Comparison of disc position stability and condylar bone remodeling between two open disc repositioning surgeries: a retrospective single-center cohort study

BACKGROUND AND OBJECTIVE

Open suturing (OSu) and Mini-screw Anchor (MsA) are two commonly used open disc repositioning surgeries for anterior disc displacement (ADD) of the temporomandibular joint (TMJ). This study assesses the differences in disc position stability (DPS) and condylar bone remodeling (CBR) between these two surgical procedures in a single center.

METHODS

A retrospective cohort study using magnetic resonance imaging (MRI) scans (preoperation, 1 week and 12 mo postoperation) of all patients who had open TMJ disc repositioning surgery from January 2016 to June 2021 at one center through two surgical techniques (OSu and MsA) was performed. The predictor variable was technique (OSu and MsA). Outcome variables were DPS and CBR. During follow-up, DPS was rated as good, acceptable and poor, and CBR was graded as improved, unchanged, and degenerated. Multivariate analysis was used to compare the DPS and CBR at 12 months after adjusting 5 factors including age, sex, Wilkes stage, preoperative bone status (normal, mild/moderate abnormal) and the degree of disc repositioning (normal, overcorrected, and posteriorly repositioned). Relative risk (RR) for DPS and CBR was calculated by multivariate logistic regression.

RESULTS

385 patients with 583 joints were included in the study. MRIs at 12 months showed that 514 joints (93.5%) had good DPS, and 344 joints (62.5%) had improved CBR. Multivariate analysis revealed that OSu had higher DPS (RR=2.95; 95% confidence interval [CI], 1.27 to 6.85) and better CBR (RR=1.58; 95%CI, 1.02 to 2.46) than MsA. Among the factors affecting DPS, females had better results than males (RR=2.63; 95%CI, 1.11 to 6.26) and overcorrected or posteriorly repositioned discs were more stable than normally-repositioned discs (RR=5.84; 95%CI, 2.58 to 13.20). The improvement in CBR decreased with age increasing (RR=0.91; 95%CI, 0.89 to 0.93). Preoperative mild/moderate abnormal bone status had a higher probability of improved CBR compared to normal preoperative bone status (RR=2.60; 95%CI, 1.76 to 3.83).

CONCLUSION

OSu had better DPS and CBR than MsA. Sex and the degree of disc repositioning impacted DPS, while age and preoperative bone status affected CBR.

Analysis of joint protein expression profile in anterior disc displacement of TMJ with or without OA

OBJECTIVE

Anterior disc displacement (ADD) is a common clinical issue and may cause osteoarthritis (OA). However, the research of protein changes in synovial fluid as disease development marker and potential treatment clue is still insufficient.

MATERIALS AND METHODS

We conducted the high-resolution mass spectrometry (MS) of synovial fluid collected from 60 patients with normal disk position to ADD and ADD with osteoarthritis (OA). The proteins with significant changes among the 3 groups were analyzed by biological information and further validated by in primary rat condyle chondrocytes and OA animal model.

RESULTS

FGL2, THBS4, TNC, FN1, OMD etc. were significantly increased in ADD without OA (p < 0.05), which reflected the active extracellular matrix and collagen metabolism. FGFR1, FBLN2, GRB2 etc. were significantly increased in ADD with OA group (p < 0.05), which revealed an association with apoptosis and ferroptosis. Proteins such as P4HB, CBLN4, FHL1, VIM continuously increase in the whole disease progress (p < 0.05). Both the in vitro and in vivo results are consistent with protein changes detected in MS profile.

CONCLUSION

This study firstly provides the expression changes of proteins from normal disc condyle relationship toward ADD with OA, which can be selected and studied further as disease progress marker and potential treatment targets.

