The association between orthodontic treatment and temporomandibular disorders diagnosis and disease characteristics.

BACKGROUND: The association between orthodontic treatment and temporomandibular disorders (TMD) has been contentious in the literature. OBJECTIVES: To analyse the associations between orthodontic treatment and TMD diagnosis and diseases characteristics. METHODS: This case-control study included 291 individuals, 192 TMDs and 99 controls. All patients underwent assessment based on a questionnaire and a clinical examination according to Axis I of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Differences in orthodontic treatment between TMDs and controls, as well as across different TMD diagnoses within the TMD group were analysed. Patients who underwent orthodontic treatment were compared to those who did not, regarding their trauma history, bruxism, aggressive teeth brushing, level of oral hygiene, pain scores, muscle tenderness scores and subjective sleep quality. RESULTS: Of the 291 participants, 119 (40.9%) underwent orthodontic treatment and 172 (59.1%) had no orthodontics experience. Orthodontic treatment included: mandibular orthodontic treatment (102 subjects) and maxillary orthodontic treatment (113 subjects) of those 47 used a headgear. Following multivariate analysis among TMDs, orthodontic treatment was associated with a good level of oral hygiene versus poor (Odds ratio [OR]: 5.17 [1.04-25.59]), lower number of tender muscles [OR = 0.84 (0.74-0.96)] and lower (better) Pittsburgh Sleep Quality Index (PSQI) scores (OR = 0.86 [0.76-0.97]). None of the studied parameters maintained a statistically significant association with orthodontic treatment in the multivariate analysis among the entire study population. CONCLUSIONS: Utilising a holistic approach, this study supports the main hypothesis that orthodontic treatment is not associated with TMD diagnosis and disease characteristics.

Dentists and physiotherapists level of collaboration in the treatment of temporomandibular disorders in France.

OBJECTIVES: Temporomandibular disorders (TMD) affect 10% of the population in France, significantly impacting patient's health and quality of life. The multifactorial etiology of TMD complicates its treatment. Consequently, adopting a multidisciplinary approach that encourages collaboration among healthcare professionals is recommended. Nevertheless, this approach does not seem to occur on a regular basis. The aim of this study was to assess the dentist's treatment support of TMD in the context of the inter-professional collaboration between dental practitioners and physiotherapists. MATERIEL AND METHODS: A cross-sectional observational study was conducted based on an online questionnaire from January 15th to April 30th, 2023. The data are collected through Professional Broad, Regional Unions of Health Professional and Healthcare Professional Communities and Territories. RESULTS: Of the 420 responses analyzed, the main first-line treatment provided by the dentist was the correction of dental occlusion (84%). The rate of referral to a physiotherapist was 57% and was 75% for second-placed treatment. The main reason for the lack of referral was a lack of awareness of physiotherapy role in the management of TDM. We observed that 70% of dental health practitioners were interested about inter-professional collaboration and the development of postgraduate training. CONCLUSION: Given the difficulty of managing TDM, efforts should be made to improve inter professional management. CLINICAL RELEVANCE: The implementation of appropriate teaching in initial training seems to be essential to allow dentists to open the range of treatment for TMD with increased knowledge of physiotherapy techniques for an adapted prescription to the patient.

Association of climacterium with temporomandibular disorders at the age of 46 years - a cross-sectional study.

OBJECTIVE: Hormonal factors have been suggested to contribute to female dominance among subjects with temporomandibular disorders (TMD). Aim of the study was to examine the association of climacteric status with TMD amongst female participants in the Northern Finland Birth Cohort (NFBC) 1966 at 46 years of age. MATERIAL AND METHODS: Among female subjects in NFBC1966, climacteric status was determined based on menstrual anamnesis and measurement of blood follicle-stimulating hormone (FSH) levels. Women with FSH > 25 IU/L and amenorrhoea > 4 months were defined as climacteric (case group, n = 71); women not diagnosed as climacteric were defined as preclimacteric (control group, n = 656). Differences between cases and controls were evaluated on self-reported TMD pain, clinical TMD signs and TMD diagnoses using modified Diagnostic Criteria for TMD (DC/TMD) protocol. Crosstabulation and logistic regression models were used to analyse differences between cases and controls. RESULTS: Compared to preclimacteric women, climacteric women had significantly more often pain on palpation in temporomandibular joints (TMJs) (OR = 2.64, 95% CI 1.12-6.21, p= .026) and more crepitus in TMJs (OR = 2.92, 95% CI 1.13-7.56, p= .027). Degenerative joint disease diagnoses were more common in climacteric than preclimacteric women (OR = 2.27, 95% CI 1.05-4.91, p= .037). Differences were statistically significant after adjusting for confounding factors (body mass index (BMI), smoking, parity). No statistically significant differences in self-reported TMD pain were noted between groups. CONCLUSION: Among females at the age of 46 years, climacterium seems associated with TMD by increasing pain on palpation in TMJs, subjective symptoms, and clinical signs indicating degenerative changes in TMJs when using DC/TMD.

