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Objective: The purpose of this study was to assess the effects of 4-week protocol of diacutaneous fibrolysis (DF) compared with simulated DF (sham-DF) on myalgia and mouth opening., Methods: In a sham randomized controlled trial, 34 women with temporomandibular disorders and myofascial pain were randomly divided as intervention group (IG) and sham-DF group (SG). The IG received 4 weeks of real DF, and the SG received sham. Pain was assessed through the visual analog scale and pressure pain thresholds (PPTs) on the temporomandibular joint (TMJ), and over the temporal and masseter muscles. The Mandibular Function Impairment Questionnaire was used to classify the participants regarding to the severity of the functional limitation related to TMD., Results: Pain scores decreased for both groups, but the IG showed lower values at week 4, with between-group differences. Bilateral temporal PPT showed higher values at week 4, with between-group differences. The SG had lower PPTs but the IG had higher PPTs, both compared to baseline results. The time-by-group interaction and the frequency of participants above 40 mm of mouth opening showed a significant difference for the IG over time with higher results at the 4-week assessment compared to its own baseline. Both groups showed lower MFIQ scores from baseline to 4-week assessment. There was a lower frequency of a moderate level of severity for the IG. No differences were observed for TMJ or for the masseter muscles PPT., Conclusion: Improvements were observed for visual analog scale scores and PPTs on temporal muscles. There was a group-by-time interaction in the IG, suggesting a possible potential use of DF for mouth opening., (Copyright © 2020. Published by Elsevier Inc.)

Orthognathic surgery is a useful treatment for the correction of mandibular deformity. Different from other occlusions, unilateral occlusion is frequently used in mastication and influences functions of temporomandibular joints (TMJs). However, stress distributions in TMJ before and after orthognathic surgeries are not under consideration in treatments, crucial to pre- and postoperative temporomandibular disorders (TMDs). The study aims to analyze stress distributions in TMJs for patients with mandibular asymmetry before and after orthognathic surgeries under the unilateral molar clenching. Ten asymptomatic subjects (control group) and 10 patients with mandibular asymmetry were recruited for the study. All patients underwent orthognathic surgeries and were grouped as preoperative and postoperative for the purpose of comparing stress variation in TMJ before and after surgery. Finite element models corresponding to the unilateral molar clenching were constructed. The contact stresses at the ipsilateral side for asymptomatic subjects were significantly greater than those at the contralateral side, while the third principal stresses at the contralateral side were significantly greater than those at the ipsilateral side. No significant difference of stress distribution in TMJ between two sides appeared for the preoperative group. After surgeries, the stress distributions were close to the normal states. The stress of the preoperative group was found to be significantly higher than those of the control and postoperative groups. The variations in stresses before and after the surgery were consistent with the signs and symptoms or recoveries of TMD. Orthognathic surgery could alleviate the high level of stresses caused by mandibular asymmetry and is helpful for the recovery of TMD.

Purpose: This study aimed to analyze the changes of the stress distributions in TMJs for the pre- and postoperative patients with mandibular prognathism under unilateral occlusions, a frequent occlusion in mastication., Methods: Pre- and six-mouth postoperative cone-beam computed tomography images of thirteen patients diagnosed with mandibular prognathism were scanned and used to construct complete maxillofacial models, assigned as the Pre and Post group, respectively. Another ten asymptomatic individuals were defined as the Control group. The inhomogeneous properties were assigned to the models. The muscle forces and boundary conditions corresponding to left and right unilateral occlusions were applied on the models. The analysis of variation (ANOVA) was chosen for the comparison among the groups., Results: The results showed that the Pre group had abnormal stress distributions ang higher stress level in TMJs, compared with those of the Post and Control groups. Moreover, from clinical cases, symptoms of temporomandibular disorders (TMDs) always followed with increased stresses., Conclusion: Generally, orthognathic surgeries could improve the stress distribution in TMJs of the patients with mandibular prognathism under the unilateral occlusions. However, the postoperative complications, especially symptoms of TMD, were closely related to changes of stress for patients with mandibular prognathism after orthognathic surgeries. Individual virtual surgery and finite element analysis should be conducted to prevent complications in TMJ.

There is large support in literature linking tinnitus to dental occlusion and temporomandibular joint disorders (TMD). However, there is no model to explain such a link. This hypothesis explains how the fusimotor system of the muscles innervated by the trigeminal motor nucleus is affected by inadequacies in the occlusion of the teeth that cause changes in posture and movement of the mandible. Reptile to mammal evolution shows that stomatognathic structures underwent changes related to mastication. Among several changes, there was the appearance of a new articulation between the mandible and skull: the temporomandibular joint. The bones of the old reptile joint, quadrate-articular, have detached from the mandible and are part of the middle ear bone chain. The former becomes the incus and the latter the malleus. This bone change also carried the tensor tympani and its trigeminal motor innervation. Inadequate occlusal contacts give rise to an adapted function of the mandible and the most common compensatory muscular response is hypertonia involving all mandibular muscles, including the tensor tympani. A fundamental clinical feature that demonstrates the involvement of the trigeminal fusimotor system is the characteristic pain by palpation, but no pain on the mandibular movement. Muscle pain is always felt in the dermatome innervated by the mandibular branch of the trigeminal nerve, which carries the motor fibers, reported as tightening, similar to cramp, and has regular behavior in intensity, duration and frequency. In addition, the patient has increased musculature volume, detected by palpation of certain anatomical landmarks, but with loss of functional efficiency. The neuromotor control of the mandibular movements is poor and when asked to make lateral jaw movement touching the teeth, it is common to observe that the patient moves the lips, eyes, and even turns the head in the same direction as the movement. There is also difficulty eating hard foods and talking fast. Tongue biting while chewing is frequent, meaning that these non-physiological events surpass protective reflex circuits. The report of ear pain, tinnitus, blocked ear sensation and sudden hearing loss is common in such patients, compatible with the tonic contraction of the tensor tympani. The fusimotor system hypothesis is able to explain all events related to the symptoms and helps to establish a correct diagnosis for certain types of hearing disorders., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Temporomandibular joint (TMJ) ankylosis is a refractory disease that is difficult to predictably treat. This study evaluated the prognosis of using standard alloplastic TMJ prostheses for the treatment of TMJ ankylosis in Chinese patients with severe mandibular deficiency. Patients treated from 2013 to 2015 were reviewed. The computer-aided design and manufacture (CAD/CAM) technique was used to guide bony mass removal and locate the TMJ prosthesis (Biomet, USA). Eleven patients were included in this study. All prostheses were successfully installed and stabilized intraoperatively. In 4 patients with severe mandibular deficiency, their mandibular ramus was elongated by the TMJ prosthesis and 2 patients were combined with Le Fort I osteotomy guided by digital templates. Their mean chin advancement was 10.19 mm. Their SNB and ramus heights were also significantly improved after operation (P < 0.05). There was no prosthesis loosening, breakage, or infection leading to removal after a mean follow-up period of 22 months (range, 12-31mos.). Mouth opening was significantly improved from 5.5 mm preoperatively to 31.5 mm postoperatively. TMJ reconstruction with standard alloplastic prosthesis is a reliable treatment for ankylosis, especially in recurrent cases. By CAD/CAM technique, it can correct jaw deformities simultaneously and produce stable results.

