A Three-branch Jointed Feature and Topology Decoder guided by game-theoretic interactions for temporomandibular joint segmentation.

Segmentation of the temporomandibular joint (TMJ) disc and condyle from magnetic resonance imaging (MRI) is a crucial task in TMJ internal derangement research. The automatic segmentation of the disc structure presents challenges due to its intricate and variable shapes, low contrast, and unclear boundaries. Existing TMJ segmentation methods often overlook spatial and channel information in features and neglect overall topological considerations, with few studies exploring the interaction between segmentation and topology preservation. To address these challenges, we propose a Three-Branch Jointed Feature and Topology Decoder (TFTD) for the segmentation of TMJ disc and condyle in MRI. This structure effectively preserves the topological information of the disc structure and enhances features. We introduce a cross-dimensional spatial and channel attention mechanism (SCIA) to enhance features. This mechanism captures spatial, channel, and cross-dimensional information of the decoded features, leading to improved segmentation performance. Moreover, we explore the interaction between topology preservation and segmentation from the perspective of game theory. Based on this interaction, we design the Joint Loss Function (JLF) to fully leverage the features of segmentation, topology preservation, and joint interaction branches. Results on the TMJ MRI dataset demonstrate the superior performance of our TFTD compared to existing methods.

Comparison of condylar position after free fibular flap mandibular reconstruction using computer-assisted and traditional techniques.

OBJECTIVES: To compare the changes in condylar position after mandibular reconstruction with free fibular flap(FFF) and the differences between computer-assisted techniques and traditional methods on CT images. METHODS: Thirty-four patients who underwent mandibular reconstruction with free fibular flap were selected according to the inclusion and exclusion criteria. In the 3D group, virtual surgical planning (VSP) with osteotomy cutting plate and placement guiding plate were used, while the traditional group underwent freehand reconstruction. The CT data of 68 temporomandibular joints (TMJs) were recorded before and immediately after surgery. The condylar position was evaluated by measuring the anterior space (AS), posterior space (PS) and superior space (SS), and the ln (PS/AS) was calculated according to the method proposed by Pullinger and Hollender. RESULTS: In the patients included in the 3D group, the condyle on the ipsilateral side moved slightly backward; however, in the patients in the traditional group, the ipsilateral side moved considerably anteroinferior. No obvious changes on the contralateral side were noted. In the 3D group, 33% of ipsilateral condyles were in the posterior position postoperatively when compared with the preoperative position (13%). In the traditional group, the number of ipsilateral condyles in the anterior position increased from 4 to 10, accounting for 53% postoperatively. Contrary to the traditional group, the 3D group presented less condylar displacement on the ipsilateral side postoperatively. CONCLUSIONS: This study showed a decreased percentage of change in condylar position postoperatively when VSP was used. Virtual surgical planning improved the accuracy of FFF mandibular reconstruction and made the condylar position more stable.

Fossils document evolutionary changes of jaw joint to mammalian middle ear.

The dual jaw joint of Morganucodon1,2 consists of the dentary-squamosal joint laterally and the articular-quadrate one medially. The articular-quadrate joint and its associated post-dentary bones constitute the precursor of the mammalian middle ear. Fossils documenting the transition from such a precursor to the mammalian middle ear are poor, resulting in inconsistent interpretations of this hallmark apparatus in the earliest stage of mammaliaform evolution1-5. Here we report mandibular middle ears from two Jurassic mammaliaforms: a new morganucodontan-like species and a pseudotribosphenic shuotheriid species6. The morganucodontan-like species shows many previously unknown post-dentary bone morphologies1,2 and exhibits features that suggest a loss of load-bearing function in its articular-quadrate joint. The middle ear of the shuotheriid approaches the mammalian condition in that it has features that are suitable for an exclusively auditory function, although the post-dentary bones are still attached to the dentary. With size reduction of the jaw-joint bones, the quadrate shifts medially at different degrees in relation to the articular in the two mammaliaforms. These changes provide evidence of a gradual loss of load-bearing function in the articular-quadrate jaw joint-a prerequisite for the detachment of the post-dentary bones from the dentary7-12 and the eventual breakdown of the Meckel's cartilage13-15 during the evolution of mammaliaforms.

[Preliminarily study of arthrocentesis combined with liquid phase concentrated growth factor injection in the treatment of unilateral temporomandibular joint osteoarthritis].

