Masticatory properties in pre-modern Holocene populations from Northern China.

Recent studies indicate that evolution of the craniofacial skeleton is influenced by dietary behavior, which in turn alters masticatory efficacy and temporomandibular joint (TMJ) stability. In this study the mechanical properties of the masticatory system and the integrity of the TMJ in human populations from Northern China, dated to between 3800 BCE and 100 CE, were assessed. The results demonstrate that the mechanical efficiency is comparable to other modern human populations, though variations are present across different populations. While the ratio of overall weighted muscle efficiency for incisor loading vs. molar loading in pastoral and some recent agricultural groups is similar to early Homo sapiens, the ratio in more ancient agricultural groups is similar to the ratio in populations with heavy anterior paramasticatory activities, such as Neandertals, Inuits, and Native Americans. The TMJ vulnerability negatively correlates with the maxillary dental arch size, and positively with the condylar size. These findings suggest that there are multi-directional strategies in adaptation to heavy anterior teeth loading, such as increasing anterior teeth loading efficiency, increasing facial height, increasing facial breath and facial orthognathy, or decreasing anterior facial length. Furthermore, populations or individuals with a smaller dental arch and high biting efficiency could more easily injure the TMJ during unilateral loadings, which may explain the higher prevalence of TMJ disorders in modern humans, especially in women. These findings further reflect the impact of diachronic changes of the masticatory apparatus and lifestyle and their impact on oral health during recent human history.

Reliability in Mandibular Movement Evaluation Using Photogrammetry in Patients With Temporomandibular Disorders.

OBJECTIVE: The purpose of this study was to propose a quantitative evaluation for mandibular opening-closing movement asymmetries and to verify the intraexaminer and interexaminer reliability using photogrammetry in individuals with and without myogenic temporomandibular disorders. METHODS: Forty-nine female participants between ages 18 and 40 were enrolled in this study. They were assigned to 2 different groups: a temporomandibular disorder group, (n = 25; 28.1 ± 3.6 years) and an asymptomatic group (n = 24; 25.6 ± 5.1 years). Data were collected through photogrammetry using Corel Draw X3 software (Corel Corp, Ottawa, Ontario, Canada) for angle measurements. Reliability analysis was done on the total sample, and the photographs were obtained by a singular examiner on 2 occasions (intraexaminer) 1 month apart and from measurement made by another examiner (interexaminer) on different days. The intraclass correlation coefficient (ICC) was applied with a significance level of 5%. RESULTS: The photogrammetry had excellent intrarater and inter-rater reliability for the evaluation of opening and closing movements of the jaw (intrarater: opening ICC = 0.99; closing ICC = 0.98; inter-rater: opening ICC = 0.89 and closing ICC = 0.82). Photogrammetry also demonstrated excellent intra- and inter-rater reliability in the evaluation of head posture (intra-rater: head deviation ICC = 0.96; head position ICC = 0.75; inter-rater: head deviation ICC = 0.98; head position ICC = 0.98). CONCLUSION: Under these experimental conditions, most angular values presented excellent intra- and interexaminer reliability.

Evidence - The intraoral palpability of the lateral pterygoid muscle - A prospective study.

The intraoral palpability of the inferior caput of the lateral pterygoid muscle has been a matter of ambiguity because of its topography. Thus, none of the recently published studies has provided reliable proof of the possibility of digital intraoral palpation, although palpation of the muscle is part of most of the examination catalogs for clinical functional analysis and functional therapy. Digital muscle palpation was performed intraorally on five preparations after exposure of the infratemporal fossa and visualization of the lateral pterygoid muscle. Direct digital palpation of the lateral pterygoid muscle was seen in all five cases. The successful palpation was carried out and approved during laterotrusion to the examined side (relaxation). While opening and closing the mouth (contraction) the muscle is palpable. In real-time kinematic measurements (MRI) an impression of the lateral caput of the left lateral pterygoid muscle of a 30-year-old control male person was found up to 6mm. Electromyographic detection by direct signal conduction with concomitant palpation is possible. The injection electrode tested in situ in the muscle was felt transorally with the palpating finger. The intraoral palpability of the inferior caput of the lateral pterygoid muscle is verified. The basic requirement for successfully palpating the lateral pterygoid muscle is the exact knowledge of muscle topography and the intraoral palpation pathway. After documented palpation of the muscle belly in cadaverous preparations, MRI and EMG also visualized palpation of the lateral pterygoid muscle in vivo. The palpation technique seems to be essential and basically feasible.

