Temporomandibular Joint Anterior Disc Displacement Research Articles

Effectiveness of modified temporomandibular joint disc reduction and suture with tragus incision assisted by arthroscopy

To investigate the effectiveness of modified temporomandibular joint disc reduction and suture with tragus incision assisted by arthroscopy for temporomandibular joint anterior disc displacement (ADD). A clinical data of 30 patients (45 sides) with temporomandibular joint ADD, who met selective criteria and were admitted between September 2022 and February 2024, was retrospectively analyzed. Among them, 15 patients (23 sides) were treated with temporomandibular joint disc reduction and suture via small incision (open operation group), and 15 patients (22 sides) with modified temporomandibular joint disc reduction and suture with tragus incision assisted by arthroscopy (arthroscopy group). There was no significant difference in gender, age, disease duration, affected side, Wilkes-Bronstein stage, preoperative visual analogue scale (VAS) score, maximal interincisal opening (MIO), and temporomandibular joint dysfunction index (DI), craniomandibular index (CMI), palpation index (PI), and other baseline data between groups ( P>0.05). VAS score, MIO, and temporomandibular joint function indicators (PI, DI, CMI) of patients were recorded at 3 months after operation, and the difference (change value) of the above indicators between pre- and post-operation was calculated. At 1 week after operation, MRI was performed to evaluate the reduction of the articular disc compared to the preoperative image. The results were classified as excellent, good, and poor, with excellent and good being considered effective reduction. The condition of condyle process repair was observed by cone beam CT (CBCT) at 3 months after operation. All incisions healed by first intention in the two groups. All patients were followed up 3-18 months (mean, 8.2 months). Facial nerve injury occurred in 3 cases in the open operation group and 1 case in the arthroscopy group, all of which returned to normal after physiotherapy and drug treatment. At 3 months after operation, MIO and VAS scores of both groups significantly improved when compared with those before operation ( P<0.05), and temporomandibular joint function indicators (PI, DI, CMI) significantly decreased ( P<0.05). The change values of MIO and temporomandibular joint function indicators in arthroscopy group were significantly higher than those in open operation group ( P<0.05). There was no significant difference in the change value of VAS score between groups ( P>0.05). There was no recurrence during follow-up. Postoperative MRI review showed that the effective reduction rate of joint disc was 95.65% (22/23) in the open operation group and 95.45% (21/22) in the arthroscopy group, with no significant difference between groups ( P>0.05). Postoperative CBCT found that early and timely effective reduction of joint disc was conducive to condyle process repair and reconstruction. Modified temporomandibular joint disc reduction and suture with tragus incision assisted by arthroscopy has a clear effect in the treatment of ADD, with less trauma, fewer postoperative complications, and good early effectiveness.

Multi-class segmentation of temporomandibular joint using ensemble deep learning

Temporomandibular joint disorders are prevalent causes of orofacial discomfort. Diagnosis predominantly relies on assessing the configuration and positions of temporomandibular joint components in magnetic resonance images. The complex anatomy of the temporomandibular joint, coupled with the variability in magnetic resonance image quality, often hinders an accurate diagnosis. To surmount this challenge, we developed deep learning models tailored to the automatic segmentation of temporomandibular joint components, including the temporal bone, disc, and condyle. These models underwent rigorous training and validation utilizing a dataset of 3693 magnetic resonance images from 542 patients. Upon evaluation, our ensemble model, which combines five individual models, yielded average Dice similarity coefficients of 0.867, 0.733, 0.904, and 0.952 for the temporal bone, disc, condyle, and background class during internal testing. In the external validation, the average Dice similarity coefficients values for the temporal bone, disc, condyle, and background were 0.720, 0.604, 0.800, and 0.869, respectively. When applied in a clinical setting, these artificial intelligence-augmented tools enhanced the diagnostic accuracy of physicians, especially when discerning between temporomandibular joint anterior disc displacement and osteoarthritis. In essence, automated temporomandibular joint segmentation by our deep learning approach, stands as a promising aid in refining temporomandibular joint disorders diagnosis and treatment strategies.