Objective: To evaluate the changes in the jaws and the upper airways of unilateral temporomandibular joint ankylosis patients who underwent condylar reconstruction via autogenous coronoid process grafts using cone-beam computed tomography (CBCT)., Study Design: The 27 included patients underwent CBCT examinations at three stages: T0 (within two weeks before surgery), T1 (two weeks after surgery), and T2 (an average of 13 months after surgery). Forty items related to the maxillofacial hard tissues and the upper airway collected at the three times and the coronoid process graft volumes after surgery were compared., Results: Some integral items related to the mandibular hard tissues exhibited statistical difference shortly after surgery. Some integral items related to maxillofacial hard tissues changing obviously long period after surgery may result from graft remodeling. Asymmetry-related item regarding local neo-condyle and some airway items were significantly different between T0 and T1. Due to variations in graft remodeling, some related local asymmetry items and airway items differed significantly between T0 and T2., Conclusions: Anteriorly and inferiorly located neo-condyles and a trend toward the pronation of the mandible were observed and the narrowness of the upper airway was improved shortly after surgery. The grafts remodeled differently and some integral and asymmetry items related to neo-condyle changed. The improvements in the upper airway were slightly reduced.

Aims: To test the hypothesis that prolonged jaw opening, as can occur during routine dental procedures, increases nociceptive sensitivity of the masseter muscle and increases cytokine expression., Methods: Sprague-Dawley rats were used to investigate behavioral and cellular changes in response to prolonged jaw opening. A surgical retractor was placed around the maxillary and mandibular incisors, and the jaw was held at near maximal opening for 20 minutes. Head-withdrawal responses to mechanical stimuli applied to the facial skin overlying the left and right masseter muscles were determined following jaw opening. Cytokine levels in the upper cervical spinal cord containing the caudal part of the spinal trigeminal nucleus were evaluated using protein antibody microarrays (n = 3). Statistical analysis was performed using a nonparametric Mann-Whitney U test., Results: Prolonged jaw opening significantly increased nocifensive head withdrawal to mechanical stimuli at 2 hours, and days 3 and 7 postinduction (P < .05). The increase in nociceptive response resolved after 14 days. Sustained jaw opening also stimulated differential cytokine expression in the trigeminal ganglion and upper cervical spinal cord that persisted 14 days postprocedure (P < .05)., Conclusion: These findings provide evidence that near maximal jaw opening can lead to activation and prolonged sensitization of trigeminal neurons that results in nociceptive behavior evoked by stimulation of the masseter muscle, a physiologic event often associated with temporomandibular disorders (TMD). Results from this study may provide a plausible explanation for why some patients develop TMD after routine dental procedures that involve prolonged jaw opening.

The Purpose of the Paper: Qualitative and quantitative analysis of selected parameters of mandible movements, electronically registered in patients with temporomandibular joint dysfunction and healthy ones., Material: Function test of the mandible movements was conducted in 175 patients. Gender distribution was 143 women and 32 men, aged 9 to 84., Methods: The studied population, after accurate clinical examination, was divided into age groups with the range of five years. All the patients had Zebris JMA computerized facebow examination done, according to the generally accepted principles and procedures., Results: Mean values of mouth opening calculated to 45.6 mm in healthy group and 37.6 mm in TMJ dysfunction group. Mean length of condylar path amounted to 39 ± 7% of the maximum value of mouth opening in the group of healthy people, 44 ± 11% in the case of muscle-based disorders, and 35 ± 11% with joint-based. The mean value of the condylar path inclination oscillated in the range of 25° to 45°., Conclusions: The ratio of length of the condylar path to the size of mouth opening may be a significant value characterising the type and degree of intensification of the TMJ dysfunctions.

A 3D finite element model of an in vitro implanted mandible was analysed. The load point was placed on the condyle in three positions (inside the mouth, centred and outside) to simulate different contact points between the mandible condyle and the temporal bone. The strain fields in the condyle were assessed and detailed around the surgical screws. The temporomandibular implant studied here was modelled on a commercial device that uses four screws to fix it in vivo in a very similar position. The boundary conditions of the numerical model simulated a load on the incisors with a 15 mm mouth aperture. The same contact loads were applied to the two condyles. Numerical results were successfully obtained for the three different contact points: the inside contact produced lower strains on the condyle. The first screw created a critical strain distribution in the bone, just under the screw. The study shows that centred and inside contact induces lower strain distributions. This suggests that spherical condyle geometry should be applied in order to reduce the strains in fixation. As the top screw was observed to play the most critical role, the third screw is in fact unnecessary, since the lower strain distribution suggests that it will be loosened., (Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Background and Objective: There is a close interaction between the mandibular and cervical systems due to the existing neurological and biomechanical communications. This study aimed to evaluate the relationship between neck disability and mandibular range of motion (ROM)., Materials and Methods: Fifty-two women aged between 18 and 40 years were recruited and allocated to four groups using two outcome measures: the Neck Disability Index (NDI) and the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD): Group I (n=13), healthy volunteers; Group II (n=13), volunteers with TMD and neck disability; Group III (n=13), volunteers with TMD and without neck disability; and Group IV (n=13), volunteers with neck disability and without TMD. Mandibular ROM was evaluated as part of the RDC/TMD clinical examination. Statistical analysis involved one-way ANOVA followed by Tukey's test for comparisons between groups. Spearman's correlation coefficients were calculated to determined correlations among the variables., Results: Significant differences were found in the mandibular ROM of functional opening in the comparisons between Groups I and III (p=0.009) and between Groups III and IV (p=0.024). No significant association was found between mandibular ROM and the NDI score (p > 0.05)., Conclusion: Based on the methodology employed, there is no association between mandibular ROM and neck disability in university women. In this sense, clinical interventions focusing on the flexibility of the temporomandibular joint does not have repercussions on the neck disability and vice versa.

Purpose: To answer 2 specific questions in relation to mandibular hypomobility after orthognathic surgery (OGS): 1) Is hypomobility after OGS permanent? 2) Is there any underlying mechanism?, Materials and Methods: A Medline and PubMed search was performed to locate relevant articles. To meet inclusion in this review, articles were required to include patients with no pre-existing temporomandibular joint (TMJ) disorders who had been treated by the commonly performed OGS procedures. Case reports, pilot studies, and review articles were excluded. Twelve electronic search articles were identified. Manual search of the reference lists of these articles added another 11 articles., Results: Of the 23 potentially relevant articles, 7 were considered eligible for inclusion. Five articles were retrospective and 2 were prospective. Vertical maxillary excess, Class II malocclusion, and Class III malocclusion were addressed in 344 patients who underwent Le Fort I maxillary osteotomy, sagittal split mandibular ramus osteotomy, or intraoral or extraoral vertical mandibular ramus osteotomy. Mandibular ramus surgeries were performed alone or in combination with Le Fort I osteotomy. Mandibular hypomobility, in terms of incisal range of motion, was measured with a ruler in 5 studies, with a Perspex triangular trismus gauge in 1 study, and with a jaw motion analyzer system in 1 study. Two studies reported permanent decreases in all ranges of mandibular motion 2 years after surgery and 5 studies did not support the notion that OGS affects mandibular mobility permanently. No mechanism for hypomobility after OGS was identified., Conclusion: Mandibular hypomobility after OGS is still in need of long-term prospective studies with homogenous patient samples of dentofacial deformities and the same TMJ conditions treated by the same experienced surgeon with adequate follow-up, internal controls, and blinding of examiners., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. All rights reserved.)

