The clinical significance of the horizontal condylar angle in patients with temporomandibular disorders

The diagnostic accuracy of cone beam computed tomography in detecting temporomandibular joint bony disorders: a systematic review

Computed tomography (CT) has been recognized as a robust and dependable technique for delineating osseous alterations and anomalies within hard tissues. The necessity for accurate diagnosis and management of patients with temporomandibular disorders in dental practices has increasingly come to the forefront. There is ongoing scholarly debate regarding the equivalence of diagnostic outcomes yielded by cone beam computed tomography (CBCT), which offers greater accessibility in dental settings than traditional CT, in identifying bony changes within the temporomandibular joint (TMJ). Our principal aim was to conduct a systematic review of studies that compare the efficacy of CT and CBCT in the detailed assessment of bone conditions affecting the TMJ. An electronic search was conducted across databases: PubMed, Medline, Web of Science, Cochrane and Scopus. Two independent reviewers screened titles and abstracts against predefined inclusion criteria. The included articles underwent rigorous critical appraisal, during which relevant data were extracted and systematically presented in a tabular format. This systematic review incorporates 5 studies published between 2006 and 2015. In 3 studies, CBCT demonstrated comparable outcomes to CT, while 2 investigations revealed significantly enhanced accuracy for CBCT compared to CT, with reported accuracies of 0.95 ± 0.04, 0.77 ± 0.17, and 89-91% for CBCT. The aggregated evidence from the included studies indicates that CBCT offers comparable or superior accuracy in detecting osseous changes within TMJ structures. Owing to its lower radiation exposure and increased accessibility, CBCT emerges as the preferred choice over conventional CT for evaluating bony structures of the TMJ.

Assessment of bony changes in temporomandibular joint in patients using cone beam computed tomography - a cross sectional study

BACKGROUND AND AIM

The aim of this study is to evaluate the changes in the temporomandibular joint (TMJ) in patients with temporomandibular disorder (TMD) and the relationship between age, sex, and types of TMJ change using Cone Beam Computed Tomography (CBCT).

METHODS AND MATERIAL

CBCT records of 200 patients (123 women and 67 men) were retrieved and assessed. Right and left TMJs were evaluated separately, resulting in a total of 400 TMJs. The images were analyzed using On demand 3D Application The radiographic findings were classified as erosion, proliferative changes mainly, including flattening and osteophytes of the condyle, sclerosis, Ely cyst, hypoplasia and hyperplasia of the condyles, ankylosis, and joint cavity. Data analysis was performed using descriptive statistics, paired T-tests, and repeated measure ANOVA (Analysis of Variance) in SPSS Software.

RESULTS

The most prevalent types of condylar bony changes observed was osteophyte (63.5%) followed by flattening of the articular surface (42%), erosion (40%), ankylosis (10%) and sclerosis (10%). 7.5% of joints showed hyperplastic condyles but only 2% showed hypoplasia. The least prevalent change observed was Ely Cyst (1%). Osteophyte was the most prevalent change observed in all age groups and both sexes except for men aged 31 ~ 50, where flattening was more frequent. A statistically significant difference was found between sex and prevalence of erosion in the age group of 10 ~ 30 (P = 0.001); as well as between sex and condylar hyperplasia in the same age group.

CONCLUSION

Based on the findings of this research, the prevalence of bony changes of TMJ from highest to lowest is as follows: osteophyte, flattening of the articular surface, erosion, ankylosis, sclerosis, hyperplastic condyles, hypoplastic condyles and Ely Cyst. CBCT is an accurate 3 dimensional imaging modality for assessment of TMJ bony structures.

Relation between Condyle Horizontal Angle and Intercondylar Angle with Disc Displacement in Patients with Temporomandibular Joint Disorders: An MRI Evaluation

Background

Internal derangement (ID) is the most common cause of temporomandibular disorders (TMDs) and extensively affects the articular disc function. The anterior disc displacement is among the most important findings in ID. Knowledge about the etiology of this condition is imperative, and the role of structural parameters in the development of TMDs has not been well evaluated.

Objectives

This study aimed to assess the relationship between condylar angulation and intercondylar angle with anterior disc displacement in patients with TMD using magnetic resonance imaging (MRI).

Materials and Methods

This case-control study evaluated 31 temporomandibular joints with internal derangement and 57 normal joints. The data retrieved from MRI included disc position in the open mouth (normal, anterior disc displacement with a reduction (DDWR) and without reduction (DDWOR), and posterior displacement (PD)), horizontal condylar angle categorized as normal (10 to 30° angle) and abnormal (<10° and >30°), and intercondylar angle. Chi-square test, T-test, and Fisher's exact were done to assess the relationship between horizontal condylar angle and intercondylar angle in patients with TMDs with DDWR and DDWOR compared with the control group.

Results

Patients with DDWR and DDWOR had higher odds of abnormal horizontal condylar angle, particularly >30° angle, which was a significant correlation (odds ratio of 0.19 and 8.3, respectively). The intercondylar angle in the patients with disc displacement was significantly smaller compared to the control group.

Conclusion

Disc displacement was correlated with abnormal horizontal angle (particularly < 30) and smaller intercondylar angle compared with the control group.

Relationship between horizontal condylar angle and radiographically detectable morphological changes of the condyle in asymptomatic and symptomatic patients with TMD

Background

The relationship between horizontal condylar angle (HCA) measurements and radiographically detectable morphological changes of the condyle in patients with temporomandibular disorder (TMD) is an area of controversy in dentistry.