Detecting anteriorly displaced temporomandibular joint discs using super-resolution magnetic resonance imaging: a multi-center study

Background: Magnetic resonance imaging (MRI) plays a crucial role in diagnosing anterior disc displacement (ADD) of the temporomandibular joint (TMJ). The primary objective of this study is to enhance diagnostic accuracy in two common disease subtypes of ADD of the TMJ on MRI, namely, ADD with reduction (ADDWR) and ADD without reduction (ADDWoR). To achieve this, we propose the development of transfer learning (TL) based on Convolutional Neural Network (CNN) models, which will aid in accurately identifying and distinguishing these subtypes. Methods: A total of 668 TMJ MRI scans were obtained from two medical centers. High-resolution (HR) MRI images were subjected to enhancement through a deep TL, generating super-resolution (SR) images. Naive Bayes (NB) and Logistic Regression (LR) models were applied, and performance was evaluated using receiver operating characteristic (ROC) curves. The model's outcomes in the test cohort were compared with diagnoses made by two clinicians. Results: The NB model utilizing SR reconstruction with 400 × 400 pixel images demonstrated superior performance in the validation cohort, exhibiting an area under the ROC curve (AUC) of 0.834 (95% CI: 0.763-0.904) and an accuracy rate of 0.768. Both LR and NB models, with 200 × 200 and 400 × 400 pixel images after SR reconstruction, outperformed the clinicians' diagnoses. Conclusion: The ResNet152 model's commendable AUC in detecting ADD highlights its potential application for pre-treatment assessment and improved diagnostic accuracy in clinical settings.

Salubrinal alleviates cartilage degradation in a rabbit temporomandibular joint osteoarthritis model

OBJECTIVE

To investigate and explain the beneficial effects of local intra-articular injection of Salubrinal on temporomandibular joint osteoarthritis (TMJOA) using a rabbit model of anterior disc displacement (ADD).

METHODS

Rabbits were divided and subjected to surgical ADD. Salubrinal was administered by intra-articular injection in the TMJ every other day for 2 and 4 weeks after operation. Histological examination and TUNEL staining were then performed. Immunohistochemistry, quantitative real-time PCR, and Western blot analysis were employed to evaluate the expression of endoplasmic reticulum (ER) stress-related markers, catabolic factors, extracellular matrix proteins, inflammatory factors, and nuclear factor-kappa B (NF-κB) activation.

RESULTS

In the ADD groups, we found that Salubrinal partly reversed condylar cartilage deterioration according to the histological analysis. Salubrinal reduced chondrocytes apoptosis while increased matrix components including Collagen II and Aggrecan. Meanwhile, Salubrinal downregulated the catabolic expression of MMP13, ADAMTS5, VEGF, TNF-α, and IL-1β. We also observed that Salubrinal inhibited ER stress activation by reducing the expression of GRP78, CHOP, ATF4, and Caspase-12. Additionally, Salubrinal suppressed the phosphorylation of NF-κB.

CONCLUSION

These results indicate that Salubrinal alleviates cartilage degradation following ADD, suggesting that intra-articular injection of Salubrinal is a potential therapeutic approach for preventing TMJOA.

Application of modified articular disc anchorage in treating the perforation and rupture of temporomandibular joint disc

OBJECTIVES

This study aimed to use modified articular disc anchorage in treating old irreducible temporomandibular joint (TMJ) disc displacement with perforation and rupture, as well as to explore its efficacy.

METHODS

A total of 31 patients (34 sides) with 47 TMJ disc perforations who underwent surgical treatment in the Affiliated Stomatolo-gical Hospital of Nanchang University from January 2018 to December 2021 were selected. According to the location of disc perforation, it has five types: posterior disc perforation (typeⅠ), anterior disc perforation (typeⅡ), lateral disc perforation (type Ⅲ), composite disc perforation, and destruction disc perforation. The modified methods of disc anchoring were divided into two types according to the location of the perforation. TypesⅠandⅢ disc perforation were trea-ted by posterior anchoring method. For posterior ancho-ring, a screw was implanted into the posterolateral side of the condylar neck, and the disc was fixed on the screw by horizontal mattress suture. TypeⅡdisc perforation and compo-site disc perforation combined typeⅡperforation were treated by anterior and posterior double-anchoring method. For anterior anchoring, anchor screws or holes were placed at the anterior edge of the condylar neck, and horizontal mattress suture was performed at the posterior edge of the anterior perforation with an anchor wire. The articular disc was then fixed on the anchor screws or holes. For the posterior anchoring method, it was the same as the previous one. Paired t test was used to analyze the visual analog scale (VAS), maximum interincisal opening (MIO), and TMJ disorder index (CMI) of the patient before surgery and 1, 3, and 6 months after surgery. Disk-condyle position relationship by magnetic resonance imaging and postoperative quality of life in postoperative were analyzed.