OBJECTIVE: To observe the clinical effect of arthrocentesis combined with liquid phase concentrated growth factor (CGF) injection in the treatment of unilateral temporomandibular joint osteoarthritis (TMJOA), in order to provide a new treatment option for TMJOA patients. METHODS: In this non-randomized controlled study, patients diagnosed with unilateral TMJOA who visited the center for temporomandibular joint disorder and orofacial pain of Peking University School and Hospital of Stomatology from June 2021 to January 2023 were selected as research objects. The patients were divided into experimental group and control group, which were selected by patients themselves. The experimental group received arthrocentesis combined with liquid phase CGF injection and the control group received arthrocentesis combined with HA injection. Both groups were treated 3 times, once every two weeks. The clinical effect was evaluated by the maximum mouth opening, pain value and the degree of mandibular function limitation 6 months after treatment. The change of condylar bone was evaluated by cone beam CT (CBCT) image fusion technology before and after treatment. RESULTS: A total of 20 patients were included in the experimental group, including 3 males and 17 females, with an average age of (34.40±8.41) years. A total of 15 patients were included in the control group, including 1 male and 14 females, with an average age of (32.20±12.00) years. There was no statistical difference in general information between the two groups (P > 0.05). There were no statistical differences in the mouth opening, pain value and the degree of jaw function limitation between the two groups before treatment (P > 0.05), and all of them improved 6 months after treatment compared with before treatment (P < 0.05). However, the mouth opening of experimental group was significantly higher than that of control group 6 months after treatment (P < 0.05), and the degree of jaw function limitation was significantly lower than that of control group (P < 0.05). CBCT 2D images showed that the condylar bone of both groups was smoother after treatment than before treatment, and image fusion results showed that 10 patients (50.0%) in the experimental group and 5 patients (33.3%) in the control group had reparative remodeling area of condylar bone, and there was no statistical difference between them (P > 0.05). Except for one CGF patient, the other patients in both groups had some absorption areas of condylar bone. CONCLUSION: The arthrocentesis combined with liquid phase CGF injection can improve the clinical symptoms and signs of unilateral TMJOA patients in short term, and is better than HA in increasing mouth opening and improving jaw function. CBCT fusion images of both patient groups show some cases of condylar bone reparative remodeling and its relevance to treatment plans still requires further study.

Effect of the application of digital technology-assisted optimization in the process of adjusting jaw position.

OBJECTIVES: The aim of this study was to demonstrate a novel jaw position adjustment technique derived from digital twins and evaluate the application effect of digital technology-assisted optimization in the process of adjusting jaw position on patients with temporomandibular disorders (TMD). METHODS: A total of 74 patients with TMD who attended the Department of Temporomandibular Joint, West China Hospital of Stomatology, Si-chuan University, between June 2022 and May 2023 were selected. The patient's initial computed tomography (CT) and bilateral temporomandibular joint data obtained by magnetic resonance imaging (MRI) were collected. The 148 joints were divided into the normal disc-condyle relationship (N) group, disc displacement with reduction (DDWR) group, and disc displacement without reduction (DDWoR) group. Assisted by digital technology, the patient's CT data were reconstructed, and a personalized reference plane was established to adjust the jaw position. A three-point bite guiding splint was designed by the adjusted occlusal space and then fabricated by 3D printing technology. It was worn by the patients and then reviewed by MRI. Before and after the adjustment of jaw position, the amount and direction of condyle and disc displacement and the angle between condyle and disc were measured as the evaluation indexes of the effect of the adjustment. The correlation with condylar displacement was evaluated. RESULTS: In the N group, the disc moved backward and downward along the X and Z axes by (-0.60±0.62) and (0.51±0.71) mm, respectively. In the DDWR group, the disc moved backward and upward along the X and Z axes by (-1.33±1.38) and (-0.09±1.31) mm, respectively. In the DDWoR group, the disc moved forward and downward along the X and Z axes by (0.49±1.76) and (1.35±1.76) mm, respectively. The angle between the condyle and the disc decreased after adjustment of the jaw position in all three groups. All patients showed improvement in symptoms after adjustment. CONCLUSIONS: Digital technology-assisted jaw position adjustment can simplify the process, reduce the sensitivity of the technique, and improve patients' disc-condyle structure and symptoms. Therefore, its application in the treatment of patients with TMD is of great clinical significance.

Skeletal, dentoalveolar and soft tissue changes after stabilization splint treatment for patients with temporomandibular joint disorders.

