Does dental rehabilitation under general anaesthetic contribute to the development of temporomandibular disorders in children and adolescents? A scoping review.

BACKGROUND: Temporomandibular disorders (TMDs) have multiple aetiological factors. Although some evidence suggests invasive and lengthy dental procedures may contribute towards TMD development, there is a relative paucity in the literature regarding an association between elements of paediatric dental general anaesthesia (pDGA) and TMDs. This review aims to consider the impact of dental rehabilitation (and its constituent elements) performed under general anaesthesia on the development of TMDs in childhood and adolescence and identify theories and/or gaps in knowledge which may benefit from future research. METHODS: Due to the need to preliminarily examine the nature and extent of the current evidence base, a scoping review approach was chosen. The review was conducted based on the framework provided by the methodological working group of the Joanna Briggs Institute (JBI) for conducting systematic scoping reviews. Electronic databases MEDLINE, Embase, Scopus, Web of Science and Cochrane Library were searched as well as the grey literature using OpenGrey, Nexis, Ethos, Google Scholar and ProQuest, with eligible studies uploaded onto Zotero (Mac Version 5.0.96.2). RESULTS: A total of 810 records were identified. After removing duplicates and those not available in English, 260 were identified for title and abstract screening. Seventy-six records underwent full-text review of which only one met the broad inclusion criteria. The most common reasons for exclusion were no specific relation to general anaesthesia, not specifically relating to dental treatment and only being concerned with TMD management. The included study found that while development of TMDs following dental rehabilitation under GA did occur in children, whether the problems caused by treatment were exacerbated by other elements of the pDGA process remains unknown. CONCLUSION: This review has confirmed a distinct paucity of research in this field. While there is no current tangible scientific evidence that common and routine dental procedures lead to TMD, the literature shows that alterations to any one or a combination of critical factors can contribute to TMD development, which may be collectively exacerbated by iatrogenic macrotrauma during the pDGA process. We have highlighted elements of pre-, peri- and post-operative pDGA, alongside biopsychosocial factors, which may contribute to TMD development in childhood and adolescence and may benefit from future research.

Effectiveness of Chuna (or Tuina) Manual Therapy for Temporomandibular Disorder: A Systematic Review.

Background: Temporomandibular disorder (TMD) affects patients' quality of life (QoL) because of the resulting structural and functional impairment and pain. Objective: This study aimed to evaluate the evidence regarding the effectiveness, safety and improvement in QoL in patients who underwent Chuna manual therapy (CMT) for TMD. Methods: We searched 11 databases and included randomized controlled trials (RCT) on CMT for TMD published before March 2020. A meta-analysis was conducted, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method was used to evaluate the evidence level. We included 12 RCTs that compared CMT and conventional care. Results: CMT showed significantly better patient pain reduction, functional improvement and QoL. A superior result was seen in the use of CMT in conjunction with Traditional Chinese Medicine (TCM) or conventional care. CMT showed no minor or serious adverse events compared with medical treatments. The evidence level was low for all outcomes, except QoL. Conclusions: We found that CMT for TMD resulted in functional improvement, pain reduction and improvement in QoL, with fewer adverse events. However, since the evidence level varied from very low to moderate due to imprecision and the risk of bias with the included studies, we are limited in determining the efficacy of Chuna therapy using these studies. High-quality, well-designed and large-scale RCTs are needed to conclusively determine the clinical efficacy of CMT in TMD.

The Manifestations of Covid-19 Infection. Manifestations in Patients with Temporomandibular Joint Disorders.