RESULTS

The incidence of perforation was 41.2% (14/34) in typeⅠ, 11.8% (4/34) in typeⅡ, 8.8% (3/34) in typeⅢ, 29.4% (10/34) in composite type, and 8.8% (3/34) in destruction type. The VAS, MIO, and CMI at 3, 6 months after operation significantly improved compared with those before operation (P<0.05). The effective reduction rate of disc was 96.77% (30/31). The quality of life at 6 months after surgery was 47.22±2.13, and the rate of excellent evaluation was 96.4% (27/28).

CONCLUSIONS

Modified articular disc anchorage achieves a good curative effect for treating temporomandibular joint disc perforation and rupture. Nevertheless, its long-term effect requires further observation.

Role of Dynamic 3 Tesla MRI in the Evaluation of Temporomandibular Joint Dysfunction

INTRODUCTION

The internal derangement of the temporomandibular joint (TMJ) is the most common type of dysfunction. Internal derangement can be divided into anterior and posterior disc displacement. Anterior disc displacement is the most common type, which is further classified into anterior disc displacement with reduction (ADDWR) and without reduction (ADDWoR). Temporomandibular joint dysfunction (TMD) symptoms are pain, reduced mouth opening, and joint sound. The main aim of this study was to correlate the clinical findings and magnetic resonance imaging (MRI) diagnosis of TMD in symptomatic and asymptomatic TMJs.

METHODS

This prospective observational study was conducted in a tertiary care hospital on a 3T Philips Achieva MRI machine with 16-array channel coils after obtaining approval from the institutional ethical committee. A total of 60 TMJs of 30 patients were included in the study. After the clinical examination of each patient, an MRI of both right and left TMJs was done. In patients with unilateral TMD, the asymptomatic side was used as the asymptomatic joint, and the affected side as the symptomatic joint. Asymptomatic patients without any symptoms of TMD were used as controls for bilateral TMD cases. MRI with high-resolution specific serial sections was obtained in both open- and closed-mouth positions. A p-value of <0.05 was considered a statistically significant agreement between clinical and MRI diagnoses of internal derangement.

RESULTS

Out of a total of 30 clinically asymptomatic TMJs, only 23 were normal on MRI. On MRI, 26 TMJs showed ADDWR and 11 showed ADDWoR. The most common shape of the disc was biconcave and the displacement was anterior in symptomatic joints. The most common type of articular eminence shape was sigmoid in ADDWR and flattened in ADDWoR. Agreement between clinical and MRI diagnosis in this study was 87.5% (p < 0.001).

CONCLUSION

 The study concluded substantial agreement between clinical and MRI diagnosis of TMJ internal dysfunction and suggests that the diagnosis of the internal dysfunction can be made clinically but the exact position, shape, and type of disc displacement can be assessed precisely with the help of MRI.

Role of Intra-articular Piroxicam in the Temporomandibular Joint After Arthrocentesis for Anterior Disc Displacement Without Reduction

STUDY DESIGN

This is comparative experimental research to evaluate the role of piroxicam in the temporomandibular joint (TMJ) after arthrocentesis.

OBJECTIVE

To evaluate the role of intra-articular piroxicam in the temporomandibular joint after arthrocentesis for anterior disc displacement without reduction.

MATERIAL AND METHODS

Twenty-two individuals (twenty-two TMJs) were evaluated clinically and radiographically for the study, and then they were randomly assigned to one of two groups. As for group I, they were given arthrocentesis using Ringer's solution (100 ml). Group II received an intra-articular injection of 20 mg/mL of piroxicam (in 1 mL of Ringer's solution) after arthrocentesis (100 mL). The same individuals were assessed both before and after surgery to determine the degree to which their symptoms had improved. Patients were seen in the clinic once a week for the first month after surgery, then once a month for the next three months.

RESULT

 Group II patients presented with better results when compared with Group I.

