Evaluation of the effects of arthrocentesis combined with occlusal stabilization splint on disc displacement without reduction-induced acute and closed lock. A prospective cohort study.

OBJECTIVE: Disc displacement without reduction (DDWoR) of the temporomandibular joint is associated with limited mouth opening and arthralgia. In the natural course of the disorder, there is a tendency to progress to degenerative joint diseases. First-line treatment aims to reduce pain and restore joint function. The current study aims to examine the efficacy of an occlusal stabilization splint applied simultaneously with arthrocentesis as first-line treatment in acute and chronic closed-locks. MATERIALS AND METHODS: The present prospective clinical trial included 40 patients who were diagnosed with DDWoR induced chronic (Group 1, n=23) and acute (Group 2, n=17) closed-locks. All participants underwent single session arthrocentesis and were applied occlusal stabilization splints. Maximum mouth opening amounts (MMO), Visual analogue scale (VAS), and McGill pain questionnaire (MPQ) scores were evaluated at baseline, on the operation day, and on seven days after the intervention. The obtained data was analyzed with the Wilcoxon signed-rank, Mann-Whitney U, Fisher's exact, Spearman's correlation tests. RESULTS: According to the baseline data, a significant increase was observed in the amount of MMO in postoperative measurements (p=0.001 and p<0.001). A statistically significant decrease in MPQ scores was observed in the postoperative period (p<0.001 and p<0.001). While a significant difference was observed between the postoperative VAS scores, the scores of Group 2 were lower (p=0.018). CONCLUSION: Although combined arthrocentesis and occlusal stabilization splint provided significant changes for acute and chronic closed-locks in line with first-line treatment goals, acute closed-lock with arthralgia responded better. CLINICAL TRIAL REGISTRATION NUMBER: NCT05671549.

A case report of temporomandibular joint tuberculosis in a neonate with eleven years follow-up.

Background: Tuberculosis of the Temporomandibular joint (TMJ) in a neonate is a rare entity. Undiagnosed/mismanaged tuberculosis can disseminate and be life-threatening to the patient. The purpose is to present a case of tubercular osteomyelitis of TMJ in a neonate with eleven years of follow-up. Case presentation: A one-and-a-half-month-old male neonate presented with a firm swelling in front of the left ear for the past 20 days. Ultrasound presented an avascular, hypoechoic lesion of 34*25*25mm. Irregular margins of underlying bone could suggest erosion. Aspiration revealed pus. ZN staining of pus revealed Mycobacterium tuberculosis. After draining the pus, the patient underwent antitubercular therapy. He revisited at ten years of age with a complaint of asymmetry. Although the patient got cured of his tuberculosis, investigations rose to a diagnosis of condylar hypoplasia with ipsilateral coronoid enlargement. A distraction of the mandible improved facial symmetry. Conclusion: Although pus revealed the presence of Acid-fast bacilli, it is not evident until there is a significant bacterial load. Escalation of tests with higher sensitivity is needed to diagnose tubercular osteomyelitis of TMJ. Patients must be made aware of possible sequelae of tubercular osteomyelitis of TMJ and need appropriate management. Oblique osteotomy at the angle and distraction improves both horizontal and vertical components of the mandible and thus improves symmetry. To the best of the author's knowledge, the following is the first case of primary tuberculosis of TMJ in a neonate and with such an extended follow-up.

Prevalence of temporomandibular disorders and bruxism in seniors.

BACKGROUND: Information on the prevalence of temporomandibular disorders (TMD) or possible/probable bruxism in seniors is heterogeneous and sparse. OBJECTIVES: To elucidate the prevalence of TMD and possible/probable bruxism in German adults aged 60 years and older. METHODS: Participants of the Interdisciplinary Longitudinal Study of Adult Development and Aging (ILSE) born between 1950-1952 (C1) and 1930-1932 (C2) were examined in 2014-2016 (fourth wave). The participants were surveyed and clinically examined by one calibrated examiner. Two questions of the Patient Health Questionnaire (PHQ) were utilized to evaluate self-reported bruxism. The clinical examination included signs of probable bruxism and the RDC/TMD examination protocol. RESULTS: Data of 191 participants was available. No RDC/TMD diagnosis was made in 83.2 %. Of the participants, 15.2 % received a single diagnosis and 1.6 % multiple diagnoses that included disc displacements (9.4 %) and degenerative joint diseases (8.9 %). A total of 24.7 % reported bruxism that included self-reported awake bruxism in 11.9 % and sleep bruxism in 16.2 %. Wear was clinically identified in 27.2 % of the participants. No sex-related differences were observed. Significant differences were detected for probable bruxism between C1 (14.1 %) and C2 (54.3 %). CONCLUSION: In the German population aged 60 years and older, the prevalence of TMD is 16.8 %. TMD is characterized by temporomandibular joint disorders, including disc displacements and degenerative joint disorders. Bruxism was observed in a quarter of the old population.

