Can PRP or Stem Cells Fix a Displaced TMJ Disc? What the Research Actually Shows

Patients diagnosed with temporomandibular joint (TMJ) disc displacement often ask a very reasonable question: “If my disc is out of place, how can an injection put it back?” It’s a logical concern — and the honest answer is that PRP and stem cell injections do not reposition displaced discs. But the research tells a far more nuanced and encouraging story than that simple fact might suggest.

This article reviews the current medical evidence on platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and stem cell therapies for TMJ disc displacement and osteoarthritis, explaining what these treatments actually do, why disc repositioning isn’t the goal, and why patients still experience significant relief.

Understanding TMJ Disc Displacement

The temporomandibular joint contains a small fibrocartilaginous disc that sits between the mandibular condyle and the temporal bone, acting as a cushion during jaw movement. In disc displacement, this disc shifts — most commonly in an anterior direction. When the disc slides back into place during mouth opening, it’s called disc displacement with reduction (often accompanied by a clicking sound). When the disc remains stuck forward and doesn’t return to its normal position, it’s called disc displacement without reduction — sometimes referred to as a “closed lock” (Scrivani SJ, Keith DA, Kaban LB. Temporomandibular Disorders. N Engl J Med. 2008;359(25):2693–2705).[1]

MRI in the open- and closed-mouth positions is the gold standard for confirming disc position and evaluating associated degenerative changes. [1]

The Key Question: Does PRP Move the Disc Back?

No — and this has been directly studied. A 2024 study by Nasef et al. enrolled 30 patients with bilateral disc displacement without reduction and treated them with arthrocentesis plus injectable platelet-rich fibrin (i- PRF) or arthrocentesis alone.[2] At 6-month follow-up, MRI showed no significant changes in disc position or morphology in either group.

However, the i-PRF group demonstrated significantly greater improvements in maximum mouth opening and pain scores compared to the control group.[2]

This finding is critically important: it proves that disc repositioning is not necessary for meaningful clinical improvement.

So What Does PRP Actually Do?

PRP is produced by centrifuging a patient’s own blood to concentrate platelets, which contain a rich array of growth factors and bioactive molecules. When activated, platelets release vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-β), insulin-like growth factor (IGF), and fibroblast growth factor (FGF), among others (Sheean AJ, Anz AW, Bradley JP. Platelet-Rich Plasma: Fundamentals and Clinical Applications. Arthroscopy. 2021;37(9):2732​-​2734).[3] These growth factors modulate inflammation, promote tissue repair, stimulate cell proliferation, and enhance angiogenesis.[3][4]

In the TMJ specifically, a 2026 review by Lin et al. described how autologous platelet-derived products modulate the TMJ microenvironment by driving mesenchymal stem cell proliferation, directing chondrogenic differentiation, and resolving inflammation through immunomodulatory cascades.[5] Unlike conventional treatments that primarily address symptoms, PRP works by mimicking natural healing mechanisms.[5]

The inflammation within the TMJ — not the disc position itself — is a major driver of pain and dysfunction. PRP targets this inflammatory environment directly, which explains why patients improve even when the disc remains displaced.

The Evidence: PRP Outperforms Other Treatments

The body of evidence supporting PRP for TMJ disorders has grown substantially. Here are the key findings:

Large-Scale Meta-Analysis (2025)

The most comprehensive analysis to date was published by Tsai et al. (2025), a systematic review and meta-analysis of 31 studies involving 1,359 patients.[6] The results showed:

• PRP vs. Arthrocentesis alone: Significant pain reduction at 6 months (MD: -1.56) and improved mandibular movement at 3 months (MD: 2.16 mm) and 6 months (MD: 2.56 mm)

• PRP vs. Hyaluronic Acid: Significant pain reduction at 3 months (MD: -2.18) and improved mandibular movement at 6 months (MD: 3.67 mm)

• PRP vs. Corticosteroids: Significant pain reduction at 1, 3, and 6 months, with improved mandibular movement at 6 months

The authors concluded that PRP injection is an effective and safe treatment for patients with TMJ disorders.[6]