The aim of the present study was to investigate the relationship between degenerative bone changes of the head of the mandible and the presence of joint effusion (JE). This study was based on sagittal magnetic resonance imaging (MRI) reports of 148 temporomandibular joints (TMJs) of 74 patients complaining of pain and/or dysfunction in the TMJ area. The mandible heads were surveyed for osteoarthritis characteristics, which were classified as osteophytosis, sclerosis or erosion. The presence of JE was checked whenever high signal intensity was observed in the articular space. The results evidenced the presence of bone changes in 30% of the sample. Osteophytes and erosions were the changes most commonly observed. JE was reported in 10% of TMJs. The results from the statistical tests revealed that bone changes in the head of the mandible are associated with the presence of JE.

The aim of this study was to predict stress modification in the temporomandibular joint (TMJ) after symphyseal distraction (SD). The study was performed using three-dimensional finite element analysis using a complete mastication model. Geometric data were obtained from MRI and CT scans of a healthy male patient and each component was meshed as various regions. The distraction was performed with a 10mm expansion after simulation of a surgical vertical osteotomy line on the model in the mandibular midline region. The geometry and mesh of the bone callus were constructed. The bone callus was modelled as a strengthened region characterized by a Young's modulus corresponding to consolidated bone to predict the long-term biomechanical effect of SD. Boundary conditions for jaw closing simulations were represented by different jaw muscle load directions. The von Mises stress distributions in both joint discs and condyles during closing conditions were analysed and compared before and after SD. Stress distribution was similar in discs and on condylar surfaces in the pre- and post-distraction models. The outcomes of this study suggest that anatomical changes in TMJ structures should not predispose to long-term tissue fatigue and demonstrate the absence of clinical permanent TMJ symptoms after SD., (Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

The present article describes the prosthodontic management of an adult patient with anterior deep bite (Angle 11/2) and concomitant temporomandibular disorder (TMD). In the presence of steep incisor inclination undesirable effects could be observed in the temporomandibular joint. The aim of our treatment was to achieve anterior guidance that harmonically relates to the condylar inclination. Once the vertical dimension of occlusion (VDO) had been increased, an adequate anterior guidance was achieved. The VDO was increased in two steps with 5 mm at the anterior region, which resulted in 2 mm increase at the molars. Restorative treatment was completed in a semi-adjustable articulator (KaVo Protar 5B) according to the patient's centric relation. The new anterior guidance was then established in an individual articulator (KaVo Protar 9) according to the increased VDO.

Purpose: The purpose was to analyze the mandibular patterns (condylar range of motion during opening; incisal range of motion during opening, lateral excursion, and protrusion; velocity during opening and closing; mandibular rotation angle during opening and closing) in patients with alloplastic total joint replacement (TJR)., Materials and Methods: Seventeen patients with different diagnoses resulting in condylar hypomobility (8 patients, 15 joints) and condylar instability (9 patients, 12 joints) had undergone alloplastic TJR. Data were recorded preoperatively and 2, 6, and at least 12 months postoperatively. For ordinal data comparison at different time points, the Wilcoxon signed-ranks test was used., Results: Analysis of the kinematic data at least 12 months postoperatively showed in patients with condylar hypomobility a statistically significant increase in all measured data except the incisal range of motion lateral excursion. In patients with condylar instability, the results showed a statistically significant decrease for incisal range of motion protrusion and laterotrusion. A slight increase in condylar range of motion, incisal range of motion linear distance, and velocity during opening and closing was found., Conclusions: Even after successful alloplastic TJR, a complete restoration of normal joint function is not achievable. Nevertheless, the kinematic data indicate that alloplastic TJR results in an improved function in patients with joint hypomobility and in a decrease of abnormal hypermobility in patients with condylar instability., (Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the clinical and functional outcomes of a custom temporomandibular hemijoint fossa/eminence implant prosthesis., Materials and Methods: This prospective cohort study enrolled patients with osteoarthritis of the temporomandibular joint. The primary study variables were pain experience, pain intensity, chewing ability, jaw opening, joint noise, and overall satisfaction of the surgical outcome at 3, 6, and 13 months after surgery. Pre- and postsurgical kinematic analyses measured maximum incisal opening, operated and unoperated condyle translations, and mandibular body axis rotation using mandibular kinematic data combined with patient-specific computed tomographic data. The primary analysis of interest concerned preoperative versus postoperative changes., Results: The study sample was composed of 36 subjects (mean age, 46 years; 94% female; 40 joints). There were statistically significant improvements between pre- and postoperative measurements for each study variable. The kinematic data documented preservation or an increase of bilateral condylar motion, mandibular axis rotation, and mandibular incisor motion., Conclusions: Temporomandibular joint hemiarthroplasty with a custom metal fossa/eminence prosthesis provides satisfactory clinical and functional outcomes when used for advanced osteoarthritis in patients with focal joint pain secondary to computed tomographically documented joint pathology., (Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

197 subjects (74 male, 123 female) were evaluated in this Study of Health in Pomerania associated project (SHIP 0). Both a clinical functional status and an instrumental analysis of functional movement patterns of the mandible were performed in each subject, in the latter case using an ultrasonic jaw motion analysis system. Correlations between instrumental movement pattern features and clinical signs and symptoms of temporomandibular joint dysfunction (TMD), such as joint sounds, palpable impairment of jaw movement, and the termination of opening movement at the incisal point, were particularly significant (p <0.005). Correlations for TMJ crepitation sounds and joint pain on palpitation from the lateral or posterior aspect tended to be less significant (p < 0.1). No association was found for pain on jaw movement or muscle tenderness in response to pressure. A multivariate logistic regression model showed a significant correlation between Helkimo Clinical Dysfunction grades 2 and 3 and the following independent variables: frequent headaches (odds ratio [OR] 4.12; p = 0.032), frequent popping sounds in the jaw joints (OR 5.79; p = 0.012), incisal paths showing conspicuous signs of dysfunction such as deviation or deflection (OR 4.35; p = 0.05), and condylar path anomalies such as jumpy, straight/inverse or irregular tracings (OR 28.59; p = 0.006). Instrumental functional analysis of condylar path tracings allows one to draw statistically valid conclusions about the occurrence of TMD symptoms. It can be helpful to perform condylar path analysis when performing risk assessments for temporomandibular dysfunction in certain situations, particularly before prosthetic rehabilitation.

