Short-Term Effects of Intra-Articular Hyaluronic Acid Administration in Patients with Temporomandibular Joint Disorders

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.

[Preliminarily study of arthrocentesis combined with liquid phase concentrated growth factor injection in the treatment of unilateral temporomandibular joint osteoarthritis]

OBJECTIVE

To observe the clinical effect of arthrocentesis combined with liquid phase concentrated growth factor (CGF) injection in the treatment of unilateral temporomandibular joint osteoarthritis (TMJOA), in order to provide a new treatment option for TMJOA patients.

METHODS

In this non-randomized controlled study, patients diagnosed with unilateral TMJOA who visited the center for temporomandibular joint disorder and orofacial pain of Peking University School and Hospital of Stomatology from June 2021 to January 2023 were selected as research objects. The patients were divided into experimental group and control group, which were selected by patients themselves. The experimental group received arthrocentesis combined with liquid phase CGF injection and the control group received arthrocentesis combined with HA injection. Both groups were treated 3 times, once every two weeks. The clinical effect was evaluated by the maximum mouth opening, pain value and the degree of mandibular function limitation 6 months after treatment. The change of condylar bone was evaluated by cone beam CT (CBCT) image fusion technology before and after treatment.

RESULTS

A total of 20 patients were included in the experimental group, including 3 males and 17 females, with an average age of (34.40±8.41) years. A total of 15 patients were included in the control group, including 1 male and 14 females, with an average age of (32.20±12.00) years. There was no statistical difference in general information between the two groups (P > 0.05). There were no statistical differences in the mouth opening, pain value and the degree of jaw function limitation between the two groups before treatment (P > 0.05), and all of them improved 6 months after treatment compared with before treatment (P < 0.05). However, the mouth opening of experimental group was significantly higher than that of control group 6 months after treatment (P < 0.05), and the degree of jaw function limitation was significantly lower than that of control group (P < 0.05). CBCT 2D images showed that the condylar bone of both groups was smoother after treatment than before treatment, and image fusion results showed that 10 patients (50.0%) in the experimental group and 5 patients (33.3%) in the control group had reparative remodeling area of condylar bone, and there was no statistical difference between them (P > 0.05). Except for one CGF patient, the other patients in both groups had some absorption areas of condylar bone.

CONCLUSION

The arthrocentesis combined with liquid phase CGF injection can improve the clinical symptoms and signs of unilateral TMJOA patients in short term, and is better than HA in increasing mouth opening and improving jaw function. CBCT fusion images of both patient groups show some cases of condylar bone reparative remodeling and its relevance to treatment plans still requires further study.

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.

Effectiveness of double-puncture temporomandibular joint arthrocentesis with viscosupplementation in different categories of severity - a prospective study

This 3-year prospective study evaluated the efficacy of temporomandibular joint (TMJ) arthrocentesis with viscosupplementation in different severity stages based on the Dimitroulis classification (categories 2-4 were included). TMJ arthrocentesis was performed under local anaesthesia, and the protocol consisted of a double-puncture technique with lavage of ≥150 cc Ringer Lactate plus viscosupplementation. Incobotulinum toxin A was administered 10-15 days preoperatively in patients with concomitant masticatory myalgia. The primary outcome was TMJ pain, assessed by visual analogue scale (VAS, 0-10), and the secondary outcomes were the maximum mouth opening (MMO, mm) and myalgia degree (0-3). All outcomes were assessed on the intervention day (T0) and after the procedure (T1) (minimum 1 month and then 3 months, 6 months, 1 year and every year since). A total of 108 patients were enrolled (mean age of 43.1 ± 18.9 years); 86 (80%) were women and 22 (20%) were men. Preoperative pain was 4.02 ± 3.12 (mean ± SD), MMO was 38.10 ± 9.56 (mean ± SD) and myalgia degree was 1.80 ± 1.18 (mean ± SD). After an average of 215.4 days (31-1253 days), a statistically significant improvement of pain (P < 0.0001), MMO (P = 0.005) and myalgia degree (P < 0.0001) was observed. The overall successful outcome of TMJ arthrocentesis with viscosupplementation was 76%. The authors observed increased arthrocentesis effectiveness and success rate with viscosupplementation in Dimitroulis category 2 (88.6%) compared to 3-4 (71.4%). An association was found between arthrocentesis with viscosupplementation failure and painful myalgia (ρ = 0.477; P < 0.0001). Thirteen patients (12%) underwent a second TMJ intervention after finalising the present trial. With a low complication rate, TMJ arthrocentesis with viscosupplementation led to an overall benefit for all the included patients. This study reinforces the important role of minimally invasive TMJ arthrocentesis as a first treatment option, with better results in the early stages compared to more severe stages.

