Efficacy of hypertonic dextrose injection (prolotherapy) in temporomandibular joint dysfunction: a systematic review and meta-analysis

Hypertonic dextrose prolotherapy (DPT) has been reported to be effective for temporomandibular disorders (TMDs) in clinical trials but its overall efficacy is uncertain. To conduct a systematic review with meta-analysis of randomized controlled trials (RCTs) to synthesize evidence on the effectiveness of DPT for TMDs. Eleven electronic databases were searched from their inception to October, 2020. The primary outcome of interest was pain intensity. Secondary outcomes included maximum inter-incisal mouth opening (MIO) and disability score. Studies were graded by "Cochrane risk of bias 2" tool; if data could be pooled, a meta-analysis was performed. Ten RCTs (n=336) with some to high risk of bias were included. In a meta-analysis of 5 RCTs, DPT was significantly superior to placebo injections in reducing TMJ pain at 12 weeks, with moderate effect size and low heterogeneity (Standardized Mean Difference:-0.76; 95% CI-1.19 to-0.32, I-2=0%). No statistically significant differences were detected for changes in MIO and functional scores. In this systematic review and meta-analysis, evidence from low to moderate quality studies show that DPT conferred a large positive effect which met criteria for clinical relevance in the treatment of TMJ pain, compared with placebo injections.Protocol registration at PROSPERO: CRD42020214305.