TMJ Disorder

What is TMJ disorder?

TMJ or temporomandibular (tem-puh-roe-man-DIB-u-lur) joint acts like a sliding hinge that connects the jawbone to the skull. Temporomandibular joint (TMJ) disorders, collectively referred to as temporomandibular disorders (TMD), affect millions of individuals, causing pain, restricted jaw movement, and reduced quality of life.

The exact cause of TMJ disorder can be hard to determine but the pain can be caused by a mix of factors ranging from teeth clenching to stress, to more chronic and systemic issues such as osteoarthritis or jaw injury.

Most of the time the pain and discomfort related to TMJ disorders lasts only a limited amount of time. Fortunately, in the event that it persists, a wide range of treatment options are available. When conservative therapies like physical therapy, oral splints, and medications fail, intra-articular injections offer an increasingly studied treatment option. Among the substances injected into the TMJ, cortisone (corticosteroids), prolotherapy, platelet-rich plasma (PRP), and hyaluronic acid (HA) have emerged as leading candidates.

Corticosteroid Injections

Corticosteroid injections are among the most commonly used intra-articular therapies for TMJ disorders. These anti-inflammatory agents provide rapid pain relief by suppressing pro-inflammatory cytokines and reducing synovial membrane inflammation. A randomized controlled trial by Al-Moraissi et al. (2020) compared corticosteroid injections to placebo and hyaluronic acid. The study demonstrated that corticosteroids significantly reduced pain and improved mandibular function in the short term (up to 3 months) (Al-Moraissi et al., 2020). However, long-term benefits were limited, and concerns persist regarding cartilage degradation with repeated injections.

Prolotherapy Injections

Prolotherapy involves injecting irritant solutions, typically hypertonic dextrose, to stimulate tissue healing through localized inflammation and fibroblast activation. Research on prolotherapy for TMJ is more limited than for corticosteroids, but emerging evidence is promising. A systematic review by Choi et al. (2019) found that prolotherapy injections improved pain, jaw function, and mouth opening in TMD patients, with effects lasting up to one year (Choi et al., 2019). The mechanism of action is believed to involve enhanced collagen synthesis and ligament strengthening. Although prolotherapy does not offer immediate relief like corticosteroids, its regenerative potential makes it appealing for chronic TMJ instability or hypermobility.

Platelet-Rich Plasma (PRP) Injections

PRP therapy utilizes autologous platelets concentrated from the patient’s own blood, injected directly into the joint to harness growth factors and cytokines that support tissue repair. A meta-analysis conducted by Zhang et al. (2022) compared PRP to hyaluronic acid and corticosteroids for TMJ osteoarthritis. PRP showed superior long-term pain reduction (up to 12 months) and functional improvement compared to corticosteroids, with fewer adverse effects (Zhang et al., 2022). The regenerative effects are attributed to its high concentration of platelet-derived growth factors, which stimulate synovial healing, cartilage repair, and modulation of inflammation.

Hyaluronic Acid Injections

Hyaluronic acid (HA) is a major component of synovial fluid, providing lubrication and shock absorption within the joint. HA injections aim to restore synovial fluid viscosity while exerting anti-inflammatory and chondroprotective effects. In a randomized clinical trial by Manfredini et al. (2018), HA injections significantly improved pain and jaw function in patients with TMJ osteoarthritis compared to placebo and corticosteroids (Manfredini et al., 2018). HA demonstrated a more gradual onset of action compared to corticosteroids but provided sustained benefits up to 6 months. Importantly, HA does not carry the cartilage-depleting risks associated with corticosteroids, making it preferable for patients with degenerative joint disease.

Comparative Effectiveness

When comparing these injection options, the systematic review by Chen et al. (2021) concluded that PRP and HA offered superior long-term efficacy compared to corticosteroids, especially for degenerative TMJ conditions. Prolotherapy showed promise for mechanical instability, although further large-scale trials are needed to confirm its efficacy and safety (Chen et al., 2021). Corticosteroids remain useful for acute inflammatory flares, but their long-term use is discouraged due to potential cartilage damage.

Conclusion

In summary, the choice of TMJ injection therapy should be guided by the patients underlying pathology and treatment goals. Corticosteroids offer fast relief but limited durability and safety concerns. HA provides sustained symptom relief and chondroprotection, particularly in osteoarthritis. PRP holds regenerative potential with lasting benefits for degenerative and inflammatory TMD. Prolotherapy may serve a niche role for patients with ligamentous laxity or joint instability. Future research should focus on head-to-head trials comparing these modalities.

References

1. Al-Moraissi, E. A., Wolford, L. M., Perez, D., Laskin, D. M., & Miloro, M. (2020). Does injection of corticosteroids into the temporomandibular joint provide better pain relief than injection of hyaluronic acid? Journal of Oral and Maxillofacial Surgery, 78(6), 977-985.
2. Choi, H. J., Kim, S. H., & Kim, S. W. (2019). Prolotherapy for the treatment of temporomandibular disorders: A systematic review and meta-analysis. Journal of Oral Rehabilitation, 46(3), 280-290.
3. Zhang, W., Li, Z., Liu, Z., & Zhang, J. (2022). Platelet-rich plasma versus hyaluronic acid for temporomandibular joint osteoarthritis: A systematic review and meta-analysis. Clinical Oral Investigations, 26(3), 2931-2944.
4. Manfredini, D., Piccotti, F., Guarda-Nardini, L., & Ferronato, G. (2018). Hyaluronic acid in the treatment of TMJ disorders: A systematic review and meta-analysis. International Journal of Oral and Maxillofacial Surgery, 47(5), 640-651.
5. Chen, J., Li, J., Li, J., & Zhang, Q. (2021). Comparison of corticosteroid, hyaluronic acid, platelet-rich plasma, and prolotherapy injections for temporomandibular joint disorders: A systematic review and network meta-analysis. Clinical Rehabilitation, 35(5), 762-771.