Comparison of Four Treatment Protocols with Intra-Articular Medium Molecular Weight Hyaluronic Acid in Induced Temporomandibular Osteoarthritis: An Experimental Study

The aim was to compare the effect between a single intra-articular infiltration (1i) and two infiltrations (2i) of medium molecular weight hyaluronic acid (MMW-HA) of high viscosity (HV) and low viscosity (LV) on the histopathological characteristics of temporomandibular joint (TMJ) osteoarthritis (OA) induced in rabbits. An experimental study was conducted on Oryctolagus cuniculus rabbits, including 42 TMJs, distributed between (1) TMJ-C, control group; (2) TMJ-OA, group with OA; (3) TMJ-OA-wt, group with untreated OA; (4) group treated with HA-HV-1i; (5) group treated with HA-HV-2i; (6) group treated with HA-LV-1i; and (7) group treated with HA-LV-2i. The results were evaluated using the Osteoarthritis Research Society International (OARSI) scale and descriptive histology considering the mandibular condyle (MC), the articular disc (AD), and the mandibular fossa (MF). The Kruskal-Wallis test was used for the statistical analysis, considering p < 0.05 significant. All treated groups significantly decreased the severity of OA compared to the TMJ-OA-wt group. The HA-HV-2i group showed significant differences in the degree of OA from the TMJ-OA group. The degree of OA in the HA-HV-2i group was significantly lower than in the HA-LV-1i, HA-LV-2i, and HA-HV-1i groups. The protocol that showed better results in repairing the joint was HA-HV-2i. There are histological differences depending on the protocol of the preparation used: two infiltrations seem to be better than one, and when applying two doses, high viscosity shows better results.

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

This mapping review aims to identify and discuss current research directions on intracavitary temporomandibular joints (TMJs) injections. The inclusion criteria allowed studies published in the last full six years, based on patients diagnosed with temporomandibular joint disorders (TMDs), treated by TMJ intra-articular injections. Medical databases covered by the Association for Computing Machinery, Bielefeld Academic Search Engine, PubMed, and Elsevier Scopus engines were searched. The results were visualized with tables, charts, and diagrams. Of the 2712 records identified following the selection process, 152 reports were qualified for review. From January 2017, viscosupplementation with hyaluronic acid (HA) was the best-documented injectable administered into TMJ cavities. However, a significant growing trend was observed in the number of primary studies on centrifuged blood preparations administrations that surpassed the previously leading HA from 2021.

Injectable Platelet-Rich Fibrin (I-PRF) Administered to Temporomandibular Joint Cavities: A Scoping Review

The aim of this review was to systematically map the research on the intra-articular administration of injectable platelet-rich fibrin (I-PRF) to the temporomandibular joints (TMJs). Medical databases covered by the ACM, BASE, Google, NLM, and ResearchGate were searched on 23 February 2023. The assessment of the level of evidence was based on the Oxford Center for Evidence-Based Medicine 2011 scale. The risk of bias was assessed for randomized controlled trials with the RoB2 tool. Extracted data were tabulated, and the changes in effect values were calculated. A total of eight studies qualified, of which five trials on 213 patients were randomized and controlled (RCTs). In each of the RTC study groups, arthrocentesis was performed, and 1-2 mL per joint of I-PRF (700 rpm/3 min/60 g centrifugation) was administered. Articular pain in three months decreased to 0-25% of the initial pre-interventional values in the study and 38-50% in the control groups. Mandible mobility increased to 121-153% and 115-120% in the I-PRF groups and controls, respectively. The main limitations of the evidence were the small number of RCTs and the lack of any RCT study groups receiving I-PRF without prior arthrocentesis. In conclusion, supplementing the temporomandibular joint rinsing with I-PRF administration further relieves pain and improves mandible mobility. The lack of RCTs on the intra-articular administration of I-PRF as a stand-alone procedure encourages further research. This research received no external funding. The review protocol has not been previously published.