CONCLUSION

It can be concluded that installing a 1 ml intra-articular injection of piroxicam at a concentration of 20 mg/ml after arthrocentesis improves the relief of symptoms, both qualitatively and quantitatively. Relief of TMJ symptoms reduced the anxiety in the patients as evaluated by the BAIS (Beck's Anxiety Inventory Scale) score.

Nonlinear Relationship between Temporomandibular Joint Disc Displacement Distance and Disc Length: A Magnetic Resonance Imaging Analysis

Objective: to explore the association between the distance of disc displacement and disc morphology in patients with temporomandibular disorders (TMDs). Methods: a total of 717 joints in 473 subjects were enrolled in this cross-sectional study. The magnetic resonance imaging (MRI) of each patient was evaluated for temporomandibular joint (TMJ) disc morphology classification and position. The distance of the disc displacement and disc length were measured for smoothing spline prediction. A stratified analysis was performed based on the types of disc positions. The disc width and length-width ratio (L/W) were also measured. Descriptive statistics, one-way analysis of variance, smoothing spline analysis, threshold analysis, and two piecewise linear regression were performed to investigate the association between the displacement distance and length of discs. Results: the differences in displacement distance among morphological categories and among different disc positions were statistically significant. Nonlinear relationships were found between distance and length in all subjects. Two turning points of distance (−1.8 mm and 1.7 mm) were found, dividing the curve into three segments. Disc width and L/W were significantly different among discs in the three segments of the curve. The correlation coefficient (β) for the three segments were as follows: −0.6 [95% confidence interval (CI) = −0.9 to −0.3, p < 0.001], 0.0 (95% CI = −0.1 to 0.0, p = 0.027), and −0.7 (95% CI = −0.8 to −0.7, p < 0.001). Nonlinear relationships were also found between the distance and length in cases with anterior disc displacement (ADD), anterior disc displacement with reduction (ADDWR), and without reduction (ADDWoR). Conclusion: the turning points of the disc displacement distance may be considered as a potential reference value for high-risk disc deformation and ADD. Disc length decreases sharply with anterior disc displacement when the disc displacement distance is over 1.7 mm. Prospective and long-term studies are required to clarify the natural course of the disc at different stages of the regression curve.

Association between bone morphology and sagittal disc position in temporomandibular joints of patients with anterior disc displacement

OBJECTIVES

To analyze the association between sagittal temporomandibular joint (TMJ) disc position of patients with anterior disc displacement evaluated by magnetic resonance imaging (MRI) and bone morphology of the TMJ evaluated by cone-beam computed tomography (CBCT).

METHODS

One hundred and seventy-eight TMJs of 97 patients were retrospectively analyzed. The TMJ disc position was evaluated using MRI and classified into four types: control group (without disc displacement), slight group (disc slightly anteriorly displaced), moderate group (disc moderately anteriorly displaced), and severe group (disc severely anteriorly displaced). The measurements of TMJ bone morphology among four groups were evaluated by CBCT through Mimics software including condyle linear dimensions (condyle length, width, and height), condylar volume and surface area, and the depth and length of the glenoid fossa, joint anterior space, joint superior space, and joint posterior space. The sagittal plane position of the condyle was also assessed. The differences in all the morphologic measurement parameters among the four groups were detected using the one-way analysis of variance or the Kruskal Wallis test, and Chi-square tests. The correlations between disc sagittal position and all the morphologic measurements were also analyzed.

RESULTS

There were significant differences in measurements of condyle linear dimensions, condylar volume and surface area, depth of the glenoid fossa, joint spaces, and distribution of the condyle sagittal positions among the four groups. By contrast, there were no statistical differences in terms of the length of the glenoid fossa among the four groups. Correlation analysis revealed that there is a statistically significant negative correlation among condyle linear dimensions, condylar volume and surface area, the depth of the glenoid fossa, joint superior space, and disc position. However, joint posterior space was positively correlated with disc position.

CONCLUSIONS

A statistically significant correlation was determined between TMJ bone morphology and different sagittal disc positions. Degenerative changes in TMJ bone morphology clinically diagnosed should be altered, which can be the patients' marker of anterior disc displacement.