Evaluation of the effect of dextrose prolotherapy versus deep dry needling therapy for the treatment of temporomandibular joint anterior disc displacement with reduction: (a randomized controlled trial)

Objectiveto compare the combined effect of Prolotherapy and Deep Dry Needling (DDN) versus DDN effect on relieving the symptoms of Temporomandibular joint (TMJ) anterior disc displacement.Patients and methodsThe clinical trial randomly allocated forty patients. The (control group) patients received four intraarticular and masseteric DDN sessions, while the (study group) patients were subjected to the exact technique followed by Prolosolution injection. The baseline preoperative measurements included Maximal interincisal opening (MIO), auscultation of the presence of clicking, and Visual Analogue Scale (VAS), which were repeated for postoperative measurements after one, two, five, and eight months.ResultsBy the end of the study, all patients expressed apparent improvement in pain MIO and clicking. The inter- and intragroup comparison revealed that the pain score values of the control group after five and eight months were significantly higher than those of the study group. The study group demonstrated more significant MIO calibration than the control group, with insignificant differences between both groups regarding the presence of clicking at any time interval. The associations between clicking and VAS values, between clicking and MIO, and between VAS values and increased MIO were positive in the test group and negative in the control group.ConclusionsDextrose Prolotherapy and DDN were beneficial. However, Prolotherapy demonstrated more significant, sustained, and correlated long-term alleviation of symptoms and increased MIO.Clinical relevanceThe study assesses the sole effect of dextrose prolotherapy on relieving the signs of TMJ anterior disc displacement apart from the impact of the penetrating needle.Clinical trial registrationThe study was registered on www.clinicaltrials.gov (#: NCT05821985) by Ahmed Nagi Alghandour.

Efficacy of Arthroscopic Diskopexy on Condylar Growth in Temporomandibular Joint Anterior Disk Displacement: A Randomized Clinical Trial.

Adolescents with temporomandibular joint (TMJ) anterior disk displacement (ADD) frequently develop dentofacial deformities. It is unknown whether adjunctive arthroscopic diskopexy compared with orthodontic treatment alone increases condylar growth and then improves dentofacial deformity. This study aimed to determine whether arthroscopic diskopexy before functional appliance (joint-occlusal treatment) or single functional appliance (occlusal treatment) increases condylar growth and improves dentofacial deformity among adolescents with TMJ ADD. A multicenter, randomized, parallel, controlled trial was conducted in 3 centers in China. Adolescents diagnosed with TMJ ADD and dentofacial deformity were enrolled. Eligible participants were randomly assigned to a joint-occlusal group or occlusal group at a ratio of 2:1. Magnetic resonance imaging scans and cephalometric radiographs were evaluated at baseline, at 8 months, and at 14 months. The primary outcome was changes in condylar height from 14 months to baseline. Secondary outcomes were changes in skeletal position. A total of 240 patients (14.65 ± 1.88 years of age) were randomized (joint-occlusal group, 160; occlusal group, 80). The overall difference in condylar height between groups was 3.65 mm (95% CI, 3.10 to 4.19 mm; P < 0.001). The between-group differences in condylar height on the left and right sides were 3.60 mm (95% CI, 2.92 to 4.28 mm; P < 0.001) and 3.69 mm (95% CI, 3.06 to 4.32 mm; P < 0.001), respectively. Significant between-group differences were noted in skeletal position (all P < 0.001). Joint-occlusal treatment can promote condylar growth and improve dentofacial deformity in adolescents after 14 months when compared with single occlusal treatment. Therapeutic, I.

TMJ anterior disc displacement anchorage surgery: a retrospective study based on a suture-free titanium screw strategy.

To evaluate the feasibility and effectiveness of using a suture-free titanium screw in repositioning anterior disc displacement without reduction (ADDwoR) of the temporomandibular joint (TMJ). A consecutive sample of twelve patients (fifteen joints) was included in this study. All patients were diagnosed with ADDwoR and showed limited mouth opening or temporomandibular joint pain symptoms. Suture-free titanium screw was placed in the condyle directly following the disc repositioning. Pre- and postoperative evaluation parameters include operation time, the visual analogue scale for pain (VAS), lateral excursion movements (LEM), maximum interincisal opening (MIO), and disc length and position on MRI. In addition, the mandibular condyle height was also measured. Statistical significance was considered when p < 0.05. The unilateral operation time was 58.54 ± 5.43min; during the 6-month period after the operation, the VAS values decreased from 87 ± 6.34 to 14.08 ± 6.65. The MIO increased from 30.07 ± 4.73 to 39.89 ± 1.69mm (p = 0.01). The TMJ disc length was prolonged from 8.23 ± 1.12 to 11.51 ± 1.29mm. The condyles showed significant remodeling, and the height of the condyle increased from 18.24 ± 4.12 increase to 19.6 ± 4.31mm. The LEM was increased from 5.27 ± 0.51 to 6.36 ± 0.62mm. The MRI images showed the stability of the disc in position during the opening and closing of the mouth. The TMJ disc position was stable during the follow-up period. Anteriorly displaced articular disc can be repositioned by a suture-free titanium screw strategy. This technique is an alternative method to address ADDwoR.

