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.


Introduction
Hyaluronic acid (HA) is the main component of the temporomandibular joint (TMJ) synovial fluid [1,2].HA is synthesized in the synovial membrane by type B fibroblastlike synoviocytes from glucuronic acid and N-acetylglucosamine under hyaluronic acid synthasis (HAS) catalysis [3].HASs convert simple sugars into the HA polymer linked via alternating β-(1→4) and β-(1→3) glycosidic bonds (Figure 1).This process occurs in the cell plasma membrane and HA is secreted into the extracellular space.By binding water, HA provides viscoelastic gel consistency to synovial fluid, reducing joint surface friction and dispersing loads [4].Delivering newly synthesized HA to the synovial fluid improves the biomechanics of the TMJ.When HA degrades, the mechanical properties of the synovial fluid are weakened [5].Mechanical overload, autoimmune diseases and infections lead to inflammation of the TMJ (arthritis), which disrupts HA metabolism [5].The main mediators identified in arthritis are tumor necrosis factor-alpha (TNF-α), cytokines IL-1, IL-6 and IL-8 and matrix metalloproteinases (MMPs) [6][7][8].The increase in the concentration of these factors stimulates HA synthesis in acute inflammation.A chronic one leads to damage of chondrocytes and subsequent degradation of cartilage tissue.This results in abundant and prolonged release of inflammatory mediators and induces inflammation of the adjacent parts of the synovial membrane (synovitis) [8,9].Synovitis reduces HA production; hence, HA degradation predominates over its synthesis.Hyaluronidases and reactive oxygen species (ROSs) degrade HA polymer chains to oligosaccharides and low-molecularweight HA [10,11].A predominance of shorter-chained HA particles reduces TMJ lubrication, increasing friction and inflammation [2,9].Clinically, this results in articular pain and TMJ hypomobility.Mobility limitation is observed in all directions [12].It results from mechanical blockage, identified in the maximal mouth-opening test, and psychological blockage, expressed by painless mandibular abduction decrease [13].
Limited mandible abduction, protrusion and lateral movements imply a decline in mastication and overall health-related life quality [14][15][16].Depending on the complexity of temporomandibular disorder (TMD) in a given case, a wide range of therapeutic methods are used.These fall into psychology, physiotherapy, pharmacotherapy, orthodontics, dental prosthetics and maxillofacial surgery [17,18].The latter involves direct interference in the TMJ structures.Open surgery, endoscopic surgery (arthroscopy) and intra-articular injections are used, depending on the TMD type and severity [19][20][21].Minimally invasive manipulations enable rinsing of the joint cavity and intra-and pericapsular administration of various substances.
Typically used injectables are dominated by (1) hyaluronic acid (HA) as a supplementing agent, (2) centrifuged blood products (CBPs), (3) drugs such as corticosteroids or non-steroidal anti-inflammatory drugs, (4) hypertonic dextrose and ( 5) unprocessed blood [22][23][24][25][26][27].The latter two are irritants used to reduce the number of episodes of chronic jaw dislocation.Therefore, they have the opposite effect than the other substances mentioned [28,29].All blood products are obtained as an autograft, typically from peripheral venous blood.Subsequent generations of CBPs differ in composition and are intended to better inhibit the progression of degeneration and even, to some extent, regenerate the cartilage of joint surfaces.These include but are not limited to plasma rich in growth factors (PRGF), platelet-rich plasma (PRP) and injectable platelet-rich fibrin (I-PRF) [30][31][32].Mechanical overload, autoimmune diseases and infections lead to inflammation of the TMJ (arthritis), which disrupts HA metabolism [5].The main mediators identified in arthritis are tumor necrosis factor-alpha (TNF-α), cytokines IL-1, IL-6 and IL-8 and matrix metalloproteinases (MMPs) [6][7][8].The increase in the concentration of these factors stimulates HA synthesis in acute inflammation.A chronic one leads to damage of chondrocytes and subsequent degradation of cartilage tissue.This results in abundant and prolonged release of inflammatory mediators and induces inflammation of the adjacent parts of the synovial membrane (synovitis) [8,9].Synovitis reduces HA production; hence, HA degradation predominates over its synthesis.Hyaluronidases and reactive oxygen species (ROSs) degrade HA polymer chains to oligosaccharides and low-molecular-weight HA [10,11].A predominance of shorter-chained HA particles reduces TMJ lubrication, increasing friction and inflammation [2,9].Clinically, this results in articular pain and TMJ hypomobility.Mobility limitation is observed in all directions [12].It results from mechanical blockage, identified in the maximal mouth-opening test, and psychological blockage, expressed by painless mandibular abduction decrease [13].