BACKGROUND: Temporomandibular disorder (TMD) is a grouping of heterogeneous disorders with multifactorial origins. Stabilization splints (SS) have demonstrated an acceptable treatment effect in TMD. The possible changes at the skeletal, dental, and soft tissue levels need to be addressed to evaluate the benefit/risk ratio of this therapeutic procedure. Accordingly, this study aimed to three­dimensionally evaluate skeletal, dentoalveolar and soft tissue changes after SS treatment for patients with TMD. METHODS: This retrospective study included 74 adult patients with myofascial and/or intra-articular disorders (25 males and 49 females), with an average age of 22.88 ± 4.8 years, who underwent SS treatment. Pre- and post-treatment Cone beam computed tomography were analysed using Invivo 6.0.3 software. The primary outcome was the vertical skeletal and dentoalveolar changes, while the secondary outcomes were the anteroposterior skeletal, dentoalveolar and soft tissue changes. Paired t-test and Wilcoxon rank sum test were used for statistical analyses. RESULTS: For the primary outcome; skeletally, there was a significant increase in mandibular plane inclination (difference: 0.82°±1.37), decrease facial height ratio (difference: 0.45%±1.07) and at the dentoalveolar level, the inclination of the functional (FOP-SN, FOP-FH) and bisecting (BOP-SN, BOP-FH) occlusal planes exhibited a significant increase too (difference: 0.38 ± 1.43°, 0.49 ± 1.62°, 0.44 ± 1.29° and 0.41 ± 1.17°, respectively) and also a decrease in the overbite (difference: -0.54 ± 0.83). For the secondary outcomes; there was a significant decrease in mandibular position (SNB) (difference: 1.60 ± 1.36°) and increase in the overjet (difference: 0.93 ± 1.04, p < 0.001) and a significant lower lip retrusion (difference: 0.33 ± 1.01 mm p < 0.01), was observed too. CONCLUSIONS: SS therapy resulted in significant vertical skeletal and dentoalveolar changes that were manifested mainly by facial height ratio, mandibular and occlusal plane changes, and to a lesser extent, significant anteroposterior skeletal, dentoalveolar, and soft tissue changes in the form of mandibular position, increased overjet and a more retrusive lower lip. These changes should be considered during patients' selection prior to initiating SS therapy.

Comparison of temporomandibular joints in relation to ages and vertical facial types in skeletal class II female patients: a multiple-cross-sectional study.

BACKGROUND: The temporomandibular joint (TMJ) is closely related to the dynamic balance and stability of mandibular function and orthodontic treatment. Skeletal class II female patients are thought to be at high risk for TMJ disease. The relationship between the TMJ and craniofacial structures is still controversial. This study compared the morphology and position of the TMJ in skeletal class II adolescents and adults with various vertical facial types using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A total of 117 skeletal class II patients were divided into three groups according to the FH-GoGn angle (hypodivergent, normodivergent and hyperdivergent), with 40 class I normodivergent patients serving as controls. Each group contained two age subgroups (adolescents: 11-14 years old, adults: 18-35 years old). The size (condylar length, height, long and short axis diameter, glenoid fossa width and depth) and shape (condylar neck inclination, condylar head angle and long axis angle, articular eminence inclination) of the condyle and fossa, joint space (anterior, superior, posterior, mesial and lateral), and position of the fossa (vertical, transverse, and anteroposterior distance) and condyle were measured and compared using CBCT. RESULTS: Class II hypodivergent patients exhibited the greatest condylar length, height, and long- and short-axis diameter; steepest articular eminence; deepest fossa depth; largest superior, mesial and lateral joint spaces; and highest fossa position in both age groups. The manifestations of class II hyperdivergent patients were mostly the opposite. In adults, except for the condylar long axis angle, the measurements of the condyle increased differently among skeletal patterns, while the measurements of the fossa decreased, as the joint spaces and fossa position remained approximately stable compared with those in adolescents. CONCLUSION: The vertical skeletal pattern, rather than the class II sagittal skeletal pattern, may be the main factor affecting the morphology and position of the TMJ. Attention should be given to the TMJ area in hyperdivergent patients with a relatively poor-fit condyle-fossa relationship. The changes in the TMJ with age were mainly morphological rather than positional and varied with skeletal pattern.

Comparison of knee joint and temporomandibular joint development in pig embryos.