Local group I mGluR antagonists reduce TMJ-evoked activity of trigeminal subnucleus caudalis neurons in female rats.

Group I metabotropic glutamate receptors (mGluR1 and mGluR5) are functionally linked to estrogen receptors and play a key role in the plasticity of central neurons. Estrogen status strongly influences sensory input from the temporomandibular joint (TMJ) to neurons at the spinomedullary (Vc/C1-2) region. This study tested the hypothesis that TMJ input to trigeminal subnucleus caudalis/upper cervical cord (Vc/C1-2) neurons involved group I mGluR activation and depended on estrogen status. TMJ-responsive neurons were recorded in superficial laminae at the Vc/C1-2 region in ovariectomized (OvX) female rats treated with low-dose estradiol (2 µg/day, LE) or high-dose estradiol (20 µg/day, HE) for 2 days. TMJ-responsive units were activated by adenosine triphosphate (ATP, 1mM) injected into the joint space. Receptor antagonists selective for mGluR1 (CPCCOEt) or mGluR5 (MPEP) were applied topically to the Vc/C1-2 surface at the site of recording 10 min prior to the intra-TMJ ATP stimulus. In HE rats, CPCCOEt (50 and 500 µM) markedly reduced ATP-evoked unit activity. By contrast, in LE rats, a small but significant increase in neural activity was seen after 50 µM CPCCOEt, while 500 µM caused a large reduction in activity that was similar in magnitude as that seen in HE rats. Local application of MPEP produced a significant inhibition of TMJ-evoked unit activity independent of estrogen status. Neither mGluR1 nor mGluR5 antagonism altered the spontaneous activity of TMJ units in HE or LE rats. High-dose MPEP caused a small reduction in the size of the convergent cutaneous receptive field in HE rats, while CPCCOEt had no effect. These data suggest that group I mGluRs play a key role in sensory integration of TMJ nociceptive input to the Vc/C1-2 region and are largely independent of estrogen status.

One-stage treatment to osteochondroma of the coronoid process and secondary facial asymmetry with coronoidectomy and reduction malarplasty: a case report and literature review.

PURPOSE: This study summarizes the literature concerning osteochondroma of the mandibular coronoid process and presents a case of 1-stage treatment for this condition and concomitant facial asymmetry. MATERIALS AND METHODS: A 20-year-old man presented with osteochondroma of the mandibular coronoid process. Radiologic images showed a mushroom-shaped coronoid growth inside the zygomatic arch with outward expansion. Coronoidectomy and reduction malarplasty were performed in 1 stage. The literature on osteochondroma of the mandibular coronoid process since 1943 was reviewed concerning etiology, pathogenesis, clinical characteristics, diagnosis, and treatment. RESULTS: At 20-month follow-up, the patient achieved markedly improved joint function and a symmetric facial appearance after excision of the osteochondroma. CONCLUSION: Coronoidectomy combined with simultaneous reduction malarplasty could be an alternative and promising method to treat osteochondroma of the coronoid process with secondary facial asymmetry.

Comprehensive treatment of temporomandibular joint disorders.