The authors present a group of patients who were treated for exacerbation of temporomandibular joint disorders (TMD) following Covid-19 infection and who in the past had successfully undergone surgery of the temporomandibular joint (TMJ). The group consisted in total of 21 patients who relapsed after contracting Covid-19. There were 4 men and 17 women, the average age was 45.6 years (28-63). The most common complaint was pain. In all cases, the pain was located in the preauricular area, 4 patients had pain in the lateral side of the neck, 1 patient had pain of the nasal alae. During clinical examination, pain was present on palpation of the masseter muscle (19 patients), temporal muscle (4 patients) and the TMJ area (4 patients). In 4 cases, pain on palpation was present in the area of the nape and sternocleidomastoid muscles. Treatment in all cases was the same: thermotherapy, muscle relaxation massage and non-steroidal anti-inflammatory drugs. Symptoms subsided in all cases within 2 weeks. In light of the Covid-19 pandemic, it is also necessary to expect an increased number of patients with TMD. The authors recommend targeted patient histories regarding Covid-19 infection when examining patients with TMD symptoms - this will certainly facilitate determining the etiology of the pain.

Auricular acupuncture in TMD - A sham-controlled, randomized, clinical trial.

This study evaluated the effect of auricular acupuncture (AA) on physical (PA) and emotional (EA) aspects of patients with temporomandibular disorders (TMDs) and compared the effect of AA with those of Sham and occlusal splints (OS). In accordance with the CONSORT guidelines, patients with TMDs were evaluated by axes I and II of the RDC-TMD. The patients were allocated among three groups: OS, Sham and AA; and followed for 8 weeks. Both intragroup and intergroup evaluation for quantitative variables were analyzed with ANOVA, one-way, followed by the Tukey test. Qualitative variables were analyzed with the Kruskal-Wallis, and Dunn tests (intergroup evaluation) and for intragroup analyses, the Friedman and Wilcoxon tests were applied. At the end of the experiment, the chi-squared test was applied to compare the three groups with respect to the number of variables that had shown improved scores. The adopted level of significance for all tests was α = 5%. Intragroup analysis showed that, in the Sham group, no improvement in performance was seen in either EA and significant was improvements in 5 variables for 9 for PA, while in the AA group, significant improvements were observed in 2 variables for EA and in 9 for PA. In the OS group at the end of this study, significant improvements were observed in 8 and 8 variables for EA and PA, respectively. The analysis of therapies used revealed that the number of variables exhibiting significantly improved outcomes after treatment was similar between the AA and OS groups, whereas the sham group showed statistically significant differences when compared with the other two groups. In conclusion, this study demonstrated that AA applied at a specific TMJ ear point was able to bring about improvements in patients with TMDs, with outcomes similar to those in patients treated with an OS. CLINICAL TRIAL REGISTRATION: RBR-69ynnw (Brazilian Registry of Clinical Trials).

Temporomandibular Joint Syndrome from an Ear Versus Dental-Related Standpoint.

Temporomandibular disorders (TMDs) are a prominent reason for visits to medical providers. The presentation of headaches within this population remains a challenging diagnosis, given the prevalence and overlap of symptomatology of both conditions. The literature demonstrates an undeniable association between headaches and TMD. Regardless of causality and etiology, the literature supports that prompt diagnosis and treatment results in improvement or resolution of symptoms, including headaches. Treatment of TMD headaches should begin with conservative measures, including medical management with NSAIDs, heat therapy, and muscle-stretching exercises.

Myofascial pain in temporomandibular disorders: Updates on etiopathogenesis and management.

OBJECTIVES: Temporomandibular disorders (TMDs) are an umbrella term encompassing disorders of both the temporomandibular joint (TMJD) and masticatory musculature (MMD). The objective of this review is to provide an overview of the etiopathogenesis, clinical features and diagnosis of MMD, and to summarize the current trends in the therapeutic management. METHODS: A review of the literature was performed from 1985 to 2020. The keywords included were "temporomandibular disorders OR temporomandibular joint disorders" AND "myofascial pain OR masticatory myofascial pain OR trigger point". A total of 983 articles were screened with abstracts and approximately 500 full text articles were included in the review based on their relevance to the topic. RESULTS: MMD's present significant challenges in diagnosis and treatment. Effective treatment requires a clear diagnosis based on an understanding of pathophysiologic mechanisms, a detailed history with assessment of predisposing local and systemic factors, perpetuating factors, a comprehensive clinical evaluation and a diagnostic workup. CONCLUSION: A thorough history and clinical examination are the gold standards for diagnosis of MMD. Serological testing may help identify underlying co-morbidities. Recent diagnostic modalities including ultrasound sonoelastography and magnetic resonance elastography (MRE) have shown promising results. The treatment goals for MMD are to control pain, restore mandibular function and facilitate the return to normal daily activity and improve the overall quality of life of a patient. Conservative modalities including home care regimens, pharmacotherapy, intraoral appliance therapy, local anesthetic trigger point injections, physiotherapy and complementary modalities may be beneficial in patients with MMD's.

