Current Clinical Research Directions on Temporomandibular Joint Intra-Articular Injections: A Mapping Review

Intra-Articular Physiological Saline in Temporomandibular Disorders May Be a Treatment, Not a Placebo: A Hypothesis, Systematic Review, and Meta-Analysis

Background: Intra-articular injections reduce pain in patients with temporomandibular joint (TMJ) disorders who are unresponsive to conservative treatment. Hyaluronic acid, blood products, and medications provide rapid relief when administered this way, although their mechanisms of action remain unclear. In control groups, which are intended to be untreated, 0.9% NaCl is typically delivered. The hypothesis that "normal saline injections in TMJ cavities produce a therapeutic effect" is proposed, with an exploration of its potential verification, alongside a systematic review and meta-analysis of studies on intra-TMJ 0.9% NaCl. Methods: Randomized controlled trials (RCTs) on patients with TMJ internal derangement, arthritis, or degeneration were selected under PRISMA 2020 and assessed with RoB2. Results: Seven RCTs with 359 patients were included. Weekly follow-ups revealed a decrease in articular pain by 23.72% (SE: 0.84%; 95% CI: 24.38-21.06%; p < 0.01), and monthly follow-ups indicated a decrease of 34.01% (SE: 1.09%; 95% CI: 36.16-31.86%; p < 0.01) compared to the baseline values. These findings were grounded in low-risk-of-bias evidence on 267 patients in five RCTs and 222 patients in four RCTs, respectively. Conclusions: The hypothesis warrants further testing to determine whether, in addition to the known biological activity of typical injectables, the mechanical action also contributes to pain relief.

Effects of Hyaluronic Acid (HA) and Platelet-Rich Plasma (PRP) on Mandibular Mobility in Temporomandibular Joint Disorders: A Controlled Clinical Trial

Hyaluronic acid (HA) is a glycosaminoglycan composed of D-glucuronic acid and N-acetylglucosamine with an up-to-several-million-Daltons chain-length responsible for the lubricating properties of the temporomandibular joint (TMJ) synovial fluid. Arthritis results in the predominance of HA degradation over synthesis leading to temporomandibular disorders (TMDs). TMD injection treatments are divided into HA supplementation and platelet-rich plasma (PRP) inflammation suppression. We questioned whether either approach lubricated the TMJ better and answered it in a two-arm equal-allocation trial with a non-concurrent active treatment control (two groups of 39 patients each). HA statistically significantly improved (p < 0.01) and PRP did not statistically significantly change (0.06 ≤ p ≤ 0.53) articular mobility compared to baselines in 128 TMJs. Statistically significant inter-group discrepancies were observed for abduction (MD = -4.05 mm; SE = 1.08; p = 0.00; d = -0.85) and protrusion (MD = -0.97 mm; SE = 0.43; p = 0.03; d = -0.51) but not for rightward (MD = -0.21; SE = 0.43; p = 0.63; d = -0.11) and leftward (MD = -0.30; SE = 0.42; p = 0.47; d = -0.16) movements. HA supplementation proved superior to PRP autografting in ad hoc TMJ lubrication and hence is more appropriate in hypomobile TMD cases of symptomatic treatment.

Hyaluronic Acid/Platelet-Rich Plasma Mixture Improves Temporomandibular Joint Biomechanics: A Systematic Review

Hyaluronic acid (HA) is the main component of the temporomandibular joint (TMJ) synovial fluid. Arthritis in temporomandibular disorders (TMDs) disrupts HA metabolism, resulting in shorter polymeric chain predominance and increased friction. Intra-articular injections of HA supplement the larger molecules of this glycosaminoglycan, and the platelet-rich plasma (PRP) delivered in this way releases growth factors, suppressing inflammation. This PRISMA-compliant PROSPERO-registered (CRD42024564382) systematic review aimed to assess the validity of mixing HA with PRP in the injectable treatment of TMJ disorders. We searched the medical literature for eligible randomized clinical trials using BASE, Google Scholar, PubMed and Scopus engines on 9 May 2024, with no time frame limit. Selected reports were assessed for risk of bias using the Cochrane RoB2 tool. Numerical data were collected on articular pain and mandibular mobility. We provided mean differences from baseline and between study and control groups at each observation point. The efficacy of TMD treatment with HA/PRP versus HA or PRP alone was assessed meta-analytically. Of 171 identified records, we selected 6 studies. In the 6-month follow-up, the mean advantage of PRP supplementation with HA was 2.52 (SE = 2.44; d = 0.83) mm and the benefit of adding PRP to HA was 1.47 (SE = 2.68; d = 0.34) mm in mandibular abduction. The pain-improvement scores were -1.33 (SE = 1.02; d = -1.05) and -1.18 (SE = 0.92; d = 0.80), respectively. Presumably, the HA/PRP range of therapeutic efficiency includes cases non-respondent to HA or PRP alone.