Objective: To identify the best loading angle with Forsus for mandible-temporomandibular joint., Methods: The changes in stress, displacement and rotation of "mandible-temporomandibular joint" were tested under -30 degrees, -15 degrees, 0 degrees, 15 degrees and 25 degrees of loading angles using a primary three dimensional finite element model., Results: From 0 degrees to 25 degrees, with the increases of loading angles the displacement gradually increased. The maximum displacement occurred at chin, with 1.692 mm, 3.456 mm and 4.630 mm displacement under 0 degrees, 15 degrees and 25 degrees respectively. The maximum displacement occurred at the alveolar ridge under -15 degrees loading, which was 0.069 mm. No special stress concentration region was identified. The displacements from infradentale to pogonion gradually increased under all conditions except for the -15 degrees loading. With the loading angles deviated from the baseline farther, the porrect displacements of chin and the counterclockwise rotation became more obvious., Conclusion: The loading angles of Forsus appliance should be controlled between 0 degrees and 25 degrees.

Background and Objective: One way of determining the direction of growth of the mandible is to consider the temporomandibular joint and movement of the mandible as a four-joint gear system, regarding growth then as an extension of the gear system. Our aim was to examine any correlations between the type of biomechanical growth extension and change in the maxilomandibular relation after Class II therapy., Subjects and Methods: A total of 130 lateral cephalograms-before and after orthodontic treatment-were available from 65 adolescent class II patients with open bite or deep bite. The two lateral cephalograms from each patient were superimposed on the occlusal plane. Cephalometric values and the vertical base point deviation were determined from biomechanical analyses, together with three distances and three angles., Results: No correlation between the cephalometric data and distances or angles were observed. Although there were no significant differences in the distances, we did note significant differences in all three angles (p < 0.05)., Conclusion: If gear system extension during growth is considered, this can be interpreted as meaning that the occlusal plane of those patients with an initially open bite dropped during treatment, but that it rose in patients with an initially deep bite.

Purpose: Prosthetic materials and bone present quite different mechanical properties. Consequently, mandible reconstruction with metallic materials (or a mandible condyle implant) modifies the physiologic behavior of the mandible (stress, strain patterns, and condyle displacements). The changing of bone strain distribution results in an adaptation of the temporomandibular joint, including articular contacts., Materials and Methods: Using a validated finite element model, the natural mandible strains and condyle displacements were evaluated. Modifications of strains and displacements were then assessed for 2 different temporomandibular joint implants. Because materials and geometry play important key roles, mechanical properties of cortical bone were taken into account in models used in finite element analysis., Results: The finite element model allowed verification of the worst loading configuration of the mandibular condyle. Replacing the natural condyle by 1 of the 2 tested implants, the results also show the importance of the implant geometry concerning biomechanical mandibular behavior. The implant geometry and stiffness influenced mainly strain distribution., Conclusion: The different forces applied to the mandible by the elevator muscles, teeth, and joint loads indicate that the finite element model is a relevant tool to optimize implant geometry or, in a subsequent study, to choose a more suitable distribution of the screws. Bone screws (number and position) have a significant influence on mandibular behavior and on implant stress pattern. Stress concentration and implant fracture must be avoided., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Temporomandibular disorder (TMD) is a collective term used to identify a group of musculoskeletal conditions of the temporomandibular region. Bruxism is a non-functional activity characterized by repeated tooth clenching or grinding in an unconscious manner. Over the time bruxism may lead to TMD by the uploading it causes. Nasal obstruction is a common complaint that necessitates mouth breathing when severe. The treatment of bruxism is frequently performed by oral appliances, which induce occlusal disengagement and relax jaw musculature and therefore reduce the force on the temporomandibular joint (TMJ). We believe that nasal obstruction may indirectly have a preemptive and therapeutic effect on sleep bruxism related TMD by causing mouth breathing., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

The standard approach for carotid endarterectomy cannot provide adequate exposure of the distal internal carotid artery in the presence of high cervical carotid bifurcation or high plaque. Limited accessibility of the distal internal carotid artery has resulted in the development of various operative techniques. Mandibular subluxation is the most simple and least invasive technique, but it does require invasive maneuvers, such as wiring, to stabilize the mandible. We use a mouthpiece made by the dentist to stabilize the mandible in the physiologic subluxated position. This technique provides an adequate exposure of the distal internal carotid artery as with the other methods, and the risk of morbidity is very low., (Copyright © 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: To investigate the rotational variations of three-dimensional (3D) trajectories at anatomic landmarks by different mandibular kinematics, we applied principal axes of inertia to the 3D trajectories. The principal rotations were determined directly from the anatomy-based trajectories produced by a patient-specific temporomandibular joint simulation. As a preliminary study, the principal rotations for a pilot group of patients with mandibular deviation were correlated with the deviation., Study Design: Three-dimensional mandibular movements from the patients with mandibular deviation were tracked based on a patient-specific splint and an optical tracking system. The dental occlusion recorded on the splint provided synchronization for initial movement in the tracking and the simulation phases. The translation and rotation recorded during tracking were applied sequentially to the mandibular model in relation to a fixed maxilla model. The sequential positions of the points of interest based on the reference coordinate system could also be simulated and traced by the same method. The landmarks selected for analysis were the points of the bilateral condyles and of the mandibular incisor. The moment of inertia tensor was calculated with respect to the 3D trajectory points. Using the unit vectors along the principal axes derived from the tensor matrix, α, β, and γ rotations (horizontal, sagittal, and frontal planes) around the z-, y-, and x-axes, respectively, were determined to represent the principal directions as principal rotations., Results: The measured rotations were correlated with the deviation in 3 orthogonal planes. Under the influence of the mandibular asymmetry, the orientations of the principal axis at the condyles increase counterclockwise in the horizontal plane and clockwise in the frontal plane. At the incisor point, the horizontal and frontal angles increase counterclockwise, but the sagittal angles increase clockwise. The interrelations between different rotations and between landmarks, defined as a correlation coefficient between principal rotations, decrease as the deviation increases., Conclusions: Three-dimensional trajectories at selected landmarks based on the reference coordinate system were evaluated using principal axes of inertia to investigate the functional characteristics of the mandible with a deviation. The movement asymmetry between the condyles increases as the deviation increases in all directions. The principal rotations at the condyles can be explained by those at the incisor with varying degrees despite the deviation., (Copyright © 2010 Mosby, Inc. All rights reserved.)

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., (© EDP Sciences, SFODF, 2010.)

Objective: To assess rotation and translation movements of the mandible at maximum mouth opening in a group of patients successfully rehabilitated after condylar fractures., Materials and Methods: Using a three-dimensional motion analyser, free movements of mouth opening were recorded in nine patients, and divided into their rotation and gliding components. Surface electromyography (EMG) of the masticatory and sternocleidomastoid (SCM) muscles was performed during maximum voluntary teeth clenching (MVC). Data were compared with those collected in healthy adults., Results: At maximum mouth opening, the total displacement of the mandibular interincisor point was 86% of reference value (p>0.05, Student's t test), with a reduced vertical displacement (84% of reference value, p=0.012). Percentage mandibular rotation was significantly larger in patients (82%) than in reference subjects (77%, p=0.005). During MVC, patients had more asymmetric EMG potentials (p=0.018), with greater mandibular torque (p<0.001), and reduced co-contraction of SCM (p=0.003). EMG indices were used to formulate an overall performance score that was related to the characteristics of mouth opening (r=0.557)., Conclusion: Notwithstanding a good recovery in the total mandibular movement, the rotation/translation components of mouth opening were modified. The overall EMG performance score could be used to predict the characteristics of mandibular motion.