Aim

This study sought to determine the effect of the HCA on radiographically morphological changes in the condyles of asymptomatic and symptomatic patients with TMD.

Material & methods

Cone beam computed tomography (CBCT) scans were used of patients with 146 temporomandibular joints (TMJ) with and without symptoms of TMD. The reconstructed axial plane was adjusted to depict the condyle in maximum width. The HCA was established and measured as the angle formed between the condylar long axis intersecting with the coronal plane. Each condyle long axial was determined independently from the other joint by two oral and maxillofacial radiologists. The average of the readings from the two examiners was used for statistical analysis.

Results

Based on the clinical symptoms, the mean of the HCA in the symptomatic joint was 27.69°, which was slightly greater than the angle measured in asymptomatic patients of 25.6°; however, this was not a statistical difference. No significant differences existed in the mean of the HCA between the joint with and without radiographic arthritic findings in both groups. In both groups, none of the arthritic findings manifested in the affected joint that had influenced the HCA.

Conclusion

The HCA was increased in the symptomatic group but had no direct influence on joint's morphological changes in the asymptomatic and symptomatic patients.

Toll-Like Receptor 4 (TLR4) Stimulates Synovial Injury of Temporomandibular Joint in Rats Through the Activation of p38 Mitogen-Activated Protein Kinase (MAPK) Signaling Pathway

Background

Synovitis is an important disease that cause intractable pain in temporomandibular joint (TMJ), and the inflammation process played a crucial role in the initiation and development of temporomandibular joint disorder. A series of investigations suggested that the increasing expression of interleukin-(IL) 1β secreted by synovial lining cells plays an important role in synovial inflammation and cartilage destruction in TMJ. In this present study, we investigated the signaling pathways which regulate the expression of IL-1β.

Material/Methods

The occlusal interference animal model was created to induce synovial injury. Forty-eight rats were divided into 4 groups: 1) control group, 2) occlusal interference group, 3) TAK-242 (a specific inhibitor targeting the Toll-like receptor (TLR)-4) group, and 4) SB203580 (a specific inhibitor targeting the p38) group. The inflammation changes were observed, and the expression of p38 and IL-1β in the synovial membranes were assayed.

Results

The results showed that downstream p38 MAPK (mitogen-activated protein kinase) signaling was triggered following the activation of TLR4. Moreover, the injection of SB203580 could inhibit the inflammatory reactions and the increased expression of IL-1β at both mRNA and protein levels.

Conclusions

The results prompted us that TLR4 may stimulates synovial inflammatory reactions and increased expression of IL-1β in rats through the activation of p38 MAPK signaling pathway, p38 was an important mediator in the mechanisms of the initiation and development of synovial injury by regulating the expression of IL-1β in synovial membranes.

Effect of Toll-Like Receptor 4 on Synovial Injury of Temporomandibular Joint in Rats Caused by Occlusal Interference

Synovitis is an important disease that causes intractable pain in TMJ. Some investigations suggested that the increasing expression of IL-1β secreted by synovial lining cells plays an important role in synovial inflammation and cartilage destruction in TMJ. In our previous research, the results demonstrated that TLR4 is involved in the expression of IL-1β in SFs from TMJ with lipopolysaccharide stimulation. However, the inflammatory response that occurred in synovial membrane is not caused by bacterial infection. In the current study, we investigated whether or not TLR4 participates in the inflammatory responses and the expression of IL-1β in synovial membrane of rats induced by occlusal interference. The results showed that obvious inflammation changes were observed in the synovial membranes and the expression of TLR4 and IL-1β was increased at both mRNA and protein levels in the occlusal interference rats. In addition, the inflammation reactions and the increased expression of IL-1β could be restrained by treatment with TAK-242, a blocker of TLR4 signaling. The results prompted us that the activation of TLR4 may be involved in the inflammatory reactions and increased expression of IL-1β in patients with synovitis and participate in the mechanisms of the initiation and development of synovial injury by regulating the expression of inflammatory mediators like IL-1β in synovial membranes.

Masseter muscular weakness affects temporomandibular synovitis induced by jaw opening in growing rats

OBJECTIVE

To evaluate the influence of impaired masseter function during growth on the development of temporomandibular synovitis.

MATERIALS AND METHODS

Sixteen 3-week-old male Wistar rats were classified into four groups. The first group served as control; and in the second group, jaw opening was forced for 3 hours when the rats were 9 weeks old. In the third and fourth groups, the masseter muscles were bilaterally resected at 3 weeks of age, and the rats in the fourth group were additionally forced to open their jaw at 9 weeks of age. All rats were sacrificed at 9 weeks. Temporomandibular joint (TMJ) tissue samples were processed for histology, and evaluated for cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions by immunohistochemistry to examine the inflammatory changes in the synovial membrane.

RESULTS

The control group showed noninflammatory changes. In the jaw-opening group, vascular dilation and weak COX-2 immunoreactivity were induced by jaw opening in the synovium. In the masseter-resection group, the masseter-resected rats exhibited moderate synovial changes while in the resection with opening group, the masseter-resected rats revealed more significant inflammatory changes including synovial hyperplasia, dilated vasculature, fibrin deposits, and intense immunoreactivity for COX-2 and iNOS, all caused by jaw opening.

CONCLUSIONS

These results suggest that masseter activity in the growth period is an important factor in the induction of temporomandibular synovitis.