Limited mandible abduction, protrusion and lateral movements imply a decline in mastication and overall health-related life quality [14][15][16].Depending on the complexity of temporomandibular disorder (TMD) in a given case, a wide range of therapeutic methods are used.These fall into psychology, physiotherapy, pharmacotherapy, orthodontics, dental prosthetics and maxillofacial surgery [17,18].The latter involves direct interference in the TMJ structures.Open surgery, endoscopic surgery (arthroscopy) and intra-articular injections are used, depending on the TMD type and severity [19][20][21].Minimally invasive manipulations enable rinsing of the joint cavity and intra-and pericapsular administration of various substances.
Typically used injectables are dominated by (1) hyaluronic acid (HA) as a supplementing agent, (2) centrifuged blood products (CBPs), (3) drugs such as corticosteroids or non-steroidal anti-inflammatory drugs, (4) hypertonic dextrose and ( 5) unprocessed blood [22][23][24][25][26][27].The latter two are irritants used to reduce the number of episodes of chronic jaw dislocation.Therefore, they have the opposite effect than the other substances mentioned [28,29].All blood products are obtained as an autograft, typically from peripheral venous blood.Subsequent generations of CBPs differ in composition and are intended to better inhibit the progression of degeneration and even, to some extent, regenerate the cartilage of joint surfaces.These include but are not limited to plasma rich in growth factors (PRGF), platelet-rich plasma (PRP) and injectable platelet-rich fibrin (I-PRF) [30][31][32].
PRP is the most widely studied CBP TMJ injectable [23].It is produced by centrifugation of blood, most often from the elbow bend, which allows the removal of the red blood cell fraction.PRP consists of plasma and platelets.Plasma contains water, electrolytes, proteins, hormones and enzymes.Platelets are the source of growth factors with anti-inflammatory and regenerative effects.This group includes (1) platelet-derived growth factor (PDGF), (2) transforming growth factor-beta (TGF-β), (3) vascular endothelial growth factor (VEGF), (4) epidermal growth factor (EGF), (5) fibroblast growth factor (FGF) and (6) insulin-like growth factor (IGF) [33,34].
HA is commercially available, which means it is practically unlimited.It can be stored for a long time, according to the manufacturer's recommendations.In turn, the availability of PRP varies depending on the quality of the patient's blood, the experience of the staff and the correctness of the centrifugation procedure.There is a risk of complete failure in the attempt to obtain PRP.In addition, treatment with PRP requires an additional bloodcollection procedure, and the product must be used immediately.In the case of a series of intra-articular injections, blood must be collected and centrifuged at each visit.These inconveniences do not apply to HA.
Knowledge regarding minimally invasive manipulations inside the TMJs is changing [35].The search for the most regeneration-promising injectable has been directed towards autografts [29,36].Concerning TMJ lubrication, medium-and high-molecular-weight HA supplementation remains irreplaceable [37,38].A current review aimed at searching for new solutions in the injection treatment of TMJs showed the existence of clinical studies presenting the intra-articular administration of a mixture of CBPs and HA [35].This means that the theoretically reasonable combination of the benefits of both substances is beginning to be clinically tested.The results of these tests could be interesting and, in the best-case scenario, revolutionize the choice of injectable substances.The low evidence of a single clinical trial, even among the best-designed trials, encourages the synthesis and meta-analysis of the results of all available research on the topic.
This systematic review aimed to assess the effectiveness of administering CBPs and HA mixtures to the TMJ cavity regarding mandibular mobility range, articular pain and healthrelated quality of life.Intra-articular administrations of placebo or any other injectable were assessment reference points.