Although the knee joint (KNJ) and temporomandibular joint (TMJ) all belong to the synovial joint, there are many differences in developmental origin, joint structure and articular cartilage type. Studies of joint development in embryos have been performed, mainly using poultry and rodents. However, KNJ and TMJ in poultry and rodents differ from those in humans in several ways. Very little work has been done on the embryonic development of KNJ and TMJ in large mammals. Several studies have shown that pigs are ideal animals for embryonic development research. Embryonic day 30 (E30), E35, E45, E55, E75, E90, Postnatal day 0 (P0) and Postnatal day 30 (P30) embryos/fetuses from the pigs were used for this study. The results showed that KNJ develops earlier than TMJ. Only one mesenchymal condensate of KNJ is formed on E30, while two mesenchymal condensates of TMJ are present on E35. All structures of KNJ and TMJ were formed on E45. The growth plate of KNJ begins to develop on E45 and becomes more pronounced from E55 to P30. From E75 to E90, more and more vascular-rich cartilage canals form in the cartilage regions of both joints. The cartilaginous canal of the TMJ divides the condyle into sections along the longitudinal axis of the condyle. This arrangement of cartilaginous canal was not found in the KNJ. The chondrification of KNJ precedes that of TMJ. Ossification of the knee condyle occurs gradually from the middle to the periphery, while that of the TMJ occurs gradually from the base of the mandibular condyle. In the KNJ, the ossification of the articular condyle is evident from P0 to P30, and the growth plate is completely formed on P30. In the TMJ, the cartilage layer of condyle becomes thinner from P0 to P30. There is no growth plate formation in TMJ during its entire development. There is no growth plate formation in the TMJ throughout its development. The condyle may be the developmental center of the TMJ. The chondrocytes and hypertrophic chondrocytes of the growth plate are densely arranged. The condylar chondrocytes of TMJ are scattered, while the hypertrophic chondrocytes are arranged. Embryonic development of KNJ and TMJ in pigs is an important bridge for translating the results of rodent studies to medical applications.

Ultrasonographic examination of masticatory muscles in patients with TMJ arthralgia and headache attributed to temporomandibular disorders.

This study used ultrasonography to compare the thickness and cross-sectional area of the masticatory muscles in patients with temporomandibular joint arthralgia and investigated the differences according to sex and the co-occurrence of headache attributed to temporomandibular disorders (HATMD). The observational study comprised 100 consecutive patients with TMJ arthralgia (71 females and 29 males; mean age, 40.01 ± 17.67 years) divided into two groups: Group 1, including 86 patients with arthralgia alone (60 females; 41.15 ± 17.65 years); and Group 2, including 14 patients with concurrent arthralgia and HATMD (11 females; 33.00 ± 16.72 years). The diagnosis of TMJ arthralgia was based on the diagnostic criteria for temporomandibular disorders. The parameters of the masticatory muscles examined by ultrasonography were subjected to statistical analysis. The pain area (2.23 ± 1.75 vs. 5.79 ± 2.39, p-value = 0.002) and visual analog scale (VAS) score (3.41 ± 1.82 vs. 5.57 ± 12.14, p-value = 0.002) were significantly higher in Group 2 than in Group 1. Muscle thickness (12.58 ± 4.24 mm) and cross-sectional area (4.46 ± 2.57 cm2) were larger in the masseter muscle than in the other three masticatory muscles (p-value < 0.001). When examining sex-based differences, the thickness and area of the masseter and lower temporalis muscles were significantly larger in males (all p-value < 0.05). The area of the masseter muscle (4.67 ± 2.69 vs. 3.18 ± 0.92, p-value = 0.004) and lower temporalis muscle (3.76 ± 0.95 vs. 3.21 ± 1.02, p-value = 0.049) was significantly smaller in Group 2 than in Group 1. An increase in VAS was significantly negatively correlated with the thickness of the masseter (r = - 0.268) and lower temporalis (r = - 0.215), and the cross-sectional area of the masseter (r = - 0.329) and lower temporalis (r = - 0.293). The masseter and lower temporalis muscles were significantly thinner in females than in males, and their volumes were smaller in patients with TMJ arthralgia and HATMD than in those with TMJ arthralgia alone. HATMD and decreased masseter and lower temporalis muscle volume were associated with increased pain intensity.

Provider assessment of the temporomandibular joint in Juvenile idiopathic arthritis: a retrospective analysis from the CARRA database.