Evaluation of the long term efficacy of Superior Repositioning Splints in Temporomandibular Joint Anterior Disc Displacement with Reduction

Evaluation of the long term efficacy of Superior Repositioning Splints in Temporomandibular Joint Anterior Disc Displacement with Reduction

Evaluation of Temporomandibular Joint Anterior Disc Displacement with Reduction: Clinical versus Magnetic Resonance Imaging Findings

Evaluation of Temporomandibular Joint Anterior Disc Displacement with Reduction: Clinical versus Magnetic Resonance Imaging Findings

Comparison between disc repositioning by open surgery versus occlusal splint in the treatment of temporomandibular joint anterior disc displacement without reduction: A retrospective cohort trial of short-term results

To compare the short-term clinical results between disc repositioning by open surgery (DROS) and stabilization splint (SS) for the treatment of temporomandibular joint (TMJ) anterior disc displacement without reduction (ADDwoR).Patients diagnosed with ADDwoR by magnetic resonance imaging (MRI) and treated by either DROS or SS from June 2020 to January 2022 were reviewed. They were selected to match the baseline data before each treatment and then to compare the clinical results including maximum interincisal opening (MIO), protrusion and lateral excursion distances, visual analogue scale (VAS) scores of pain, diet, and quality of life (QoL) and their effective rates, total satisfaction rate after 3 and 6 months of the treatment, and between the 2 treatment methods. SPSS software was used to analyze the statistical differences.A total of 175 patients were included in the study. There were 95 patients in the DROS group and 80 patients in the SS group. MIO and VAS scores were significantly improved after each treatment at 3 and 6 months (p < 0.05). DROS improved more at 6 months than 3 months (p < 0.001), whereas SS had no significant changes (p > 0.05). DROS had significantly better MIO, VAS score and effect rates than SS (p < 0.001). The total satisfaction rate was 94.73% in DROS and 86.25% in SS. The protrusion and lateral excursions decreased after DROS at 3 months (p < 0.001) but improved at 6 months to better than before the surgery (p = 0.03, p = 0.10). There were no significant changes in protrusion and lateral excursions after SS (p > 0.05, p > 0.05).DROS had better short-term clinical results than SS in the treatment of ADDwoR.

The Retrospective Study of Magnetic Resonance Imaging Signal Intensity Ratio in the Quantitative Diagnosis of Temporomandibular Condylar Resorption in Young Female Patients.

According to the literature, there is no reliable and quantitative method available for the diagnosis and prognosis of early or potential temporomandibular joint (TMJ) condylar resorption (CR) thus far. The purpose of this study was to raise a new noninvasive method to quantitatively evaluate condylar quality using the signal intensity ratio (SIR) on magnetic resonance imaging (MRI) in order to assist in the diagnosis of TMJ CR. A retrospective exploratory study was performed to compare the condyle-to-cerebral cortex signal intensity ratios (SIR) on MRI among young female patients. We included 60 patients, and they were divided into three groups: the bilateral normal TMJ group (group 1), the bilateral TMJ anterior disc displacement (ADD) but without CR group (group 2), and the bilateral TMJ anterior disc displacement (ADD) with CR group (group 3). The SIR difference between the three groups was analyzed by the Kruskal-Wallis test (K-W test). The sensitivity, specificity, accuracy, and area under curve (AUC) were calculated by the receiver operating characteristic (ROC) curves. There was high consistency between the surgeon and the radiologist in the evaluation of the magnetic signal intensity with intraclass correlation coefficients of 0.939-0.999. The average SIR was 1.07 in the bilateral normal TMJ group (group 1), 1.03 in the ADD without CR group (group 2), and 0.78 in the ADD with CR group (group 3). It could be found by the K-W test that group 3 was significantly different from group 1 and group 2 (p < 0.05), while there was no significant difference between group 1 and group 2. The optimal critical SIR value was 0.96 for the diagnosis of CR according to the ROC curves and Youden index (p < 0.001, AUC = 0.9). The condyle-to-cerebral cortex SIR can be used as a noninvasive diagnostic tool for the quantitative evaluation of condylar quality and diagnosis and prognosis of CR. SIR ≥ 0.96 indicates a healthy condyle, while SIR < 0.96 is considered the optimal critical value for the diagnosis of CR. These findings are important for personalized and accurate treatment and prognosis prediction.