Selection
Of the 171 records identified, 91 were excluded due to duplication and 80 were screened (Figure 2).Of the 28 that underwent full-text evaluation, 22 were excluded with reasons provided (Table A1) and 6 were included in the review (Table 1).The inter-rater agreement was 93.75% and κ = 0.86.
The included studies are characterized in Table 2.The diagnosis was limited to TMD or osteoarthritis or specified the type of internal derangement.The number of subjects ranged from 10 to 30 per group.Most research teams opted for arthrocentesis before injection.Controls included HA alone, PRP alone or corticosteroids.Follow-up was at least 6 months, allowing for meta-analysis of 6-month variable values.
The risk of bias ranged from low, through some concerns, to high, as detailed in Figures 3 and 4.    The risk of bias ranged from low, through some concerns, to high, as detailed in Figures 3 and 4.

Individual Studies
Mandibular abduction was assessed in all eligible studies (Table 3).Mean baseline  The risk of bias ranged from low, through some concerns, to high, as detailed in Figures 3 and 4.

Individual Studies
Mandibular abduction was assessed in all eligible studies (Table 3).Mean baseline values were collected for all patient groups.The longest available follow-up period was

Individual Studies
Mandibular abduction was assessed in all eligible studies (Table 3).Mean baseline values were collected for all patient groups.The longest available follow-up period was 12 months.The most numerous mandibular abduction variables were extracted for the 1-and 6-month follow-ups.During the first month, some investigators conducted more frequent check-ups.Apart from one study comparing the HA plus PRP group with the PRP alone group, no statistically significant differences were observed in the initial values.They ranged from an average of 23 to an average of 36.5 mm.The smallest mean mouth opening at the end of treatment in the group of patients was 31 mm in patients treated for TMJ osteoarthritis in the trial of Hegab et al. [40].The treatment in this group was performed by combining arthrocentesis with intra-articular HA injection and achieved an average of 8 mm of improvement [40].Apart from one receiving HA alone in the study by Harba et al., all patient groups achieved a statistically significant mean improvement in mouth-opening range [43].After 6 months, both available studies noted statistically significant differences in the treatment results in favor of the HA plus PRP mixture versus PRP alone.Assessing the change in mandibular abduction gave contradictory results when comparing HA with PRP versus HA alone.One study showed statistical significance of such a difference in favor of the HA + PRP mixture, the remaining three presented no statistical significance of the differences between the means for the groups treated with HA + PRP and those receiving HA.
The availability of pretreatment and follow-up values for the articular pain variable was identical to that for the mandibular abduction (Table 4).In each study, the differences in the initial values between the groups were not statistically significant.Mean pain started at a minimum of 6.5 points and decreased to a maximum of 3.5 points.In the groups treated with the HA and PRP mixture, the highest mean pain score at the end of the follow-up was 2.25 points.Each treatment provided a statistically significant improvement compared to the preintervention assessment.After 6 months, the differences between HA and PRP treatment and PRP alone were statistically significant in both available studies.Two trials proved, and two others did not present, statistically significant differences between treatment with both substances and HA alone.
None of the eligible clinical trials assessed health-related quality of life.