Post-traumatic stress, prevalence of temporomandibular disorders in war veterans: Systematic review with meta-analysis.

INTRODUCTION: The physical and psychological effects of war are not always easy to detect, but they can be far-reaching and long-lasting. One of the physical effects that may result from war stress is temporomandibular disorder (TMD). OBJECTIVE: To evaluate the prevalence of TMD sign and symptoms among war veterans diagnosed with PTSD. METHODS: We systematically searched in Web of Science, PubMed and Lilacs for articles published from the inception until 30 December 2022. All documents were assessed for eligibility based on the following Population, Exposure, Comparator and Outcomes (PECO) model: (P) Participants consisted of human subjects. (E) The Exposure consisted of exposition to war. (C) The Comparison was between war veterans (subjects exposed to war) and subjects not exposed to war. (O) The Outcome consisted of presence of temporomandibular disorders sign or symptoms (we considered pain to muscle palpation in war veterans). RESULTS: Forty studies were identified at the end of the research. We chose only four study to draw up the present systematic study. The included subjects were 596. Among them, 274 were exposed to war, whereas the remaining 322 were not exposed to war stress. Among those exposed to war, 154 presented sign/symptoms of TMD (56.2%) whereas only 65 of those not exposed to war (20.18%). The overall effect revealed that subjects exposed to war and diagnosed with PTSD had a higher prevalence of TMD signs (pain at muscle palpation) than controls (RR 2.21; 95% CI: 1.13-4.34), showing an association PTSD war-related and TMD. CONCLUSIONS: War can cause lasting physical and psychological damage that can lead to chronic diseases. Our results clearly demonstrated that war exposure, directly or indirectly, increases the risk of developing TMJ dysfunction and TMD sign/symptoms.

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.

Chondrocyte apoptosis in temporomandibular joint osteoarthritis promotes bone resorption by enhancing chemotaxis of osteoclast precursors.

OBJECTIVE: This study aimed to explore the effect and mechanism of chondrocyte apoptosis on the chemotaxis of osteoclast precursors (OCPs) during bone destruction. DESIGN: The relationship between cartilage and bone destruction was verified with a rat temporomandibular joint osteoarthritis (TMJOA) model. The pan-caspase inhibitor Z-VAD-FMK (ZVAD) was applied to confirm the chemotactic effect of chondrocyte apoptosis on OCPs. Synthesis and release of the key chemokine CX3CL1 in apoptotic and non-apoptotic chondrocytes was assessed with IHC, IF, WB, and ELISA. The function of CX3CL1-CX3CR1 axis in the chemotaxis of OCPs was examined by CX3XR1 inhibitor AZD8797 (AZD) and si-CX3CL1. The regulatory effect of p38 MAPK on CX3CL1 release was verified by p38 inhibitor PH-797804. RESULTS: A temporal and spatial association between cartilage degradation and bone resorption was found in the TMJOA model. The caspase-dependent chondrocyte apoptosis promoted chemotaxis of OCPs, which can be restrained by ZVAD. CX3CL1 was significantly upregulated when chondrocytes underwent apoptosis, and it played a critical role in the recruitment of OCPs, blockage of CX3CL1-CX3CR1 axis resulted in less bone resorption in TMJOA. P38 MAPK was activated in apoptotic chondrocytes, and had a regulatory effect on the synthesis and release of CX3CL1. After inhibition of p38 by PH-797804, the chemotactic effect of apoptotic chondrocytes on OCPs was limited. CONCLUSIONS: This study indicates that apoptosis of chondrocytes in TMJOA enhances chemotaxis of OCPs toward osteoclast precursors through upregulation of the p38-CX3CL1 axis, thereby promoting the activation of local osteoclasts.