Vitamin D and Temporomandibular Disorders: What Do We Know So Far?

BACKGROUND AND AIMS: Vitamin D is synthesized in the skin with the aid of ultraviolet-B radiation, playing a variety of roles in the body. Temporomandibular disorders (TMDs) are a group of pathological conditions involving the temporomandibular joints as well as the masticatory muscles and othersurrounding tissues. In the present narrative review, we investigated the potential role of vitamin D in the etiology of temporomandibular disorders in order todetermine whether the current knowledge supports 25-hidroxyvitamin D (25-OHD) supplementation in temporomandibular disorders associated with insufficient or deficient levels of vitamin D. METHODS: A literature research was performed in PubMed, Scopus, Science Direct, and Google Scholar databases, and a total of 10 articles were included for analysis. RESULTS: Among the observational studies published to date, investigating the role for vitamin D in the etiology of TMDs, six of them suggest that there is a connection between the two aspects. In this context, patients suffering from TMD, with deficient levels of vitamin D (<30 ng/mL), are most likely to benefit from supplementation, whereas individuals with vitamin D level >50ng/mL probably have little benefit from supplementation. CONCLUSION: Vitamin D might be a safe, simple, and potentially beneficial way to prevent TMDs or to reduce pain; however, more randomized and placebo-controlled trials are required before any firm conclusions can be drawn.

Sleep bruxism: an overview for clinicians.

Bruxism is characterised by clenching or grinding of the teeth due to contraction of the masseter, temporalis and other jaw muscles. Bruxism may lead to masticatory muscle hypertrophy, tooth surface loss, fracture of restorations or teeth, hypersensitive or painful teeth and loss of periodontal support. Sleep bruxism has previously been viewed as a dysfunctional movement or pathological condition, whereas it is now accepted as a centrally controlled condition with various systemic risk factors. It has been postulated that sleep bruxism may have a protective role during sleep, for example in relation to airway maintenance or in stimulating saliva flow. A diagnosis of sleep bruxism may be made via patient report and clinical interview, clinical examination, intraoral appliances or recording of muscle activity. Bruxism in itself does not require treatment: management is only indicated where problems arise as a result of bruxism. Oral appliances primarily aim to protect the dentition from damage caused by clenching/grinding, although they may reduce muscle activity. Irreversible occlusal adjustments have no basis in evidence in the management of bruxism. Behavioural strategies include biofeedback, relaxation and improvement of sleep hygiene. Administration of botulinum toxin (Botox) to the masticatory muscles appears to reduce the frequency of bruxism, but concerns have been raised regarding possible adverse effects. Dentists should be aware of the potential aetiology, pathophysiology and management strategies of sleep bruxism.

La artritis reumatoidea juvenil y su influencia en la alteración de desarrollo de la mandíbula / Juvenile rheumatoid arthritis and its influence on the alteration of jaw development

La artritis reumatoidea juvenil (ARJ) es una enfermedad inflamatoria autoinmune que se presenta en niños menores de 16 años. Es de curso crónico, etiología desconocida, y afecta sobre todo las articulaciones, como la temporomandibular (ATM). El daño de la ATM puede ocasionar: alteraciones en el crecimiento facial (micrognatia), maloclusión clase II, mordida abierta anterior, desviaciones laterales, erosiones óseas, destrucción del cón-dilo, oclusión disfuncional y alteración de la estética facial, entre otras consecuencias. La posición oclusal neurofisiológica lograda por medio de elementos electrónicos, como el Transcutaneus Electrical Neural Stimulation (TENS), y mantenida por el Dispositivo Intaroral (DIO) podría posibilitar la remodelación de la cabeza del cóndilo, en pacientes en crecimiento, en los que la enfermedad se halla controlada, regulando así también la sintomatología dolorosa...