Short-term efficacy of exercise therapy for temporomandibular disorders: a case control study.

[Purpose] This study compared the short-term outcomes of manual therapy performed by a dentist and home exercises performed by patients as a single exercise therapy program for temporomandibular joint anterior disc displacement without reduction. [Participants and Methods] In this study we included seventeen patients with temporomandibular joint anterior disc displacement without reduction, moderate or greater temporomandibular joint functional impairment, and no treatment interventions. Patients receiving treatment underwent exercise therapy at the time of their first visit, whereas those in the non-treatment group received only an explanation of the condition. We evaluated the clinical symptoms (maximum painless opening distance, pain on motion and mastication, and degree of difficulty in daily life) at the first visit and at the two-week follow-up visit. [Results] For both groups, maximum painless opening distance and degree of difficulty in daily life improved significantly. For the treatment group, the pain on motion and mastication values significantly improved throughout the assessment period. [Conclusion] An exercise therapy program may be useful for the early treatment of temporomandibular joint anterior disc displacement without disc reduction.

Indirect versus direct anterior repositioning splint in management of temporomandibular joint anterior disc displacement with reduction (randomized controlled trial)

Indirect versus direct anterior repositioning splint in management of temporomandibular joint anterior disc displacement with reduction (randomized controlled trial)

Evaluation of intraarticular injection of hyaluronic acid with platelet rich plasma for treatment of temporomandibular joint anterior disc displacement with and without reduction

Background For patients who failed to respond to conservative measures for temporomandibular joint (TMJ) internal derangement after arthrocentesis, several intraarticular injections have been shown to be an effective treatment modality to reduce pain, improve joint movement and range of motion. Purpose Our study aim was to evaluate the efficacy of intraarticular injection of hyaluronic acid (HA) and platelet rich plasma (PRP) in the treatment of TMJ anterior disc displacement with (DDwR) and without (DDwoR) reduction after arthrocentesis. Patients and methods This prospective clinical study involved 20 patients with TMJ anterior disc displacement, assigned into two equal groups. Group 1 included 10 patients with DDwR and group 2 included 10 patients with DDwoR. Both groups were treated with arthrocentesis and intraarticular injection of 1 ml of equal amount of HA and PRP into the superior joint space. Visual analog scale (VAS), maximum mouth opening (MMO), lateral jaw movements and joint clicking sounds were assessed at each follow up period (1 week, 1 month, 3 months, and 6 months) for both groups. The collected data was then statistically analyzed. Results Pain intensity decreased in both groups; in group 1, mean VAS decreased from 6.9 to 0.6 while in group 2, VAS decreased from 6.8 to 0.8. MMO mean for group 1 increased from 32.4 to 44.9 mm. In group 2, MMO increased from 24 to 34.6 mm. TMJ lateral movement for group 1 increased from 6 to 8.7 mm and for group 2, it increased from 5.5 to 7.2 mm. Number of patients with TMJ clicking in group 1 decreased from 8 to 1 while in group 2, patients had no clicking sounds from the start. MRIs showed no change before and after study in both groups as disc remained at same position. Conclusions Intraarticular injection of HA and PRP mixture was found to be clinically effective in the treatment of TMJ disorders in both anterior DDwR and DDwoR groups; however, no significant difference was noticed on the disc position on the MRI.

Efficacy of Arthroscopic Discopexy on Condylar Growth in Temporomandibular Joint Anterior Disc Displacement: A Randomized Clinical Trial

Efficacy of Arthroscopic Discopexy on Condylar Growth in Temporomandibular Joint Anterior Disc Displacement: A Randomized Clinical Trial

Finite element analysis of various thickness occlusal stabilization splint therapy on unilateral temporomandibular joint anterior disc displacement without reduction