Network Meta-Analysis

A network meta-analysis by Li et al. (2022), which compared all available therapies for TMJ disc displacement across 26 studies, ranked arthrocentesis + PRP injection and PRP injection alone as the best-performing therapies for both mouth opening improvement and pain alleviation.[7] The authors concluded that PRP injection is “probably the best treatment overall for patients with disc displacement owing to its anti-inflammatory, analgesic, and lubricating effects”.[7]

Double-Blinded Randomized Controlled Trial

Dasukil et al. (2022) conducted a double-blinded RCT of 90 patients comparing arthrocentesis alone, arthrocentesis + hyaluronic acid, and arthrocentesis + PRP.[8] At 6 months, the PRP group achieved the greatest improvement in pain (mean VAS dropping from 7.56 to 1.66), the largest gain in mouth opening (from 21.37 mm to 34.10 mm), and the most significant reduction in joint sounds.[8]

Systematic Review of Autogenous Injections (2025)

A 2025 systematic review by Orzeszek et al. examining 13 studies found that all PRP and PRF injection protocols reviewed were effective in reducing pain and improving mobility in patients with TMD, with PRP

generally outperforming hyaluronic acid, corticosteroids, and saline. No serious adverse events were reported.[9]

What About TMJ Osteoarthritis?

For patients who have both disc displacement and osteoarthritis — a common combination — the evidence is particularly encouraging.

Liu et al. (2023) conducted a randomized controlled trial of 70 patients with TMJ osteoarthritis comparing PRP to hyaluronic acid.[10] The PRP group showed superior outcomes in pain intensity, maximum mouth opening, TMJ sound scores, and — notably — imaging improvement at 6 months.[10] This suggests PRP may have disease-modifying effects beyond symptom relief.

A 2025 systematic review by Sillmann et al. found that while PRP showed potential benefits, cell-derived orthobiologics (such as mesenchymal stem cells) demonstrated significantly greater improvements in TMJ pain and maximum mouth opening compared to hyaluronic acid.[11] Preclinical research has shown that stem cells exert anti-inflammatory and chondroregenerative effects in TMJ osteoarthritis models, with potential for actual cartilage regeneration (Matheus et al., 2022).[12]

A 2026 study by Baş and Tepecik compared 12-month outcomes of arthrocentesis + i-PRF in 89 patients with either TMJ osteoarthritis or disc displacement without reduction.[13] Both groups improved significantly, but the osteoarthritis group showed greater relative pain reduction (-66.4% vs. -52.5%), while the disc displacement group achieved larger functional gains in mouth opening (+19.7% vs. +8.8%). [13]

The Body Adapts: Pseudodisc Formation

One of the most fascinating aspects of TMJ biology is the body’s ability to adapt to disc displacement over time. The retrodiscal tissue — the tissue behind the disc — can undergo a process called fibrochondrogenesis, essentially remodeling itself to function as a “pseudodisc.”

A long-term MRI follow-up study by Bristela et al. (2017) found that 45% of TMJs with disc displacement without reduction developed a pseudodisc within 4 to 8 years.[14] Pain resolved in the majority of

patients, and mouth opening improved in 80%, regardless of whether a pseudodisc formed.[14]

A 2026 study published in JCI Insight by Yuan et al. used single-cell RNA sequencing to uncover the cellular mechanisms behind this adaptation, identifying specific fibroblast and mural cell populations that drive the replacement of loose connective tissue with dense connective tissue and cartilaginous masses.[15] This research opens the door to therapies that could actively enhance this natural remodeling process.

The Natural History: Why Treatment Still Matters

While some patients with disc displacement without reduction improve spontaneously — a landmark study by Kurita et al. (1998) found that 43% became asymptomatic and 33% improved within 2.5 years — approximately 25% continued to be symptomatic or required treatment. [16] Patients with MRI evidence of osteoarthritis at baseline had a poorer prognosis.[16]

A longitudinal MRI study by Hu et al. (2016) showed that without intervention, discs in the non-reducing group tended to become shorter, move further forward, and distort more seriously over time.[17] This progressive deterioration provides a rationale for early intervention with regenerative therapies that may slow or halt degenerative changes.