Does intra-articular injection of tenoxicam after arthrocentesis heal outcomes of temporomandibular joint osteoarthritis? A randomized clinical trial.

BACKGROUND: Temporomandibular joint osteoarthritis (TMJ-OA) is a degenerative disease and manifests itself with pain and limitation of movement in the jaws. Arthrocentesis alone or in combination with intraarticular injections is one of the most commonly used treatment methods in these patients. The aim of the study is to examine the effectiveness of arthrocentesis plus tenoxicam injection and to compare it with arthrocentesis alone in patients with TMJ-OA. METHODS: Thirty patients with TMJ-OA who were treated randomly with either arthrocentesis plus tenoxicam injection (TX group) or arthrocentesis alone (control group) were examined. Maximum mouth opening (MMO), visual analog scale (VAS) pain values, and joint sounds were the outcome variables, which were evaluated at pre-treatment and at 1, 4, 12, and 24 weeks after treatment. Statistical significance was set at p < 0.05. RESULTS: The gender distribution and mean age were not significantly different between the two groups. Pain values (p < 0.001), MMO (p < 0.001), and joint sounds (p < 0.001) improved significantly in both groups. However, there was no significant difference between the groups in terms of outcome variables [pain (p = 0.085), MMO (p = 0.174), joint sounds (p = 0.131)]. CONCLUSIONS: Arthrocentesis plus tenoxicam injection showed no better outcomes in terms of MMO, pain, and joint sounds compared with arthrocentesis alone in patients with TMJ-OA. TRIAL REGISTRATION: Injection of Tenoxicam Versus Arthrocentesis Alone in the Treatment of Temporomandibular Joint Osteoarthritis, NCT05497570. Registered 11 May 2022. Retrospectively registered, https://register. CLINICALTRIALS: gov/prs/app/action/SelectProtocol?sid=S000CD7A&selectaction=Edit&uid=U0006FC4&ts=6&cx=f3anuq.

The Influence of Visual Input on Electromyographic Activity and Patterns of Masticatory and Cervical Spine Muscles in Emmetropic Caucasian Subjects by Gender.

(1) Background: The objective of the research was to analyze the change of visual input on electromyographic activity and patterns of masticatory and cervical spine muscles in emmetropic Caucasian subjects by gender. Supposedly, visual input should not influence activity and electromyographic patterns of masticatory and cervical spine muscles in emmetropic Caucasian subjects by gender. (2) Methods: After applying the inclusion criteria, 50 emmetropic Caucasian subjects were included in the study. Four muscle pairs were analyzed: the temporalis muscle (TA), the masseter muscle (MM), the digastric muscle (DA), and the sternocleidomastoid muscle (SCM), during resting and functional activity. (3) Results: It was observed that there were no significant statistical differences in activity and bioelectrical patterns between open and closed eyes in women and men, with the exception of clenching on dental cotton rollers in DA-left and DA mean between tests in women. The observed statistical results had a small effect size, successively equal to 0.32 and 0.29. (4) Conclusions: Changes in the influence of visual input do not affect electromyographic activity and patterns of masticatory and cervical spine muscles in emmetropic Caucasian women and men.

Exploratory Study on Central Sensitization and Bioelectrical Activity of the Selected Masticatory Muscles in Subjects with Myopia.

BACKGROUND: Myopia is one of the most common eye disorders involving abnormal focusing of light rays. The studies recognize the association between the stomatognathic and visual systems. This compound may have a neurological basis associated with disorders such as central sensitization. The main aim of this study was to evaluate the influence of central sensitization on the bioelectrical activity of selected muscles of the masticatory organ in subjects with myopia. METHODS: Selected masticatory and cervical spine muscles were analyzed using an eight-channel BioEMG III electromyograph. Central sensitization was analyzed using the central sensitization inventory. RESULTS: Statistical analysis revealed significantly higher scores on the central sensitization inventory in subjects with axial myopia compared to subjects without refractive error. Repeated positive correlations were observed in the sternocleidomastoid muscle activity and negative correlations in the digastric muscle activity during open and closed eyes in myopic subjects. CONCLUSIONS: Subjects with myopia have an increased score in the central sensitization inventory. The increase in the central sensitization inventory score is connected with the changes within the electromyographic activity of the masticatory and neck muscles. The effect of central sensitization on masticatory muscle activity in myopic subjects requires further study.