[Three-dimensional morphological changes in the temporomandibular joints of patients with anterior disc displacement with reduction]

OBJECTIVES

To investigate the differences in the temporomandibular joints (TMJs) between patients with anterior disc displacement with reduction (ADDwR) and asymptomatic subjects by using 3D morphometric measurements.

METHODS

A total of 15 patients with ADDwR and 10 asymptomatic subjects were enrolled. Then, 3D models of the maxilla and mandible were reconstructed using MIMICS 20.0. Nine morphologic parameters of TMJs on both sides were measured on the 3D solid model. The differences in the parameters were analyzed between the patients and the asymptomatic subjects and between the left and right sides of each group.

RESULTS

The horizontal and coronal condylar angles on the ipsilateral side of the patients were significantly greater than those of the asymptomatic subjects (P<0.01). Meanwhile, the sagittal ramus angle (SRA), medial joint space, lateral joint space, superior joint space, anterior joint space, and posterior joint space in the patients were significantly lower than those in the asymptomatic subjects (P<0.01).

CONCLUSIONS

ADDwR will increase the condylar angles to be significantly greater than the normal level and decrease SRA and articular spaces to be significantly smaller than the normal level. The condyles will be displaced upward, closer to the fossa.

Relations between anterior disc displacement and maxillomandibular morphology in skeletal anterior open bite with changes to the mandibular condyle

In this study we investigated the relation between anterior disc displacement (ADD) and maxillomandibular morphology in skeletal anterior open bite with changes to the mandibular condyle. Thirty female patients (60 joints) with both conditions were evaluated. Magnetic resonance imaging of the temporomandibular joint (TMJ) was used to diagnose both ADD and changes to the mandibular condyle (erosion, osteophyte, and deformity). The relations among ADD, changes to the mandibular condyle, and maxillomandibular morphology were examined statistically. Changes to the mandibular condyle had a higher score than sym anterior open bite, the deviated side in asymmetric anterior open bite, and the non-deviated side. The score for disc displacement on the non-deviated side was lower than both the sym side and the deviated side. Unilateral changes to the mandibular condyle and unilateral disc displacement were not apparent in sym anterior open bite, but a unilateral non-displaced disc was seen only on the asymmetric side. Mandibular condylar changes were significantly more common on the deviated, than on the non-deviated, side. The SNB angle was significantly smaller, and the ANB, GZN, and SN-mandibular plane angles were significantly larger in sym anterior open bite. Overjet, ANB angle, GZN angle, and SN-MP angle were significantly larger, and the SNB angle was significantly smaller, in the presence of ADD without reduction and mandibular condylar deformity. We conclude that the prevalence of ADD without reduction and changes to the mandibular condyle were related to mandibular asymmetry and mandibular morphology in anterior open bite. This retrospective study suggests that ADD without reduction and mandibular condylar bone changes may be related to the progression of skeletal class II open bite and mandibular asymmetry in cases of skeletal open bite.

Characterization of a rat model with temporomandibular joint osteoarthritis following a surgical anterior disc displacement

This study has characterized a rat model with temporomandibular osteoarthritis (TMJ-OA) following a surgical anterior displacement of their articular disc (ADD). The well-established model of OA, induced by an intra-articular injection of complete Freund's adjuvant (CFA) into the TMJ, was used for comparison purposes. Male Wistar rats were assigned into two surgical groups, namely, ADD (anterior disc displacement) and sham-operated (surgical access, without ADD). Additional groups received an intra-articular infiltration of CFA (50 μl/site; 1:1 oil/saline emulsion), or the vehicle (0.9% NaCl). The separate experimental subgroups were euthanized at 15, 30 or 60 days and their left TMJs were collected for histological, immunohistochemistry and micro-CT analyses. The serum levels of IL-1β, IL-6 and TNF were analyzed. The fibrocartilage thicknesses were increased in the ADD groups at all of the analyzed time-points. In the CFA group, fibrocartilage thickenings were seen only in the posterior thirds at 15 days. The ADD group displayed an increase of the proteoglycan contents and ADAMTS5 immunopositivity in the fibrocartilage at 30 and 60 days, without any variations of the collagen contents or the osteoclast activation. Upon the micro-CT evaluation, the ADD group presented increments of their trabecular separations and bone surfaces, with reduced trabecular thicknesses and bone volumes, plus osteophyte formations and condyle flattenings, from 30 to 60 days. The IL-1β, TNF or IL-6 serum levels were undetectable. The surgical ADD in the rats led to long-term OA-like alterations, with typical structural and morphological derangements of the TMJ, representing a reliable experimental model to investigate the TMJ-OA-related mechanisms.