Introduction: Patterns of stress generation in the temporomandibular joint (TMJ) after mandibular protraction with a construction bite of 5 mm advancement and 4 mm opening were investigated by using a 3-dimensional finite element method; the results were reported in Part 1. In Part 2, the effects of varying the construction bite are reported., Methods: A 3-dimensional computer-aided design model was developed from the magnetic resonance images of a growing boy (age, 12 years), by using I-DEAS NX (version 11.0, Siemens PLM Software, Plano, Tex). Sagittal advancement was 5 mm, as in Part 1; however, the vertical openings of the construction bite were changed from 4 mm to 2 and 6 mm. The stresses thus obtained were compared for differences in magnitude and pattern., Results: Tensile stresses migrated more posteriorly on the condylar head with increased bite height. The locations of the tensile stresses in the glenoid fossa were similar in all simulations. The TMJ as a whole showed increased loading with the increasing vertical openings., Conclusions: This study indicates that increasing the construction bite height might give more favorable stress patterns in the TMJ, thereby improving the condylar response to functional appliances. The findings of this preliminary study need to be investigated in an animal model and in humans before deriving clinical implications.

Introduction: This study was designed to evaluate patterns of stress generation in the temporomandibular joint after mandibular protraction, by using a 3-dimensional finite element method. The results of the initial investigation are reported here in Part 1. The effects of varying the construction bite are reported in Part 2., Methods: A 3-dimensional computer-aided design model was developed from the magnetic resonance images of a growing boy (age, 12 years), by using I-DEAS NX (version 11.0, Siemens PLM Software, Plano, Tex). The model simulated mandibular protraction, with 5 mm of sagittal advancement and 4 mm of vertical opening. Stress distributions on the condylar neck, the glenoid fossa, and the articular disc in the anteroposterior and mediolateral directions were assessed., Results: Tensile stresses were located on the posterosuperior aspects and compressive stresses on the anterior and anterosuperior aspects of the condylar head. Tensile stresses were found in the posterior region of the glenoid fossa near the attachment of the posterior connective tissues., Conclusions: These results suggest that, on mandibular protraction, the mandibular condyle experiences tensile stresses in the posterosuperior aspect that might help explain condylar growth in this direction. Similarly, on the glenoid fossa, tensile stresses are created in the region of posterior connective tissues; this might be correlated with the increased cellular activity in this region. Further study with variable vertical heights of the construction bites is needed.

Introduction: Our aim in this study was to investigate the position of the glenoid fossa in subjects with Class III malocclusion associated with mandibular protrusion to better clarify the role of this craniofacial component in Class III skeletal disharmony., Methods: A sample of 30 subjects, aged 8 years +/- 6 months, with skeletal and dental Class III malocclusion associated with mandibular protrusion, normal skeletal vertical relationships, and normal mandibular dimensions, was compared with a control group of 33 subjects with skeletal and dental Class I relationships. The comparisons between the Class III group and the control group on the cephalometric measures for the assessment of glenoid fossa position were performed with the Mann-Whitney U test at P <0.05., Results: Subjects with Class III malocclusion had a significantly more mesial position of the glenoid fossa, when compared with the control group as measured with 3 parameters., Conclusions: An anterior position of the glenoid fossa is a possible diagnostic anatomic feature of Class III malocclusion associated with mandibular protrusion. An effective measurement to evaluate glenoid fossa position in craniofacial relationships is the cephalometric distance from the glenoid fossa to the frontomaxillary-nasal suture.

Trismus after head and neck cancer treatment may severely limit mandibular functioning. Interventions aimed at reducing trismus can only be evaluated when the amount of variation associated with these measurements is known. The aim of this study was to analyse the variation in mouth-opening measurements in patients treated for head and neck cancer, with and without trismus. Maximal mouth opening was measured in 120 patients in two sessions of three repeated measurements by one observer. To analyse the influence of interobserver variation on mouth-opening measurements a subgroup of 30 patients was measured by a second observer. The standard deviation of the six measurements per patient was used as the variation in measurements of maximal mouth opening. No significant difference was found in maximal mouth opening in patients with (n=33) or without (n=87) trismus. The interobserver intraclass correlation coefficient (ICC) was 0.98. Intraobserver ICC and intersession ICC reliabilities both were 0.99. The variation in the mean values of the three measurements was only slightly smaller than the variation of the single measurements. Variation in maximal mouth opening in patients with trismus does not differ from variation in maximal mouth opening in patients without trismus. Interobserver variation is limited.

Limitation of mandibular movement is one of the cardinal signs of temporomandibular disorders. Temporomandibular Opening Index (TOI) is a new technique to determine the restricted mouth opening in temporomandibular joint dysfunction syndrome (TMD). The purpose of this study was to compare the TOI of Turkish children with and without TMD in primary, mixed, and permanent dentitions. In this study, a total of 270 children were evaluated. One hundred thirty-five (135) subjects had no signs or symptoms of TMD (Group 1), while the remaining 135 subjects did have signs and symptoms of TMD (Group 2). Forty-five (45) patients were selected for each dentition for two groups. "Maximum Voluntary Mouth Opening" (MVMO) values and TOI ranges were calculated. A Mann-Whitney U test and a Kruskal Wallis test were used to compare the data (p<0.05). TOI showed statistical differences between all dentitions with and without TMD (p<0.05). There were no significant differences between different dentitions or genders in Group 1 or Group 2 (p<0.05).

The objective of this investigation was to test the hypothesis that alteration of the occlusions of patients suffering from temporomandibular disorders (TMD) to one that is neuromuscularly, rather than anatomically based, would result in reduction or resolution of symptoms that characterize the TMD condition. This hypothesis was proven correct in the present study, where 313 patients with TMD symptoms were examined for neuromuscular dysfunction, using several electronic instruments before and after treatment intervention. Such instrumentation enabled electromyographic (EMG) measurement of the activities of the masticatory muscles during rest and in function, tracking and assessment of various movements of the mandible, and listening for noises made by the TMJ during movement of the mandible. Ultra low frequency and low amplitude, transcutaneous electrical neural stimulation (TENS) of the mandibular division of the trigeminal nerve (V) was used to relax the masticatory muscles and to facilitate location of a physiological rest position for the mandible. TENS also made it possible to select positions of the mandible that were most relaxed above and anterior to the rest position when the mandible was moved in an arc that began at rest position. Once identified, the neuromuscular occlusal position was recorded in the form of a bite registration, which was subsequently used to fabricate a removable mandibular orthotic appliance that could be worn continuously by the patient. Such a device facilitated retention and stabilization of the mandible in its new-found physiological position, which was confirmed by follow up testing. Three months of full-time appliance usage showed that the new therapeutic positions achieved remained intact and were associated with improved resting and functioning activities of the masticatory muscles. Patients reported overwhelming symptom relief, including reduction of headaches and other pain symptoms. Experts consider relief of symptoms as the gold standard for assessment of effectiveness of TMD treatment. It is evident that this outcome has been achieved in this study and that taking patients from a less to a more physiological state is an effective means for reducing or eliminating TMD symptoms, especially those related to pain, most notably, headaches.