The prevalence and symptoms of temporomandibular disorders in head and neck cancer patients.

OBJECTIVES: This retrospective patient survey aimed to assess the prevalence of temporomandibular disorders (TMD) before and after curative oncological treatment and to identify possible risk factors. MATERIALS AND METHODS: Patients with squamous cell carcinoma in the tonsil or base of the tongue were included (n = 217). Medical records were collected to assess TMD prevalence before oncological treatment and at 6- and 12-month follow-up. Fisher's test and Pitman's test were used. RESULTS: Significantly reduced mouth opening was observed after oncological treatment at 6- and 12-month follow-up (p < .001). Symptoms from the temporomandibular joint and jaw muscles plus pain upon palpation (p = .0083, p < .001, respectively) and self-reported pain upon chewing (<0.001) and opening the mouth (<0.001) increased 12 months following radiotherapy. Pain and degree of mouth opening prior to treatment, self-reported depression, overall health status, brachytherapy and jaw exercise during radiotherapy were factors affecting the increase of TMD symptoms. CONCLUSION: All TMD symptoms escalated significantly one year after radiotherapy except self-reported sounds from the temporomandibular joint. Reduction in the degree of mouth opening and pain in the jaw muscles and the temporomandibular joint when opening the mouth and upon chewing were commonly reported symptoms following radiotherapy. Several potential risk factors were identified.

Identification of human temporomandibular joint fibrocartilage stem cells with distinct chondrogenic capacity.

OBJECTIVE: This study was aimed to identify the residence of human fibrocartilage stem cells (hFCSCs), characterize their stem cell properties and investigate the functional mechanisms which regulate fibrocartilage stem cells (FCSCs) toward chondrogenic differentiation during cartilage homeostasis and repairing. METHODS: Cytological characteristics of hFCSCs and human orofacial mesenchymal stem cells (hOFMSCs) were analyzed. Chondrogenic potential of hFCSCs was compared with hOFMSCs both in vitro and in vivo. Regulatory role of SOX9 during FCSCs chondrogenesis was studied by shRNA interference in vitro, and by GFP+ FCSCs treatment in rat condylar cartilage defect model. SOX9 expression was also examined in temporomandibular joint osteoarthritis (TMJOA) patients' cartilage surface. RESULTS: hFCSCs exhibited typical mesenchymal stem cell characteristics, with significantly stronger chondrogenic capability compared to hOFMSCs. Moreover, hFCSCs showed remarkably increased expression of SOX9. During cartilage pellet culture, there was stronger SOX9 expression in hFCSCs than hOFMSCs. SOX9 shRNA interference downregulated chondrogenic capability of hFCSCs in vitro, as well as disrupting migration and chondrogenic differentiation of GFP+ FCSCs toward mature chondrocytes in rat condylar cartilage defect. Of note, SOX9 expression was also found suppressed in the condylar superficial zone of TMJOA patients. CONCLUSION: We found the existence of FCSCs in human TMJ cartilage, and characterized their distinct stem cell features. SOX9 is essential for hFCSCs chondrogenic differentiation, and a comprehensive understanding of the regulatory role of SOX9 in hFCSCs would be important for exploring potential intervention strategy of condylar cartilage degradation during TMJ disorders.

Inflammation and Temporomandibular Joint Derangement.

Temporomandibular disorders (TMD) are a common stomatognathic disease affecting all age groups. Patients with internal derangement (ID) or osteoarthritis (OA) of temporomandibular joint (TMJ) often have TMJ synovitis. When TMJ synovial membrane is damaged, many inflammatory cytokines are produced and secreted from TMJ synoviocytes to synovial fluid of TMJ. It has been widely reported that many kinds of biologic factors are produced from TMJ synoviocytes stimulated with interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. One of the major symptoms of TMD is pain of the TMJ. Many study groups have studied relations between the development of TMJ pain and biologic factors secreted into synovial fluid of TMJ. Here, we summarize previous reports trying to elucidate this correlation. On the other hand, it has been reported that a new molecular mechanism of IL-1beta secretion called inflammasome is involved in several diseases with sterile inflammation. Because TMJ synovitis with ID and OA of TMJ is also sterile inflammation, inflammasome may be involved in the development of TMJ synovial inflammation. This review describes some molecular mechanisms underlying inflammation in TMJ, especially in TMJ synovitis, which may be useful for the development of new therapies against TMD.