Occlusal stabilization splint is the most common treatment modality for temporomandibular joint disorders, but the optimal thickness is still uncertain. This study investigated the effect of the occlusal splint with different thicknesses on the stress distribution of the temporomandibular joint. Cone-beam computed tomography and magnetic resonance images were used to reconstruct the maxillofacial and disc, and the unilateral anterior disc displacement without reduction was established manually as the basic model. Occlusal splint with 5 different thickness levels (2, 3, 4, 5, and 6 mm) was added to the basic model as the study models. The displacement and stress distribution of the disc were evaluated. The maximum von Mises stress of the condylar cartilage was the largest on the affected side, whereas the maximum von Mises stress of the disc was the largest on the unaffected side. The disc stress on the affected side was mainly distributed on the posterior zone and the intermediate zone for the unaffected side. The maximum von Mises stress of the bilaminar region on the affected side was greater than the unaffected side. The stress of the disc and bilaminar region was the lowest on the affected side in the 2 mm model. The disc displacement on the affected side gradually increased, whereas, on the unaffected side, it fluctuated. These results showed that occlusal stabilization splint could decrease the stress of disc and bilaminar region, and 2 mm was considered the optimal thickness for the treatment of unilateral temporomandibular joint anterior disc displacement without reduction.

COL5A1 RS12722 Is Associated with Temporomandibular Joint Anterior Disc Displacement without Reduction in Polish Caucasians.

Numerous reports describe the association between the single-nucleotide polymorphism (SNP) rs12722 and rs13946 in the COL5A1 gene and injuries, such as Achilles tendon pathology, anterior cruciate ligament (ACL) injuries, and tennis elbow. Hence, there were no studies investigating COL5A1 and temporomandibular joint (TMJ) pathology. The aim of this study is to evaluate the relationship between COL5A1 rs12722 and rs13946 SNPs and TMJ articular disc displacement without reduction (ADDwoR). In this case-control study, the study group consisted of 124 Caucasian patients of both sexes. Each patient had a history of ADDwoR no more than 3 months prior. The control group comprised 126 patients with no signs of TMD according to DC/TMD. Genotyping of the selected SNPs was performed by real-time PCR using TaqMan probes. The significance of the differences in the distribution of genotypes was analyzed using Pearson’s chi-square test. Logistic regression modeling was performed to analyze the influence of the 164 investigated SNPs on ADDwoR. The COL5A1 marker rs12722 turned out to be statistically significant (p-value = 0.0119), implying that there is a difference in the frequencies of TMJ ADDwoR. The distribution of rs12722 SNPs in the study group TT(66), CC(27), CT(31) vs. control group TT(45), CC(26), CT(51) indicates that patients with CT had an almost 2.4 times higher likelihood of ADDwoR (OR = 2.41) than those with reference TT (OR = 1), while rs13946 genotypes were shown to be insignificant, with a p-value of 0.1713. The COL5A1 rs12722 polymorphism is a risk factor for ADDwoR in the Polish Caucasian population.

Arthroscopic versus open disc repositioning and suturing techniques for the treatment of temporomandibular joint anterior disc displacement: 3-year follow-up study

The aim of this study was to evaluate the outcomes of temporomandibular joint (TMJ) arthroscopic and open disc repositioning procedures in the management of anterior disc displacement (ADD). All consecutive patients treated with arthroscopic (group I) or open (group II) disc repositioning between April 2014 and August 2018 were included prospectively. The patients were assessed clinically (1, 3, 6, 12, 24, and 36 months postoperative) and with magnetic resonance imaging (MRI). The statistical analysis was performed using IBM SPSS Statistics v.22.0; P < 0.05 was considered significant. A total of 177 patients (227 joints) were included: 104 patients (130 joints) in group I and 73 patients (97 joints) in group II. There were statistically significant improvements in pain score, clicking, quality of life, diet, and maximum inter-incisal opening when comparing pre- and postoperative clinical parameters within the two groups (P < 0.05 at all time-points for all clinical parameters); however, improvements occurred earlier in group I (at 1 month) than in group II (6 months). Postoperative MRI revealed an overall success rate of 98.1% in group I and 97.3% in group II. New bone formation was found in 70.2% in group I and 30.1% in group II. Arthroscopy may be a better choice for ADD patients, with the advantages of faster clinical improvement and recovery, minimal invasiveness, and better condylar remodelling.

Assessment of Occlusal Appliance for the Reposition of Temporomandibular Joint Anterior Disc Displacement With Reduction.

