Mineral deposition intervention through reduction of phosphorus intake suppresses osteoarthritic lesions in temporomandibular joint.

OBJECTIVE: To explore the suppressing impact of low phosphorus intake on osteoarthritic temporomandibular joint and the possible mechanisms of nuclear acid injury in the insulted chondrocytes. DESIGN: Chondrocytes were loaded with fluid flow shear stress (FFSS) with or without low phosphorus medium. Seventy-two mice (sampled at 3-, 7- and 11-wk, n = 6) and forty-eight rats (sampled at 12-wks for different testing purpose, n = 6) were applied with unilateral anterior crossbite (UAC) with or without low phosphorus diet. In the FFSS model, the Ca and P content, molecules related to nucleic acid degradation and the mineral-producing responses in chondrocytes were detected. The effect of culture dish stiffness on chondrocytes osteogenic differentiation was measured. In the UAC model, the content of Ca and P in serum were tested. The condylar cartilage ossification and stiffness were detected using micro-CT, scanning electron microscope and atomic force microscope. RESULTS: FFSS induced nucleic acid degradation, Pi accumulation and mineral-producing responses in the cultured chondrocytes, all were alleviated by low P medium. Stiffer dish bottoms promoted the osteogenic differentiation of the cultured chondrocytes. UAC stimulated cartilage degeneration and chondrocytes nucleic acid damage, increased PARP 1 and serum P content, and enhanced ossification and stiffening of the cartilage, all were suppressed by low phosphorus diet (all, P < 0.05). CONCLUSION: Nucleic acid damage takes a role in phosphorus production in osteoarthritic cartilage, contributing to the enhanced mineralization and stiffness of the cartilage that in turn promotes cartilage degradation, which can be alleviated by low phosphorus intake.

Induction, Treatment, and Prevention of Temporomandibular Joint Ankylosis-A Systematic Review of Comparative Animal Studies.

PURPOSE: Several animal models of temporomandibular joint ankylosis (TMJA) have been described for more than the past 2 decades. The aim of this study was 2-fold: 1) to compile and summarize the evidence of animal studies that compare different forms to induce, treat (disease already established), or prevent (after trauma) TMJA; and 2) to address the following focused question: what is the quality of reporting in these studies? MATERIALS AND METHODS: A systematic review was conducted. Animal studies conducted up to October 2019 comparing at least 2 procedures to induce, treat (disease already established), or prevent (after trauma) TMJA were considered. Compliance with the Animal Research Reporting In Vivo Experiments guidelines was checked for all studies. Studies evaluating treatment of TMJA or preventive measures also were evaluated using the SYstematic Review Center for Laboratory animal Experimentation's risk of bias tool for animal studies. RESULTS: A total of 24 studies were included. The studies were evaluated for feasibility regarding data synthesis, and a meta-analysis was not suitable because of methodological differences, mainly regarding the animal model chosen and surgical procedures performed to induce TMJA. In 17 articles, authors aimed to investigate different procedures to induce TMJA (fibrous, fibro-osseous, or bony). In 7 articles, different treatment or preventive strategies were compared. The sheep was the most used animal in models of TMJA. Only 25% (6 of 24) of studies reported some step to minimize bias (ie, blinding of investigators, randomization procedures, or allocation concealment). Approximately 54% (13 of 24) of articles clearly commented on study limitations and potential sources of bias. Further animal studies on TMJA should consider improving their reporting standards to increase their validity and improve the reproducibility of animal experiments.