The implementation of a decision-tree did not increase decision-making in patients with temporomandibular disorders in the public dental health service.

OBJECTIVE: Many patients with temporomandibular disorders (TMD) seem to go undetected within primary dental health care. Primarily we evaluated if the implemented intervention increased the clinical decision-making for TMD patients; secondarily we evaluated if other factors could be identified that predicted performed or recommended TMD treatment. MATERIAL AND METHODS: This case-control study was carried out within the Public Dental Health service in Västerbotten County, Sweden. An intervention based on a decision-tree with three screening questions for TMD (3Q/TMD) was implemented during 2015 in four clinics and compared with the remaining county. A total of 400 individuals were selected-200 3Q-positives and 200 3Q-negatives. The 3Q/TMD consists of Q1-frequent jaw pain, Q2-frequent pain on function, and Q3-frequent catching and/or locking of jaw. The 3Q/TMD answers were analyzed in relation to TMD treatment and any TMD related decision that was collected from the digital dental records. RESULTS: The intervention did not increase the frequencies of traceable clinical decisions among patients with TMD. CONCLUSIONS: Despite the implemented intervention aimed, the indicated undertreatment of patients with TMD remains. Future studies are still needed to gain a deeper understanding of the clinical decision-making process for TMD patients in general practice dentistry.

Quality improvement of functional diagnostics in dentistry through computer-aided diagnosis: a randomized controlled trial.

Functional diagnostic examinations such as clinical functional analysis and manual structural analysis ('orthopedic tests') allow the dentist to establish a structured diagnosis. Previously, the process of correlating findings with the appropriate diagnoses was guided by human thought processes alone. The experimental diagnostic randomized controlled trial (RCT) in this study investigated whether computer-aided diagnosis (CADx) of temporomandibular disorders (TMD) offers quality advantages over traditional diagnosis (TRAD). SUBJECTS AND METHODS: Thirty-nine 5th-year dental students (examiners) at a university in Hamburg, Germany, received joint training in the diagnosis of TMD by clinical functional analysis and manual structural analysis ('orthopedic tests'). This study is based on anonymized data from 10 patients who were consecutively recruited at a specialized TMJ treatment center. The examiners were randomly allocated to two groups. Each examiner established a structured diagnosis through a traditional diagnostic method and by computer-aided diagnosis (CMDfact 4 functional diagnostics software) of five cases, each using the AB/BA crossover design. The diagnoses established by each individual examiner were then compared with the corresponding reference diagnoses (gold standard) and with those of the other examiners. RESULTS: Cohen's kappa coefficient analysis showed that median agreement with the reference diagnoses was significantly higher (P < 0.001) with computer assistance (median 0.692) than without it (0.553). Fleiss' kappa showed that the median interexaminer consistency of diagnoses was significantly higher (P < 0.001) with computer assistance (0.497) than with traditional diagnostic methods alone (0.271). Likewise, the number of false-positive and false-negative diagnoses was significantly lower with computer assistance (P < 0.001). CONCLUSIONS: This study determined that dentists who are less experienced and not specialized in dental functional diagnostics achieve a significantly better and more consistent diagnostic quality with computer assistance by means of the system used in this study. Therefore, it seems advisable to extend computer-aided diagnostics to further functional examination techniques (condylar position analysis and jaw motion analysis).

Increased levels of intramuscular cytokines in patients with jaw muscle pain.