Oral Glucosamine in the Treatment of Temporomandibular Joint Osteoarthritis: A Systematic Review.

Temporomandibular disorders (TMDs) occur frequently within the general population and are the most common non-dental cause of orofacial pain. Temporomandibular joint osteoarthritis (TMJ OA) is a degenerative joint disease (DJD). There have been several different methods of treatment of TMJ OA listed, including pharmacotherapy among others. Due to its anti-aging, antioxidative, bacteriostatic, anti-inflammatory, immuno-stimulating, pro-anabolic and anti-catabolic properties, oral glucosamine seems to be a potentially very effective agent in the treatment of TMJ OA. The aim of this review was to critically assess the efficacy of oral glucosamine in the treatment of TMJ OA on the basis of the literature. PubMed and Scopus databases were analyzed with the keywords: (temporomandibular joints) AND ((disorders) OR (osteoarthritis)) AND (treatment) AND (glucosamine). After the screening of 50 results, eight studies have been included in this review. Oral glucosamine is one of the symptomatic slow-acting drugs for osteoarthritis. There is not enough scientific evidence to unambiguously confirm the clinical effectiveness of glucosamine supplements in the treatment of TMJ OA on the basis of the literature. The most important aspect affecting the clinical efficacy of oral glucosamine in the treatment of TMJ OA was the total administration time. Administration of oral glucosamine for a longer period of time, i.e., 3 months, led to a significant reduction in TMJ pain and a significant increase in maximum mouth opening. It also resulted in long-term anti-inflammatory effects within the TMJs. Further long-term, randomized, double-blind studies, with a unified methodology, ought to be performed to draw the general recommendations for the use of oral glucosamine in the treatment of TMJ OA.

Evaluation of temporomandibular joint dysfunction in traumatic brain injury patients.

BACKGROUND: The aim of this study was to evaluate the frequency of temporomandibular joint dysfunction and related factors in patients with traumatic brain injury. METHODS: A total of 60 participants, 30 patients with traumatic brain injury and 30 healthy volunteers of similar age, have been included in this study, which was designed as a hospital-based cross sectional study. Fonseca questionnaire was used to evaluate and classify the temporomandibular joint dysfunction. Temporomandibular joint range of motion was evaluated with a digital calliper, and masticatory muscles pressure pain threshold was evaluated with an algometer. Labial commissure angle measurement was used to evaluate the severity of facial paralysis. Complications related to traumatic brain injury were recorded in patients with traumatic brain injury. RESULTS: According to Fonseca questionnaire score, 80% of traumatic brain injury patients and 16.7% of the control group had temporomandibular dysfunction (p < .001). In the intergroup comparison, a significant decrease was found in all temporomandibular range of motion and masticatory muscles pressure pain threshold parameters in favour of the traumatic brain injury group (p < .001). Labial commissure angle and Fonseca questionnaire scores were higher in the traumatic brain injury group (p < .001). The frequency of temporomandibular dysfunction was more common in traumatic brain injury patients with headache than in those without headache, as shown by the results of the Fonseca questionnaire (p = .044). CONCLUSION: Compared to healthy controls, patients with traumatic brain injury experienced issues with the temporomandibular joint more frequently. Additionally, TBI patients with headaches had a greater frequency of temporomandibular joint dysfunction. Therefore, it is advised to check for temporomandibular joint dysfunction in traumatic brain injury patients during follow-up. In addition, the presence of headache in traumatic brain injury patients may be a stimulant for temporomandibular joint dysfunction.

The Longitudinal Relationship between Jaw Catching/Locking and Pain.