Temporomandibular joint (TMJ) function was evaluated following endoscope-assisted transoral open reduction and miniplate fixation of displaced bilateral condylar mandibular fractures. The transoral treatment of bilateral condylar fractures was performed in 13 patients from May 2000 to December 2004. Eleven of the 13 patients had additional mandibular fractures. Out of 26 fractures of the condylar process, 11 were located at the condylar neck and 15 were subcondylar. One, 6 and 12 months after surgery TMJ function was evaluated. Anatomic reduction was achieved using an endoscope-assisted transoral approach even when the condylar fragment was displaced medially and in fractures with comminution. Good TMJ function was noted 6 and 12 months after surgery. Mouth opening was measured to be more than 40 mm without deviation. Postoperative range of motion with a satisfying lateral excursion was found. Early rehabilitation and pre-injury TMJ function was achieved following minimally invasive anatomic fracture reduction.

This study quantified by, electrovibratography, the amount of mandible protrusion required to decrease significantly temporomandibular joint (TMJ) vibratory energy as an aid in the diagnosis of the recapture of anteriorly displaced disk. Eighteen patients diagnosed as having anterior disk displacement with reduction and TMJ clicking were submitted to electrovibratographic examination at the first appointment and treated with a stabilizing appliance and anterior positioning appliance with 1 to 5 mm protrusion. Vibratory energy was checked in each of these positions. Baseline data were used as control. At the first appointment, the patients had vibrations with more elevated intensities at the middle and late phases of the mouth opening cycle. At only one clinical step, mandible protrusion was obtained with the anterior repositioning appliance, ranging from 1 to 5 mm protusion. At each new position, a new electrovibratographic exam was made. After the 5-mm mandibular projection, only 2 patients presented vibration, with means between 0.6 and 2.8 Hz. Data were analyzed statistically by ANOVA and Tukey's test (alpha=0.05). The outcomes of this study indicate that 3 mm is the minimum amount of mandible protrusion to significantly decrease the TMJ vibratory energy and to recapture the displaced articular disk.

Objective: To evaluate the morphological and histological responses of the glenoid fossa to mandibular lateral shift in growing rats., Materials and Methods: A resin plate was placed on the upper incisors of 4-week-old rats in the experimental groups to displace the mandible to the left during closure. The rats were killed after 2, 4, 8, and 12 weeks. The morphometric measurements were performed on dry skulls, and tissue blocks were processed for periodic acid and Schiff's reagent (PAS) staining to examine the new bone formation., Results: Gross measurements showed asymmetry in both the position and size of the fossae between the two sides after 4 weeks of lateral shift. The glenoid fossa on the ipsilateral side was repositioned relatively backward, outward and upward compared with the contralateral side and control group, whereas the fossa on the contralateral side was relocated relatively forward and downward compared with the control group. The length of the fossa was smaller on the ipsilateral side than on contralateral side and control group. At 2 weeks, the amount of newly formed bone in the posterior region of the fossa was higher in the experimental group than the control group., Conclusion: It is suggested that the mandibular lateral shift causes asymmetry in the position and size of the glenoid fossa and that this phenomenon can be related to different bilateral directional new bone formation in the posterior region.

Objective: To investigate changes in functional characteristics of the temporomandibular joint (TMJ) mechanoreceptors under mandibular lateral shift., Materials and Methods: Forty 7-week-old male Wistar rats were divided into control and experimental groups. Rats in the experimental group received a modified guiding appliance (MGA) that was designed to shift the mandible to the left side in the occlusal position. Single-unit activities of the TMJ mechanoreceptors were evoked by indirect stimulation of passive jaw movement. Electrophysiologic recordings of TMJ units were obtained 1, 3, 5, 7, and 9 weeks after MGA setting from the gasserian ganglion., Results: At 1 week after mandibular shift, the firing thresholds were the lowest and the maximum instantaneous frequencies were the highest in TMJ units. At 5 weeks, the firing thresholds in the nonshifted side were significantly lower than those in the shifted side. The maximum instantaneous frequencies in the nonshifted side were significantly higher than those in the shifted side at 1, 5, and 7 weeks., Conclusion: These results suggest that the functional lateral shift of the mandible could alter the response properties of TMJ mechanoreceptors, particularly on the nonshifted side.

The osteogenesis imperfecta congenita (OMIM 166210) type II phenotype can be caused by mutation in either the COL1A1 gene or the COL1A2 gene that encode the chains of type I procollagen, the major protein in bones. Patients can therefore present a combination of features, including multiple long bone fractures and deformities, growth deficiency, joint laxity, hearing loss, blue sclera, and dentinogenesis imperfecta. The purpose of this study is to describe a clinical case of this syndrome, focusing on the anatomy of the temporomandibular joint (TMJ) that was assessed using computed tomography (CT) method. Clinical examination included evaluation of mandibular dynamics and investigation of temporomandibular dysfunction (TMD).

In former works, we had proved that test persons with sound temporomandibular joints (TMJs) used a mandibularly fixed hinge axis (MFHA) and were able to pilot the mandible by solely two kinematical degrees of freedom. We wondered if we could evaluate the MFHA the same way for patients who had problems with their TMJs. Actually, the MFHA could be determined likewise. The results could provide information on the reason for the distortion of the movement of the TMJs, which cannot be yielded by X-ray radiographs.

The aim of the present study was to elucidate the relationship between biomechanical changes of the temporomandibular joint (TMJ) and internal derangement (ID) symptoms in mandibular asymmetry. Posteroanterior cephalograms (PA) of 140 patients with TMJ ID associated with mandibular asymmetry were used to investigate the inclination of the frontal occlusal plane (FOP), and were analysed in conjunction with the results of a report providing information on ID symptoms. A three-dimensional (3D) finite element model (FEM) of the entire mandible was created to investigate the distribution of TMJ forces during clenching. The inclination of the FOP was modified to simulate various degrees of vertical asymmetry. The stresses on the TMJ on the ipsilateral and contralateral sides were analysed and their values were compared with those of the standard model. The results showed that the symptomatic sides were significantly related to the degree of inclination of the FOP. Increasing its angulation resulted in a decrease of the symptoms on the ipsilateral side and an increase of those on the contralateral side. The analysis showed that stress-distribution patterns and overall stresses of the articular disc were influenced by the angulation of inclination of the FOP. These mechanical changes exhibited a distinct relationship with the prevalence of ID in the patients. These results suggest that disturbances in the stresses either in amount or direction due to occlusal inclination can be responsible for ID. Therefore, an attempt to establish a flat occlusal plane is an important orthodontic treatment objective in maintaining the normal health and structure of the TMJ.