AIMS: Changing lifestyles, decreasing physical activity, which is increasing the number of degenerative joint diseases of various etiology, and certain dental procedures are increasing the number of patients complaining of pain in their temporomandibular joints. The aim of the study was to assess the benefits of comprehensive physiotherapy sessions in order to decrease the number of temporomandibular joint problems, thereby improving the patient's quality of life. METHODOLOGY: An examination by a dentist determined each patient's treatment plan, which consisted of a medical exam, physical therapy and education. Each form of treatment was applied 10 times at intervals of 7-14 days. The main goal of the therapeutic physical education was to redress the muscle imbalance in the mandibular joint. This was achieved by restoring balance between the masticatory muscles, along with releasing the spastic shrouds found in the masticatory muscles. The aim of education was to teach the patient exercises focused on the temporomandibular joint and masticatory muscles. The intensity of the exercises and their composition were individually adjusted and adapted to their current state. Physical therapy consisted of the application of pulsed magnetic therapy, laser therapy, and non-invasive positive thermotherapy. RESULTS: The above procedure was conducted on a therapeutic group of 24 patients (3 men and 20 women). In the course of therapy, there were no complications, and all patients adhered to the prescribed regime. None reported any side effects. The mean treatment duration was 123 +/- 66 days. The outcome of the therapy was evaluated as described in the methodology, the degree of pain affecting the joint, and the opening ability of the mouth. In both parameters, there was a significant decline in patient pain. CONCLUSIONS: In a study devoted to tactics of rehabilitation treatment for temporomandibular joint disorders, the need for comprehensive long-term therapy, involving education, and learning proper chewing habits was made apparent for recovery and pain reduction. A priority in physical therapy, and combinations of pulsed magnetic therapy and hyperthermia-positive peloids, are also beneficial.

Orthodontic-surgical treatment: neuromuscular evaluation in skeletal Class II and Class III patients.

OBJECTIVES: The aim of this study was the evaluation of the neuromuscular response to treatment according to diagnostic phases, as a follow-up of patients under surgical orthodontic treatment. The patient sample was subdivided into sub-samples, according to clinical characteristics. MATERIALS AND METHODS: All of the patients who underwent orthognathic surgery in the Department of Orthodontics (University of Milan) were subjected to periodic electromyographic evaluation of the masticatory muscles (masseter and anterior temporal muscles), and to electrokinesiographic evaluation of the mandibular movements. The patient sample comprised 80 patients (37 males; and 43 females) at the end of growth. The electromyographic instruments used in the study included a Freely and a K6-I electromyography. Statistical evaluation was carried out with the Student's t-tests for independent samples. RESULTS: There are many differences between the skeletal Class II and skeletal Class III patients that are shown through the analysis of these data obtained. In the beginning phases of the treatment the muscular activities were higher in the Class II patients than in the Class III patients. Nevertheless this difference was reversed at the end of the treatment. A similar difference could be found in the mandibular kinesiology, in fact the maximum mandibular opening movement was greater in the skeletal Class II patients than in the skeletal Class III patients at the beginning of the treatment. At the end of the treatment this difference was lost. At the beginning of the treatment the Class II patients showed a greater protrusive movement of the mandibular than the Class III patients. At the end the treatment however this gap was reduced without being reversed. CONCLUSIONS: Functional evaluation in patients in surgical orthodontic therapy is an important element in the diagnostic-therapeutic recordings, so as to reduce as much as possible any incorrect neuromuscular activity that can result in relapse.

Differential ascending projections of temporomandibular joint-responsive brainstem neurons to periaqueductal gray and posterior thalamus of male and female rats.

Several craniofacial pain conditions, including temporomandibular joint disorders (TMJDs), are more prevalent in women than men. The basis for sex differences in deep craniofacial pain is not known. The present study compared the magnitude of ascending projections from temporomandibular joint (TMJ)-responsive neurons in trigeminal brainstem with the ventrolateral periaqueductal gray (vlPAG) or posterior nucleus of the thalamus (Po) in males and female rats. Fluorogold (FG) was injected into vlPAG or Po, and TMJ-responsive neurons were identified by Fos-like immunoreactivity (Fos-LI) after mustard oil injection. TMJ-evoked Fos-LI was similar in males and females; however, significant differences in cell counts were seen for FG single-labeled and Fos/FG double-labeled neurons in trigeminal brainstem. After vlPAG injections, the number of FG-labeled neurons in trigeminal subnucleus interpolaris (Vi), ventral interpolaris/caudalis transition (vl-Vi/Vc), and dorsal paratrigeminal region (dPa5) was greater in females than males. The percentage of Fos/FG double-labeled neurons in vl-Vi/Vc and dPa5 after vlPAG injection also was greater in females than males. In contrast, after Po injections, males displayed a greater number of FG-labeled neurons in superficial laminae (Lam I/II) of trigeminal subnucleus caudalis (Vc) and upper cervical spinal cord (C(1-2)) and deeper laminae (Lam III/V) at C(1-2) than females. The percentage of Fos/FG double-labeled neurons in Lam I/II of Vc after Po injection also was greater in males than females. These data revealed significant sex differences in ascending projections from TMJ-responsive neurons in trigeminal brainstem. Such differences may influence the ability of males and females to recruit autonomic reflexes and endogenous pain control circuits relevant for TMJ nociception.