Intra-Articular Injections into the Inferior versus Superior Compartment of the Temporomandibular Joint: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to validate the hypothesis that intra-articular injections into the inferior temporomandibular joint compartment are more efficient than analogous superior compartment interventions. Publications reporting differences between the above-mentioned techniques in the domains of revealing articular pain, decreasing the Helkimo index, and abolishing mandibular mobility limitation were included. Medical databases covered by the Bielefeld Academic Search Engine, Google Scholar, PubMed, ResearchGate, and Scopus engines were searched. The risk of bias was assessed using dedicated Cochrane tools (RoB2, ROBINS-I). The results were visualized with tables, charts, and a funnel plot. Six reports describing five studies with a total of 342 patients were identified. Of these, four trials on a total of 337 patients were qualified for quantitative synthesis. Each eligible report was at moderate risk of bias. From 19% to 51% improvement in articular pain, 12-20% lower Helkimo index, and 5-17% higher maximum mouth opening were observed. The evidence was limited by the small number of eligible studies, discrepancies regarding the substances used, possible biases, and the differences in observation times and scheduled follow-up visits. Despite the above, the advantage of inferior over superior compartment temporomandibular joint intra-articular injections is unequivocal and encourages further research in this direction.

Disc-condyle relationship alterations following stabilization splint therapy or arthrocentesis plus hyaluronic acid injection in patients with anterior disc displacement: a retrospective cohort study

OBJECTIVE

The objective of this study was to quantitatively evaluate the efficacy of stabilization splint (SS) therapy or arthrocentesis plus hyaluronic acid (HA) injection in the treatment of anterior disc displacement (ADD) through magnetic resonance imaging (MRI).

METHODS

99 subjects were collected in this study. 46 subjects received SS treatment (SS group), 53 subjects received arthrocentesis plus HA injection (HA group). Joints with anterior disc displacement with reduction (ADDwR) and anterior disc displacement without reduction (ADDwoR) were compared separately. MRI before the beginning of the treatment and after a set of treatment were used for measurement. Disc-condyle relationship and positions of condyles and discs were determined by disc-condyle angles and X-Y coordinates.

RESULTS

The disc-condyle angles decreased significantly in the SS group (P < .0001). Whereas no significant change was found in the HA group. Substantial anteroinferior condyle movement was detected in the SS group, slight anterior movement of condyles was discovered in the HA group. Anterior shift of discs position was observed in HA group and joints with ADDwoR in the SS group.

CONCLUSIONS

SS was effective in improving the disc-condyle relationship in ADD subjects, while significant improvement of disc-condyle relationship cannot be achieved through arthrocentesis plus HA injection.

A Scoping Review of the Use of Pioglitazone in the Treatment of Temporo-Mandibular Joint Arthritis

Thiazolidinediones (TZDs) are a group of diabetes medications currently being investigated for anti-arthritis effectiveness, one of which is pioglitazone. The purpose of this scoping review is to evaluate the potential use of pioglitazone in the treatment of temporomandibular joint (TMJ) arthritis. The criteria of eligibility were studies with the diagnosis of arthritis and pioglitazone treatment with a change in any inflammation index as an outcome. Of the 1169 records initially identified following the selection process, two animal studies and four clinical studies were included in the review. Improvements from the baseline were observed in each treatment group for each inflammation indicator. The results of the animal studies on the temporomandibular joints and on patients with rheumatoid and psoriatic arthritis indicate that the drug in question may have potential to treat arthritis, including within the temporomandibular joint.