Non-Steroidal Anti-Inflammatory Drugs Administered Intra-Articularly in Temporomandibular Joint Disorders: A Systematic Review and Meta-Analysis

Objectives: This systematic review was designed to summarize randomized controlled trials of intra-articular administration of non-steroidal anti-inflammatory drugs (NSAIDs) for temporomandibular disorders. Methods: Randomized controlled trials regarding intra-articular injections of non-steroidal anti-inflammatory drugs for temporomandibular disorders were included in the review. The final search was conducted on 16 June 2024 in the Bielefeld Academic Search Engine, PubMed, and Scopus databases. Results: Of the 173 identified studies, 6 were eligible for review. In trials comparing arthrocentesis alone to arthrocentesis with NSAIDs, slight differences in joint pain were noted. For tenoxicam, differences were under 1 point on a 0-10 scale after 4 weeks, with inconsistent results. Piroxicam showed no significant difference, and pain levels were minimal in both groups. For maximum mouth opening (MMO), tenoxicam showed no significant difference. Piroxicam increased MMO by nearly 5 mm, based on one small trial with bias concerns. Conclusions: Currently, there is no strong scientific evidence supporting the injection of NSAIDs into the temporomandibular joint to relieve pain or increase jaw movement. Preliminary reports on piroxicam with arthrocentesis and tenoxicam or diclofenac without rinsing justify further research.

Update on Evidence and Directions in Temporomandibular Joint Injection Techniques: A Rapid Review of Primary Research

This rapid review summarizes the latest primary research in temporomandibular joint (TMJ) injection treatment. The final literature searches were conducted on 4 January 2024. Selection was performed systematically following predefined eligibility criteria. Randomized control trials concerning the treatment of TMJ disorders with intra-articular injections were included. Studies on more invasive interventions were excluded. Quality of life, joint pain and range of mandibular mobility were assessed. Ultimately, 12 studies covering a total of 603 patients qualified. They concerned: (1) arthrocentesis (AC) and the administration of, (2) injectable platelet-rich fibrin (I-PRF), (3) platelet-rich plasma (PRP), (4) hyaluronic acid (HA), (5) non-steroidal anti-inflammatory drugs (NSAIDs), and (6) hypertonic dextrose (HD) with a local anesthetic. The dominant approach was to perform arthrocentesis before administering the appropriate injection substance (I-PRF, PRP, HA, or NSAID). Two current studies on the intra-articular administration of NSAIDs, specifically tenoxicam and piroxicam, are noteworthy. A mixture of PRP and HA was injected in another two trials. These two innovative approaches may prove to be significant directions for further research on injection treatment of TMJs.

Progress in the Study of Temporomandibular Joint Lavage in Temporomandibular Joint Disorder

With the continuous development and progress of medicine, there are many methods for the treatment of temporomandibular disorders, among which temporomandibular joint lavage is also constantly developed. In the past century, through the efforts of some scholars and clinical summary, the understanding of this disease has been deepened and broadened. At present, through continuous exploration of the treatment methods, the lavage is relatively mature, and has achieved good clinical results. In this paper, the application of temporomandibular joint lavage in the treatment of temporomandibular joint disorders, its treatment methods, treatment mechanism, the auxiliary of other drugs, indications, complications and so on were discussed.

Efficacy of Injectable Platelet-Rich Fibrin (I-PRF) in Managing Temporomandibular Joint Pain: A Prospective Clinical Study

BACKGROUND

Temporomandibular joint (TMJ) pain is a common condition that can significantly impact an individual's quality of life. Current treatment options often fall short of providing long-lasting relief. So, this prospective clinical study aimed to investigate the efficacy of injectable platelet-rich fibrin (I-PRF) in mitigating TMJ pain.