One of the essential causes of disk disorders is the pathologic change in the ligamentous attachments of the disk-condyle complex. In this paper, the response of the soft components of a human temporomandibular joint during mouth opening in healthy and two pathologic situations was studied. A three-dimensional finite element model of this joint comprising the bone components, the articular disk, and the temporomandibular ligaments was developed from a set of medical images. A fiber reinforced porohyperelastic model was used to simulate the behavior of the articular disk, taking into account the orientation of the fibers in each zone of this cartilage component. The condylar movements during jaw opening were introduced as the loading condition in the analysis. In the healthy joint, it was obtained that the highest stresses were located at the lateral part of the intermediate zone of the disk. In this case, the collateral ligaments were subject to high loads, since they are responsible of the attachment of the disk to the condyle during the movement of the mandible. Additionally, two pathologic situations were simulated: damage of the retrodiscal tissue and disruption of the lateral discal ligament. In both cases, the highest stresses moved to the posterior part of the disk since it was displaced in the anterior-medial direction. In conclusion, in the healthy joint, the highest stresses were located in the lateral zone of the disk where perforations are found most often in the clinical experience. On the other hand, the results obtained in the damaged joints suggested that the disruption of the disk attachments may cause an anterior displacement of the disk and instability of the joint.

Distraction osteogenesis has been accepted as an alternative treatment modality for hypoplastic mandibles. Knowledge about the changes occurring in the temporomandibular joint region during mandibular distraction osteogenesis is, however, limited and controversial. Stress distribution in the temporomandibular joint region during unilateral vertical mandibular ramus distraction was studied using a finite element model. The finite element model was based on computed tomography scans and magnetic resonance imaging scans of a patient with unilateral hypoplasia of the right mandibular ramus caused by juvenile idiopathic arthritis. The character of stress distribution in the temporomandibular joint and mandible was analyzed quantitatively at different intervals of the vertical mandibular ramus elongation. During the distraction phase, the condyles, articular disks, and glenoid fossa regions were loaded with a differentiated stress pattern. The affected right condyle, disk, and fossa were submitted to increasing loads with increasing elongation compared with the contralateral temporomandibular joint. Loading on the unaffected left side shifted posteriorly and slightly laterally, because the left condyle was the center of rotation. The loading of the temporomandibular joint regions was low during the active distraction phase, although local areas were subjected to elevated peak stresses.

The aim of the present study was to establish whether the early signs of various orofacial dysfunctions, malocclusions, or occlusal interferences can predict the development of temporomandibular dysfunction (TMD) in young adults. Forty-eight subjects referred for speech therapy and 49 controls participated in all four stages of this longitudinal study. The subjects were examined at the ages of 7, 10, 15, and 19 years. The phoniatrician diagnosed errors in place of articulation and problems in the movement and co-ordination of the speech articulators. Occlusion, TMD signs (palpatory tenderness of the masticatory muscles, and of temporomandibular joints (TMJ), jaw deviation on opening, and clicking), mandibular movement capacity and occlusal interferences were registered by the orthodontist. Multiple logistic regression models were applied in order to evaluate whether single signs of TMD at the age of 19 years were related to previous/present malocclusions or interferences, to misarticulations of speech, problems in oral motor skills, or other signs of TMD. The effect of gender was also considered. The results showed that excessive overjet was the only variable which seemed to consistently increase the risk of TMD. In addition, girls seemed to be more prone to the development of TMD than boys. Although, during growth, there were both local and central factors associated occasionally with TMD development, the predictive value of those variables in the estimation of the individual risk of TMD was rather small.

Purpose: We sought to examine possible changes in pattern and concentration of type II collagen in the condylar cartilage and articular disc of the temporomandibular joint (TMJ) in response to unilateral extraction of mandibular teeth in a rabbit model as a means of elucidating the effects of unilateral mastication on the TMJ., Methods: A total of 12 experimental rabbits were killed either 3 or 6 weeks after the extractions, and 3 additional rabbits without extractions were used as controls. TMJ blocks from both sides of each of the 15 animals were examined for type II collagen via an immunoperoxidase procedure., Results: Anti-type II collagen antibody (Ab) binding was detected mainly in the hypertrophic chondroblast layer of the condylar cartilage of normal rabbits. At 3 weeks after unilateral extraction of teeth, anti-type II collagen Ab binding to the territorial matrix of the hypertrophic chondroblast layer of the condylar cartilage and to the disc was stronger than normal. The increase in Ab binding appeared more dramatic on the nonfunctional side than on the functional side of TMJ. Variations from the normal pattern of anti-type II collagen Ab binding in terms of distribution through the extracellular matrix and fibrillar appearance were also observed., Conclusion: The findings suggest that the condylar cartilage and disc adapt to the imbalance induced by unilateral extraction of teeth through chondrocyte repair responses involving collagen II expression that appear to differ between the functional and nonfunctional sides of the TMJ.

Objective: The purpose of this study was to investigate the results of performing a lateral pterygoid myotomy with reattachment to the condylar stump to restore more normal function after total joint reconstructive surgery., Study Design: Twenty-four joints were reconstructed in 14 patients with stock Christensen chrome-cobalt prostheses. Patients were separated into 2 groups. Group I consisted of 4 joints without reattached lateral pterygoid muscle (-LPM), and group II consisted of 20 joints with reattachment of the lateral pterygoid muscle to the condylar stump (+LPM). Patients were evaluated at an average of 15 months postoperatively to assess mandibular movement. Group I was compared with group II, and statistical analysis was performed through the use of the Mann-Whitney test. Patient satisfaction was evaluated by using postoperative questionnaires., Results: Group II had an average interincisal opening 7.3 mm greater than Group I (P <.001). Lateral movements averaged 3.86 mm in Group II versus 0.5 mm in Group I (P <.05). Protrusion was 2.83 mm greater in Group II than in Group I (P = 0.53)., Conclusion: The reattachment of the lateral pterygoid muscle to the condylar stump during total joint reconstructive surgery may provide the patient with greater interincisal opening, lateral excursions, and protrusive movement. The preliminary data from these small, nonrandomized groups are promising for improved function following total joint reconstruction.

Purpose: Our goal was to evaluate long-term stability and function of 5 condyles reconstructed with vascularized second metatarsal joint grafts., Materials and Methods: Four patients were reconstructed with 5 vascularized metatarsal grafts. These reconstructed joints were then followed for an average of 12.5 years. These patients represent the entire series and were all successfully contacted and reevaluated for this article. Measures of opening, deviation, excursion, symmetry, and clinical symptoms relating to the reconstructed joints are evaluated., Results: Mean preoperative interincisal aperture was 12 mm, and postoperative aperture 48.5 mm. Three unilaterally treated patients had lateral excursion with opening. The mean deflection was 4.3 mm toward the operated side. Lateral and protrusive movements were limited in reconstructed joints, but up to 3 mm of protrusion was shown at 12.5 years. Subjectively, all patients rated their function as acceptable and were able to occlude and masticate without difficulty. Symmetry at rest was improved by surgery., Conclusions: Vascularized metatarsal joints represent a potentially suitable long-term substitute for condylar reconstruction. This limited series shows the technical viability of the procedure. A larger series may be warranted to compare this promising technique with conventional methods of temporomandibular joint reconstruction., (Copyright 2003 American Association of Oral and Maxillofacial Surgeons)