Viscosupplementation in the upper and lower compartments of the temporomandibular joint checked by ultrasonography in an ex vivo and in vivo study

Viscosupplementation (VS) of the temporomandibular joint (TMJ) aims to treat temporomandibular dysfunction (TMD) by stimulating synovial cells to improve intracapsular lubrication. The purpose of the present study was to assess a VS protocol planned with the aid of cone-beam computed tomography (CBCT) and checked by ultrasonography (US). The study was carried out in 3 stages. The first was to check the correspondence between the proposed facial reference points and the osseous components of the joint by means of CBCT. In the second stage, the upper and lower compartments of 20 TMJs of fresh frozen cadavers were injected with coloured liquids, and the accuracy of the technique was confirmed by dissecting the anatomical specimens. The third stage consisted of VS in 10 patients (20 TMJs), with real-time verification of the location of the needle tip by means of ultrasonography. CBCT confirmed the correct locations of the marked points used in the proposed VS protocol. The dissections showed that 13 of the 14 injections effectively reached the upper and lower compartments. The location of the needle tip was effectively verified by ultrasonography, confirming the correct access to both compartments. The proposed protocol was effective for accessing the upper and lower compartments of the TMJ. The evaluated protocol proved to be accurate, safe and clinically reproducible means of VS in the upper and lower compartments of the TMJ.

Patient-Reported Quality of Life versus Physical Examination in Treating Temporomandibular Disorders with Intra-Articular Platelet-Rich Plasma Injections: An Open-Label Clinical Trial

Temporomandibular disorders, often manifested by articular pain, limitation of the mouth opening range, and unpleasant acoustic symptoms originating from inside the joint, have been associated with reduced quality of life. These symptoms, among others, can be treated with intra-articular injections of various substances, including repeated platelet-rich plasma (PRP) administration. The reported study was designed as an uncontrolled open-label clinical trial of consecutive cases. The participants completed a Fonseca questionnaire and evaluated acoustic symptoms, and spontaneous and provoked pain on VAS, and were subjected to a physical examination before, during, and after PRP therapy. The total Fonseca questionnaire results were statistically significantly (p < 0.05) correlated with 340 out of 348 (98%) other variables. The fully subjective assessment of the presence and intensity of acoustic symptoms coming from the temporomandibular joints was correlated with the physical examination results (0.45-0.63) and the maximum mouth opening with the maximum pain-free mouth opening (0.73-0.87). There were no correlations observed between the patient's and the physician's assessment of mandibular mobility. The Fonseca questionnaire seems to cover the entire spectrum of temporomandibular disorders, making it a balanced tool for assessing the quality of life in TMDs. However, it is worth considering extending the standard 3-point response scale to an 11-point one. The patient is somewhat able to perform a self-diagnosis with regard to the acoustic symptoms, but it is not possible for them to determine without measurement whether the range of mandibular mobility is appropriate..

Autologous Stem Cells Transplants in the Treatment of Temporomandibular Joints Disorders: A Systematic Review and Meta-Analysis of Clinical Trials

This systematic review aims to analyze the outcomes of the treatment of temporomandibular joint (TMJ) articular pain (AP) and restricted maximum mouth opening (MMO) with intra-articular administration of mesenchymal stem cells (MSCs). The inclusion criteria allowed primary studies involving AP and/or MMO pre-treatment and post-intervention values. Medical databases that were covered by ACM Digital, BASE, EBSCOhost, Google Scholar, PubMed, Scopus, and Web of Science engines were searched. The risk of bias was assessed with RoB 2 and ROBINS-I tools. The results were tabulated, plotted, and analyzed for regression. A total of 5 studies involving 51 patients/69 TMJs were identified, and 4 studies on 50 patients/67 TMJs were synthesized. Interventions were each time effective in decreasing AP and increasing MMO in a 6-month follow-up period by an average of about 85% and over 40%, respectively. Regression analysis showed a good fit of the logarithmic model for AP relief (5.8 − 0.8 ln x; R² = 0.90) and MMO increase (33.5 + 2.4 ln x; R² = 0.89). The results for AP and MMO were based on 3 studies in 39 patients and 4 studies in 50 patients, respectively, all at high risk of bias. The intra-articular administration of MSCs to TMJs, based on weak evidence, may be highly effective in reducing AP and improving MMO. This study received no funding.