Repeated PRP Injections: A Dose-Response Relationship

Evidence suggests that multiple PRP injections may provide cumulative benefit. Sikora et al. (2022) studied 40 patients who received five sequential PRP administrations and found a consistent linear decrease in pain with each successive injection (regression model: -0.4x + 4.2, R = 0.98).[18] Articular pain improved in 71% of treated joints, chewing quality improved in 63% of patients, and painless mandibular abduction improved in 78%.[18]

PRP vs. i-PRF: Understanding the Difference

Not all platelet concentrates are the same. Injectable platelet-rich fibrin (i-PRF) is a newer formulation that differs from traditional PRP in its growth factor release kinetics. While PRP demonstrates a pronounced burst release of growth factors within the first 15 minutes, i-PRF exhibits a more controlled, sustained release over a 10-day period (Miron et al., 2024).[19] This sustained release may better support the multi-phase healing process in the TMJ.

The Bottom Line

The patient who asks, “How can an injection fix my displaced disc?” deserves an honest and complete answer:

1. PRP and stem cell injections do not reposition displaced TMJ discs. MRI studies confirm the disc remains in its displaced position after treatment.[2]
2. Disc repositioning is not necessary for clinical improvement. The majority of patients experience significant reductions in pain and meaningful improvements in jaw function despite the disc remaining displaced.[2][6][8]
3. The mechanism of benefit is biological, not mechanical. PRP delivers concentrated growth factors that reduce inflammation, promote tissue healing, and modulate the joint microenvironment.[3] [5]
4. PRP outperforms other injectable treatments including hyaluronic acid and corticosteroids across multiple meta-analyses and randomized controlled trials.[6][7]
5. The body naturally adapts to disc displacement through retrodiscal tissue remodeling, and regenerative therapies may support this process.[14][15]
6. For patients with concurrent osteoarthritis, PRP and especially stem cell therapies show potential disease-modifying effects beyond symptom relief.[10][11][12]

The goal of regenerative injection therapy for TMJ disc displacement is not to put the disc back — it is to create a healthier joint environment that reduces pain, improves function, and supports the body’s own remarkable capacity for adaptation and healing.

