OBJECTIVE: To explore the efficacy differences among different acupuncture frequencies for pain of temporomandibular disorders (TMD). METHODS: A total of 42 patients with TMD pain were randomly divided into a low-frequency group, a medium-frequency group, and a high-frequency group, with 14 patients in each group. All groups received acupuncture treatment at bilateral Hegu (LI4) and Yanglingquan (GB34), as well as ipsilateral Tinggong (SI19), Jiache (ST6), and Xiaguan (ST7), with each session lasting 30 minutes. The low-frequency group received acupuncture once per week, the medium-frequency group received acupuncture twice per week, and the high-frequency group received acupuncture three times per week, for a total duration of four weeks. The graded chronic pain scale (GCPS) score, visual analogue scale (VAS) score, jaw functional limitation scale-20 (JFLS-20) score, and pressure pain threshold (PPT) were assessed in the three groups before and after treatment, as well as at the four-week follow-up after treatment completion. RESULTS: Compared before treatment, GCPS and JFLS-20 scores were significantly decreased in all the groups after treatment (P<0.05), and VAS scores were significantly decreased in the high-frequency and medium-frequency groups (P<0.05), PPT values at different measurement sites were increased significantly in the high-frequency group (P<0.05). After treatment, GCPS, JFLS-20, and VAS scores in the high-frequency group were lower than those in the medium-frequency and low-frequency groups (P<0.05), while some PPT values were higher than the other two groups (P<0.05). At follow-up, GCPS, JFLS-20, and VAS scores remained significantly lower in all the groups compared to baseline (P<0.05), PPT values were increased significantly in the high-frequency and medium-frequency groups (P<0.05), with the high-frequency group showing lower GCPS, JFLS-20, and VAS scores and higher PPT values compared to the other two groups (P<0.05). CONCLUSION Acupuncture three times per week is more effective in reducing TMD pain intensity compared to once or twice per week, and can also alleviate some mandibular functional impairments. The therapeutic effects persist for at least four weeks after treatment completion.
Humans ; Male ; Female ; Adult ; Acupuncture Therapy/methods* ; Temporomandibular Joint Disorders/physiopathology* ; Middle Aged ; Young Adult ; Treatment Outcome ; Acupuncture Points ; Pain Management ; Adolescent ; Pain Measurement

Temporomandibular joint osteoarthritis (TMJ-OA) is a common disease often accompanied by pain, seriously affecting physical and mental health of patients. Abnormal innervation at the osteochondral junction has been considered as a predominant origin of arthralgia, while the specific mechanism mediating pain remains unclear. To investigate the underlying mechanism of TMJ-OA pain, an abnormal joint loading model was used to induce TMJ-OA pain. We found that during the development of TMJ-OA, the increased innervation of sympathetic nerve of subchondral bone precedes that of sensory nerves. Furthermore, these two types of nerves are spatially closely associated. Additionally, it was discovered that activation of sympathetic neural signals promotes osteoarthritic pain in mice, whereas blocking these signals effectively alleviates pain. In vitro experiments also confirmed that norepinephrine released by sympathetic neurons promotes the activation and axonal growth of sensory neurons. Moreover, we also discovered that through releasing norepinephrine, regional sympathetic nerves of subchondral bone were found to regulate growth and activation of local sensory nerves synergistically with other pain regulators. This study identified the role of regional sympathetic nerves in mediating pain in TMJ-OA. It sheds light on a new mechanism of abnormal innervation at the osteochondral junction and the regional crosstalk between peripheral nerves, providing a potential target for treating TMJ-OA pain.
Animals ; Osteoarthritis/physiopathology* ; Mice ; Sympathetic Nervous System/physiopathology* ; Temporomandibular Joint Disorders/physiopathology* ; Arthralgia ; Sensory Receptor Cells ; Disease Models, Animal ; Norepinephrine ; Male ; Temporomandibular Joint/physiopathology* ; Pain Measurement