Syntheses
The range of mandibular mobility expressed as abduction values decreased significantly in each group receiving the HA/PRP mixture.The initial intergroup mean values of mouth opening were 29. Figure 5 illustrates the in-question variable values for individual patient groups and relative time points.As in the case of the articular pain variable, trend lines were drawn for the mean values for the groups treated with individual agents.Good fits of the logarithmic regression model were obtained in each case, i.e., for HA with PRP (R 2 = 0.91), HA only (R 2 = 0.69), and PRP only (R 2 = 0.65).The difference in the mean intergroup treatment results between HA with PRP and HA after 1 month was 1.22 (SE = 3.01) mm.The analogous mean difference compared to patients treated with PRP alone was 4.45 (SE = 3.73) mm.In both comparisons, the differences favored the therapy with the mixture of both substances.However, they were not statistically significant.After 6 months, the difference in HA with PRP treatment was observed to be 3.21 (SE = 3.85) mm compared to HA alone and 6.46 (SE = 5.14) mm compared to PRP injection alone.These were also not statistically significant.
In each group of patients, there was a statistically significant decrease in the intensity of articular pain on a 0-10 scale.Initially, the mean intergroup values were 7.14 (SD = 0.51), 6.93 (SD = 0.31) and 7.20 (SD = 0.28) in the patient group treated with HA and PRP, HA alone and PRP alone, respectively.After 1 month, the means were 1.77 (SD = 0.73), 2.32 (SD = 1.12) and 4.65 (SD = 3.46), and after 6 months, 0.90 (SD = 0.89), 1.87 (SD = 1.61) and The difference in the mean intergroup treatment results between HA with PRP and HA after 1 month was 1.22 (SE = 3.01) mm.The analogous mean difference compared to patients treated with PRP alone was 4.45 (SE = 3.73) mm.In both comparisons, the differences favored the therapy with the mixture of both substances.However, they were not statistically significant.After 6 months, the difference in HA with PRP treatment was observed to be 3.21 (SE = 3.85) mm compared to HA alone and 6.46 (SE = 5.14) mm compared to PRP injection alone.These were also not statistically significant.Summarizing the results, Table 5 presents the discrepancies in mandibular abduction increase and articular pain relief between HA/PRP treatment versus HA or PRP control in 6-month observation.All comparisons include randomized controlled trials of various risks of bias.There is an observed difference in intergroup means between articular pain scores for the HA with PRP, HA and PRP groups.They are −0.55 (SE = 0.67) and −2.88 (SE = 1.60) in favor of HA with PRP over HA and PRP, respectively, at 1 month of follow-up, but are not statistically significant.At 6 months, they are −0.97 (SE = 1.01) and −1.40 (SE = 1.23) for HA and PRP over HA with PRP, respectively, albeit also not statistically significant.
Summarizing the results, Table 5 presents the discrepancies in mandibular abduction increase and articular pain relief between HA/PRP treatment versus HA or PRP control in 6-month observation.All comparisons include randomized controlled trials of various risks of bias.

Interpretation
Treatment with HA, PRP or their combination resulted in a mandibular abduction increase and articular pain intensity decrease in the study as well as control groups [39][40][41][42][43][44].This means that, compared to preintervention ones, the mean scores improved in each patient group, but did not necessarily in every patient.TMDs constitute a large group of diseases, which, despite similar symptoms and a similar clinical course, differ in etiology and may require different therapeutic approaches [20,45,46].
Currently, arthritis, disc displacement, degenerative joint disease and subluxation are distinguished as diagnoses manifesting articular pain [20,45,46].Arthritis is a broad category of manifestations of specific diseases, which always requires a search for the cause of inflammation.Identification of the cause allows for the proper direction of treatment towards its removal.Among internal derangement diagnoses, the displacement of the disc with and without reduction predominates.It has been proven that intra-articular injections bring relief in both cases, but despite this, these are different clinical situations that usually qualify for combined treatment [42].Degenerative disease requires identification and removal or limitation of the cause.The possibility of its reversal at the tissue level is also seen in autografts of mesenchymal stem cells.In habitual dislocation, intra-articular injections limit the number of dislocation episodes.In such cases, irritating preparations are used [28,29].
The diagnosis of TMD often combines mandibular hypomobility with arthritis as a causative factor [18,26].However, this does not exclude the coexistence of disc displacement or degenerative joint disease [20,45,46].The results of this systematic review prove that the HA/PRP mixture improves TMJ movements and resolves articular pain better than HA or PRP alone in almost every patient group tested.Presumably combined therapy effectiveness spectrum covers cases non-respondent to HA or PRP alone.