Temporomandibular joint involvement as a positive clinical prognostic factor in necrotising external otitis.

OBJECTIVE: Necrotising otitis externa is associated with high morbidity and mortality rates. This study investigated whether temporomandibular joint involvement had any prognostic effect on the course of necrotising otitis externa in patients who had undergone hyperbaric oxygen therapy after failed medical and sometimes surgical therapy. METHODS: A retrospective case series was conducted of patients in whom antibiotic treatment and surgery had failed, who had been hospitalised for further treatment and hyperbaric oxygen therapy. RESULTS: Twenty-three patients with necrotising otitis externa were identified. The temporomandibular joint was involved in four patients (17 per cent); these patients showed a constant gradual improvement in C-reactive protein and were eventually discharged free of disease, except one patient who was lost to follow up. Four patients (16 per cent) without temporomandibular joint involvement died within 90 days of discharge, while all patients with temporomandibular joint involvement were alive. Three patients (13 per cent) without temporomandibular joint involvement needed recurrent hospitalisation including further hyperbaric oxygen therapy; no patients with temporomandibular joint involvement required such treatment. CONCLUSION: Patients with temporomandibular joint involvement had lower rates of recurrent disease and no mortality. Therefore, we suggest considering temporomandibular joint involvement as a positive prognostic factor in necrotising otitis externa management.

Professional karate-do and mixed martial arts fighters present with a high prevalence of temporomandibular disorders.

BACKGROUND/AIM: Facial trauma in sports has been associated with temporomandibular disorders. Because of the intensity and duration of training needed for elite-level competitions, high-performance athletes can have two to five times more traumatic injuries than recreational athletes. This study aimed to investigate the prevalence of temporomandibular disorders in high-performance martial arts fighters and compare it with the prevalence in recreational athletes and non-athletes. MATERIAL AND METHODS: The Research Diagnostic Criteria for Temporomandibular Disorders was used to diagnose and classify professional karate-do practitioners (group I; n = 24), amateur karate-do practitioners (group II; n = 17), high-performance mixed martial arts fighters (group III; n = 13), and non-athletes (n = 28). The groups were compared with the chi-square test and tested for the difference between two proportions using a significance level of 5% (P < 0.05). RESULTS: The prevalence of temporomandibular disorders in groups I (54.2%; P = 0.003) and III (61.5%; P = 0.002) was significantly higher than in group IV (14.3%). The prevalence in group II was similar to that in group IV (P > 0.05). A diagnosis of arthralgia from disk displacement was made more frequently in groups I (45.8%; P = 0.013) and III (38.5%; P = 0.012) than in group IV (7.1%). The chronic pain associated with TMD was low intensity and low disability. CONCLUSIONS: While there was a high prevalence of temporomandibular disorders in the professional athletes in our study, the prevalence of the condition in recreational athletes was similar to that in individuals who did not practice martial arts.

Manual reduction of articular disc after traumatic extraction of mandibular third molar: a case report.

INTRODUCTION: Disc displacement without reduction with limited opening is an intracapsular biomechanical disorder involving the condyle-disc complex. With the mouth closed, the disc is in an anterior position in relation to the condylar head and does not reduce with mouth opening. This disorder is associated with persistent limited mandibular opening. CASE REPORT: The patient presented severe limitation to fully open the mouth, interfering in her ability to eat. Clinical examination also revealed maximum assisted jaw opening (passive stretch) with less than 40 mm of maximum interincisal opening. Magnetic resonance imaging was the method of choice to identify the temporomandibular disorders. CONCLUSION: By means of reporting this rare case of anterior disc displacement without reduction with limited opening, after traumatic extraction of a mandibular third molar, in which manual reduction of temporomandibular joint articular disc was performed, it was possible to prove that this technique is effective in the prompt restoration of mandibular movements.