Orofacial pain and joint-related dysfunction can negatively affect daily jaw function. A common cause for limitations in jaw movements is joint-related dysfunction such as various forms of catching and locking. However, knowledge is limited regarding the development and natural course of joint-related jaw dysfunction and its relationship to the onset and course of orofacial pain. Therefore, the aim was to evaluate the incidence, prevalence, and gender differences in jaw catching/locking over time and in relation to orofacial pain in the general population. Data from 3 validated screening questions on orofacial pain and jaw catching/locking were collected from all routine dental checkups in the Public Dental Health Services in Västerbotten, Sweden, from 2010 to 2017. Logistic generalized estimating equation was used to account for repeated observations and Poisson regression for incidence analysis. In total, 180,308 individuals (aged 5-104 y) were screened in 525,707 dental checkups. In 2010, based on 37,647 individuals, the prevalence of self-reported catching/locking was higher in women than in men (3.2% vs. 1.5%; odds ratio, 2.11; 95% confidence interval [CI], 1.83-2.43), and this relationship and magnitude remained similar throughout the study period. The annual incidence rate was 1.1% in women and 0.5% in men. Women were at a higher risk than men for reporting both first onset (incidence rate ratio [IRR], 2.29; 95% CI, 2.11-2.49) and persistent (IRR, 2.31; 95% CI, 2.04-2.63) catching/locking. For the onset subcohort (n = 135,801), an independent onset of orofacial pain or jaw catching/locking exclusively was reported by 84.1%, whereas a concurrent onset was reported by 13.4%. Our findings of higher incidence, prevalence, and persistence in women than in men indicate that the gender differences seen for orofacial pain are evident also for jaw catching/locking. The findings also suggest independent onset of self-reported catching/locking and orofacial pain, which reinforces the pathophysiological differences between these conditions.

Development of the Primary and Secondary Jaw Joints in the Mouse.

This study assesses the morphogenesis of the primary and secondary jaw joints. A collection of 11 murine heads, ranging from prenatal stage E13.5 to postnatal stage P10, were prepared as histological serial sections (thickness 8-10µm) and stained conventionally in order to examine them with light microscopy. Next, the regions of the developing temporomandibular joint and the middle ear ossicles were three dimensionally reconstructed using AnalySIS® software. This study gained new insight into the spatio-temporal development of the temporomandibular joint and the auditory ossicles. Furthermore, we newly visualized in 3D that during the developmental period from stages E16 to P4 two morphologically well-functional joints (the primary and secondary jaw joints) exist on either side and are mechanically connected via Meckel's cartilage. Potential separation mechanisms of these two joints are discussed and options for mathematical analysis are suggested.

Therapeutic effects of kartogenin on temporomandibular joint injury by activating the TGF-ß/SMAD pathway in rats.

Patients with temporomandibular dysfunction (TMD) usually suffer from pathology or malpositioning of the temporomandibular joint (TMJ) disk, leading to the degenerative lesion of condyles. Kartogenin can promote the repair of damaged cartilage. This study aimed to explore whether intra-articular injection of kartogenin could alleviate the TMJ injury induced by type II collagenase. We measured the head withdrawal threshold and found that kartogenin alleviated the pain around TMD induced by type II collagenase. We observed the morphology of the condylar surface and found that kartogenin protected the integration of the condylar surface. We analyzed the density of the subchondral bone and found that kartogenin minimized the damage of TMJ injury to the subchondral bone. We next explored the histological changes and found that kartogenin increased the thickness of the proliferative layer and more collagen formation in the superficial layer. Then, to further ensure whether kartogenin promotes cell proliferation in the condyle, we performed immunohistochemistry of proliferating cell nuclear antigen (PCNA). The ratio of PCNA-positive cells was significantly increased in the kartogenin group. Next, immunofluorescence of TGF-ß1 and SMAD3 was performed to reveal that kartogenin activated the TGF-ß/SMAD pathway in the proliferative layer. In conclusion, kartogenin may have a therapeutic effect on TMJ injury by promoting cell proliferation in cartilage and subchondral bone. Kartogenin may be promising as an intra-articular injection agent to treat TMD.

Association of HMGB1 levels in synovial fluid with the severity of temporomandibular joint osteoarthritis.

