer more from sleep disorder breathing. Thus, sleep bruxism seems to be not only an oral health related problem in obstructive apnea. Consequently, interdisciplinary interventions are crucial for effectively treating these patients.

TRIAL REGISTRATION

The study was approved by the Ethics Committee of Philipps-University Marburg (reg. no. 13/22-2022) and registered at the "German Clinical Trial Register, DRKS" (DRKS0002959).

Pain symptoms are associated with two-point discrimination threshold in patients with temporomandibular disorders

OBJECTIVE

This study aimed to explore the associations of orofacial two-point discrimination (2-PD) test result with pain symptoms and psychological factors in patients with Temporomandibular Disorders (TMDs).

METHODS

193 patients with TMDs were included in this study. Patients' demographics, pain intensity, and psychological status were recorded. The 2-PDs in the bilateral temporal, zygomatic, mandibular, and temporomandibular joint (TMJ) regions of the patients were measured. Statistical analyses were conducted to observe the associations between variables.

RESULTS

For Pain-related TMDs (PT) patients, Monthly Visual Analogue Scale (VAS-M) and Current Analogue Scale (VAS-C) were correlated with TMJ, zygomatic and temporal 2-PDs. Patients with PT tended to have higher TMJ 2-PDs[Right: β = 1.827 mm, 95%CI(0.107, 3.548), P = 0.038], zygomatic 2-PDs[Right: β = 1.696 mm, 95%CI(0.344, 3.048), P = 0.014], temporal 2-PDs[Left: β = 2.138 mm, 95%CI(0.127, 4.149), P = 0.037; Right: β = 1.893 mm, 95%CI(0.011, 3.775), P = 0.049]. Associations were also observed between VAS-C and TMJ 2-PDs[Left: β = 0.780, 95%CI(0.190, 1.370), P = 0.01; Right: β = 0.885, 95%CI(0.406, 1.364), P = 0.001], Zygomatic 2-PDs[Right: β = 0.555, 95%CI(0.172, 0.938), P = 0.005]; VAS-M and TMJ 2-PDs[Left: β = 0.812, 95%CI(0.313, 1.311), P = 0.002; Right: β = 0.567, 95%CI(0.152, 0.983), P = 0.008], zygomatic 2-PDs[Left: β = 0.405, 95%CI(0.075, 0.735), P = 0.016; Right: β = 0.545, 95%CI(0.221, 0.870), P = 0.001], and temporal 2-PDs [Left: β = 0.741, 95%CI(0.258, 1.224), P = 0.003; Right: β = 0.519, 95%CI(0.063, 0.975), P = 0.026].

CONCLUSION

TMJ, zygomatic, and temporal 2-PDs were significantly associated with PT and pain intensity. Age, gender and psychological factors were not associated with orofacial 2-PDs. PT patients exhibited weaker tactile acuity compared to Non-PT patients. Further discussion on the underlying mechanism is needed.

CLINICAL RELEVANCE

Orofacial tactile acuity of TMDs patients was associated with their pain symptoms, which researchers should take account into when performing 2-PD tests for TMDs patients. The 2-PD test can be considered as a potential tool along with the current procedures for the differentiations of PT and Non-PT.

The association between chronotype profile and temporomandibular disorders among college students

BACKGROUND

Temporomandibular joint disorders (TMDs) are common in young adults, and the link between chronotype profile and TMDs is unclear.

OBJECTIVE

This study examined TMD prevalence and chronotype distribution and explored the relationship between chronotype and TMDs in young adults.

MATERIALS AND METHODS

A total of 663 students from Sichuan University completed questionnaires. Chronotype profiles were assessed using the Morningness-Eveningness Questionnaire, and TMDs were screened using the Fonseca Memory Index. To validate the findings, 68 TMD patients and 136 controls were enrolled.

RESULTS

The prevalence of TMDs was 69.7%, with significant differences among chronotype profiles. The intermediate profile was the most common chronotype. Eveningness profile was associated with higher TMDs prevalence and severity. Muscle pain and side movement difficulty scores were higher in eveningness and intermediate profiles. Female gender (OR 2.345; 95% CI 1.668-3.297) was a TMD risk factor, while morningness profile (OR 0.537; 95% CI 0.297-0.970) was protective. Validation with TMD patients and controls supported these findings, showing higher eveningness profile prevalence in the TMD groups.

CONCLUSIONS

TMDs have a high prevalence in college students, chronotype profiles shown to be associated with TMDs. Morningness is the protection factor in TMDs and PT, eveningness is a risk factor for IT.