Affective relationships as predictors of TMD symptoms in young adults / Relações afetivas como preditoras de sintomas de DTM em adultos jovens

Abstract Introduction Orofacial pain is a critical TMD symptom that can influence physical and social capacity. Objective To evaluate the association of temporomandibular disorders (TMD) symptoms with affective relationships and demographic variables in young adults. Material and method A cross-sectional study involving 395 young adults was developed. Diagnostic Criteria for TMD, anxiety, and depression were collected from questionnaires. The Dental Health Component of the Index of Orthodontic Treatment Need measures the orthodontic treatment need. Questionnaires also contained questions related to the previous orthodontic treatment. Logistic regression models were adjusted, estimating crude odds ratio with the 95% confidence intervals. The variables with p<0.20 in the analyses were assessed in a multiple logistic regression model, remaining with p≤0.10. Result There was no significant association of TMD symptoms with sex, age, medication use for pain, previous orthodontic treatment, orthodontic treatment need, anxiety, and depression (p>0.05). Individuals without an affective relationship are 1.78 (95%CI: 0.99-3.17) times more likely to report TMD symptoms. Conclusion Affective relationships showed an association with TMD symptoms in young adults.

Resumo Introdução A dor orofacial é um sintoma crítico da DTM que pode influenciar a capacidade física e social. Objetivo Avaliar a associação dos sintomas das desordens têmporomandibulares (DTM) com as relações afetivas e variáveis demográficas em adultos jovens. Material e método Estudo transversal envolvendo 395 adultos jovens foi realizado. Os critérios diagnósticos para DTM, ansiedade e depressão foram coletados a partir de questionários. O Componente de Saúde Bucal do Índice de Necessidade de Tratamento Ortodôntico mensurou a necessidade de tratamento ortodôntico. Os questionários também continham questões relacionadas ao tratamento ortodôntico anterior. Modelos de regressão logística foram ajustados, estimando odds ratio bruto com os intervalos de confiança de 95%. As variáveis com p<0.20 nas análises foram avaliadas em modelo de regressão logística múltipla, permanecendo as variáveis com p≤0.10. Resultado Não houve associação significativa dos sintomas de DTM com sexo, idade, uso de medicamentos para dor, tratamento ortodôntico prévio, necessidade de tratamento ortodôntico, ansiedade e depressão (p>0.05). Indivíduos sem relacionamento afetivo têm 1.78 (IC95%:0.99-3.17) vezes mais chance de relatar sintomas de DTM. Conclusão Os relacionamentos afetivos mostraram associação com os sintomas de DTM em adultos jovens.

Poloxamer micellar system for intra-articular injection of 15-deoxy-Δ12,14-prostaglandin J2 with improved bioavailability and anti-inflammatory properties in the temporomandibular joint of rats.

Painful conditions of the temporomandibular joint (TMJ) are challenging to manage and most attempts often result in unsatisfactory outcomes. In such context, nanocarrier systems, such as polymeric micelles, have been showing encouraging results in solving therapeutic limitations. Poloxamers are widely used, especially PL 407, because of their high biocompatibility and approval by the Food and Drug Administration (FDA) for clinical use. 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) has shown important antinociceptive and anti-inflammatory activity. The present study evaluated the efficacy and viability of the micellar system of PL-15dPGJ2 in a formalin-induced acute pain model in the temporomandibular joint of rats. The PL-15dPGJ2 was prepared and characterized. The animals were pretreated with an intra-articular injection of PL-15dPGJ2 followed by the formalin challenge. The nociceptive response was evaluated at different time-periods and the periarticular tissue and articular wash were collected for analysis. We found that intra-articular injection of PL-15d-PGJ2 produced pain relief at lower concentrations and in a sustained manner compared with free 15d-PGJ2. Moreover, a strong anti-inflammatory effect was observed with decreased levels of key pro-inflammatory cytokines and modulation of the leukocyte migration process. Our findings suggest that 15d-PGJ2 combined with a poloxamer micellar system provided clinical relevance in terms of bioavailability, long-lasting effect, and safe dosage. The formulation investigated herein is a promising micellar carrier system for managing pain conditions of the TMJ.

Pediatric Mandibular Condylar Fractures With Concomitant Cervical Spine Injury: A Treatment Protocol for Prevention of Temporomandibular Joint Ankylosis.