BACKGROUND: HMGB1 usually serves as a damage-associated molecular pattern (DAMP) molecule (also known as alarmin) that regulates the inflammatory and immune responses via different receptors or direct uptake. Numerous studies have reported the association between HMGB1 and inflammatory diseases; however, its role in temporomandibular joint (TMJ) osteoarthritis (OA) has not been elucidated. In this retrospective study, we aimed to investigate HMGB1 levels in the synovial fluid (SF) in patients with TMJOA and TMID, their correlation with TMJOA and TMID severity, and the therapeutic effect of sodium hyaluronate (hyaluronic acid, HA) on TMJOA. METHODS: SF samples were analyzed for 30 patients with TMJ internal derangement (TMJID) and TMJOA, along with visual analog scale (VAS) scores, radiographic stages, and mandibular functional limitations. The SF levels of HMGB1, IL-1ß, IL-18, PGE2, RAGE, TLR4, and iNOS were determined via an enzyme-linked immunosorbent assay. To evaluate the therapeutic effects of HA, pre-treatment and post-treatment clinical symptoms were also compared in patients of the TMJOA group who had received an intra-articular injection of HA. RESULTS: VAS and Jaw Functional Limitation Scale (JFLS) scores were significantly higher in the TMJOA group than in the TMNID group, as were SF levels of HMGB1, TLR4, IL-1ß, IL-18, PGE2, and iNOS. The synovial HMGB1 level was positively correlated with the VAS score (r = 0.5512, p = 0.0016) and mandibular functional limitations (r = 0.4684, p = 0.0054). The cut-off value for the HMGB1 level as a diagnostic biomarker was 986.8 pg/ml. The SF level of HMGB1 yielded an area under the curve value (AUC) of 0.8344 for predicting TMJOA. HA alleviated TMJ disorders by significantly reducing the VAS score and improving the maximum extent of mouth opening in both the TMJID and TMJOA groups (p < 0.05). Moreover, patients in both the TMJID and TMJOA groups exhibited significant improvement in the JFLS score following HA treatment. CONCLUSIONS: Our results indicate that HMGB1 is a potential marker for predicting the severity of TMJOA. Intra-articular HA injection exerts a positive therapeutic effect on TMJOA; however, further investigations are warranted to validate its therapeutic effect in the late phase of visco-supplementation treatment.

Assessing change in functional outcomes and quality of life in myogenic temporomandibular disorders undergoing botulinum toxin injection: A before-and-after comparison.

PURPOSE: This prospective study aimed to evaluate the changes in functional outcomes and quality of life after the injection of botulinum toxin (BTX) into the masticatory muscles for the management of myogenic temporomandibular disorders (TMDs). MATERIALS AND METHODS: This study was conducted with 45 individuals who presented with clinically myogenic TMDs according to the Diagnostic Criteria for Temporomandibular Disorders. All patients received BTX injections in the temporalis and masseter muscles. The Oral Health Impact Profile-Temporomandibular Dysfunction (OHIP-TMD) questionnaire was used to evaluate the effects of treatment on quality of life. The OHIP-TMD, visual analogue scale (VAS), and maximum mouth opening (MMO) scores before and 3 months after BTX injection were evaluated. RESULTS: The preoperative and postoperative assessments revealed a statistically significant reduction (p ≤ 0.001) in the average overall OHIP-TMD scores. A significant increase in the MMO scores and a significant decrease in the VAS scores were observed (p < 0.001). CONCLUSIONS: The injection of BTX into the masticatory muscles is beneficial for improving the clinical and quality of life parameters in the management of myogenic TMD.

Long term complications of costochondral graft reconstruction in temporomandibular joint ankylosis of the young- A Systematic Review.

Costochondral graft has been a popular reconstruction choice in the past for temporomandibular joint ankylosis in young individuals. However, accounts of growth hampering complications have also been observed. Our systematic review aims to compile all existing evidence to determine the occurrence of these unfavourable clinical outcomes as well as factors affecting them to provide a better judgement on further use of these grafts. A systematic review was conducted following PRISMA guidelines where databases like PubMed, Web of science and Google Scholar were searched for the purpose of data extraction. Observational studies performed on patients younger than 18 years of age with a minimum follow-up of one year were selected. Incidence of long term complications like reankylosis, abnormal graft growth, facial asymmetry and others were considered as outcome variables. Eight articles with a total of 95 patients were selected where complications like reankylosis (6.32%), graft overgrowth (13.70%), insufficient graft growth (22.11%), no graft growth (3.20%) and facial asymmetry (20%) were reported. Other complications like mandibular deviation (3.20%), retrognathia (1.05%) and prognathic mandible (3.20%) were also observed. Our review concludes that the occurrence of these complications was noteworthy. Thus use of costochondral graft for reconstruction in temporomandibular ankylosis in young patients holds significant risk in development of growth abnormalities. However, modifications in surgical procedure such as use of appropriate graft cartilage thickness and the presence and type of interpositional material can favourably affect the frequency and type of growth abnormality.