BACKGROUND: The aim of this study was to investigate cytokine levels in the masseter muscle, their response to experimental tooth-clenching and their relation to pain, fatigue and psychological distress in patients with temporomandibular disorders (TMD) myalgia. METHODS: Forty women, 20 with TMD myalgia (Diagnostic Criteria for TMD) and 20 age-matched healthy controls participated. Intramuscular microdialysis was performed to sample masseter muscle cytokines. After 140 min (baseline), a 20-minute tooth-clenching task was performed (50% of maximal voluntary contraction force). Pain (Numeric rating scale 0-10) and fatigue (Borg's Ratings of Perceived Exertion 6-20) were assessed throughout microdialysis, while pressure-pain thresholds (PPT) were assessed before and after microdialysis. Perceived stress (PSS-10) and Trait Anxiety (STAI) were assessed before microdialysis. RESULTS: The levels of IL-6, IL-7, IL-8 and IL-13 were higher in patients than controls (Mann Whitney U-test; P's < 0.05) during the entire microdialysis. IL-6, IL-8 and IL-13 changed during microdialysis in both groups (Friedman; P's < 0.05), while IL-1ß, IL-7 and GM-CSF changed only in patients (P's < 0.01). IL-6 and IL-8 increased in response to tooth-clenching in both groups (Wilcoxon test; P's < 0.05), while IL-7, IL-13 and TNF increased only in patients (P's < 0.05). Patients had higher pain and fatigue than controls before and after tooth-clenching (P < 0.001), and lower PPTs before and after microdialysis (P < 0.05). There were no correlations between cytokine levels, pain or fatigue. Also, there were no differences in stress or anxiety levels between groups. CONCLUSIONS: In conclusion, the masseter levels of IL-6, IL-7, IL-8 and IL-13 were elevated in patients with TMD myalgia and increased in response to tooth-clenching. Tooth-clenching increased jaw muscle pain and fatigue, but without correlations to cytokine levels. This implies that subclinical muscle inflammation may be involved in TMD myalgia pathophysiology, but that there is no direct cause-relation between inflammation and pain.

Temporomandibular Dysfunction and Voice-Related Quality of Life Impairment.

OBJECTIVE: Muscle tension in the head and neck may co-occur with temporomandibular dysfunction (TMD) possibly leading to voice change. Several studies have reported a correlation between TMD and dysphonia. However, literature on TMD and voice-related quality of life (QOL) is scant. This study aimed to investigate the relationship between TMD and self-perceived voice-related QOL impairment. METHODS: Patients from TMD clinic were prospectively surveyed on voice-related quality of life using the Voice Handicap Index (VHI) questionnaire. Patients were queried using paper and pen upon initial evaluation in dentistry clinic for temporomandibular disorders by a single dentist or dental assistant in the otolaryngology department. RESULTS: A total of 53 patients completed the VHI. 80% of patients presenting to TMD clinic had VHI scores above zero, but most had minimal to mild impairment. Forty-two patients had scores between 1 and 86, (average 10.98); 11 patients had a score of zero (20.75%). Total average score: 8.70, range: 0-86, median: 4. Functional average score: 3.13, range: 0-29, median: 1. Physical average score: 3.58. range: 0-25, median: 2. Emotional average score: 1.98, range: 0-32, median: 0; these averages did not differ from historical controls. CONCLUSION: The majority of patients presenting to TMD clinic also presented with some level of voice-related QOL impairment, although minimal and consistent with historical VHI controls. Data indicates that TMD disease may be primarily defined as functionally and physically uncomfortable. Incorporation of interdisciplinary care, with laryngology, speech pathology, physical therapy, counseling, and pain management may be warranted. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:315-317, 2024.

Morphological analysis of the temporomandibular joint in patients with anterior disc displacement.

This study aims to investigate the morphological characteristics of the temporomandibular joint (TMJ) in the patients with anterior disc displacement with reduction (ADDwR) and the alterations after occlusal splint treatment. Thirty ADDwR patients and ten asymptomatic subjects were recruited. Thirteen parameters were adopted, along with automatic computation and presentation of the joint space to characterize the TMJ morphologies. Statistical results showed that morphological discrepancies between the patients and the asymptomatic subjects were ubiquitous. The adjustment of condyle position through occlusal splint treatment can result in joint spaces widening and has positive effects on mitigating the conditions of ADDwR.

Is There a Relationship between Salivary Cortisol and Temporomandibular Disorder: A Systematic Review.