BACKGROUND: Temporomandibular joint (TMJ) involvement is an often underrecognized complication of juvenile idiopathic arthritis (JIA) that can cause decreased mandibular growth, altered facial morphology, and orofacial pain. It is estimated that the TMJ is affected in 30-45% of children with JIA. Standardized physical examination and imaging evaluations are important in accurately assessing active TMJ arthritis and sequalae. Little is known about the rate at which providers evaluate TMJ involvement in their clinical practice. METHODS: Data were obtained from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry. Data fields related to assessment for TMJ arthritis were added in 2019. Patients were included in the study if they had a diagnosis of JIA and had data recorded between January 2020 and August 2021. Standard descriptive statistics were used to describe demographic and clinical features. RESULTS: A total of 17,761 visits were reviewed for a total of 7473 patients with JIA. A total of 52.7% of patients had maximal mouth opening (MMO) recorded as finger breadths or total incisal distance (TID). Only 8% had TID measured. A total of 5.0% had MRI with contrast performed. A total of 939 patients had a diagnosis of TMJ arthritis. Of these, 28.5% had an MRI documented, 83% had an MMO documented, and 40% had TID measured. Few patient-level characteristics were statistically related to having MMO assessed. MRI was more likely to be obtained in older and in female patients. MMO was recorded at a given visit > 80% of the time at 17 sites, and it was recorded < 1% of the time at 8 sites. MRIs were infrequently performed at all sites, with 27 sites having no MRIs obtained and only 7 sites having an MRI obtained at > 10% of visits. CONCLUSIONS: MMO is not consistently measured in patients with JIA, and it is rarely measured quantitatively. Similarly, TMJ MRIs are rarely obtained in patients with JIA. Site of care is more associated with TMJ assessments than patient-level characteristics. These data suggest that provider education is needed to improve the assessment of the TMJ in patients with JIA to enable earlier recognition and prevent long-term complications.

The utilization of decision trees on orthopantomographic and lateral panoramic graphs for the diagnosis of unilateral anterior disc displacement of the temporomandibular joint.

BACKGROUND: Investigation is to utilize decision trees in conjunction with orthopantomography (OPT) and lateral panoramic graphy (LPG) to diagnose unilateral anterior disc displacement (ADD) of the temporomandibular joint. METHODS: In this study, 161 patients with images obtained through all three imaging methods, MRI, OPT, and LPG, were selected from the archives. The participants were categorized into two groups: the study group, comprising 89 patients with unilateral anterior disc displacement, and the control group, consisting of 72 healthy individuals. Measurements, including 2 angles (antero-posterior angle and superior-inferior angle) and 3 distance parameters (anterior joint space distance, superior joint space distance, and posterior joint space distance), were conducted on each imaging modality dataset. To assess the obtained measurement data within each patient, the differences from each measurement were calculated. Statistical analysis of the measurement differences between the control and study groups was carried out with independent t test, and decision trees were generated using the SPSS 25 decision tree module 5.0. RESULTS: In ADD patients, it was statistically significantly found that the APA increased while the SIA decreased for angle measurements. But for linear measurements, AS increased while the SS and PS decreased in MRI, OPT, and LPG. CONCLUSION: ADD can be diagnosed in OPT and LPG. The identification of the specific type of ADD that occurs in the temporomandibular joint is not feasible.

TRIM52 knockdown inhibits proliferation, inflammatory responses and oxidative stress in IL-1ß-induced synovial fibroblasts to alleviate temporomandibular joint osteoarthritis.