In pediatric patients with mandible fractures and concomitant cervical spine injury (CSI), treatment strategies may occasionally compete: condylar fractures require functional therapy with range of motion exercises of the temporomandibular joint (TMJ), while CSI requires neck immobilization. The authors report the case of a child presenting with bilateral condylar head fractures, a right parasymphyseal fracture, and concomitant CSI treated with cervical collar immobilization, who ultimately developed TMJ ankylosis. Here, the authors review mandibular condylar fracture management and suggest an approach for the pediatric patient presenting with condylar fractures and concomitant CSI requiring immobilization. To preserve range of motion at the TMJ, it is critical to prevent external restriction by prolonged cervical collar use. Instead, these patients benefit from a protocol utilizing conventional halo or noninvasive, pinless halo cervical spine stabilization. Without limitation of the TMJ, condylar fracture rehabilitation and healing may proceed unhindered.

Bruxism in children: Use of the Functional Plane of Monaco (FPM).

BACKGROUND: Bruxism is a condition that results from hyperactivity in the central nervous system, and factors such as stress or other anxious conditions increase the frequency of episodes. When bruxism occurs at a young age, tooth wear can occur. The extent of wear can lead to the need for restorative dentistry and prosthetic treatments to restore the morphological and functional integrity of the teeth, with high costs associated with such treatments. CASE REPORT: A healthy 15-year-old boy presented to the orthodontist observation. His incisal ridges appeared thin, without mamelons, and with increased translucency. For treatment, the authors used only the Functional Plane of Monaco (FPM), a device which he had to wear 16 hours during the day. CONCLUSION: The orthodontist successfully treated an orthopaedic/orthodontic case with the FPM device.

Management of an edentulous patient with temporomandibular disorders by using CAD-CAM prostheses: A clinical report.

This clinical report describes the application of computer-aided design and computer-aided manufacturing (CAD-CAM) complete dentures (CDs) in 4 visits and a 2-year follow-up period for a patient with temporomandibular disorders (TMDs), severe occlusal disturbances, and parafunctional habits. The use of a Gothic arch tracing for recording the maxillomandibular relationship and verifying muscular function was particularly helpful in such a symptomatic patient. A trial period was used to determine patient acceptance and adaptation to the new CDs.

Estrogen Promotes Mandibular Condylar Fibrocartilage Chondrogenesis and Inhibits Degeneration via Estrogen Receptor Alpha in Female Mice.

Temporomandibular joint degenerative disease (TMJ-DD) is a chronic form of TMJ disorder that specifically afflicts people over the age of 40 and targets women at a higher rate than men. Prevalence of TMJ-DD in this population suggests that estrogen loss plays a role in the disease pathogenesis. Thus, the goal of the present study was to determine the role of estrogen on chondrogenesis and homeostasis via estrogen receptor alpha (ERα) during growth and maturity of the joint. Young and mature WT and ERαKO female mice were subjected to ovariectomy procedures and then given placebo or estradiol treatment. The effect of estrogen via ERα on fibrocartilage morphology, matrix production, and protease activity was assessed. In the young mice, estrogen via ERα promoted mandibular condylar fibrocartilage chondrogenesis partly by inhibiting the canonical Wnt signaling pathway through upregulation of sclerostin (Sost). In the mature mice, protease activity was partly inhibited with estrogen treatment via the upregulation and activity of protease inhibitor 15 (Pi15) and alpha-2-macroglobulin (A2m). The results from this work provide a mechanistic understanding of estradiol on TMJ growth and homeostasis and can be utilized for development of therapeutic targets to promote regeneration and inhibit degeneration of the mandibular condylar fibrocartilage.

A method for preventive intervention regarding temporomandibular pain and dysfunction.