Repeated Intra-Articular Administration of Platelet-Rich Plasma (PRP) in Temporomandibular Disorders: A Clinical Case Series

Background: Temporomandibular joint disorders (TMDs) are manifested, inter alia, by pain and limited scope of the mandibular abduction. Among the treatment strategies for these ailments, intra-articular injections of autologous blood preparations, including platelet-rich plasma (PRP), are administered. This prospective case series was aimed at assessing the effectiveness of repeated platelet-rich plasma (PRP) administration to the TMJ cavities in terms of reducing articular pain and increasing the mobility of the mandible. Material and methods: 40 consecutive patients diagnosed with TMJ pain qualified for the case series. The entire treatment program consisted of five PRP administrations and a summary appointment. Regression was analyzed for (1) intensity of spontaneous pain; (2) effectiveness of spontaneous pain relief; (3) mastication efficiency values; (4) painless mandibular abduction; (5) maximum mouth opening. The correlations between the abovementioned variable series were analyzed. Results: The mean spontaneous pain decreased consistently with successive PRP administrations in line with the regression model: −0.4x + 4.2 (R2 = 0.98). Articular pain improvement was reported in 71% of joints treated. Improvement in chewing quality at the end of the entire injection cycle was found in 63% of patients. The equations for the linear regression models for painless mandibular abduction (five applications of PRP) and maximum mouth opening (the first four applications of PRP) were x + 34 (R2 = 0.89) and 0.6x + 43.6 (R2 = 0.96), respectively. Improvement in these domains was found in 78% and 53% of patients, respectively. The strongest correlations were found between pain and chewing efficiency (−0.95), pain and painless mandible abduction (−0.96), and painless mandibular abduction and mastication efficiency (0.94). Conclusion: PRP injections into TMJ cavities should be considered as a low invasive, highly accessible form of treatment for various TMDs causing pain and mandible movement limitation.

Treatment of Mandibular Hypomobility by Injections into the Temporomandibular Joints: A Systematic Review of the Substances Used

INTRODUCTION

Hyaluronic acid, steroids and blood products are popularly injected into the temporomandibular joint (TMJs) to relieve pain and increase the extent of mandibular abduction. The purpose of this review is to identify other injectable substances and to evaluate them in the above-mentioned domains.

MATERIAL AND METHODS

The review included articles describing clinical trials of patients treated with intra-articular injections with or without arthrocentesis.

RESULTS

The following emerging substances were initially evaluated to be effective in treating TMJ pain and increasing the amplitude of mandibular abduction: analgesics, dextrose with lidocaine, adipose tissue, nucleated bone marrow cells and ozone gas.

DISCUSSION

Better effects of intra-articular administration are achieved by preceding the injection with arthrocentesis.

CONCLUSIONS

The most promising substances appear to be bone marrow and adipose tissue.

The Administration of Hyaluronic Acid into the Temporomandibular Joints' Cavities Increases the Mandible's Mobility: A Systematic Review and Meta-Analysis

OBJECTIVES

The purpose of this systematic review with meta-analysis is to identify clinical studies concerning the impact of intra-articular administration of hyaluronic acid (HA) on mandibular mobility and to make an attempt at determining the efficacy of HA in this indication.

METHODS

The review included primary studies involving groups of at least 10 patients who were diagnosed with pain in the temporomandibular joint and who were injected with hyaluronic acid as the only intervention. The outcomes pursued were changes in mandibular mobility and pain intensity. Four databases of medical articles were searched, including PubMed and BASE. The risk of bias was assessed using the Cochrane methodology tools. The therapy's efficacy was calculated in the domains of mandibular abduction, protrusive movement, lateral mobility, and pain relief. For these values, the regression and correlation with variables characterizing the interventions were analyzed.