To explore the mechanism of tripartite motif 52 (TRIM52) in the progression of temporomandibular joint osteoarthritis (TMJOA). Gene and protein expression were tested by quantitative real-time polymerase chain reaction and western blot, respectively. The levels of pro-inflammatory cytokines and oxidative stress factors were evaluated using enzyme-linked immunosorbent assay and biochemical kit, respectively. Cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays were carried out to assess cell proliferation. Immunofluorescence was used to detect the expression of CD68 and Vimentin in primary synovial fibroblasts (SFs). Haematoxylin and eosin staining and Safranin O/Fast green were used to evaluate the pathological damage of synovial and cartilage tissue in rats. TRIM52 was upregulated in the synovial tissue and SFs in patients with TMJOA. Interleukin (IL)-1ß treatment upregulated TRIM52 expression in TMJOA SFs and normal SF (NSF), promoting cell proliferation, inflammatory response and oxidative stress in NSF, SFs. Silence of TRIM52 relieved the cell proliferation, inflammatory response and oxidative stress induced by IL-1ß in SFs, while overexpression of TRIM52 enhanced IL-1ß induction. Meanwhile, IL-1ß induction activated toll-like receptor 4 (TLR4)/nuclear factor (NF)-κB pathway, which was augmented by upregulation of TRIM52 in NSF, and was attenuated by TRIM52 knockdown in SFs. Besides, pyrrolidinedithiocarbamic acid ameliorated IL-1ß-induced proliferation and inflammatory response by inhibiting TLR4/NF-κB signalling. Meanwhile, TRIM52 knockdown inhibited cell proliferation, oxidative stress and inflammatory response in IL-1ß-induced SFs through downregulation of TLR4. TRIM52 promoted cell proliferation, inflammatory response, and oxidative stress in IL-1ß-induced SFs. The above functions were mediated by the activation of TLR4/NF- κB signal pathway.

The relationship of ALPK1, hyaluronic acid and M1 macrophage polarization in the temporomandibular joint synovitis.

M1 macrophage polarization and synovitis play an important role in the pathogenesis of temporomandibular joint osteoarthritis (TMJOA). Reduced molecular weight of hyaluronic acid (HA) in synovial fluid of patients with TMJOA. In addition, high molecular weight hyaluronic acid (HMW-HA) is often used clinically to treat TMJ inflammation. As a pattern recognition receptor of the cytoplasm, ALPK1 was found to be pro-inflammatory in a variety of diseases. However, the relationship of ALPK1, HA and M1 macrophage polarization in TMJ synovitis remains unclear. We aimed to investigate the role of ALPK1 and HA in macrophage polarization and TMJ synovitis and the underlying mechanisms. The results demonstrated that ALPK1 was highly upregulated in the synovial macrophages in the inflamed TMJ synovium of patients. Low molecular weight hyaluronic acid (LMW-HA) promoted the expression of ALPK1 and M1 macrophage-associated genes. Besides, rhALPK1 promoted the expression of M1 macrophage-associated factors and the nuclear translocation of PKM2. Furthermore, ALPK1 knockout mice exhibited limited infiltration of macrophages and decreased expression levels of M1 macrophage-associated genes in CFA-induced TMJ synovitis. While HMW-HA inhibited the expression of ALPK1 and M1 macrophage polarization. Our results elucidated that ALPK1 promoted TMJ synovitis by promoting nuclear PKM2-mediated M1 macrophage polarization, whereas HMW-HA inhibited the expression of ALPK1 as well as M1 macrophage polarization.

Association Between Articular Eminence Structure and Joint Spaces in Temporomandibular Joints with Anterior Disc Displacement.

BACKGROUND AND AIMS: The association among the joint spaces, articular eminence morphology, and disc displacement is not well documented in the literature. This study aims to evaluate and compare the joint spaces and the articular eminence structure (eminence height [Eh] and inclination [Ei]) using cone-beam computed tomography (CBCT) of temporomandibular joints (TMJs) with anterior disc displacements and joints with normal disc position. METHODS: The study groups consisted of 75 TMJs of 39 patients. The disc status of TMJs was diagnosed with magnetic resonance imaging, and the measurements were performed on CBCT. Three groups, that is, normal disc position (NDP) group, anterior disc displacement with reduction (ADDWR) group, and anterior disc displacement without reduction (ADDWoR) group, were established. Anterior, superior, posterior joint spaces (AJS, SJS, and PJS, respectively), articular Eh, and articular Ei were measured. Statistical Package for the Social Sciences version 22 was used for statistical analysis. Shapiro-Wilk test was used to check the normality of data. Intergroup comparisons of categorical variables were assessed with Fisher-Freeman-Halton test. For comparison of continuous variables parameters, Mann-Whitney U test and Kruskal-Wallis test were used. Statistical significance level was determined as P < 0.05. RESULTS: Significant differences were not found in intergroup comparisons for PJS. However, the difference between groups was found to be significant for AJS, SJS, Eh, and Ei. Intergroup comparisons were performed for these parameters. No significant difference was found between the NDP group and the ADDWR group for AJS, SJS, Eh, and EI. The mean AJS, SJS, Eh, and Ei values in ADDWoR were found to be significantly lower compared to the corresponding values in both NDP and ADDWR groups. CONCLUSION: Decreased AJS and SJS when TMJ is evaluated with CBCT may be an indicator of ADDWoR. Authors suggest that narrowed articular Ei and reduced articular Eh can be one of the predisposing factors for anterior disc displacement.