OBJECTIVE: Adolescent girls frequently suffer from temporomandibular disorder (TMD) symptoms and associated headache. A program aimed at informing about risk behavior for TMD symptoms, how to influence harmful habits and about general relaxation was tested. MATERIAL AND METHODS: Eighty girls at two high schools, 16 years of age, with or without symptoms, were invited to the health information on two occasions and 60 girls participated. Firstly, a questionnaire regarding symptoms and oral parafunctional habits was administrated. Structured information was given about the normal anatomy and function of muscles and joints, about the occlusion, oral habits and symptoms of orofacial pain/dysfunction and headache. General relaxation was instructed and trained. At a three-month follow-up, the same questionnaire regarding symptoms as at baseline was completed. RESULT: The information provided was perceived as useful and instructive. At the follow-up, 77% reported that they used what they had learned. Headache once a week or more decreased from 49% at baseline to 35% and headache 'never/rarely' changed from 11% to 25% (p = .002). Reported joint sounds had decreased by the follow-up (p = .053), as had the use of chewing gum (p = .002). A majority of the girls suggested that the information should be scheduled during school hours. CONCLUSION: Health information about the jaw system can influence risk factors for TMD symptoms and the frequency of symptoms among adolescent girls.

Prevalence of Temporomandibular Disorders in Rheumatoid Arthritis and Associated Risk Factors: A Nationwide Study in Taiwan.

AIMS: To investigate the association between temporomandibular disorders (TMD) and rheumatoid arthritis (RA), as well as potential risk factors for TMD and the preventive effect of medications on TMD, by using the Taiwan National Health Insurance Research Database. METHODS: In total, 17,317 patients newly diagnosed with RA and 17,317 matched controls without RA were followed up from 2000 to 2010. Cox regression was used to determine risk factors for developing TMD. Kaplan-Meier curve with log-rank test was used to determine the cumulative risk of TMD in RA patients and the effects of antirheumatic medications. RESULTS: Cox regression showed a higher risk of developing TMD if patients had RA (adjusted hazard ratio [HR] 2.538, P < .001) and a lower risk if patients were of male gender and elderly (≥ 40 years) in comparison to younger patients (20 to 29 years) (P < .01). Patients with insomnia, stroke, and mental disorders had, respectively, 4.756, 6.929, and 9.671 times the number of events of TMD compared to those without diseases (P < .001). No patients with RA treated with disease-modifying antirheumatic drugs (DMARDs) developed TMD after the 11-year follow-up. CONCLUSION: RA patients had 2.538 times the events of TMD compared with non-RA patients during this trial in Taiwan. The other risk factors for developing TMD included female gender, younger age, insomnia, stroke, and mental disorders. The DMARDs had a beneficial effect on prevention of TMD.

Orthodontics and the temporomandibular joint: What orthodontic providers need to know.

Currently, there are three major groups of dentists who provide orthodontic services to the public: postgraduate trained orthodontists, postgraduate trained pediatric dentists, and general dentists who have taken various orthodontic training courses. All of them can expect to encounter a variety of clinical situations that require a proper understanding of how normal temporomandibular joints (TMJs) function, and also how the masticatory system can develop pain-dysfunction problems; those problems are classified and defined as temporomandibular disorders (TMDs). In this paper, six "intersections" between these groups of practitioners and those clinical situations will be discussed, with an emphasis on practical approaches to managing problems that may arise during orthodontic treatment. Specific recommendations are offered to help clinicians recognize clinical problems and to deal with them successfully.

Protection of the Temporomandibular Joint During Syndromic Mandibular Distraction With a Novel Condylar Offloading Device.

Mandibular distraction for severe micrognathia in syndromic patients often leads to temporomandibular joint (TMJ) ankylosis, which requires further interventions to regain joint motion. The increased incidence of postdistraction ankylosis is likely related to increased prevalence of preoperative joint pathology in syndromic micrognathic patients. Previous studies have demonstrated that offloading the pressure on the condyle during the distraction process can prevent such TMJ pathology. In this article, the authors describe a successful new method for offloading the condyle to prevent postdistraction ankylosis using an external TMJ offloading device.

The Effect of New Oral Care Technologies on the Need for Dentists in 2040.