Limitations
The source studies were not homogeneous in terms of diagnosis.Intra-articular administration of hyaluronic acid has an important lubricating effect, and injection of autologous blood products has regenerative potential.While in most cases of TMDs, both mechanisms are desirable, the severity of hypomobility and degeneration are elements that make up the diagnosis [45,46,[54][55][56][57].It would be more appropriate to conduct separate meta-analyses, for disk displacement with or without reduction, arthritis and degenerative joint disease [56][57][58].However, in this systematic review, the limited number of studies precludes dividing them into subgroups.
The search was conducted in English, which may have resulted in missing records unindexed with English keywords.Due to the scarcity of the source material, studies with uncertain and with high risk of bias were included in the synthesis.

Strengths
The strengths of this systematic review include (1) detailed eligibility criteria, (2) comprehensiveness of the search, (3) adherence to PRISMA guidelines and (4) meta-analytic evaluation of treatment effectiveness in both articular pain and mandibular mobility domains.

Implications
HA with PRP presents better mandibular mobility improvement than using either of these substances separately.However, these are differences based on small numbers of study groups and between means with high standard deviations.Testing the statistical significance of these differences gave a negative result (p > 0.05).Also, the mean pain relief efficacy discrepancy in the groups of patients treated with HA and PRP is not statistically significant compared to the HA or PRP control (p > 0.05).
Nevertheless, the differences in the best documented 1-and 6-month follow-up periods are noticeable and in favor of the mixture of both injectables.Hence, the lack of statistical significance was probably also due to the small number of patient groups and large discrepancies between them.This justifies further research into combining HA and centrifuged blood products in TMD treatment.

Protocol and Criteria
This systematic review with meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses PRISMA 2020 and registered in the PROSPERO International Prospective Register of Systematic Reviews database under number CRD42024564382 [59].
The eligibility criteria were developed using the SPIDER tool (version 2012.07.24;Central Manchester NHS Foundation Trust, Manchester, UK) and are presented in Table 6 [60].

Searches
Final searches in medical research article databases were performed on May 9, 2024, using the following engines: (1) Bielefeld Academic Search Engine (BASE; Bielefeld University Library, Bielefeld, Germany); (2) Google Scholar (Google LLC, Mountain View, CA, USA); (3) PubMed (National Library of Medicine, Bethesda, MD, USA); (4) Scopus (Elsevier, Amsterdam, Netherlands).There were no limits on the time frame for searches.
The search strategy was based on preliminary searches and the current mapping review [23].The query "temporomandibular AND (hyaluronic OR hyaluronan OR ha) AND (blood OR plasma OR fibrin OR prgf OR prp OR prf OR i-prf OR lpcgf) AND (intraarticular OR intra articular OR injection)" was applied to all search engines.In the case of the Google Scholar engine, the search was performed on title content only, as the unfiltered results provided by this search engine go beyond the scope of the query.

Selection and Collection
Identified records from all engines were input to the Rayyan automation tool (version 2024-08-08, Qatar Computing Research Institute, Doha, Qatar and Rayyan Systems, Cambridge, MA, USA) [61].Then the manual deduplication was performed by M.C.Records that successfully underwent the stages above and were subsequently assessed blindly in terms of suitable titles and abstracts by two independent researchers (K.L. and F.B.).Cohen's kappa agreement between researchers was calculated with the MedCalc Inter-rater agreement tool (version 22.032, MedCalc Software Ltd., Ostend, Belgium).Records were promoted to the next stage of full-text evaluation in case of assessors' disagreement.
Two independent researchers (M.C. and K.L.) performed the data collection stage.On inconsistency, a consensus was made.If necessary, a casting voice of a third researcher (M.S.) was asked.For this process, no automation tool was used.The tables presenting and comparing numerical data were prepared using the Google Workspace package (version 2024.07.06,Google LLC, Mountain View, CA, USA).
Characterizing data included (1) diagnosis, (2) study group number of patients, (3) study group number of TMJs, (4) study group substance, (5) control group number of patients, (6) control group number of TMJs, (7) control group substance and (8) follow-up duration.To determine the effectiveness of the therapy, numerical data regarding (1) the extent of mandibular abduction, (2) articular pain and (3) health-related quality of life were extracted.Imaging or navigation were not considered, despite their supposed benefits in degenerative joint disease diagnosis and invasive TMD treatment [62].
Pain was transformed to a scale of 0-10, regardless of how its intensity was assessed.Mandibular mobility was determined as a value in millimeters.Depending on availability, the items collected were maximum unassisted abduction, maximum manually assisted abduction and maximum pain-free abduction.If the previously mentioned variable was unavailable, the next one was included.Regardless of the measurement method, the life-quality score was intended to be converted into a percentage.Variable values were extracted for baseline ones and all available follow-up periods.