Evaluation of stress distribution values at the temporomandibular joint and distalization of teeth during en-masse retraction of the mandibular dentition using buccal shelf bone screws: A FEM study.

INTRODUCTION: Present Finite-element-method (FEM) study evaluates the stress distribution values at the Temporomandibular-Joint (TMJ) during en-masse retraction of the mandibular dentition using buccal shelf bone screws with varying magnitudes of forces. MATERIAL AND METHODS: Nine replicas of a pre-existing three-dimensional finite element model of the craniofacial skeleton and articular disc from Cone-Beam-Computed-Tomography (CBCT) data and Magnetic-Resonance-Imaging (MRI) data of a patient were used. Buccal shelf (BS) bone screws were inserted buccal to the mandibular second molar region. Forces of magnitudes 250 gm, 350 gm and 450 gm were applied through NiTi coil springs along with stainless-steel archwires of sizes 0.016 × 0.022-inch, 0.017 × 0.025-inch and 0.019 × 0.025-inch. RESULTS: On the articular disc, the maximum stress was observed at the inferior region and the inferior part of the anterior and posterior zone at all force levels. The stress on the articular disc and displacement of teeth increased with increase in force levels in all the 3 archwires. The maximum stress at the articular disc and displacement of teeth was observed for 450 gm force and the least for 250 gm force. No significant difference in the amount of displacement of teeth or the stresses produced at the articular disc was seen with increasing the size of the archwire. CONCLUSION: With the present FEM study, we can deduce that it is better to use forces of lower levels on patients with temporomandibular-disorders (TMD) so as to reduce the stresses produced at the TMJ to avoid worsening of the TMD condition.

Effects of orthodontic camouflage treatment vs orthodontic-orthognathic surgical treatment on condylar stability in Class II hyperdivergent patients with severe temporomandibular joint osteoarthrosis: a retrospective observational study.

OBJECTIVES: To investigate the differences in profile changes and stability of the condyles between orthodontic camouflage treatment assisted by vertical control and that accomplished via orthognathic surgery in Class II hyperdivergent patients with TMJ osteoarthrosis (TMJOA). MATERIALS AND METHODS: This study included 27 Class II hyperdivergent TMJOA patients (54 condyles) who received orthodontic camouflage treatment (13 patients) or orthognathic surgery (14 patients) Cone-beam computerized tomography (CBCT) scans were taken before treatment (T1) and 1 year after treatment (T2). Cephalometric and TMJ measurement analyses were conducted to evaluate the change in profile and condyles from T1 to T2 using independent samples t-test and paired t-test. Three-dimensional (3D) deviation analysis was also performed to evaluate the stability of condyles from T1 to T2. RESULTS: Both groups showed significant profile improvement from T1 to T2. The changes in Z angle and ANB angle were larger in the surgical group than in the orthodontic group. Condylar width, length, and height remained stable after treatment in the orthodontic group (P > .05), while they reduced by 0.67 ± 0.85 mm, 1.14 ± 1.10 mm, and 1.07 ± 1.34 mm, respectively, in the surgical group (P < .05). Superior, posterior, medial, and lateral joint spaces were significantly reduced in the orthodontic group (P < .05). 3D deviations intuitively showed that condylar bone in the orthodontic group was more stable than that in the surgical group. CONCLUSIONS: For Class II hyperdivergent patients with severe TMJOA, orthodontic camouflage treatment with vertical control can effectively maintain the stability of condyles while significantly improving the profile. Surgical treatment yields a better profile but may increase the risk of condyle resorption.

Effects of osseous structure based on three-dimensional reconstructive imaging evaluation in the assessment of temporomandibular joint disc position.

OBJECTIVES: This pilot morphological study aimed to investigate the association between anterior disc displacement (ADD) and the status of the mandibular condyle and articular fossa. MATERIALS AND METHODS: Thirty-four patients were divided into a normal articular disc position group and an ADD with and without reduction group. Images reconstructed were used to determine multiple group comparisons of these three different types of disc position, and the diagnostic efficacy for the morphological parameters with significant group difference was analyzed to assess. RESULTS: The condylar volume (CV), condylar superficial area (CSA), superior joint space (SJS), and medial joint space (MJS) all exhibited obvious changes (P < 0.05). Additionally, they all had a reliable diagnostic accuracy in differentiating between normal disc position and ADD with an AUC value from 0.723 to 0.858. Among them, the CV, SJS, and MJS (P < 0.05) had a significantly positive impact on the groups by analysis of multivariate logistic ordinal regression model. CONCLUSIONS: The CV, CSA, SJS, and MJS are significantly associated with different disc displacement types. The condyle in ADD exhibited altered dimensions. These could be promising biometric markers for assessing ADD. CLINICAL RELEVANCE: The morphological changes of mandibular condyle and glenoid fossa were significantly influenced by the status of disc displacement, and condyles with disc displacement had three-dimensionally altered condylar dimensions, irrespective of age and sex.