Association Between Orofacial Pain and Anxiety: A Systematic Review

The prevalence of orofacial pain continues to increase. Additionally, the rising number has been accompanied by reduced quality of life of its sufferers. An assumed association between orofacial pain and anxiety has surfaced due to the results of several studies that show higher occurrence of anxiety in people experiencing orofacial pain, compared to those who are orofacial-pain-free. The aim of this systematic review was to discover past research on orofacial pain and its relationship to anxiety, and to understand the relationship between acute and chronic orofacial pain and anxiety. The current systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) rules. Study searches were carried out using three databases, namely PubMed, ScienceDirect, and Scopus. Article selection was carried out in several stages and was based on inclusion and exclusion criteria and continued by assessing the methodological quality and risk of bias of each article. The risk of bias was analyzed by using the critical review tool for cross-sectional studies from the Joanna Briggs Institute (JBI). The selection process led to a review process of 13 cross-sectional research articles. The systematic review showed a positive relationship between orofacial pain and anxiety, with variations in the strength of the relationship (weak to moderate). Most articles revealed that anxiety is a risk factor for orofacial pain. A correlation between chronic orofacial pain and anxiety was mentioned in several studies. It can be concluded that there is an existing relationship between orofacial pain and anxiety, especially chronic orofacial pain. Prospero registration number: CRD42023385409.

Does Emotional State Improve Following Temporomandibular Joint Total Joint Replacement?

BACKGROUND

Temporomandibular joint total joint replacement (TMJTJR) offers patients the opportunity for improved function and reduced pain. TMJTJR also has the potential to affect a patient's emotions in a positive or negative manner.

PURPOSE

The purpose of this study was to evaluate changes in emotional state for subjects undergoing TMJTJR.

STUDY DESIGN, SETTING, SAMPLE

The authors implemented a retrospective cohort study. Subjects who received TMJTJR were identified from the TMJ Inter Network, which is a study group comprising more than 130 temporomandibular joint surgeons. Subjects between the ages of 18 and 65 years with complete medical records and pre/post TMJTJR video/audio recordings were enrolled in the study.

PREDICTOR VARIABLE

The predictor variable was time (preoperative and postoperative).

MAIN OUTCOME VARIABLES

The primary outcome variable is change in the emotional state. All subjects had preoperative (T0) recorded interview as well as a postoperative (T1) interview at 3 to 6 months. The eight-category emotional state was classified as neutral, happy, sad, angry, fearful, disgusted, surprised, and bored. The three-category emotional state was classified as neutral, positive, and negative. The emotional state was measured using artificial intelligence at T0 and T1. The secondary outcome variable was pain score and maximal interincisal opening.

COVARIATES

The covariates are gender, age, diagnosis, prosthetic side, TMJTJR design, and TMJTJR type.

ANALYSES

The relationship between emotional state change and covariates was examined using both the χ2 test and the Kruskal-Wallis H test. The significance of the change in categorical data after surgery was examined using the McNemar-Bowker test. P values < .05 were considered statistically significant.

RESULTS

Thirty-three subjects were included in the study. The mean age was 30.09 ± 8.69 with 15 males (45%) and 18 females (55%). The percentage of subjects with preoperative neutral, happy, sad, angry, and fearful emotional states was 24, 15, 24, 9, and 27%, respectively. The percentage of subjects with postoperative neutral, happy, sad, angry, and fearful emotional states was 21, 39, 21, 12, and 6%, respectively. The change in emotional state was statistically significant (P = .037). There was no statistically significant relationship between covariates and emotional state changes (P > .05).

CONCLUSION

According to the assessment of artificial intelligence, TMJTJR improves the emotional state of patients.

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

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

Exploring the Relationship between Perfectionism and Pain in Patients with Temporomandibular Disorders: A Cross-Sectional Study

Objectives

The purpose of this cross-sectional study was to examine the relationship between perfectionism and pain in patients with temporomandibular disorders (TMDs).

Methods

A total of 345 TMD patients were included. A questionnaire consisting of questions of demographic information, the 15-item short form of the Hewitt and Flett Multidimensional Perfectionism Scale, and the Patient Health Questionnaire-4 (PHQ-4) was distributed. According to the diagnostic criteria for TMDs, patients were categorized as pain-related (PT) and non-pain-related (NPT) groups, whereas PT patients were further divided into patients with pain-related TMDs only (OPT) and patients with combined pain-related and intra-articular TMDs (CPT). Data were analyzed using the chi-square test, Spearman's correlation, and logistic regression analysis with the significance level set at p < 0.05.