Manual reduction of articular disc after traumatic extraction of mandibular third molar: a case report

Introduction: Disc displacement without reduction with limited opening is an intracapsular biomechanical disorder involving the condyle-disc complex. With the mouth closed, the disc is in an anterior position in relation to the condylar head and does not reduce with mouth opening. This disorder is associated with persistent limited mandibular opening.Case report:The patient presented severe limitation to fully open the mouth, interfering in her ability to eat. Clinical examination also revealed maximum assisted jaw opening (passive stretch) with less than 40 mm of maximum interincisal opening. Magnetic resonance imaging was the method of choice to identify the temporomandibular disorders.Conclusion: By means of reporting this rare case of anterior disc displacement without reduction with limited opening, after traumatic extraction of a mandibular third molar, in which manual reduction of temporomandibular joint articular disc was performed, it was possible to prove that this technique is effective in the prompt restoration of mandibular movements.

Introdução: o deslocamento do disco articular sem redução com abertura limitada é uma desordem intracapsular que envolve o complexo côndilo-disco. Na posição de boca fechada, o disco articular se encontra numa posição anterior em relação à cabeça da mandíbula e não sofre redução com a abertura de boca. Essa desordem está associada à abertura mandibular limitada e persistente.Caso clínico:o paciente relatava travamento da mandíbula que não permitia uma abertura completa da boca, interferindo, assim, na capacidade de se alimentar. Também era possível observar-se uma abertura assistida (alongamento passivo) com uma distância vertical menor que 40 mm entre os incisivos. A ressonância magnética foi o método de escolha para o diagnóstico das desordens temporomandibulares.Conclusão:por meio da descrição de um caso raro de deslocamento anterior do disco articular sem redução e com abertura limitada, após exodontia traumática do terceiro molar inferior, em que foi realizada a redução manual do disco articular da articulação temporomandibular, provou-se ser essa uma técnica eficaz no rápido restabelecimento dos movimentos mandibulares.

Effect of dexamethasone prodrug on inflamed temporomandibular joints in juvenile rats.

INTRODUCTION: Juvenile idiopathic arthritis (JIA) often causes inflammation of the temporomandibular joint (TMJ) and has been treated with both systemic and intra-articular steroids, with concerns about effects on growing bones. In this study, we evaluated the impact of a macromolecular prodrug of dexamethasone (P-DEX) with inflammation-targeting potential applied systemically or directly to the TMJ. METHODS: Joint inflammation was initiated by injecting two doses of complete Freund's adjuvant (CFA) at 1-month intervals into the right TMJs of 24 growing Sprague-Dawley male rats (controls on left side). Four additional rats were not manipulated. With the second CFA injection, animals received (1) 5 mg of P-DEX intra-articularly (n = 9), (2) 15 mg of P-DEX into the tail vein (n = 7), or (3) nothing in addition to CFA (n = 8). The rats were killed 28 days later and measured by radiography for ramus height (condylar superior to gonion inferior [CsGoInf]), by micro-computed tomography for condylar width (CW) and bone volume/standardized condylar volume (BV/CV), and by histology for retrodiscal inflammatory cells. Inflammation targeting of systemic P-DEX was confirmed by IVIS infrared dye imaging. Inflammation and bone growth were compared between groups using analysis of variance and Pearson's correlations. RESULTS: CFA caused a significant reduction in CsGoInf (p < 0.05), but neither route of P-DEX administration had an effect on CsGoInf or CW at CFA injection sites. BV/CV was significantly reduced in both inflamed and control condyles as a result of either steroid application (p < 0.05). The inflammatory infiltrate was overwhelmingly lymphocytic, comprising 16.4 ± 1.3 % of the field in CFA alone vs. <0.01 % lymphocytes in contralateral controls (p < 0.0001). Both P-DEX TMJ (10.1 ± 1.2 %) and systemic P-DEX (8.9 ± 1.7 %) reduced lymphocytes (p < 0.002). The total area of inflammatory infiltrate was significantly less in the systemic injection group than in the group that received CFA injections alone (2.6 ± 1.5 mm(2) vs. 8.0 ± 1.3 mm(2); p = 0.009), but not in the group that received intra-articular P-DEX (8.8 ± 1.2 mm(2)). CONCLUSIONS: High-dose systemic administration of inflammation-targeting P-DEX is more effective than an intra-articular injection in reducing TMJ inflammation, but both routes may affect TMJ bone density.