OBJECTIVES: This study aimed to investigate the correlation between clinical symptoms and unilateral chewing habits in patients with temporomandibular disorder (TMD) accompanied by tinnitus. METHODS: A total of 285 patients diagnosed with TMD at the Department of Stomatology of the First Medical Center of Chinese People's Liberation Army General Hospital between December 2020 and May 2024 were included and divided into two groups: tinnitus group and non-tinnitus group. Analysis was conducted on the proportion of patients with unilateral chewing habits in both groups, the correlation between the side of tinnitus and the side of unilateral chewing, and the correlation of tinnitus with TMD clinical symptoms (joint clicking, joint pain, and limited mouth opening) and unilateral chewing habits. The correlation of the type of disc displacement with unilateral chewing and tinnitus was also examined. RESULTS: In the tinnitus group, the proportions of patients with and without unilateral chewing habits were 90.70% (39/43) and 9.30% (4/43), respectively. In the non-tinnitus group, the proportions of patients with and without unilateral chewing habits were 76.03% (184/242) and 23.97% (58/242), respectively. The proportion of patients with unilateral chewing habits in the tinnitus group was significantly higher than in the non-tinnitus group (χ²=4.613, P<0.05). Correlation analysis showed a positive correlation between tinnitus and unilateral chewing habits (P<0.05). In the left-sided tinnitus group, the proportion of left-sided unilateral chewers [54.55% (12/22)] was higher than that of right-sided unilateral chewers [45.45% (10/22)]. In the right-sided tinnitus group, the proportion of right-sided unilateral chewers [81.82% (9/11)] was higher than that of left-sided unilateral chewers [18.18% (2/11)]. The difference was statistically significant (χ²=7.282, P<0.05). A positive correlation was also found between the side of tinnitus and the side of unilateral chewing habits (P<0.05). The proportion of patients with pain was significantly higher in the tinnitus group than in the non-tinnitus group (P<0.05). No significant difference in the proportion of joint clicking or limited mouth opening and disc displacement (no disc displacement, unilateral disc displacement, bilateral disc displacement, reducible disc displacement, or irreducible disc displacement) was found between the tinnitus and non-tinnitus groups (P>0.05). CONCLUSIONS TMD with unilateral chewing habits may be a contributing factor to unexplained tinnitus. Unexplained tinnitus is correlated with joint pain in patients with TMD.
Humans ; Tinnitus/physiopathology* ; Temporomandibular Joint Disorders/physiopathology* ; Mastication ; Male ; Adult ; Female ; Middle Aged ; Habits

Collagen is the building component of temporomandibular joint (TMJ) discs and is often affected by inflammation in temporomandibular disorders. The macromechanical properties of collagen are deteriorated by chronic inflammation. However, the mechanism by which inflammation influences disc function remains unknown. The relationship between the ultrastructure and nanomechanical properties of collagen in inflamed discs should be clarified. Seven-week-old female Sprague-Dawley rats were randomly divided into two groups. Chronic TMJ inflammation was induced by intra-articular injection of complete Freund's adjuvant, and samples were harvested after 5 weeks. Picrosirius staining revealed multiple colours under polarized light, which represented alternative collagen bundles in inflamed discs. Using atomic force microscopy scanning, the magnitude of Young's modulus was reduced significantly accompanied with disordered collagen fibril arrangement with porous architecture of inflamed discs. Transmission electron microscopy scanning revealed a non-uniform distribution of collagen fibres, and oversized collagen fibrils were observed in inflamed discs. Fourier transform infrared microspectroscopy revealed a decrease in 1 338 cm/amide II area ratio of collagen in different regions. The peak positions of amide I and amide II bands were altered in inflamed discs, indicating collagen unfolding. Our results suggest that sustained inflammation deteriorates collagen structures, resulting in the deterioration of the ultrastructure and nanomechanical properties of rat TMJ discs.
Animals ; Collagen ; ultrastructure ; Female ; Fibrillar Collagens ; ultrastructure ; Freund's Adjuvant ; adverse effects ; Inflammation ; chemically induced ; metabolism ; pathology ; Injections, Intra-Articular ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Temporomandibular Joint ; Temporomandibular Joint Disc ; physiopathology ; ultrastructure ; Temporomandibular Joint Disorders ; physiopathology

INTRODUCTIONTemporomandibular joint disorders (TMJDs) are caused by several factors such as anatomical, neuromuscular and psychological alterations. A relationship has been established between TMJDs and postural alterations, a type of anatomical alteration. An anterior position of the head requires hyperactivity of the posterior neck region and shoulder muscles to prevent the head from falling forward. This compensatory muscular function may cause fatigue, discomfort and trigger point activation. To our knowledge, a method for assessing human postural attitude in more than one plane has not been reported. Thus, the aim of this study was to design a methodology to measure the external human postural attitude in frontal and sagittal planes, with proper validity and reliability analyses.

METHODSThe variable postures of 78 subjects (36 men, 42 women; age 18-24 years) were evaluated. The postural attitudes of the subjects were measured in the frontal and sagittal planes, using an acromiopelvimeter, grid panel and Fox plane.

RESULTSThe method we designed for measuring postural attitudes had adequate reliability and validity, both qualitatively and quantitatively, based on Cohen's Kappa coefficient (> 0.87) and Pearson's correlation coefficient (r = 0.824, > 80%).

CONCLUSIONThis method exhibits adequate metrical properties and can therefore be used in further research on the association of human body posture with skeletal types and TMJDs.