Results

There were 68 patients in the NPT group, 80 in the OPT group, and 197 in the CPT group. PT patients had significantly higher perfectionism scores (63.58 ± 13.63) than NPT patients (56.32 ± 12.95, p < 0.001). The PHQ-4 score in the PT group was also higher. After adjusting the PHQ-4 scores, perfectionism scores of the PT group were 6.11 points higher than those in the NPT group (p < 0.001). There were no statistical differences in all parameters of OPT and CPT groups (p > 0.05). Perfectionism in total, other-oriented perfectionism (OOP), and socially prescribed perfectionism (SPP) showed significant but weak correlations with PHQ-4 scores (p < 0.001), while self-oriented perfectionism (SOP) was also significantly but very weakly correlated with PHQ-4 scores (p < 0.05).

Conclusions

Pain-related TMD patients exhibited higher perfectionism scores than NPT patients, and neither their perfectionism nor pain scores were correlated with intra-articular diseases of TMJ. OOP and SOP presented weak correlations with psychological distress in TMD patients. It is suggested that pain-related TMD patients could be screened for perfectionism and perfectionism could be considered when proposing psychological treatment strategies to PT patients.

Correlation Between the Prevalence of Temporomandibular Disorders and Their Association With Psychological Distress in Central Saudi Arabia

Background In this study, we aimed to determine the prevalence of temporomandibular disorders (TMDs) and their association with psychological distress in the central region of Saudi Arabia. Methodology In this cross-sectional study, a questionnaire was sent randomly to residents of Al-Qassim province. They were asked to complete a TMD pain screener, the Patient Health Questionnaire-4 (PHQ-4), and the Generalized Anxiety Disorder Scale (GAD-7). Correlations between symptoms of pain-related TMDs and PHQ-4 and GAD-7 scores were analyzed using Spearman's correlation test. Frequencies and percentages were calculated for sex, age, TMD, PHQ-4, GAD-7, and TMD pain-screener responses. A chi-square test was performed to determine the association between demographic data and psychological profiles. Results The majority of the respondents (59.4%) reported at least one symptom of pain-related TMDs. The TMD pain score was positively correlated with PHQ-4 and GAD-7 scores. Conclusions Residents of the Al-Qassim region who experienced elevated levels of psychological distress had significantly more pain-related TMD symptoms. These findings imply a link between psychological distress and TMD symptoms.

Prevalence of Temporomandibular Disorders Between 2015-2021: A Literature Review

The prevalence of temporomandibular disorder (TMD) is significantly high around the world. We conducted a literature review to determine the prevalence of TMD globally and in Saudi Arabia based on published studies. This review article collected 35 full-text articles after searching PubMed for TMD prevalence between 2015-2021. Assessing the prevalence of TMDs is important for several reasons, including providing an overview of the incidence of such disorders, educating the community, clarifying the gender and age group with the highest prevalence, establishing a program to prepare specialists to treat these disorders, and identifying the appropriate number of specialists by comparing TMD prevalence to Saudi Arabia's census. Out of 35 selected articles, thirty studies were done outside Saudi Arabia, and five were local. Less than 40% prevalence of TMD has been reported with associated factors such as gender, psychological status, and age. The female gender has shown a higher TMD rate than the male gender. Some authors have suggested conducting a temporomandibular joint (TMJ) assessment in the pediatric clinic. Moreover, TMD screening is an important tool for every patient visiting the dental clinic to assess TMJ status and treat TMD at early stages, especially in non-painful cases.

Association of congenitally missing teeth with adult temporomandibular disorders in the urban health checkup population

BACKGROUND

Congenitally missing tooth is the most common dental abnormality which leaves spaces in the arch, leads to numerous forms of malocclusion due to the Bolton index discrepancy and is even associated with abnormal craniofacial morphology. Even though the roles of malocclusion and tooth loss in temporomandibular disorders (TMD) development remain controversial, basic researches have found some common molecules are involved in osteoarthritis and dental agenesis. However, the association of congenitally missing teeth with TMD is unknown. We hence investigated the association of congenitally missing teeth with TMD.

METHODS

A cross-sectional analysis of 586 control participants (male: 287, female: 299, 38.33 ± 11.65 years) and 583 participants with non-third molar congenitally missing teeth (male: 238, female: 345, 39.13 ± 11.67 years) who consecutively received routine dental and TMD checkup according to Diagnostic Criteria for Temporomandibular Disorders Axis I in Health Management Center, Xiangya Hospital was performed. Logistic regression analysis was used to study the association of congenitally missing teeth with TMD.