Purpose: In this study, we examined the hypothesis that uncontrolled oxidative stress causes collapse of the lubrication system, which is considered a major initiator of temporomandibular joint (TMJ) dysfunction. The oxidative stress was evaluated by measuring the overall antioxidant capacity of the low-molecular-weight antioxidants in the TMJ, using cyclic voltammetry (CV), in synovial fluid from normal and anchored disc phenomenon (ADP) TMJs., Materials and Methods: Synovial fluids samples were taken from 13 normally functioning and 33 ADP TMJs. The samples were frozen initially on collection and analyzed in CV to measure their overall reducing power., Results: CV measurements of the fluids collected from 90% of the healthy joints showed an anodic waves at peak potential [Ep(a)1/2] of 290 +/- 30 mV. Of the samples 56% showed another wave at 650 +/- 100 mV. These waves were generally absent in the fluid collected from ADP TMJs, but 2 new waves at 465 +/- 90 mV and greater than 750 mV were detected in 68% and 87% of the patients, respectively., Conclusions: The results show more anodic waves, most of which of higher potentials (greater than 750 mV) in ADP TMJs, indicating that the capacity to cope with oxidative stress is lower in these joints. It is not clear whether this is due to absence of low-molecular-weight antioxidants or their consumption by uncontrolled production of reactive oxygen species, which might be the initial step in the collapse of the lubrication system., (Copyright 2002 American Association of Oral and Maxillofacial Surgeons)

Normal development of the mandible as well as some portions of the upper jaw and face are related to good function of the masticatory apparatus: the integrity and interaction of bony and soft-tissue structures may be highly disturbed by injury of the TM joints and result in facial and occlusal disharmonies. When the neuromuscular system is in harmony, the mandibular muscles collectively exert their effect on both position and movement of the jaw and the loading of forces on the TM joints is optimal and balanced. Unfortunately, TMJ fractures may alter completely this balance with loss of the support to the mandible against the temporal component and loss of the functional effect of the lateral pterygoid muscle on the mandible. Disturbances in the harmonious interplay of the masticatory muscles may result in facial alteration and asymmetries. If not treated, the dysplastic patterns of growth continues and worsens during the years.

Purpose: The purpose of this study was to investigate the incidence of reoperation after temporomandibular joint arthroscopic surgery in 315 consecutive patients (488 joints)., Study Design: The clinical data and operative reports of all patients who underwent arthroscopic procedures from 1995 to 2000 were reviewed retrospectively. Patients had a preoperative clinical and panoramic radiographic evaluation. Most of the patients had disk displacement without reduction. In the remaining patients, the intra-articular pathologic conditions ranged from disk displacement with reduction to degenerative joint disease. The outcome assessment was based on reduction in pain, improvement in vertical dimension of mouth opening, and mandibular excursions. The same surgical team performed all arthroscopic procedures. Before surgery, all patients received at least 3 to 6 months of nonsurgical therapy consisting of anti-inflammatory medications, muscle relaxants, splint therapy, physiotherapy, exercise, moist heat, cold laser, ultrasound, and soft diet or a combination thereof. Patients were monitored postoperatively for as long as 5 years., Results: Results showed that approximately 20% of those patients who had temporomandibular joint arthroscopic surgery underwent further temporomandibular joint procedures ranging from repeat arthroscopic surgery to open-joint arthrotomy., Conclusion: Temporomandibular joint surgical arthroscopy is an appropriate therapeutic modality for patients with temporomandibular joint internal derangements, with reoperation required for only 20% of patients.

Unlabelled: Children seldom experience major facial trauma. However, minor injuries such as facial lacerations, abrasions and dental trauma are more common and naturally get less attention. Children with TMJ trauma usually present with pain, limited jaw movement and even malocclusion. However, these findings are not always recognized and sometimes get overlooked when chin laceration is the only sign. Plain x-rays can contribute to the diagnosis but in many cases are inconclusive and are difficult to interpret. Often, there is a diagnostic dilemma, especially when the clinical findings are not clear and normal occlusion is hard to restore. We present 3 out of 12 children in whom we diagnosed condylar head fracture following minor facial trauma. All children had normal physiological occlusion. Most of them had mild clinical signs such as limited mouth opening, pain and tenderness upon palpation of the joint. Routine plain films were not conclusive. The diagnosis was made or confirmed with CT scan. Early diagnosis of TMJ fracture in children is mandatory for the prevention of long term functional and esthetically debilitating sequela., Conclusion: A thorough clinical examination and normal occlusion do not rule out condylar head fracture after chin trauma. Plain films are of limited value in the diagnosis of such fractures. CT should be considered for the evaluation of these children.

This study was designed to compare the effectiveness of a passive jaw motion device, the Therabite, and wooden tongue depressors (WTD), in patients with temporomandibular joint and muscle disorders, who did not improve after manual manipulation of the mandible and flat bite plane therapy. Forty-three patients were enrolled in the study and were classified as joint or muscle groups according to the Research Diagnostic Criteria for TMD. Twenty-four were assigned to the joint group, and 19 patients were assigned to the muscle group. The patients were assigned at random to three treatment subgroups: 1. passive jaw motion device therapy (Therabite); 2. wooden tongue depressors therapy (WTD); and 3. control group. All subjects received flat bite plane appliance therapy throughout the treatment period. Mandibular range of motion was measured for maximum opening (MO), right and left lateral (Rt. Lateral, Lt. Lateral) and protrusive (Pr) movements. Pain level was also assessed at the beginning and at the end of the treatment. The results suggested that a passive jaw motion device is effective in increasing range of motion in both groups of temporomandibular disorder patients, joint (intracapsular) and muscle (extracapsular). It also appears to decrease pain in patients with temporomandibular disorders. Pain was relieved to a greater degree in the muscle group than the joint group.

Temporomandibular joint (TMJ) sounds are very common among patients with temporomandibular disorders (TMD), but also in non-patient populations. A variety of different causes to TMJ-sounds have been suggested e.g. arthrotic changes in the TMJs, anatomical variations, muscular incoordination and disc displacement. In the present investigation, the prevalence and type of different joint sounds were registered in 125 consecutive patients with suspected TMD and in 125 matched controls. Some kind of joint sound was recorded in 56% of the TMD patients and in 36% of the controls. The awareness of joint sounds was higher among TMD patients as compared to controls (88% and 60% respectively). The most common sound recorded in both groups was reciprocal clickings indicative of a disc displacement, while not one single case fulfilling the criteria for clicking due to a muscular incoordination was found. In the TMD group women with disc displacement reported sleeping on the stomach significantly more often than women without disc displacement did. An increased general joint laxity was found in 39% of the TMD patients with disc displacement, while this was found in only 9% of the patients with disc displacement in the control group. To conclude, disc displacement is probably the most common cause to TMJ sounds, while the existence of TMJ sounds due to a muscular incoordination can be questioned. Furthermore, sleeping on the stomach might be associated with disc displacement, while general joint laxity is probably not a causative factor, but a seeking care factor in patients with disc displacement.