Evaluation of the accuracy of a fully digital method of measuring sagittal condylar inclination.

OBJECTIVES: This clinical study aimed to evaluate the accuracy of a fully digital technique for measuring sagittal condylar inclination (SCI), as well as validating whether differences existed between the left and right SCI values of the same participant, to provide a reference for clinical practice. METHODS: Ten participants with good occlusal relationship and normal temporomandibular joint were recruited. Three methods were used to measure the SCI values of the participants, namely, A (mechanical facebow transferring and mechanical articulator-based measuring method with physical protrusive interocclusal registration), B (face scan-based virtual facebow and virtual articulator-based measuring method with digital protrusive interocclusal registration), and C (jaw motion tracking system-based measuring method). With the group subjected to methods A and C as the control, the SCI values obtained by the three methods were statistically analyzed. The left and right SCI values of the same participant were also compared. RESULTS: The left and right SCI values measured by method A were 41.70°±7.09° and 42.80°±8.62°, those by method B were 35.09°±12.49° and 37.63°±12.10°, and those by method C were 39.43°±8.72° and 38.45°±6.91°. No significant difference existed among the SCI values measured by the three methods (P>0.05). Meanwhile, no statistical difference existed between the SCI values on the left and right sides of the same participant (P>0.05). CONCLUSIONS: The accuracy of the virtual facebow and digital protrusive occlusal registration based SCI measuring method was the same as that of mechanical facebow based and jaw motion tracking system-based methods. The SCI values on the left and right sides of the same participant were similar. Clinically, an appropriate SCI measurement and setting strategy can be selected based on the actual situations.

Metabolic profiling of synovial fluid in human temporomandibular joint osteoarthritis.

Introduction: Temporomandibular joint (TMJ) osteoarthritis (OA) is a common TMJ degenerative disease with an unclear mechanism. Synovial fluid (SF), an important component of TMJ, contains various proteins and metabolites that may directly contribute to OA. The present study aimed to investigate the influence of SF in TMJOA at the metabolite level. Methods: Untargeted and widely targeted metabolic profiling were employed to identify metabolic changes in SF of 90 patients with different TMJOA grades according to TMJ magnetic resonance imaging. Results: A total 1498 metabolites were detected. Most of the metabolites were amino acids and associated metabolites, benzene and substituted derivatives, and lipids. Among patients with mild, moderate and severe TMJOA, 164 gradually increasing and 176 gradually decreasing metabolites were identified, indicating that biosynthesis of cofactors, choline metabolism, mineral absorption and selenocompound metabolism are closely related to TMJOA grade. Combined metabolomics and clinical examination revealed 37 upregulated metabolites and 16 downregulated metabolites in patients with pain, of which 19 and 26 metabolites were positively and negatively correlated, respectively, with maximum interincisal opening. A model was constructed to diagnose TMJOA grade and nine biomarkers were identified. The identified metabolites are key to exploring the mechanism of TMJOA. Discussion: In the present study, a metabolic profile was constructed and assessed using a much larger number of human SF samples from patients with TMJOA, and a model was established to contribute to the diagnosis of TMJOA grade. The findings expand our knowledge of metabolites in human SF of TMJOA patients, and provide an important basis for further research on the pathogenesis and treatment of TMJOA.

Biomechanical study of temporomandibular joints of patients with temporomandibular disorders under incisal clenching: A finite element analysis.

Temporomandibular disorders (TMD) encompass a collection of pathologies. Within the multitude of etiological factors contributing to TMD, mechanical factors hold significant importance. The aim of this investigation was to assess the magnitude and distribution of stresses encountered by the temporomandibular joints (TMJs) during incisal clenching among TMD patients while also elucidating the mechanical pathogenesis underlying TMD. Ten asymptomatic subjects and ten TMD patients were recruited. The Control, Bilateral, and Unilateral groups were set. The contact stress, maximum principal stress, and minimum principal stresses of TMJ structures among the groups were compared. In addition, comparisons of the contact stress distribution among the groups were adopted. In the Control and Bilateral groups, the magnitudes of stresses (contact stress, maximum and minimum principal stresses) between the right and left sides showed no significant difference (P > 0.05). For unilateral TMD patients,the minimum principal stress on the condyle in the Uni-N group (the normal side) was significantly greater than thatin the Uni-T group (the TMD side)(P = 0.016, mean difference 9.99 MPa [95 %CI: 3.11 to 16.87]). Furthermore, stresses on the condyle and fossa of the patients were significantly greater than those of asymptomatic subjects (P < 0.05). The contact stress distributions were concentrated in the Control group while irregular in the TMD groups. In conclusion, asymmetrical contact stress distributions were observed in unilateral TMD, with excessive stresses on the healthy side. The protection of the healthy TMJ during treatment is recommended for patients with unilateral TMD.