Adolescent ; Adult ; Female ; Humans ; Male ; Movement ; physiology ; Posture ; physiology ; Reproducibility of Results ; Temporomandibular Joint Disorders ; diagnosis ; physiopathology ; Young Adult

Anterior disc displacement is a common subtype seen in temporomandibular disorders (TMD) patients. It may cause mandibular movement disorders, such as clicking of joint, intermittent closed lock, limitation of mouth opening, etc. These disorders may affect the life qualities of patients. Anterior disc displacement may also cause mandibular malformations, especially among adolescents, which may affect the growth of condyle, therefore may have a correlation with mandibular retrusion or mandibular deviation when grown up. This paper going to review the influences of anterior disc displacement on oral mandibular function and morphology and their biological mechanisms.
Adolescent ; Humans ; Mandible ; abnormalities ; pathology ; Mandibular Condyle ; growth & development ; Mandibular Diseases ; etiology ; Movement ; Retrognathia ; etiology ; Temporomandibular Joint Disorders ; etiology ; physiopathology

Acupuncture Therapy ; methods ; Adult ; Female ; Humans ; Jaw ; physiopathology ; Male ; Middle Aged ; Temporomandibular Joint Disorders ; physiopathology ; therapy ; Young Adult

The aim of this study was to design a simple, economic, with high Common Mode Rejection Ratio (CMRR), preamplifier and multi-channel masticatory muscle surface electromyography (sEMG) signal acquisition system assisting to diagnose temporomandibular disorders (TMD). We used the USB interface technology in the EMG data with the aid of the windows to operate system and graphical interface. Eight patients with TMD and eight controls were analyzed separately using this system. In this system, we analyzed sEMG by an optional combination of time domain, frequency domain, time-frequency, several spectral analysis, wavelets and other special algorithms under multi-parameter. Multi-channel sEMG System of Masticatory Muscles is a simple, economic system. It has high sensitivity and specificity. The sEMG signals were changed in patients with TMD. The system would pave the way for diagnosis TMD and help us to assess the treatment effect. A novel and objective method is provided for diagnosis and treatment of oral-maxillofacial disease and functional reconstruction.
Algorithms ; Computer Graphics ; Data Collection ; Electromyography ; Humans ; Masticatory Muscles ; physiology ; physiopathology ; Sensitivity and Specificity ; Signal Processing, Computer-Assisted ; Temporomandibular Joint Disorders ; diagnosis ; User-Computer Interface

OBJECTIVE: To determine the distribution features of surface stress on the bilateral condyles of the normal mandible and the unilateral mandible model for 3 kinds of surgeries of temporomandibular joint ankylosis under normal occlusal strength. METHODS: The normal mandible 3-dimensional finite element model and the 3-dimensional finite element mandible model for 3 kinds of surgeries of unilateral temporomandibular joint ankylosis were built. The jaw triangle area and the condyle transverse ridge was fixed and bound at mid-point. And 100 N of load was applied to the first molars of the bilateral mandible to obtain a von Mises stress diagram of the condylar surface and the unit von Mises stress of the condylar surface. Statistical analysis was carried out. RESULTS: The transmission of von Mises stress at the operated side of fractured articular arthroplasty of the condylar was interrupted. The von Mises stress at the operated side of the condylar in the group of point-surface contact joint reconstruction was bigger than that of the normal group (P<0.05) whereas there was no significant difference between the group of surface-surface contact joint reconstruction group and the normal group (P>0.05). The von Mises stress of the condylar at the non-operated side in the group of fractured articular arthroplasty was bigger than that of the normal group (P<0.05), whereas there was no significant difference between the group of point-surface contact or surface-surface contact group and the normal group (P>0.05). CONCLUSION The surface-surface articular reconstruction is beneficial to the recovery of the masticatory function without increasing the burden for contralateral temporomandibular joint and is helpful to the joint. Thus this surgical method is recommended.
Ankylosis ; surgery ; Dental Stress Analysis ; statistics & numerical data ; Finite Element Analysis ; Humans ; Male ; Mandibular Condyle ; physiopathology ; Middle Aged ; Models, Biological ; Reconstructive Surgical Procedures ; methods ; Stress, Mechanical ; Temporomandibular Joint Disc ; surgery ; Temporomandibular Joint Disorders ; surgery

The purpose of this review is to provide a reference for researchers in investigating the tissue engineering of the temporomandibular joint (TMJ) disc. Currently tissue engineering of the TMJ disc is in its infancy, and cell source is one of the key factors that define the development of the tissue engineering of TMJ disc. In this paper, 6 kinds of cells: the TMJ disc native cells, chondrocytes, dermal fibroblasts, bone marrow-derived mesenchymal stem cells, adipose-derived stem cells, and embryonic stem cells are introduced. In addition, the possibility that these cells can be used as cell sources for TMJ disc tissue engineering is described.
Animals ; Chondrocytes ; cytology ; Fibroblasts ; cytology ; Humans ; Joint Prosthesis ; Skin ; cytology ; Temporomandibular Joint Disc ; cytology ; pathology ; physiopathology ; Temporomandibular Joint Disorders ; rehabilitation ; surgery ; therapy ; Tissue Engineering ; methods ; trends