This article addresses changes in technology of oral self-care or professional care that may increase or decrease the demand for dentists by 2040. The focus is on dental caries, periodontitis, and temporomandibular joint disorders (TMD), as the first two are the main areas of current practice and because TMD is an area for growth. To address this question, the authors examined the scientific literature and government registries to identify recent or soon-to-be-available technologies. They also examined the state of translational efficiency, dissemination, and adoption of advances into dental practice. The pipeline of applicable technology is limited. Nevertheless, between now and 2040, emerging technologies will continue to reduce the need for training more dentists, while no technologies are emerging that will significantly increase the need. Technology in dentistry is adopted slowly as is true in other medical specialties. If a breakthrough product did appear, the results of industry-sponsored trials would be viewed skeptically by the profession, and considerable time would be required to establish the applicability of the findings to the broader population. Greater integration of dentistry into preventive medicine, with dentists offering point-of-service medical testing for systemic disease as suggested by the American Dental Association (ADA), would require a paradigm shift, can occur only over a lengthy period, and is unlikely to impact this assessment. This article was written as part of the project "Advancing Dental Education in the 21st Century."

Effect of interocclusal appliance on bite force, sleep quality, salivary cortisol levels and signs and symptoms of temporomandibular dysfunction in adults with sleep bruxism.

OBJECTIVE: The purpose was to evaluate the effect interocclusal appliance therapy on bite force (BF), sleep quality and salivary cortisol levels in adults with SB diagnosed by polysomnography. As a secondary aim, signs and symptoms of temporomandibular dysfunction (TMD) were evaluated. DESIGN: Forty-three adults (19-30 y/o) were divided into two groups: experimental group (GSB), composed of 28 subjects with SB, and control group (GC), without SB and TMD (n=15). GSB was treated with stabilization interocclusal splint and evaluated at time intervals: before (baseline), one month (T1) and two months (T2) after therapy began, to collect data related to BF, sleep quality (Pittsburgh Sleep Quality Index), salivary cortisol levels and TMD. GC was also examined three times and received no therapy. Data were analysed by means of normality tests, t-test/Mann-Whitney and One-way ANOVA repeated measures (Tukey post-test). Two-way ANOVA test for repeated measures was applied to verify the effect time*group interaction on the variance of each dependent variable (α=0.05). RESULTS: GSB showed an increase in BF and a positive effect on muscular symptomatology, range of mandibular movements and sleep quality; in GC these parameters did not differ. Cortisol concentration decreased between baseline and T1 in GSB (F(1,31)=4.46; test power=62%; p=0.017). The variance observed for BF, TMD and sleep quality among time points was dependent on the group (moderate effect size: partial Eta square >0.16; test power >80%). CONCLUSIONS: The results suggested that short-term interocclusal appliance therapy had a positive effect on BF, temporomandibular symptomatology, sleep quality and salivary cortisol levels in adults with SB.

Knowledge and competence in temporomandibular disorders among Swedish general dental practitioners and dental hygienists.

OBJECTIVE: The aim of this study was to investigate knowledge and competence in temporomandibular disorders (TMD) among dentists and dental hygienists working in the public dental service (PDS) in Sweden. MATERIALS AND METHODS: The study population comprised all general dentists (n = 110) and dental hygienists (n = 80) working in the PDS in two Swedish counties: Kronoberg (K) and Blekinge (B). The participants filled out a questionnaire comprised of 15 questions. RESULTS: The results of these questions are presented. The overall response rate for the general dentists was 87%, while the rate for the dental hygienists was 71%. Statistically significant differences between the general dentists in the two counties were found regarding the following: education in the field of TMD over the last 5 years (K: 37%, B: 73%), evaluation of occlusion when examining patients with suspected TMD ('always': K: 61%, B: 82%), and a desire for consultation of the OFP (orofacial pain)/TMD specialist by telephone (K: 71%, B: 44%). Regarding the dental hygienists, there was a statistically significant difference concerning the use of the treatment modality 'reassurance' (K: 41%, B: 7%). CONCLUSIONS: The majority of the dental care providers in both counties - irrespective of professional category - had a positive attitude towards patients with TMD. Knowledge and competence in the field are sparse and require postgraduate education. There is a great need of an OFP/TMD specialist for more complicated patients and a need to implement updated knowledge and competence in the PDS in these two counties.