BACKGROUND: This systematic review examines and evaluates the relationship between salivary cortisol levels and temporomandibular disorder (TMD) in young adult patients. METHOD: Six databases-PubMed, Scopus, Web of Science, Google Scholar, ProQuest, and Cochrane Library-were utilized to screen eligible studies. A systematic search was performed based on PECO questions and eligibility criteria. The research question for this review was "Do salivary cortisol levels correlate with TMD in individuals aged 18-40?" The risk of bias for quality assessment was determined by the Cochrane tool. PRISMA guidelines were followed while performing this review. RESULT: A total of fourteen studies were included in this review. Of these, eleven were observational studies (four cross-sectional and seven case-control), and three were randomized control trials. Eleven of the included studies presented a low to moderate risk in the qualitative synthesis. The total sample size of the included studies was 751 participants. The included studies suggest higher salivary cortisol levels in TMD patients than in healthy individuals. CONCLUSIONS: The findings of this review indicate higher salivary cortisol levels in adult patients with TMD than in healthy controls. Thus, supportive psychological treatment and clinical modalities should be provided to patients with TMD. Moreover, higher-quality studies with low heterogeneity are required to support this finding.

Temporomandibular Disorders and Orthodontics: how to conduct a screening examination? / Dysfonctionnements temporo-mandibulaires et orthodontie : comment conduire un examen de dépistage ?

Introduction: Common Temporomandibular Disorders (TMD) involve the masticatory muscles, temporomandibular joints, and/or their associated structures. Clinical manifestations can vary, including sounds (cracking, crepitus), pain, and/or dyskinesias, often corresponding to a limitation of mandibular movements. Signs or symptoms of muscular or joint disorders of the masticatory system may be present before the initiation of orthodontic treatment, emerge during treatment, or worsen to the point of stopping treatment. How do you screen for common TMD in orthodontic treatment? Materials and Methods: The main elements of the interview and clinical examination for screening common TMD in the context of orthodontic treatment are clarified and illustrated with photographs. Moreover, complementary examinations are also detailed. Results: A clinical screening form for common TMD is proposed. A synthetic decision tree helping in the screening of TMD is also presented. Conclusion: In the context of an orthodontic treatment, the screening examination for common TMD includes gathering information (interview), a clinical evaluation, and possibly complementary investigations. The orthodontist is supported in this approach through the development of a clinical form and a dedicated synthetic decision tree for the screening of TMDs. Systematically screening for common TMD before initiating orthodontic treatment allows the orthodontist to suggest additional diagnostic measures, implement appropriate therapeutic interventions, and/or refer to a specialist in the field if necessary.

Introduction: Les dysfonctionnements temporo-mandibulaires (DTM) concernent les muscles masticateurs, les articulations temporo- mandibulaires et/ou leurs structures associées. Les manifestations cliniques peuvent être diverses : bruits (craquements, crépitements), algies et/ou dyscinésies correspondant le plus souvent à une limitation des mouvements mandibulaires. Or, des signes ou symptômes de troubles musculaires ou articulaires de l'appareil manducateur peuvent être présents avant le début de la prise en charge orthodontique, voire apparaître en cours de traitement ou s'aggraver au point de remettre en question la poursuite du traitement engagé. Comment conduire un dépistage de DTM communs dans le cadre d'une prise en charge orthodontique ? Matériel et méthodes: Les éléments essentiels de l'entretien et de l'examen clinique d'un dépistage des DTM communs dans le cadre d'une consultation d'orthodontie sont clarifiés et illustrés à l'aide de photographies. Le recours aux examens complémentaires a également été détaillé. Résultats: Une fiche clinique de dépistage des DTM communs est proposée. Un arbre décisionnel synthétique aidant au dépistage des DTM est présenté. Conclusion: Dans le cadre d'une consultation d'orthopédie dento-faciale, l'examen de dépistage des DTM communs inclut un recueil d'informations (entretien), une évaluation clinique et éventuellement des examens complémentaires. L'orthodontiste est soutenu dans cette démarche par la création d'une fiche clinique et d'un arbre décisionnel synthétique dédiés au dépistage des DTM. Effectuer systématiquement un dépistage des DTM communs avant d'initier un traitement orthodontique permettra à l'orthodontiste de proposer des moyens diagnostiques supplémentaires si nécessaire, et de mettre en place la prise en charge adéquate et/ou de référer à un spécialiste du domaine pour démarrer le traitement orthodontique dans les meilleures conditions.

Biomechanical study of temporomandibular joints of patients with temporomandibular disorders under incisal clenching: A finite element analysis.