The relationship between dental occlusion/temporomandibular joint status and general body health: part 2. Fascial connection of TMJ with other parts of the body.

In part 1 of this study, it was discussed that dental occlusion/temporomandibular joint (TMJ) status is functionally connected to general body health. The purpose of this part of the study was to attempt to formulate a conceptual account, the "fascial connection theory for TMJ and other parts of the body," to explain the functional connection between TMJ and other parts of the body. The first hypothesis that was studied is that TMJ and other parts of body are connected through the fascia as asserted by the myofascial-release schools, and the second one is that they are connected through the meridian system constituted of fascia (connective tissue). The fascial connection theory proposed here can explain the functional connection between dental occlusion/TMJ and other parts of the body based on either myofascial release or the qi and meridian system, or a combination of the two. Therefore, dental occlusion should be built up and maintained in a normal natural condition, and causes of deterioration of TMJ status should be treated in an effort to restore the natural condition. Other possible mechanisms that can account for these connections require elucidation, and additional experimental investigation should be undertaken.

The influence of auditory and visual information on the neuromuscular control of chewing crispy food.

The influence of auditory and/or visual information on the neuromuscular control of chewing a crispy food was investigated. Participants chewed biscuits of three different levels of crispness under four experimental conditions: no masking, auditory masking, visual masking, and auditory plus visual masking. The order of the four masking condition blocks was randomized. The sound of chewing was masked by loud sounds on a headphone, and visual masking of the food was achieved by closing the eyes. Mechanical tests were performed on the biscuits to determine their characteristics, yield force, and sound production. Skull vibration, jaw-muscle activity, and jaw movement were measured while the subjects chewed and swallowed the food. Auditory and/or visual masking did not have a significant effect on skull vibration, muscle activity, and number of chewing cycles until swallowing. However, auditory and/or visual masking significantly increased the chewing cycle duration, but only for the participants who started the experiments with auditory and/or visual masking. The other participants were not influenced by masking. The memory of the unmodified stimuli helped these subjects to maintain their habitual chewing rate in later trials.

[Dentofacial Orthopedics to treat facial asymmetries before six years of age. How to balance craniofacial growth and enhance temporomandibular function]. / Traiter orthopédiquement les asymétries avant six ans ou comment symétriser la croissance cranio-faciale et optimiser le fonctionnement temporo-mandibulaire.

Minor facial asymmetries that can be detected in newborn infants indicate that facial growth for this child will also be asymmetric. When practitioners observe a displacement of the mandible in temporary dentition it probably indicates the presence of asymmetric masticatory function and they should look for an inter-temporal axial asymmetry by tracing cutaneous landmarks in the vicinity of the external ears. If they find the possible presence of asymmetric remodeling of glenoid fossas, they have to anticipate future temporo-mandibular disorders. By using a measurement grid (Orthogrille type) placed on the teeth of the upper plaster cast, they can assess sagittal and transverse status of the temporary teeth. If indicated, they can use acrylic plates fitted with sectional distalizing or expansion screws designed for full or partial arch correction. They can also modify the upper occlusal plane inclination by using acrylic bite blocks that keep all of the teeth from occluding and thus allow the displaced mandible to return to symmetrical movements during mastication and at the same time allow the temporal bones to remodel symmetrically. Finally, they can re-center the two dental arches and their midlines with a Frankel re-centering device that will also restore harmony to respiratory and vocalization functions. Thanks to this type of orthopedic treatment carried out for patients before they reach the age of six the asymmetric direction of their facial growth will become normal and the functioning of their temporo-mandibular joints will become optimal.

