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Concept: Masseteric nerve

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BACKGROUND: In the last years, several methods and devices have been proposed to record the human mandibular movements, since they provide quantitative parameters that support the diagnosis and treatment of temporomandibular disorders. The techniques currently employed suffer from a number of drawbacks including high price, unnatural to use, lack of support for real-time analysis and mandibular movements recording as a pure rotation. In this paper, we propose a specialized optical motion capture system, which causes a minimum obstruction and can support 3D mandibular movement analysis in real-time. METHODS: We used three infrared cameras together with nine reflective markers that were placed at key points of the face. Some classical techniques are suggested to conduct the camera calibration and three-dimensional reconstruction and we propose some specialized algorithms to automatically recognize our set of markers and track them along a motion capture session. RESULTS: To test the system, we developed a prototype software and performed a clinical experiment in a group of 22 subjects. They were instructed to execute several movements for the functional evaluation of the mandible while the system was employed to record them. The acquired parameters and the reconstructed trajectories were used to confirm the typical function of temporomandibular joint in some subjects and to highlight its abnormal behavior in others. CONCLUSIONS: The proposed system is an alternative to the existing optical, mechanical, electromagnetic and ultrasonic-based methods, and intends to address some drawbacks of currently available solutions. Its main goal is to assist specialists in diagnostic and treatment of temporomandibular disorders, since simple visual inspection may not be sufficient for a precise assessment of temporomandibular joint and associated muscles.

Concepts: Mandible, Joint, Motion capture, Temporomandibular joint, Temporomandibular joint disorder, Camera, Masseteric nerve

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OBJECTIVE: Endoscope-assisted transoral open reduction and internal fixation (EAORIF) for mandibular condyle fractures has recently become popular because it is minimally invasive, provides excellent visibility without a large incision, and reduces surgical scarring and the risk of facial nerve injury. This report describes a retrospective clinical study that compared certain clinical parameters, including postoperative function, between the retromandibular (RM) approach and EAORIF. METHODS: Fifteen patients were treated by the RM approach, whereas 15 underwent EAORIF between July 2006 and September 2011 at Kyushu Dental College, Japan. Clinical indices comprised fracture line, fracture type, number of plates used, surgical duration, bleeding amount, and functional items, including maximum interincisal opening, mandibular deviation on the opening pathway, malocclusion, facial paresthesia, and temporomandibular joint pain and clicking. RESULTS: The areas subjected to either approach included lower neck and subcondyle. The RM approach was used for mandibular condyle fractures with dislocation of a small bone segment. Both groups used 2 plates in all cases. Surgical duration, maximum interincisal opening, mandibular deviation, occlusion, and temporomandibular joint function at 6 months after surgery were comparable between groups. The average bleeding amount in the EAORIF group was greater than in the RM group. One patient from the RM group developed facial paresthesia that persisted for 6 months after surgery. CONCLUSIONS: It was concluded that surgical treatment was suitable for fractures of the lower neck and subcondylar. Both procedures showed good results in the functional items of this study.

Concepts: Bone, Surgery, Mandible, Joint, Cranial nerves, Temporomandibular joint, Temporomandibular joint disorder, Masseteric nerve

28

OBJECTIVE: MicroRNAs (miRNAs) are recognised as important regulators of a variety of fundamental biologic processes. Our study was undertaken to examine the role of MicroRNA-203 (miR-203) in modulating nitric oxide (NO) expression in female Sprague-Dawley rat mandibular condylar chondrocytes (MCCs) via targeting transient receptor potential vanilloid 4 (TRPV4) and to demonstrate the possible mechanism of NO inhibition by chondroprotective factor 17β-oestradiol (E2). METHODS: The expression of TRPV4 in mandibular condylar cartilage tissue and MCCs was detected by immunohistochemistry, immunofluorescence (IF), RT-PCR and Western blot, respectively. Primary SD rat MCCs were exposed to lipopolysaccharide (LPS), plus Ruthenium Red, 4α-phorbol 12,13-didecanoate (4αPDD), over-expressed miR-203 or E2 (10(-9) to 10(-6)M), the cellular supernatants were used for NO assay, miR-203 levels were measured by quantitative RT-PCR while TRPV4 expression changes were analysed by Western blot. The dual luciferase activity assay was performed to identify the target gene of miR-203. RESULTS: TRPV4 and miR-203 were stably expressed in MCCs. The MCCs' expression of NO evoked by LPS could be enhanced or depressed by Ruthenium Red or 4αPDD. The dual luciferase assay suggested that TRPV4 was the direct target gene of miR-203. Over-expression of miR-203 inhibited the expression of TRPV4 and increased NO expression in MCCs. E2 inhibited NO expression by inhibition of miR-203, which was concurrent with the up-regulation of TRPV4 expression level in MCCs. CONCLUSION: Our findings first suggested that miR-203 could up-regulate NO expression in female rat MCCs via targeting TRPV4. Moreover, the inhibition of NO by E2 might be at least in part through this mechanism.

Concepts: Antibody, Gene, Gene expression, Molecular biology, Mandible, Cartilage, Laboratory techniques, Masseteric nerve

26

Objective: To compare the efficacy of a regional masseteric nerve block (MNB) in the management of myofascial pain of masseteric origin, relative to trigger point injection (TrP-Inj) and intra-oral stabilization appliance (IOA). Study design: A retrospective chart review of 200 patients treated for myofascial pain of masseteric origin was performed. Sixty patients met the eligibility criteria and were grouped based on their treatment regimen; IOA, TrP-Inj or MNB. Pain scores recorded at pre-treatment (baseline), 30 minutes post-treatment, and 2 weeks post-treatment were analyzed. Results: Treatment with MNB resulted in significant reduction in pain at 30 minutes and two weeks post-treatment compared to TrP-Inj and IOA. Conclusion: MNB provided an immediate and sustained therapeutic effect for the management of myofascial pain for at least up to two weeks. MNB is a simple and valuable tool in the management of myogenous pain, especially for the non-orofacial pain practitioner.