Temporomandibular disorders (TMD) encompass a collection of pathologies. Within the multitude of etiological factors contributing to TMD, mechanical factors hold significant importance. The aim of this investigation was to assess the magnitude and distribution of stresses encountered by the temporomandibular joints (TMJs) during incisal clenching among TMD patients while also elucidating the mechanical pathogenesis underlying TMD. Ten asymptomatic subjects and ten TMD patients were recruited. The Control, Bilateral, and Unilateral groups were set. The contact stress, maximum principal stress, and minimum principal stresses of TMJ structures among the groups were compared. In addition, comparisons of the contact stress distribution among the groups were adopted. In the Control and Bilateral groups, the magnitudes of stresses (contact stress, maximum and minimum principal stresses) between the right and left sides showed no significant difference (P > 0.05). For unilateral TMD patients,the minimum principal stress on the condyle in the Uni-N group (the normal side) was significantly greater than thatin the Uni-T group (the TMD side)(P = 0.016, mean difference 9.99 MPa [95 %CI: 3.11 to 16.87]). Furthermore, stresses on the condyle and fossa of the patients were significantly greater than those of asymptomatic subjects (P < 0.05). The contact stress distributions were concentrated in the Control group while irregular in the TMD groups. In conclusion, asymmetrical contact stress distributions were observed in unilateral TMD, with excessive stresses on the healthy side. The protection of the healthy TMJ during treatment is recommended for patients with unilateral TMD.

Biomechanical effects of mandibular deviation on the temporomandibular joint in patients with mandibular prognathism under incisal occlusion.

PURPOSE: The aim of this study was to investigate the biomechanical effects of mandibular deviation on the TMJ in patients with mandibular prognathism before and after orthognathic surgery using three-dimensional finite element analysis. METHODS: Eight patients with mandibular prognathism without deviation, eight patients with mandibular prognathism with deviation and sixteen normal subjects were recruited. Three-dimensional models of the maxillofacial were reconstructed using MIMICS. Nine muscle forces were used to simulate incisal occlusion and contact was used to simulate fossa-disc-condyle interactions. RESULTS: Before surgery, the stress in the TMJ was generally greater in the Pre-MD&MP group than in the Pre-MD group; it was much greater in both groups than in the control group, ranging from about 2 to 12 times as great in the Pre-MD group and from about 5 to 64 times as great in the Pre-MD&MP group. After orthognathic surgeries, the stresses in the Post-MP&MD were significantly reduced by approximately 21.7 % to 93.4 %. And in the Post-MP group, the stresses were reduced by approximately 1.4 % to 51.1 %. CONCLUSION: Mandibular deviation exacerbated the abnormal stress distribution in the TMJ of patients with mandibular prognathism. Orthognathic surgeries could improve the stress distribution in patients with mandibular prognathism (with and without deviation). TMD was closely related to the stress levels of the TMJ.

Classification and Diagnosis of Temporomandibular Disorders and Temporomandibular Disorder Pain.

Designing classification systems and developing diagnostic criteria for temporomandibular disorders is difficult. An appreciation of the utility and applicability of these entities requires an understanding of the importance of each, the differences between the two, and how they may be optimally operationalized for both clinical and research activities in light of their inherent advantages and limitations. In addition, consideration for adopting newer approaches, such as following ontological and precision-based medicine principles, accounting for genetics/epigenetic and neurobiological factors, and the inclusion of biomarkers will potentially result in more thorough and comprehensive classification systems and diagnostic criteria.

Characterization of head and neck pain symptoms of patients presenting to a tertiary care pain clinic.

OBJECTIVE: To characterize the presentation and symptomatology of individuals presenting with pain in head and neck regions. METHODS: A retrospective chart-review was performed on patients with pain in the HFN presenting to a tertiary pain center in Turkey between January 2016 and January 2017. Information regarding the characteristics of pain and medical and treatment history were extracted and reviewed. RESULTS: Among 197 subjects, 135 (68.5%) were females. The average duration of pain was 60.13 ± 92.32 months. The pain was continuous in presentation and severe in intensity in 43.1% and 51.8% of the subjects, respectively. The pain was associated with at least one somatosensory symptom in 12.1% of subjects. Common diagnoses were trigeminal neuralgia, persistent idiopathic facial pain, and migraine headaches. CONCLUSION: Painful disorders of the HFN are associated with varying and perplexing signs and symptoms. Such patients should undergo a comprehensive clinical assessment with a multidisciplinary team.