Physiological effects of anterior repositioning splint on temporomandibular joint disc displacement: a quantitative analysis

Anterior repositioning splints (ARS) are used primarily for the management of temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDwR). However, the exact physiological effects of ARS are still unclear. This study investigated the short and long-term effects of ARS on disc and condyle angles/positions by metric analysis. Twenty-two subjects diagnosed with ADDwR were recruited. Maxillary full-coverage ARS were fabricated, and MRI of TMJs was obtained before splint treatment, immediate post-insertion and 6 months after splint treatment. Disc-condyle relationship was determined by disc-condyle angle measurement. Disc and condyle positions were described as X-Y coordinates with the summit of glenoid fossa as the origin of the coordinates. Thirty-two TMJs were classified as ADDwR and 12 were normal. Upon ARS insertion, all TMJs with ADDwR got normal disc-condyle relationships. The condyles moved significantly forward and downward, while the discs moved significantly backward and upward. MRI at 6 months after treatment (without ARS insertion) indicated that only 40·6% (13/32) of the joints were maintained in the normal disc-condyle relationship. The majority of condyles returned to their pre-treatment positions, while the discs generally moved anteriorly again. The use of ARS resulted in forward and downward condyle movement, and a concurrent backward movement of the disc resulting in ideal spatial disc-condyle relationship. The stability of this relationship, however, could not be maintained in the majority of TMJs upon ARS removal. Findings explain the good short-term clinical outcomes with ARS and their relatively lower efficacy in the long term.

Does condylar height decrease more in temporomandibular joint nonreducing disc displacement than reducing disc displacement?: A magnetic resonance imaging retrospective study

The aim of the study was to compare condylar height changes of anterior disc displacement with reduction (ADDwR) and anterior disc displacement without reduction (ADDwoR) in temporomandibular joint (TMJ) quantitatively, to get a better understanding of the changes in condylar height of patients with anterior disc displacement who had received no treatment, and to provide useful information for treatment protocol. This longitudinal retrospective study enrolled 206 joints in 156 patients, which were divided into ADDWR group and ADDwoR group based on magnetic resonance imaging examination. The joints were assessed quantitatively for condylar height at initial and follow-up visits. Also, both groups were further divided into 3 subgroups according to age: <15 years group, 15 to 21 years group, and 22 to 35 years group. Paired t test and independent t test were used to assess intra- and intergroup differences. The average age of the ADDwR group was 19.65 years with a mean of 9.47 months' follow-up. The follow-up interval of the patients with ADDwoR was 7.96 months, with a mean age of 18.51 years. Condylar height in ADDwoR tended to decrease more than those in ADDwR, especially during the pubertal growth spurt and with the presence of osteoarthrosis, meaning ADDwoR could cause a severe disturbance in mandibular development. Thus, an early disc repositioning was suggested to avoid decrease in condylar height.

Radiological follow-up results of untreated anterior disc displacement without reduction in adults

The aim of this study was to assess the radiographic changes in untreated adults with bilateral anterior disc displacement without reduction. A cohort study was designed to compare the bone changes, effusion, disc configuration, and pseudo-disc changes on two magnetic resonance images obtained at least 24 months apart. Twenty-eight patients (22 female, six male) with a mean age of 33.1 years (range 20-57 years) were included. The mean interval between the initial visit and the follow-up visit was 36.2 months. At the initial visit, the frequencies of bone changes, effusion, disc deformation, and pseudo-disc changes were 51.79%, 35.71%, 100%, and 0%, respectively. At follow-up, the frequency of effusion had decreased significantly. The frequency of bone changes had increased significantly to 75%, but newly formed cortical bone was present in five condyles. All discs remained deformed. Pseudo-disc changes were detected in five joints. Over a long period of observation, there was a significant decrease in effusion and a significant increase in bone changes. However, some adaptive changes occurred.