The aim of our study was to evaluate the success rates and prognoses of patients treated with occlusal appliances used to reposition the temporomandibular joint anterior disc displacement with reduction (ADDWR). A sample of 144 consecutive patients (210 joints) diagnosed with ADDWR based on MRI were included in our study. Disc recapture was confirmed in a mandible-anterior position to eliminate joint clicking based on magnetic resonance imaging (MRI). Anterior repositioning appliance (ARS) was applied to keep the mandible in this position. The occlusal surface of the ARS was ground down by 1 mm approximately every 4 weeks for bite reconstruction. MRI was carried out before treatment, 6 months after the start of treatment, at the end of the treatment, and at their last follow-up visit. A Cox regression model was used to estimate the risk of failure of the treatment. The mean treatment duration was 9.5±2.6 months. A total of 177 joints (84.3%) were successfully repositioned at the end of splint treatment according to MRI. Regular follow-up indicated that almost 53% of the patients had normal disc-condyle relationships after 2 years. Sex, age, treatment duration, and orthodontics used were included in the final Cox regression model, with hazard ratios of 1.375, 1.141, 0.396, and 0.364, respectively. ARS is inferior for recapturing ADDWR in the long-term. It is thus better to explore other more effective methods to reposition the displaced disc in patients with ADDWR.

Yang\u2019s Classification of Juvenile TMJ Anterior Disc Displacement Contributing to Treatment protocols

This study aims to establish a new staging system of temporomandibular joint (TMJ) anterior disc displacement (ADD) and evaluate its role in guiding the treatment plan. A consecutive sample of 522 juvenile patients (780 joints) diagnosed as ADD based on magnetic resonance imaging (MRI) was included and analyzed. 674 joints received TMJ treatments according to our staging system, while 106 joints rejected any treatment; only for follow-up. The outcomes were judged according to our success criteria. The prognosis of our staging system was also evaluated in comparison to Wilkes classification. Kaplan–Meier survival analysis showed that significant stratifications of the ameliorative rate were found at all subgroups within any two stages in our staging system, except for subgroups between stages 0 and 1, stages 2 and 3, and stages 3 and 4. After analyzing the interactions between different candidate prognostic factors in a Cox model, the relative risks of deterioration of ADD included treatment methods (HR = 42.94, P < 0.0001), disease course (HR = 0.98, P = 0.0019), stages of ADD (HR = 3.81, 9.62, 12.14, P = 0.016, 0.000,0.000 respectively for stage 2, stage 3 and stage 4) and the interaction between ADD stages and treatment methods. The C index of this model was 0.87. The new staging system of TMJ ADD appears reliable, and benefits to making treatment planning and predicting the prognosis.

Temporomandibular joint anterior disc displacement with reduction in a young population: Prevalence and risk indicators.

Temporomandibular joint (TMJ) anterior disc displacements with reduction (ADDR) are commonly found in the young population and often found to be associated with biomechanical and anatomical factors. Until now, most knowledge on ADDR among children and adolescents comes from studies performed on Caucasian subjects. To assess the clinically determined prevalence rates of ADDR among the young Indonesian population and to evaluate its risk indicators. In this cross-sectional study, 1562 pupils and students of 7-21years old completed a questionnaire and underwent a clinical examination. The prevalence rates of ADDR were 7.0% among children (7-12years), 14.4% among adolescents (13-18years), and 12.3% among young adults (19-21years). Logistic regression analyses revealed that increasing age and lip biting were associated with ADDR in children, whereas pen biting was associated with ADDR in the adolescent population. None of the included factors were found to be associated with ADDR in the young adult population. The present findings indicate that prevalence of ADDR increases with age, with a peak during the years of adolescence. Biomechanical factors seem to play a significant role in ADDR development.

Intra-articular injections of hyaluronic acid for anterior disc displacement of temporomandibular joint

Anterior disc displacement (ADD) of temporomandibular joint (TMJ) is regarded as one of the major findings in temporomandibular disorders (TMD). It is related to joint noise, pain, mandibular dysfunction, degenerative change and osteoarthritis. In the mean time, the pathological changes were found in synovial membrane and synovial fluid. Hyaluronic acid is a principal component of the synovial fluid which plays an important role in nutrition, lubrication, anti-inflammation and cartilage repair. The synthesis, molecule weight, and concentration of hyaluronic acid are decreased during TMD and cause TMJ degenerative changes. The clinical conditions, pathological changes, the mechanism of action for hyaluronic acid and the treatment of anterior disc displacement of TMJ are discussed in this article.