METHODS

A total of 68 participants, aged 18-60 years, clinically diagnosed with TMJ pain, were recruited from dental clinics and specialist referrals. Participants were randomly assigned to either the intervention group (I-PRF injections) or the control group (placebo). Primary outcome measures included TMJ pain intensity and jaw function, assessed using the Visual Analog Scale and functional examinations, respectively. Secondary outcomes comprised patient-reported outcomes (PROs) on quality of life and satisfaction. Data were collected at baseline and six, 12, and 24 weeks post intervention.

RESULTS

Baseline characteristics demonstrated successful randomization, with no significant differences in age, gender, or TMJ pain duration between groups. Post intervention, the intervention group exhibited a significant and sustained reduction in TMJ pain intensity compared to controls (p<0.001). Improvements in jaw function were also notable in the intervention group at all follow-up time points (p<0.001). PROs related to quality of life and satisfaction substantially increased in the intervention group compared to controls (p<0.001).

CONCLUSION

I-PRF demonstrated significant efficacy in reducing TMJ pain intensity, improving jaw function, and enhancing PROs. These findings support the consideration of I-PRF as a valuable therapeutic intervention for individuals with TMJ pain.

Intra-Articular Local Anesthetics in Temporomandibular Disorders: A Systematic Review and Meta-Analysis

This systematic review with meta-analysis was conducted to evaluate the effectiveness of local anesthetic administration into temporomandibular joint cavities in relieving pain and increasing mandibular mobility. Randomized controlled trials were included with no limitation on report publication dates. Final searches were performed on 15 October 2023, using engines provided by the US National Library, Bielefeld University, and Elsevier Publishing House. The risk of bias was assessed using the Cochrane Risk of Bias 2 tool. Articular pain and mandible abduction values and their mean differences were summarized in tables and graphs. Eight studies on a total of 252 patients evaluating intra-articular administration of articaine, bupivacaine, lidocaine, and mepivacaine were included in the systematic review. None of the eligible studies presented a high risk of bias in any of the assessed domains. An analgesic effect of intra-articular bupivacaine was observed for up to 24 h. In the long-term follow-up, there were no statistically significant changes in quantified pain compared to both the baseline value and the placebo group, regardless of the anesthetic used (articaine, bupivacaine, and lidocaine). There is no scientific evidence on the effect of intra-articular administration of local anesthesia on the range of motion of the mandible. Therefore, in the current state of knowledge, the administration of local anesthetics into the temporomandibular joint cavities can only be considered as a short-term pain relief measure.

Autologous Blood Injections in Temporomandibular Hypermobility: A Systematic Review

The injection of autologous blood (AB) is one of the methods of treatment of recurrent dislocations in the temporomandibular joints (TMJs). Due to the low invasiveness of this technique, it is reasonable to evaluate it in accordance with the standards of evidence-based medicine. The purpose of this systematic review is to identify primary studies on AB injection for the treatment of TMJ hypermobility and assess the therapy for effectiveness. This systematic review was conducted in accordance with the current "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" guidelines. Controlled randomized trials comparing dislocation episode rates, range of motion in the TMJ, or articular pain intensity were adopted as the eligibility criteria. Final searches were conducted on 11 June 2023 using Bielefeld Academic Search Engine, Elsevier Scopus, and the National Library of Medicine: PubMed. Trials were assessed using the "Oxford Center for Evidence-Based Medicine 2011 Levels of Evidence" scale and "A revised Cochrane risk-of-bias tool for randomized trials". The results of the individual studies were tabulated, syntheses were illustrated in graphs. Twenty two studies involving 982 patients were included in the qualitative analysis, of which seven studies involving 390 patients were subject to quantitative analysis. None of the included randomized controlled trials presented a high risk of bias, 75% of them raised some concerns. In a three-month observation, administration of AB was more efficient in limiting temporomandibular dislocations than hypertonic dextrose (1 study, 32 patients, relative risk = 0.33, odds ratio = 0.29) and no difference in outcomes was observed between intracavitary and pericapsular administration compared to pericapsular injection alone (2 studies, 70 patients, relative risk = 1.00, odds ratio = 1.00). Injections of AB into the temporomandibular joints are effective in preventing further TMJ dislocation episodes in 75-94% of patients. This study received no funding.