P2X and NMDA receptor involvement in temporomandibular joint-evoked reflex activity in rat jaw muscles.

We have previously shown that injection of the excitatory amino glutamate into the rat temporomandibular joint (TMJ) evokes reflex activity in both anterior digastric (DIG) and masseter (MASS) muscles that can be attenuated by prior TMJ injection of an N-methyl-d-aspartate (NMDA) receptor antagonist. The aim of the present study was to test if jaw muscle activity could also be evoked by P2X receptor agonist injection into the rat TMJ region and if the reflex activity could be modulated by TMJ injection of P2X receptor antagonist or NMDA receptor antagonist. The selective P2X subtype agonist alpha,beta-methylene adenosine 5'-triphosphate (alpha,beta-me ATP) and vehicle (phosphate-buffered saline) or the selective P2X antagonist, 2'-(or-3')-O-(2,4,6-trinitrophenyl) adenosine 5'-triphosphate (TNP-ATP) or the selective NMDA antagonist (+/-)-d-2-amino-5-phosphonovalerate(APV) were injected into the rat TMJ region. Electromyographic (EMG) reflex activity was recorded in both DIG and MASS muscles. Compared with the baseline EMG activity, alpha,beta-me-ATP injection into the TMJ (but not its systemic administration) following pre-injection of the vehicle significantly increased the magnitude and the duration of ipsilateral DIG and MASS EMG activity in a dose-dependent manner. The alpha,beta-me-ATP-evoked responses could be antagonized by pre-injection of TNP-ATP into the same TMJ site but contralateral TMJ injection of TNP-ATP proved ineffective. Furthermore, the alpha,beta-me-ATP-evoked responses could also be antagonized by APV injected into the same TMJ site but not by its systemic injection. These results indicate the interaction of peripheral purinergic as well as glutamatergic receptor mechanisms in the processing of TMJ nociceptive afferent inputs that evoke reflex activity in jaw muscles.

Effects of the myofascial release in diffuse systemic sclerosis.

OBJECTIVE: To improve breathing and functionality of the temporomandibular joint (TMJ) and hands, by increasing the range of motion (ROM), and to reduce the level of pain. METHOD: Twenty myofascial release (MR) sessions in 2002 with assessments (chest expansion, mouth opening, ROM of wrist and fingers). Between the 19th and the 20th session there was a break of 110 days. Every winter, 1-3 sessions have been made. RESULTS: Chest: expansion increased by 3.5 cm and pain was eliminated at the scar from a biopsy; TMJ: an 8mm increase in mouth opening with pain eliminated; hands and fingers: increase of ROM in all joints of fingers and wrists, of up to 100%, reduction in ulcerations and recovery of nail growth. CONCLUSION: The connective tissue affected by diffuse systemic sclerosis (dSSc) is subject to remodeling through MR, receding when the work is interrupted. Resuming the treatment on a regular basis increased the ROM in joints, reduced the effects of the Raynaud Phenomenon and the pain.

Comparative study of intermaxillary relationships of manual and swallowing methods.