Assessments
The risk of bias was determined using the Cochrane RoB 2: A revised Cochrane riskof-bias tool for randomized trials (version 2019.08.22,The Cochrane Collaboration, London, UK) [63].The results of this evaluation were visualized using the Robvis tool (version 2023, University of Bristol, Bristol, UK) [64,65].
The effect measures included mean differences between the values during observation and the baseline and between the values for the study and control groups at a given observation point.These were calculated with MedCalc software (version 22.023, MedCalc Software Ltd., Ostend, Belgium) and the Practical Meta-Analysis Effect Size Calculator tool (version 2023.11.27, George Mason University, Philadelphia, PA, USA).
Only randomized controlled trials were included in the synthesis.Raw data and mean differences were tabulated and presented in graphs.Google Workspace software (version 2024-06-28, Google LLC, Mountain View, CA, USA) was used for visualization.
Certainty was assessed by calculating the effect size (Cohen's d) and determining the characteristics of patient groups for individual effect measures with the Practical Meta-Analysis Effect Size Calculator tool (version 2023.11.27, George Mason University, Philadelphia, PA, USA).

Conclusions
The only CBP currently combined with HA in the TMJ injection treatment is PRP.HA/PRP treatment results are beneficial compared to the initial mandibular abduction and articular pain values.The improvements are quantitatively superior to administering HA or PRP alone, yet statistically insignificant most likely due to the small number of patient groups analyzed.Presumably, the HA/PRP range of therapeutic efficiency includes cases non-respondent to HA or PRP alone.

Figure 1 .
Figure 1.Hyaluronic acid (Haworth projection).Carbon atoms forming glycosidic bonds are numbered in blue.Square brackets and the letter "n" indicate multiplication of the illustrated fragment of the hyaluronic acid chain.Author: Vaccinationist.License: Public Domain.

Figure 1 .
Figure 1.Hyaluronic acid (Haworth projection).Carbon atoms forming glycosidic bonds are numbered in blue.Square brackets and the letter "n" indicate multiplication of the illustrated fragment of the hyaluronic acid chain.Author: Vaccinationist.License: Public Domain.

Figure 6 .
Figure 6.Articular pain on a 0-10 scale over time (months) [39-44].There is an observed difference in intergroup means between articular pain scores for the HA with PRP, HA and PRP groups.They are −0.55 (SE = 0.67) and −2.88 (SE = 1.60) in favor of HA with PRP over HA and PRP, respectively, at 1 month of follow-up, but are not statistically significant.At 6 months, they are −0.97 (SE = 1.01) and −1.40 (SE = 1.23) for HA and PRP over HA with PRP, respectively, albeit also not statistically significant.Summarizing the results, Table5presents the discrepancies in mandibular abduction increase and articular pain relief between HA/PRP treatment versus HA or PRP control in 6-month observation.All comparisons include randomized controlled trials of various risks of bias.

Table 1 . Included reports. First Author Publication Year Digital Object Identifier or PubMed Identifier Title
https://doi.org/10.17219/dmp/127446Evaluation of the participation of hyaluronic acid with platelet-rich plasma in the treatment of temporomandibular joint disorders Saad [44] 2017 https://doi.org/10.21608/edj.2017.76108Intra articular injection of hyaluronic acid alone in comparison with hyaluronic acid and PRP in the treatment of internal derangement of temporomandibular joint

Table 5 .
Summary of findings at 6-month follow-up.

Table 5 .
Summary of findings at 6-month follow-up.