Concepts: Medical statistics, Retrospective, Pain, Acupuncture, Myofascial pain syndrome, Trigger point, Masseteric nerve, Nerves

26

A 10-year-old girl presented to the Emergency Department with temporomandibular joint pain, malocclusion, and trismus after a bicycle accident.

Concepts: Mandible, Skull, Joint, Joints, Temporomandibular joint, Temporomandibular joint disorder, Dublin, Masseteric nerve

25

The abnormal cartilage/bone metabolism in unilateral condyle may be a direct factor that contributes to developmental mandibular laterognathism. However, although many molecules have been demonstrated to play crucial roles in the development of temporomandibular joints, the exact molecular mechanisms that lead to the disrupted condylar cartilage/bone development were greatly unknown. In this retrospective study, our findings revealed that serum alkaline phosphatase (ALP) level in adult patients with developmental mandibular laterognathism was lower than that in control subjects, and the serum ALP levels continue to reduce in adult patients (>20 years old). Although the exact relationship between the lower serum ALP level and developmental mandibular laterognathism is unclear, the findings further support the opinion that the condylar growth may sustain for a long time in the affected condyle in patients with developmental mandibular laterognathism and offer an alternative choice to use total serum ALP activity as a possible biomarker to assess condylar growth activity in patients with developmental mandibular laterognathism.

Concepts: Chemistry, Mandible, Alkaline phosphatase, Joint, Joints, Temporomandibular joint, Masseteric nerve

23

The purpose of our retrospective study was to evaluate the results of orthognathic treatment, distraction osteogenesis, and/or prosthetic reconstruction of the temporomandibular joints in patients with juvenile idiopathic arthritis (JIA).Twelve patients with severely affected temporomandibular joints (TMJs) and reduced ramus height were treated with mandibular advancement with orthognathic surgery (11) and additional bilateral or unilateral mandibular ramus distraction (3) or additional bilateral or unilateral prosthetic reconstruction of the TMJ (3). One patient was treated surgically with bilateral TMJ prosthetic reconstruction only. The patients were followed up clinically and radiologically with emphasis on healing, TMJ function, stability of the occlusion, skeletal stability, and facial appearance for an average of 2.3 years after the final surgery. The mean mandibular advancement was 10.1 mm. The mean relapse at pogonion was 2.1 mm, which represents 20.8% of the surgical advancement. The occlusion was stable in 11/12 patients. The TMJ function was good and the facial esthetics improved in all patients. Orthognathic treatment and mandibular ramus distraction osteogenesis provide beneficial lengthening of the mandibular body in JIA patients with asymptomatic and stabile condyles. In adult patients with relapse of the disease or postoperative condylar relapse prosthetic total joint replacement is a reliable and safe alternative.

Concepts: Mandible, Joint, Arthritis, Joints, Oral and maxillofacial surgery, Temporomandibular joint, Masseteric nerve, Stylomandibular ligament

2

The Ehlers-Danlos syndromes (EDS) are hereditary disorders that affect the connective tissue and collagen structures in the body. Several types of EDS have been identified. Oral and mandibular structures, which include oral soft tissue, dentition, facial and head pain, and the functioning of the temporomandibular joint (TMJ), are variably affected in the various types of EDS. These various manifestations of EDS have been noted for many years, but newer diagnostic techniques and studies are shedding additional light on the challenges faced by EDS patients in the area of oral and mandibular disorders. Further, the impact of temporomandibular disorder (TMD) on musculoskeletal dysfunction and vice versa, make this an important feature to recognize. Oral and mandibular hypermobility of the TMJ with associated consequences of EDS are noted. These features, diagnostic parameters and treatment procedures are presented. © 2017 Wiley Periodicals, Inc.

Concepts: Collagen, Mandible, Joint, Connective tissue, Ehlers-Danlos syndrome, Temporomandibular joint, Temporomandibular joint disorder, Masseteric nerve

0

To evaluate the usefulness of diet board feeding as a model for temporomandibular joint (TMJ) research, characterize dietary loading-related morphometric changes in the mandibular condylar cartilage of aging rats, and investigate changes in type I and type II collagen expression in different age, sex, and diet groups.

Concepts: Death, Mandible, Joint, Joints, Temporomandibular joint, Temporomandibular joint disorder, Masseteric nerve

0

A retrospective study was performed to determine the efficacy of a tethering procedure developed to achieve a more rigid fixation and more reliable outcome in patients with refractory dislocation of the temporomandibular joint. The cases of eight patients with dementia and systemic diseases who underwent this technique were reviewed. In these eight patients, the condyles of 13 joints were ligated using wire between screws placed in the eminence and condylar head. Additional screw-wire ligations were applied to reinforce the restraint of movement in five of the 13 joints with suspected uncontrolled dislocation. The procedure was performed successfully, and the patients were followed-up for an average of 25months. In one patient, dislocation recurred 1year postoperatively due to wire breakage. The five joints in which a double set of screw-wire tethering was applied showed no recurrence or wire disturbance. This technique may, therefore, have short-term efficacy in cases that are refractory to standard procedures, although the material used for ligation should be investigated further. This approach can contribute to the quality of life of patients, particularly those with a short life-expectancy.

Concepts: Bone, Patient, Mandible, Joint, Joints, Temporomandibular joint, Jaw, Masseteric nerve