Surgical treatment of condylar head fractures, the way to minimize the postraumatic TMJ ankylosis.

Management of condylar head fractures (CHF) of the temporomandibular joint (TMJ) remains a source of controversy. Based on established literature, group of CHFs and conservative treatment connected with period of maxillomandibular fixation (MMF) increases the risk for TMJ ankylosis. This paper presents anatomical and functional results of surgical treatment of condylar head fractures in a group of 24 patients (29 joints). Fractures were diagnosed based on conventional radiographs and computed tomography (CT) scans. Utilising an intraoperative arthroscopy authors evaluated actual intraarticular posttraumatic changes. This study presents acceptable functional and radiological results of surgical treatment of condylar head fractures with more than 3-year follow-up. The authors believe that re-establishing the pretraumatic anatomic position of the TMJ components (fragment and the disc) and early postoperative rehabilitation are inevitable to minimize the risk of postraumatic TMJ ankylosis (Tab. 2, Fig. 8, Ref. 31).

Effect of jaw-opening exercise on prevention of temporomandibular disorders pain associated with oral appliance therapy in obstructive sleep apnea patients: A randomized, double-blind, placebo-controlled trial.

PURPOSE: There are no studies on the prevention of temporomandibular joint and/or masticatory muscle pain (TMD pain) associated with oral appliance (OA) therapy in patients with obstructive sleep apnea (OSA). The aim of this study was to determine the effect of jaw-opening exercise on TMD pain associated with OA therapy in OSA patients. METHODS: Twenty-five OSA patients without pain-related TMD were consecutively enrolled into a two-arm, randomized, double-blind, placebo-controlled trial. One group performed jaw-opening exercise (JE, n=13), and the other group performed placebo exercise (PE, n=12) for 1-month, and had started 2-weeks prior to insertion of an adjustable OA. TMD sign using the Research Diagnostic Criteria for Temporomandibular Disorders and TMD pain intensity using a visual analog scale (VAS) in the morning and daytime were evaluated at baseline (pre-exercise) and at 2-weeks, 1-month, and 3-months after OA insertion. RESULTS: Pain-related TMD was not observed in the JE-group at all evaluation periods, although one subject in the PE-group was diagnosed with arthralgia at the 1-month evaluation. The JE-group showed lower morning and daytime VAS scores than the those of the PE-group at all evaluation periods, and significant group differences were found in terms of chewing pain and jaw-opening pain in the morning at the 1-month evaluation, and of jaw-opening pain during daytime at the 3-month evaluation (P<0.05). CONCLUSIONS: Within the limitations of the study, jaw-opening exercise prior to OA therapy reduced the risk of TMD pain associated with OA use. Therefore, jaw-opening exercise may contribute to the prevention of TMD pain.

[Orthognathic surgery: the incisor decompensation and its effect on articulation]. / L'orthodontie chirurgicale dans le traitement de la dysharmonie dento-maxillaire : le repositionnement incisif et son impact articulaire.

INTRODUCTION: The surgical protocols are based on arches preparation before or immediately after the surgical phase. Incisor guides normalization is achieved by incisor decompensation in three dimensions. Place and extend of surgical movements depend on the incisor position obtained at the end of orthodontic preparation. Extraction versus non extraction depends on incisor position planning. Orthognathic surgery induces muscular and temporo-mandibular joint stress which can cause temporo mandibular dysfunction (TMD). OBJECTIVES: This article studies relations between incisor decompensation amplitude, orthognathic surgical procedures and risk to create or to increase TMD. CONCLUSIONS: Sagittal, vertical and transversal incisor decompensation impact to place and amplitude of surgical movements. Incisor decompensation does not seem to induce TMD during orthodontic preparation even if occlusal guide controls are lost. Temporo mandibular dysfunction degrees define surgical movements area, moderate specially mandibular surgical movements and incisor decompensation objectives.