Introduction: Nearly all of non-dental related chronic orofacial pain problems are temporomandibular disorders (TMDs). TMDs are associated with joint pain, sounds and limitation of mandibular movements. Although TMDs are not life threatening conditions; nevertheless they negatively affect the patients' quality of life making the treatment necessary.
Objective: To assess the effect of intra-articular injection of liquid phase concentrated growth factors (LPCGF), in patients with restricted mouth opening associated with irreducible disc displacement (DDwR).

Methodology: 12 patients with painful DDwR and limited mouth opening were enrolled in the study. Patients received an intra-articular injection of 2ml LPCGF with a 3D printed stabilization appliance (SA). The patients' symptoms were assessed clinically through Helkimo Anamnestic dysfunction index (Ai) and the maximum mouth opening (MMO) was measured at baseline as well as 1 week, 4 weeks, and 12 weeks post-treatment.

Results: There was a significant relief in symptoms at the 4, and 12 weeks follow-up periods (p = 0.001, p < 0.001 respectively). The mean of MMO at the baseline was 31.75 mm, while 1 week after the injection it was significantly increased to 33.50 mm (p <0.001).Moreover, by 12 weeks, the MMO was significantly improved (37.50 ± 2.54; p <0.001).

Conclusion: Intra-articular injection of LPCGF and SA could be considered a management protocol for patients suffering from DDwR as it relieved TMD symptoms and increased the MMO.