RESULTS

The congenitally missing teeth group included 581 hypodontia and 2 oligodontia participants. The congenitally missing anterior teeth participants, the congenitally missing posterior teeth participants and participants with both congenitally missing anterior and posterior teeth accounted for 88.34%, 8.40% and 3.26% of the congenitally missing teeth group respectively. Congenitally missing teeth group had greater ratios of females and orthodontic history. Participants with congenitally missing teeth had a significantly higher prevalence of overall TMD (67.24%) in comparison to control participants (45.90%). After adjusting age, gender, presence of congenitally missing teeth, number of congenitally missing teeth, number of non-congenitally missing teeth, number of dental quadrants with missing teeth, visible third molar and orthodontic history, the variables of age, gender, presence of congenitally missing teeth and number of dental quadrants with missing teeth were significant for overall TMD. Multivariable logistic regression analysis showed congenitally missing tooth was significantly related with overall TMD [odds ratio (OR):1.689(1.080-2.642), P = 0.022], intra-articular TMD [OR: 1.711(1.103-2.656), P = 0.017] and pain-related TMD [OR: 3.093(1.321-7.239), P = 0.009].

CONCLUSION

Congenitally missing tooth is a risk factor for TMD. When treating the congenitally missing teeth population, TMJ evaluation and multidisciplinary strategies are necessary.

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.

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.

Repeated Intra-Articular Administration of Platelet-Rich Plasma (PRP) in Temporomandibular Disorders: A Clinical Case Series

Background: Temporomandibular joint disorders (TMDs) are manifested, inter alia, by pain and limited scope of the mandibular abduction. Among the treatment strategies for these ailments, intra-articular injections of autologous blood preparations, including platelet-rich plasma (PRP), are administered. This prospective case series was aimed at assessing the effectiveness of repeated platelet-rich plasma (PRP) administration to the TMJ cavities in terms of reducing articular pain and increasing the mobility of the mandible. Material and methods: 40 consecutive patients diagnosed with TMJ pain qualified for the case series. The entire treatment program consisted of five PRP administrations and a summary appointment. Regression was analyzed for (1) intensity of spontaneous pain; (2) effectiveness of spontaneous pain relief; (3) mastication efficiency values; (4) painless mandibular abduction; (5) maximum mouth opening. The correlations between the abovementioned variable series were analyzed. Results: The mean spontaneous pain decreased consistently with successive PRP administrations in line with the regression model: −0.4x + 4.2 (R2 = 0.98). Articular pain improvement was reported in 71% of joints treated. Improvement in chewing quality at the end of the entire injection cycle was found in 63% of patients. The equations for the linear regression models for painless mandibular abduction (five applications of PRP) and maximum mouth opening (the first four applications of PRP) were x + 34 (R2 = 0.89) and 0.6x + 43.6 (R2 = 0.96), respectively. Improvement in these domains was found in 78% and 53% of patients, respectively. The strongest correlations were found between pain and chewing efficiency (−0.95), pain and painless mandible abduction (−0.96), and painless mandibular abduction and mastication efficiency (0.94). Conclusion: PRP injections into TMJ cavities should be considered as a low invasive, highly accessible form of treatment for various TMDs causing pain and mandible movement limitation.

Evaluation of the efficacy of platelet rich fibrin (I-PRF) intra-articular injections in the management of internal derangements of temporomandibular joints - a controlled preliminary prospective clinical study

Background

The temporomandibular joint (TMJ) is one of the most complex joints in the body. Temporomandibular disorders (TMD) are among the most troublesome disorders for patients, as they can cause pain, affect oral functions and disturb dentists on the level of diagnosis and treatment. The most common symptoms of temporomandibular joint disorders are articulated sounds (such as clicking or TMJ crepitation), joint pain in comfort and function situations (jaw movements), pain or strain in masseter and jaw muscles and or restricted mandibular movements. One of the most modern biocompatible substances used to treat joint disorders, including the TMJ, is platelet-rich plasma (PRP) and injectable platelet-rich fibrin (I-PRF). This study aims to evaluate the efficacy of platelet-rich fibrin (I-PRF) intra-articular injections in managing internal derangements of temporomandibular.

Methods

Twenty patients suffering from a unilateral click due to temporomandibular disorders were individually injected with 1 mL of (I-PRF) twice 1 week apart into the superior joint space of the TMJ with the internal disorder. Data were recorded and evaluated by the Helkimo index. This evaluation was conducted three times; 1 week after the first injection, 1 week after the second injection, and 6 months after the first injection.

Results

The clicking disappeared entirely in 14 out of 20 patients after 1 week of getting the first injection, and in all patients after 1 week of getting the second injection, and returned to two of them after a six-month since the first injection.

Conclusion

Preliminary results showed the efficacy of the Injectable Platelet-Rich Fibrin (I-PRF) in managing articular clicking in patients with internal disorders of the temporomandibular joint. Injectable Platelet Rich Fibrin has significant clinical efficacy in treating the articular clicking resulting from internal temporomandibular joint disorders.