To assess the efficacy of chincup therapy for mandibular growth retardation in early orthopedic treatment of Class III malocclusion. An electronic search for articles reporting randomized clinical trials, controlled clinical trials, and cohort studies testing the efficacy of chincup appliance for Class III malocclusion published up to the present was done through four databases: Cochrane Central Register of Controlled Trials (CENTRAL; to March 2010), MEDLINE (1950-March 2010), EMBASE (1980-March 2010), and CBM (1978-March 2010). Study quality assessment and data extraction were done by two reviewers independently. Meta-analysis was done with the assistance of Revman 5.01. The search resulted in 50 articles. After selection following the established criteria, four cohort studies qualified for the final review analysis. The results showed that chincup therapy decreased SNB angle and increased ANB angle; the total pooled weighted mean difference values (95% confidence interval) were −1.18 (−1.69, −0.67; P < .00001) and 1.90 (0.60, 3.21; P = .004), respectively. Two studies showed a increase in Gonial angle (P < .05) but no significant change in the mandibular length (Cd-Gn; P = .059 and .39, respectively). One study indicated that chincup therapy exerted no effect on mandibular growth retardation, and mandibular growth continued after the treatment in a downward direction. There are insufficient data in these studies to make clear recommendations regarding the efficacy of chincup therapy in the retardation of mandibular growth.