Long-term results of ORIF of condylar head fractures of the mandible: A prospective 5-year follow-up study of small-fragment positional-screw osteosynthesis (SFPSO).

BACKGROUND: Optimum treatment of condylar head fractures (CHF) remains subject to controversy. There are currently a variety of alternative techniques applied, data in literature are often inconsistent and especially systematic long-term data on results after treatment by open reduction and internal fixation (ORIF) have so far not been available. This study in hand is the first long-term prospective study of ORIF after CHF based on osteosynthesis with 1.7 mm small-fragment positional screws (SFPSO)via a retroauricular transmeatal approach (RA). METHODS: The study made use of radiologic, anatomic and objective functional parameters (axiography and MRI) to assess vertical height, disk mobility, protrusive and translatory movement as well as potential physical complaints. Included were surgical long-term sequelae after RA, such as incidence of stenosis of the auditory canal, the facial nerve and resulting disturbance of facial skin sensitivity. Retroauricular scars were evaluated according to the Vancouver Scar Scale. Helkimo and RDC/TMD indices were applied for patient's self-assessment of quality of life aspects after ORIF via RA. The sample in the first follow-up trial (FFT) in the years 2003-2004 comprised 26 patients (36 CHF). 22 patients (31 CHF) were re-evaluated in a second follow-up trial (SFT) between 2006 and 2008. A reference collective (43 patients, 56 CHF) treated with ORIF from 1993 to 2000 mainly by mini- or microplates (MMP) served as a surgical control group. RESULTS: Five years after ORIF all fractured condyles (FC) continued to show stable anatomic restoration of the pre-trauma vertical height. FC treated with SFPSO exhibited a significantly superior range of motion (p < 0.05) of disk and condyle during mouth opening and protrusion compared to a previous MMP reference collective. Also, no difference was found between condylar mobility of FC five years after surgery and non-fractured condyles (NFC). SFPSO had thus successfully achieved a sustainable, stable physiological restoration of protrusive mobility of the articular disk and condyle. Remarkably, these long-term results were even slightly better in SFT vs. FFT (p < 0.05). Except for sporadically occurring minor complaints, the patients' subjective overall long-term perception of the success of the treatment was equally positive to the surgeons' objective assessment. CONCLUSIONS: This first long-term prospective follow-up study, based on objective assessment tools, demonstrates that in all cases the major goals of ORIF in CHF could be fully achieved. These goals are: restoration of vertical height viz. prevention of occlusal disorders, physiological function of disk and condyle as well as of the lateral pterygoid muscle. Accordingly, ORIF of CHF e.g. with SFPSO and via the RA secures both a long-term functionally and anatomically stable result and as best as possible pain-free result for the patient, a central prerequisite of optimum perceived HRQoL. The paper has been amended by an extensive review part that covers the current knowledge of the major surgical aspects regarding the treatment of condylar head fractures.

Electromyogram biofeedback training for daytime clenching and its effect on sleep bruxism.