Temporomandibular Joint Gape Angles in Normal and Painful Domestic Felines.

The purpose of this study was to determine and compare the gape angles (temporomandibular joint range of motion with mouth opening) of conscious and anesthetized domestic felines and to compare gape angles with and without evidence of oral pain. This prospective study evaluated the gape angle of 58 domestic felines. The cats were grouped into painful (n = 33) and nonpainful cohorts (n = 25) and gape angles were compared during conscious and anesthetized conditions. Gape angles were determined based on measurements of the maximal interincisal distance and lengths of the mandible and maxilla followed by calculation of the law of cosines. The mean feline gape angle (standard deviation) was determined to be 45.3° (8.6°) and 50.8° (6.2°) for conscious and anesthetized felines respectively. There was no significant difference between painful and non-painful feline gape angles during conscious (P = .613) or anesthetized (P = .605) evaluations. There was a significant difference between anesthetized and conscious gape angles (P < .001) for both painful and non-painful cohorts. This study determined the standardized, normal feline temporomandibular joint (TMJ) gape angle in both conscious and anesthetized states. This study suggests that the feline gape angle is not a useful indicator of oral pain. By determining the feline gape angle, which was previously unknown, further evaluation of its utility as a non-invasive clinical parameter for evaluation of restrictive TMJ motions as well as its use for serial evaluations may be pursued.

[Quality Evaluation of Temporomandibular Joint Images from 3 High-resolution Dynamic Sequences].

Objective To compare the image quality of three high-resolution dynamic MRI methods for evaluating the motion of temporomandibular joint disc and condyle. Methods Twenty-five patients with suspected temporomandibular joint disorders were examined by single-shot fast spin-echo (SSFSE),fast imaging employing steady-state acquisition (FIESTA),and spoiled gradient echo (SPGR) on the oblique sagittal position.Two radiologists performed subjective and objective evaluation on the images with double-blind method.The subjective evaluation included the signal intensity of mandibular condyle,articular disc,soft tissue around articular disc,and lateral pterygoid muscle,the contrast between articular disc and condyle,the contrast between articular disc and surrounding soft tissue,condylar motion,and disc movement.The objective evaluation indexes included image signal intensity,signal-to-noise ratio (SNR),and contrast-to-noise ratio (CNR).The subjective and objective indexes of the image quality were compared between the three sequences. Results The SSFSE sequence had lower signal intensity of articular disc and higher signal intensity of condyle and surrounding soft tissue than FIESTA and SPGR sequences (all P<0.001).The SPGR sequence showed higher signal intensity of lateral pterygoid muscle than the SSFSE and FIESTA sequences (P=0.017,P<0.001).Among the three sequences,SSFSE sequence showed the clearest articular disc structure (χ2=41.952,P<0.001),the strongest contrast between articular disc and condyle (χ2=35.379,P<0.001),the strongest contrast between articular disc and surrounding soft tissue (χ2=27.324,P<0.001),and the clearest movement of articular disc (χ2=44.655,P<0.001).SSFSE and FIESTA sequences showed higher proportion of disc displacement and reduction than SPGR sequence (all P<0.001).The CNR (χ2=21.400,P<0.001),SNR (χ2=34.880,P<0.001),and condyle signal intensity (F=337.151,P<0.001) demonstrated differences among SSFSE,FIESTA,and SPGR sequences.The CNR of SSFSE sequence was higher than that of FIESTA sequence (P<0.001),while it had no significant difference between SSFSE and SPGR sequences (P=0.472).In addition,the SSFSE sequence had higher SNR and signal intensity than FIESTA and SPGR sequences (all P<0.001). Conclusion The best image quality can be observed from SSFSE sequence where both the structure and movement of temporomandibular joint are well displayed.Therefore,SSFSE is preferred for the examination of temporomandibular joint movement.