Abstract
Hyaluronic acid (HA) is a glycosaminoglycan composed of D-glucuronic acid and N-acetylglucosamine with an up-to-several-million-Daltons chain-length responsible for the lubricating properties of the temporomandibular joint (TMJ) synovial fluid. Arthritis results in the predominance of HA degradation over synthesis leading to temporomandibular disorders (TMDs). TMD injection treatments are divided into HA supplementation and platelet-rich plasma (PRP) inflammation suppression. We questioned whether either approach lubricated the TMJ better and answered it in a two-arm equal-allocation trial with a non-concurrent active treatment control (two groups of 39 patients each). HA statistically significantly improved (p < 0.01) and PRP did not statistically significantly change (0.06 ≤ p ≤ 0.53) articular mobility compared to baselines in 128 TMJs. Statistically significant inter-group discrepancies were observed for abduction (MD = -4.05 mm; SE = 1.08; p = 0.00; d = -0.85) and protrusion (MD = -0.97 mm; SE = 0.43; p = 0.03; d = -0.51) but not for rightward (MD = -0.21; SE = 0.43; p = 0.63; d = -0.11) and leftward (MD = -0.30; SE = 0.42; p = 0.47; d = -0.16) movements. HA supplementation proved superior to PRP autografting in ad hoc TMJ lubrication and hence is more appropriate in hypomobile TMD cases of symptomatic treatment.