Bruxism contributes to the development of temporomandibular disorders as well as causes dental problems. Although it is an important issue in clinical dentistry, no treatment approaches have been proven effective. This study aimed to use electromyogram (EMG) biofeedback (BF) training to improve awake bruxism (AB) and examine its effect on sleep bruxism (SB). Twelve male participants (mean age, 26·8 ± 2·5 years) with subjective symptoms of AB or a diagnosis of SB were randomly divided into BF (n = 7) and control (CO, n = 5) groups to undergo 5-h daytime and night-time EMG measurements for three consecutive weeks. EMG electrodes were placed over the temporalis muscle on the habitual masticatory side. Those in the BF group underwent BF training to remind them of the occurrence of undesirable clenching activity when excessive EMG activity of certain burst duration was generated in week 2. Then, EMGs were recorded at week 3 as the post-BF test. Those in the CO group underwent EMG measurement without any EMG BF training throughout the study period. Although the number of tonic EMG events did not show statistically significant differences among weeks 1-3 in the CO group, events in weeks 2 and 3 decreased significantly compared with those in week 1, both daytime and night-time, in the BF group (P < 0·05, Scheffé's test). This study results suggest that EMG BF to improve AB tonic EMG events can also provide an effective approach to regulate SB tonic EMG events.

Temporomandibular disorders: a human systems approach.

The face and associated cranial, oral and dental structures are among the most complicated areas of the body, contributing to an array of common orofacial disorders that include temporomandibular disorders (TMD), orofacial pain disorders and orofacial sleep disorders. This paper presents a broad, inclusive approach to diagnosis and management of TMD that reflects both conceptual models of human systems in understanding chronic illnesses as well as systematic reviews of treatment for successful management.

Case report of recurrent temporomandibular joint open lock associated with abrupt reduction of displaced articular disk.

PATIENT: This report describes the case of a 51-year-old male patient who initially presented at age 23 with a habitual intermittent open lock (at >35mm) in the left temporomandibular joint (TMJ). The patient was able to manage this affliction through rapid-repetition jaw opening and closing. Tomography of the joint showed no irregular morphology, but intraoral examination revealed an occlusal interference at the mandibular left third molar during leftwards excursion. For this patient, alteration of lateral guidance using a palatal plate attached to the maxillary left canine precluded this intermittent open lock, but at 22 years of age, the open lock recurred and could not be relieved by the patient, who was unable to assume an occlusal position. Because conservative treatment was ineffective, a pumping manipulation technique was applied to reduce the open lock, after which the patient has maintained good jaw function. MRI taken before and after repositioning indicated that abrupt reduction of a displaced articular disk was the cause of the open lock, and that this articular disk was restored to its proper position during the manipulation. DISCUSSION: Most TMJ open locks occur as anterior dislocation, where the mandibular head becomes trapped anterior to the articular eminences, causing excessive opening and difficulty closing. Our clinical findings from this patient indicate that open lock can occur through abrupt reduction of a displaced articular disk, particularly in patients with chronic internal derangement of the TMJ. CONCLUSION: TMJ open lock can occur following abrupt reduction of a displaced articular disk.

Chronic temporomandibular disorders are not necessarily associated with a compromised endogenous analgesic system.

AIMS: To test whether temporomandibular disorders (TMD) case-control differences in conditioned pain modulation (CPM) exist, using a mechanically evoked temporal summation (TS) model. METHODS: A series of 10 repetitive, mildly noxious, mechanical stimuli were applied to the fingers of 30 women with TMD, who had a primary diagnosis of masticatory myofascial pain, and 30 age-matched healthy women. The subjects rated the pain intensity caused by the 1st, 5th, and 10th stimuli in the series. To evaluate CPM, the same series of mechanical stimulations were applied with concomitant exposure of the other hand to a painfully cold water bath. Statistical inferences were based on t tests, chi-square tests, or analysis of variance (ANOVA), as appropriate. RESULTS: Pain ratings increased significantly with stimulus repetition (P < .01) and CPM significantly reduced TS of pain (P < .01). Of particular note, both groups showed very similar degrees of CPM, with no significant group difference. CONCLUSION: Painful TMD is not necessarily associated with a compromised ability to engage the endogenous analgesic system in an experimental setting.