Mallampati score in patients with temporomandibular joint disorders: A pilot case-control study.

OBJECTIVES: Temporomandibular joint disorder (TMD) is defined as any functional abnormalities in different parts of the face and neck. The Mallampati index is an indicator for determining the extent of airway blockage. No study has examined the relationship between TMD and Mallampati score. Most studies have investigated the relationship between temporomandibular joint problems and sleep problems. This pilot study aimed to assess the Mallampati index scores among TMD patients. MATERIAL AND METHODS: Eighty-four people were divided into the case (based on RDC/TMD) and control groups. Demographic information, neck circumference, tongue size, Mallampati score, and other variables were asked of people. STOP-BANG and Pittsburgh Sleep Quality Index (PSQI) were also completed for each patient. Data were analyzed with Chi-square, Fisher's exact, and Mann-Whitney tests. RESULTS: The Mallampati and PSQI questionnaire scores in the case group were significantly higher than those in the control group (p < 0.001). The results showed that larger tongue and neck circumference patients had a higher Mallampati score. Pearson correlation coefficient showed that the Mallampati score had a direct and significant relationship with body mass index and PSQI (p < 0.001). CONCLUSIONS: The results of this study show that Mallampati scores were significantly higher among patients with TMD than among healthy individuals.

Quantitative and qualitative condylar changes following stabilization splint therapy in patients with temporomandibular joint disorders with and without skeletal lateral mandibular asymmetry: a cone beam computed tomographic study.

BACKGROUND: Temporomandibular disorders (TMDs) encompass pain and dysfunction in the jaw, muscles, and adjacent structures. This study aimed to explore the quantitative (condylar position, morphology) and qualitative (bone mineral density (BMD)) therapeutic outcomes following a stabilization splint (S.S.) therapy in adult patients diagnosed with TMD (Arthralgia) with/without lateral mandibular asymmetry (MA) using cone beam computed tomography (CBCT). METHODS: In this retrospective clinical study, 60 adult TMD patients who received S.S. therapy were enrolled and allocated into the TMD group (TMDG) and TMD with MA group (TMD + MAG). The diagnosis was made according to the Diagnostic Criteria for TMD (DC/TMD) AXIS I. MA was measured from the mid-sagittal plane to the Menton point. CBCT was used to scan the temporomandibular joints pre- (T0) and post- (T1)-treatment for three-dimensional analysis. Intra- and intergroup statistical comparisons were performed using the Wilcoxon signed ranks and the Kruskal‒Wallis test. RESULTS: For quantitative comparisons, there was a statistically significant difference between T0 and T1 in the joint spaces of TMD + MAG (anterior, superior, posterior, and coronal lateral on the deviated side as well as in the superior, coronal medial joint space of the contralateral side). Morphologically, the deviated side had a narrower condylar width, reduced condylar height, and a steeper eminence angle. In contrast, the contralateral side tended to have a greater condylar length. For qualitative measurements, BMD also showed statistical significance between T0 and T1 in the majority of the condyle slopes (AS, SS, PS, and LS on the deviated side and in AS and MS on the contralateral side) of TMD + MAG. Additionally, only the AS and PS showed significance in TMDG. CONCLUSION: Multiple joint space widening (AJS and CMS) and narrowing (SJS, PJS, and CLS) could characterize the deviated side in TMD + MA. Factors like narrower condylar width, reduced condylar height, and steeper eminence angle on the deviated side can worsen TMD + MA. Proper alignment of the condyle-disc position is essential for optimal function and load distribution, potentially affecting bone mineral density (BMD). MA plays a prominent role in disturbing bone densities. S.S. therapy shows more evident outcomes in TMD + MAG (on the deviated side compared to the contralateral side) than the TMDG.