This study compared the mandibular displacement from three methods of centric relation record using an anterior jig associated with (A) chin point guidance, (B) swallowing (control group) and (C) bimanual manipulation. Ten patients aged 25-39 years were selected if they met the following inclusion criteria: complete dentition (up to the second molars), Angle class I and absence of signs and symptoms of temporomandibular disorders and diagnostic casts showing stability in the maximum intercuspation (MI) position. Impressions of maxillary and mandibular arches were made with an irreversible hydrocolloid impression material. Master casts of each patient were obtained, mounted on a microscope table in MI as a reference position and 5 records of each method were made per patient. The mandibular casts were then repositioned with records interposed and new measurements were obtained. The difference between the two readings allowed measuring the displacement of the mandible in the anteroposterior and lateral axes. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant differences (p>0.05) among the three methods for measuring lateral displacement (A=0.38 +/- 0.26, B=0.32 +/- 0.25 and C=0.32 +/- 0.23). For the anteroposterior displacement (A=2.76 +/- 1.43, B=2.46 +/- 1.48 and C=2.97 +/- 1.51), the swallowing method (B) differed significantly from the others (p<0.05), but no significant difference (p>0.05) was found between chin point guidance (A) and bimanual manipulation (C). In conclusion, the swallowing method produced smaller mandibular posterior displacement than the other methods.

Comparative study of intermaxillary relationships of manual and swallowing methods

This study compared the mandibular displacement from three methods of centric relation record using an anterior jig associated with (A) chin point guidance, (B) swallowing (control group) and (C) bimanual manipulation. Ten patients aged 25-39 years were selected if they met the following inclusion criteria: complete dentition (up to the second molars), Angle class I and absence of signs and symptoms of temporomandibular disorders and diagnostic casts showing stability in the maximum intercuspation (MI) position. Impressions of maxillary and mandibular arches were made with an irreversible hydrocolloid impression material. Master casts of each patient were obtained, mounted on a microscope table in MI as a reference position and 5 records of each method were made per patient. The mandibular casts were then repositioned with records interposed and new measurements were obtained. The difference between the two readings allowed measuring the displacement of the mandible in the anteroposterior and lateral axes. Data were analyzed statistically by ANOVA and Tukey's test at 5 percent significance level. There was no statistically significant differences (p>0.05) among the three methods for measuring lateral displacement (A=0.38 ± 0.26, B=0.32 ± 0.25 and C=0.32 ± 0.23). For the anteroposterior displacement (A=2.76 ± 1.43, B=2.46 ± 1.48 and C=2.97 ± 1.51), the swallowing method (B) differed significantly from the others (p<0.05), but no significant difference (p>0.05) was found between chin point guidance (A) and bimanual manipulation (C). In conclusion, the swallowing method produced smaller mandibular posterior displacement than the other methods.

Este estudo comparou o deslocamento mandibular a partir de 3 métodos de registro da relação cêntrica usando um jig anterior associado com: (A) guia da ponta do mento; (B) deglutição grupo controle (C) manipulação bimanual. As moldagens dos arcos maxilares e mandibulares foram feitas com hidrocolóide irreversível. Os modelos de estudo de cada paciente foram obtidos e montados em máxima intercuspidação como uma posição de referência no microscópio. Foram obtidos 5 registros de cada método em 10 pacientes. Os modelos mandibulares foram reposicionados com os registros interpostos e novas medidas foram obtidas. A diferença entre as duas leituras permitiu a medida do deslocamento mandibular nos eixos ântero-posterior e laterais. ANOVA não demonstrou diferença estatisticamente significativa entre os 3 métodos em relação ao registro do deslocamento lateral (A = 0,38 ± 0,26, B = 0,32 ± 0,25 e C = 0,32 ± 0,23). Quanto ao deslocamento anteroposterior, ANOVA e o teste de Tukey (a=0,05) indicaram diferença estatisticamente significante entre os três métodos (A=2,76 ± 1,43, B=2,46 ± 1,48 e C=2,97 ± 1,51). Não houve diferença estatisticamente significante entre A e C. A deglutição propiciou menor deslocamento mandibular posterior que os outros métodos.

Jaw clenching: muscle and joint forces, optimization strategies.

Realistic masticatory muscle and temporomandibular joint forces generated during bilateral jaw clenching are largely unknown. To determine which clenching directions load masticatory muscles and temporomandibular joints most heavily, we investigated muscle and joint forces based on feedback-controlled electromyograms of all jaw muscles, lines of action, geometrical data from the skull, and physiological cross-sectional areas acquired from the same individuals. To identify possible motor control strategies, we applied objective functions. The medial pterygoid turned out to be the most heavily loaded muscle for all bite directions. Biting with accentuated horizontal force components provoked the highest loading within the medial and lateral pterygoids. The largest joint forces were also found for these bite directions. Conversely, the lowest joint forces were detected during vertical biting. Additionally, joint forces with a clear posterior orientation were found. Optimization strategies with the elastic energy as objective function revealed the best fit with the calculated results.

