Management of DDwoR: Hypertonic Dextrose vs CGF

Disc displacement without reduction (DDwoR) represents a major therapeutic challenge due to the alteration of retro-discal tissues and synovial inflammation. Beyond functional discomfort, neutrophil infiltration — marked by high levels of myeloperoxidase (MPO) in the synovial fluid — exposes patients to an increased risk of osteoarthritis. Addressing this issue, this prospective randomized clinical trial (RCT) evaluated the efficacy of two regenerative approaches combined with the use of a stabilization appliance (SA).

The central objective was to compare intra-articular injection of hypertonic dextrose (HD) with concentrated growth factors (CGF) in 24 patients suffering from DDwoR. The authors tested the hypothesis that these injectable therapies, by promoting tissue repair and inflammatory modulation, could restore mandibular kinetics while sustainably reducing pain.

To validate these protocols, patients were divided into two equal groups (n=12). Clinical follow-up was structured around measurements at 1 week, 4 weeks, and 24 weeks post-intervention, including the visual analogue scale (VAS) for pain and maximum assisted mouth opening (MMO). Simultaneously, biochemical analysis of MPO levels in the synovial fluid before and 6 months after treatment served as an objective marker of intra-articular inflammatory activity.

Clinical trial methodology

This prospective, parallel-arm, blinded (evaluator and analyst) randomized controlled trial (RCT) included 24 patients diagnosed with disc displacement without reduction (DDwoR) of the temporomandibular joint. The objective was to compare two regenerative injection therapy approaches as an adjunct to conventional splint therapy.

Patients were randomly divided into two equal groups (n=12):

• Group I (HD + SA): Intra-articular injection of hypertonic dextrose combined with the use of a rigid occlusal stabilization splint.
• Group II (CGF + SA): Intra-articular injection of concentrated growth factors combined with the same type of stabilization splint.

Injections were performed specifically into the upper joint space. The follow-up protocol included clinical assessments at four key stages: before treatment (baseline), then at 1 week, 4 weeks, and 24 weeks (6 months) post-intervention.

The analysis was based on two major clinical criteria: pain intensity via the visual analogue scale (VAS) and maximal assisted mouth opening (MMO). In parallel, a biochemical analysis was performed on synovial fluid samples collected before treatment and at 6 months to measure the evolution of Myeloperoxidase (MPO) levels, a biomarker of inflammation and neutrophilic infiltration.

Results: Clinical efficacy and reduction of inflammation

Data from this randomized clinical trial (n=24) demonstrate a significant improvement in clinical and biochemical parameters for both tested therapeutic protocols (Hypertonic Dextrose vs. Concentrated Growth Factors), with no statistical superiority of one over the other.

Improvement of clinical parameters (VAS and MMO)

Clinical evaluation at 1, 4 and 24 weeks revealed a constant progression of the patients' condition in both groups:

• Pain relief (VAS): A significant reduction in pain was recorded from the first postoperative month, a benefit that was sustained until the end of the 6-month follow-up (p < 0.001).
• Maximum Mouth Opening (MMO): Assisted maximum opening increased in a statistically significant manner in both groups (p < 0.001), thus restoring part of the mandibular kinetics altered by disc displacement.

Biochemical analysis of synovial fluid (MPO)

The study examined levels of Myeloperoxidase (MPO), an enzyme marker of neutrophil infiltration and intra-articular tissue damage. The results show an effective modulation of the inflammatory environment:

Inter-group comparisons

The comparative analysis between Group I (HD + SA) and Group II (CGF + SA) highlights the following points:

• Absence of superiority: Although MPO concentrations dropped drastically after injection compared to baseline levels, no statistically significant difference was observed between the two groups regarding the final concentration of the enzyme in the synovial fluid.
• Therapeutic equivalence: Both intra-articular injection modalities, when combined with a stabilization splint, offer comparable results in reducing inflammation and functional recovery.

Clinical analysis and biological impact

The results of this randomized clinical trial (RCT) highlight the equivalent efficacy of hypertonic dextrose (HD) prolotherapy and concentrated growth factors (CGF) in the management of disc displacement without reduction (DDwoR). For the practitioner, the significant improvement in assisted maximum mouth opening (MMO) and the lasting reduction in pain (VAS) from the first month (p < 0.001) confirm that these regenerative therapies act as powerful adjuncts to stabilization appliances (SA).

The strength of this study lies in the analysis of myeloperoxidase (MPO) in the synovial fluid. The marked decrease in MPO levels at 6 months (p = 0.002) demonstrates a reduction in neutrophil infiltration and intra-articular inflammation. This suggests that the injection does not merely lubricate the joint, but actively modifies the biochemical environment of the condylar-disc complex, potentially slowing the progression towards osteoarthritis.

Limits and perspective

Although the data are statistically robust, the sample size remains modest with 24 patients. Furthermore, the 24-week follow-up allows for the observation of medium-term stability, but does not predict the long-term durability of the results beyond six months. Unlike certain purely mechanical approaches (simple arthrocentesis), the use of HD or CGF here aims for a structural repair of the discal ligaments and retro-discal tissues.

Implications for daily practice

Concretely, the study validates two minimally invasive protocols before considering more extensive surgery. The choice between HD and CGF can be made according to the technical equipment available at the practice: dextrose prolotherapy is simple and inexpensive, while CGF exploits the patient's autologous potential but requires immediate centrifugation.

Summary of results

This randomized controlled trial conducted on 24 patients demonstrates that intra-articular injection of hypertonic dextrose (HD) or concentrated growth factors (CGF), combined with a stabilization splint, significantly reduces pain (VAS) and increases maximum mouth opening (MMO) from one month of follow-up (p < 0.001). At 24 weeks, both protocols induce a drastic decrease in the inflammatory biomarker myeloperoxidase (MPO) in the synovial fluid (p = 0.002), with no statistical superiority of one technique over the other.

In concrete terms, for the practitioner:

• Technical freedom of choice: You can choose either HD or CGF as a complement to an occlusal splint; the clinical and biological benefits on irreducible disc displacement are equivalent at 6 months.
• Economic alternative: Prioritize hypertonic dextrose (prolotherapy) for a simpler and less expensive implementation than CGF, which requires blood sampling and centrifugation.
• Real biological action: Integrate these injections to treat objective intra-articular inflammation (reduction in MPO) and restore mandibular kinetics, thus offering a solid alternative before considering invasive surgery.

Technical lexicon of the study

DDwoR (Disc Displacement without Reduction): Severe mechanical locking of the TMJ. The articular disc remains trapped in an anterior position relative to the condyle, preventing any return to normal during opening and drastically limiting mandibular range of motion.

Prolotherapy (Hypertonic Dextrose - HD): The gold standard regenerative injection therapy in this study. It aims to trigger a healing reaction to strengthen compromised disc ligaments and retro-discal tissue.

CGF (Concentrated Growth Factors): The biological vector for regeneration. These concentrated growth factors are injected directly into the upper joint space to restore disc structure and joint function.

Myeloperoxidase (MPO): The biomarker of tissue aggression. This enzyme detected in the synovial fluid reveals neutrophil infiltration and the intensity of local inflammation, foreshadowing osteoarthritic damage.

MMO (Maximum Mouth Opening): The clinical barometer of mobility. This is the measurement of the maximum assisted mouth opening, used here to validate the effectiveness of mechanical unlocking after treatment.

Stabilization Appliance (SA): The essential therapeutic auxiliary. This rigid occlusal splint is used in synergy with injections to stabilize the joint and optimize the relief of joint pain.

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