References

1. Temporomandibular Disorders. Scrivani SJ, Keith DA, Kaban LB.. The New England Journal of Medicine. 2008;359(25):2693​-​2705. doi: 10.1056/NEJMra0802472.
2. Evaluation of Intra-Articular Injection of Injectable Platelet-Rich Fibrin, Anterior Repositioning Splint and Arthrocentesis in Treatment of Temporomandibular Joint Internal Derangement. Nasef M, Alashmawy M, Abdelrahman A, et al.. The British Journal of Oral & Maxillofacial Surgery. 2024;62(8):710-715. doi:10.1016/j.bjoms. 2024.05.002.
3. Platelet-Rich Plasma: Fundamentals and Clinical Applications. Sheean AJ, Anz AW, Bradley JP.. Arthroscopy : The Journal of Arthroscopic & Related Surgery : Official Publication of the Arthroscopy Association of North America and the International Arthroscopy Association. 2021;37(9):2732​-​2734. doi:10.1016/j.arthro. 2021.07.003.
4. Use of Platelet-Rich Plasma in Rheumatic Diseases. Yessirkepov M, Fedorchenko Y, Zimba O, Mukanova U.. Rheumatology International. 2024;45(1):13. doi:10.1007/s00296-024-05776-1.
5. Evolution and Mechanistic Insights of Platelet-Derived Products in Temporomandibular Joint Regeneration. Lin C, Jin Y, Li D, et al.. Frontiers in Cell and Developmental Biology. 2026;14:177‌6592. doi: 10.3389/fcell.2026.1776592.
6. Effectiveness of Platelet-Rich Plasma for Treating TMJ Disorders: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Tsai JH, Tam KW, Yang JD, Hsu TH.. Pain Medicine (Malden, Mass.). 2025;:pnaf042. doi:10.1093/pm/pnaf042.
7. Diverse Therapies for Disc Displacement of Temporomandibular Joint: A Systematic Review and Network Meta-Analysis. Li J, Zhang Z, Han N.. The British Journal of Oral & Maxillofacial Surgery. 2022;60(8):1012-1022. doi:10.1016/j.bjoms.2022.04.004.
8. Intra-Articular Injection of Hyaluronic Acid Versus Platelet-Rich Plasma Following Single Puncture Arthrocentesis for the Management of Internal Derangement of TMJ: A Double-Blinded Randomised Controlled Trial. Dasukil S, Arora G, Boyina KK, et al.. Journal of Cranio-Maxillo-Facial Surgery : Official Publication of the European Association for Cranio-Maxillo-Facial Surgery. 2022;50(11): 825-830. doi:10.1016/j.jcms.2022.10.002.
9. Autogenous Injections in Temporomandibular Disorders: A Systematic Review. Orzeszek S, Malysa A, Jenca A, et al.. Journal of Clinical Medicine. 2025;14(18):6640. doi:10.3390/jcm14186640.
10. Platelet-Rich Plasma Therapy for Temporomandibular Joint Osteoarthritis: A Randomized Controlled Trial. Liu SS, Xu LL, Liu LK, Lu SJ, Cai B.. Journal of Cranio-Maxillo-Facial Surgery : Official Publication of the European Association for Cranio-Maxillo-Facial Surgery. 2023;51(11):668-674. doi:10.1016/j.jcms.2023.09.014.
11. Intra-Articular Injection of Orthobiologics for Temporomandibular Joint Osteoarthritis: A Systematic Review of Randomized Controlled Trials. Sillmann YM, Monteiro JLGC, Haugstad M, et al.. International Journal of Oral and Maxillofacial Surgery. 2025;54(7):624-638. doi: 10.1016/j.ijom.2025.01.008.
12. Stem Cell-Based Therapies for Temporomandibular Joint Osteoarthritis and Regeneration of Cartilage/Osteochondral Defects: A Systematic Review of Preclinical Experiments. Matheus HR, Özdemir ŞD, Guastaldi FPS.. Osteoarthritis and Cartilage. 2022;30(9): 1174-1185. doi:10.1016/j.joca.2022.05.006.
13. Comparison of Clinical Outcomes Between DDWOR and TMJ-OA Patients Treated With Arthrocentesis and Injectable PRF: A 12-Month Follow-Up Study. Baş MZ, Tepecik T.. Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology. 2026;141(6):745-750. doi: 10.1016/j.oooo.2025.11.003.
14. Magnetic Resonance Imaging of Temporomandibular Joint With Anterior Disk Dislocation Without Reposition – Long-Term Results. Bristela M, Schmid-Schwap M, Eder J, et al.. Clinical Oral Investigations. 2017;21(1):237-245. doi:10.1007/s00784-016-1800-9.
15. Distinct Mural Cells and Fibroblasts Drive Fibrochondrogenesis in Retrodiscal Tissue Following Temporomandibular Joint Disc Displacement. Yuan W, Chen Y, Yan R, et al.. JCI Insight. 2026;:e196343. doi:10.1172/jci.insight.196343.
16. Natural Course of Untreated Symptomatic Temporomandibular Joint Disc Displacement Without Reduction. Kurita K, Westesson PL, Yuasa H, et al.. Journal of Dental Research. 1998;77(2):361-5. doi: 10.1177/00220345980770020401.
17. Changes in Disc Status in the Reducing and Nonreducing Anterior Disc Displacement of Temporomandibular Joint: A Longitudinal Retrospective Study. Hu YK, Yang C, Xie QY.. Scientific Reports. 2016;6:34253. doi:10.1038/srep34253.
18. Repeated Intra-Articular Administration of Platelet-Rich Plasma (PRP) in Temporomandibular Disorders: A Clinical Case Series. Sikora M, Sielski M, Chęciński M, et al.. Journal of Clinical Medicine. 2022;11(15):4281. doi:10.3390/jcm11154281.
19. Ten years of injectable platelet‐rich fibrin. Miron RJ, Gruber R, Farshidfar N, Sculean A, Zhang Y.. Periodontology 2000. 2024;94(1): 92-113. doi:10.1111/prd.12538.