RESULTS

In total, 16 reports on 20 study groups with a total of 1007 patients qualified for the review. The mean effectiveness in the domain of mandibular abduction over the 6-month follow-up period was 122% of the initial value, and the linear regression model can be expressed as 0.5x + 36. The level of pain in the same time frame decreased to an average of 29%. The severity of pain 6 months after the beginning of treatment positively correlates with the number of injections per joint (0.63), the total amount of drug administered in milliliters (0.62), and the volume of drug administered monthly per joint (0.50).

LIMITATIONS

In some studies, the patient groups were heterogeneous in terms of diagnosis. The studies varied depending on the joint into which the HA was administered. The synthesized studies differed with regard to the method of measuring the mandible abduction amplitude.

CONCLUSIONS

The increase in the amplitude of mandibular abduction was expressed as the quotient of the mean values during the observation periods, and the initial value was achieved in all study groups, and in the linear regression model, it was 0.5 mm on average per month. Multiple administrations of the drug may reduce the analgesic effectiveness of the treatment.

Intramuscular Injections and Dry Needling within Masticatory Muscles in Management of Myofascial Pain. Systematic Review of Clinical Trials

Background: Myofascial pain is an important cause of disability among the whole population, and it is a common symptom of temporomandibular joint disorders (TMDs). Its management techniques vary widely; however, in recent years, there has been a growing interest especially in needling therapies within masticatory muscles, due to their simplicity and effectiveness in pain reduction. Methods: The construction of the following study is based on PICOS and PRISMA protocols. A systematic literature search was conducted based on the PubMed and BASE search engines. Searching the abovementioned databases yielded a total of 367 articles. The screening procedure and analysis of full texts resulted in the inclusion of 28 articles for detailed analysis. Results: According to analyzed data, clinicians manage myofascial pain either with wet or dry needling therapies. The most thoroughly studied approach that prevails significantly within the clinical trials is injecting the botulinum toxin into the masseter and temporalis. Other common methods are the application of local anesthetics or dry needling; however, we notice the introduction of entirely new substances, such as platelet-rich plasma or collagen. In the analyzed articles, the target muscles for the needling therapies are most commonly localized by manual palpation although there are a variety of navigational support systems described: EMG, MRI or EIP electrotherapy equipment, which often aid the access to located deeper lateral and medial pterygoid muscle. Conclusions: Needling therapies within masticatory muscles provide satisfactory effects while being simple, safe and accessible procedures although there still is a need for high quality clinical trials investigating especially injections of non-Botox substances and needling within lateral and medial pterygoid muscles.

Variants and Modifications of the Retroauricular Approach Using in Temporomandibular Joint Surgery: A Systematic Review

Introduction: The retroauricular approach (RA) has been developed in order to expose the temporomandibular joint in a way that minimizes the risk of injury to the facial nerve and masks the postoperative scar. One of its characteristics is an excellent posterolateral view of the mandibular head, which allows for the preservation of the lateral temporomandibular joint ligaments in the course of open intracapsular surgery. Aim: The aim of this study is to systematically review the currently used variants and modifications of RA. Materials and Methods: The construction of the following study is based on PICOS and PRISMA protocols. A systematic literature search was performed based on the PubMed and BASE search engines; furthermore the authors performed a more detailed search in the Google Scholar article database as well as a loop search within the references of papers included in the systematic review. Results: Searching medical articles databases, Google Scholar, and references yielded a total of 85 records. First the titles and abstracts were blindly screened which was followed by a full-text eligibility check resulting in eventually including and qualifying 7 articles for detailed analysis. Discussion: All known variants and modifications of RA are characterized by high safety for the facial nerve and an aesthetically hidden scar. There were no reports of auricle necrosis in the collected material. Conclusions: In this systematic review, 2 variants and 2 modifications of RA that allow for open temporomandibular joint surgery have been identified; all of them together cover a large spectrum of indications for joint surgery, including reposition and osteosynthesis of mandibular head fractures, eminoplasty, or eminectomy and treatment of some forms of ankylosis.