A systematic review of the effectiveness of physical therapy interventions for temporomandibular disorders.

BACKGROUND AND PURPOSE: The purpose of this qualitative systematic review was to assess the evidence concerning the effectiveness of physical therapy interventions in the management of temporomandibular disorders. METHODS: A literature search of published and unpublished articles resulted in the retrieval of 36 potential articles. RESULTS: Twelve studies met all selection criteria for inclusion in the review: 4 studies addressed the use of therapeutic exercise interventions, 2 studies examined the use of acupuncture, and 6 studies examined electrophysical modalities. Two studies provided evidence in support of postural exercises to reduce pain and to improve function and oral opening. One study provided evidence for the use of manual therapy in combination with active exercises to reduce pain and to improve oral opening. One study provided evidence in support of acupuncture to reduce pain when compared with no treatment; however, in another study no significant differences in pain outcomes were found between acupuncture and sham acupuncture. Significant improvements in oral opening were found with muscular awareness relaxation therapy, biofeedback training, and low-level laser therapy treatment. DISCUSSION AND CONCLUSION: Most of the studies included in this review were of very poor methodological quality; therefore, the findings should be interpreted with caution.

Short- and long-term efficacy of brief cognitive-behavioral therapy for patients with chronic temporomandibular disorder pain: a randomized, controlled trial.

We evaluated the short- and long-term efficacy of a brief cognitive-behavioral therapy (CBT) for chronic temporomandibular disorder (TMD) pain in a randomized controlled trial. TMD clinic patients were assigned randomly to four sessions of either CBT (n=79) or an education/attention control condition (n=79). Participants completed outcome (pain, activity interference, jaw function, and depression) and process (pain beliefs, catastrophizing, and coping) measures before randomization, and 3 (post-treatment), 6, and 12 months later. As compared with the control group, the CBT group showed significantly greater improvement across the follow-ups on each outcome, belief, and catastrophizing measure (intent-to-treat analyses). The CBT group also showed a greater increase in use of relaxation techniques to cope with pain, but not in use of other coping strategies assessed. On the primary outcome measure, activity interference, the proportion of patients who reported no interference at 12 months was nearly three times higher in the CBT group (35%) than in the control group (13%) (P=0.004). In addition, more CBT than control group patients had clinically meaningful improvement in pain intensity (50% versus 29% showed > or =50% decrease, P=0.01), masticatory jaw function (P<0.001), and depression (P=0.016) at 12 months (intent-to-treat analyses). The two groups improved equivalently on a measure of TMD knowledge. A brief CBT intervention improves one-year clinical outcomes of TMD clinic patients and these effects appear to result from specific ingredients of the CBT.

Unilateral application of an inflammatory irritant to the rat temporomandibular joint region produces bilateral modulation of the jaw-opening reflex.

The aim of this study was to determine the effect of unilateral acute inflammation of craniofacial deep tissues on the ipsilateral and contralateral jaw-opening reflex (JOR). The effects of mustard oil (MO), injected into the temporomandibular joint region, were tested on the JOR recorded in the digastric muscle and evoked by low-intensity electrical stimulation of the ipsilateral and contralateral inferior alveolar nerve in anesthetized rats. The MO injection induced a long-lasting suppression of the amplitude of both ipsilaterally and contralaterally evoked JOR, although the latency and duration of the JOR were unaffected. The suppressive effect was more prominent for the contralaterally evoked JOR, and observed even when background activity in the digastric muscle was increased by the MO injection. The results indicate that changes in the JOR amplitude following MO injection do not simply reflect alterations in motoneuronal excitability, and suggest that inflammation of deep craniofacial tissues modulates low-threshold sensory transmission to the motoneurons.