This systematic review aimed to critically appraise the evidence regarding the effect of bracket ligation type on the periodontal conditions of adolescents undergoing orthodontic treatment.Search terms included randomized controlled trial (RCTs), controlled clinical trials, ligation, bracket, periodontal, inflammation. Risk of bias assessment was made using the Cochrane risk of bias tool and the quality of evidence was assessed with GRADE.Electronic Database search of published and unpublished literature was performed without language restriction in May 25, 2016 (MEDLINE via Pubmed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Clinical Trials.gov and National Research Register).Of 140 articles initially retrieved, 8 were eligible for inclusion in the systematic review, while 4 RCTs with unclear risk of bias were included in the quantitative synthesis, all comparing self-ligating to conventional steel ligated brackets. Random effects meta-analyses were implemented. At 4–6 weeks after bracket placement there was no evidence to support the use of either type of bracket for achieving improved plaque- (PI) and gingival index (GI). At 3–6 months, there was scarce evidence of greater PI increase for conventional brackets. GI and pocket depth pooled estimates did not reveal significant differences between the two systems. The quality of the evidence was moderate according to GRADE for all outcomes.Overall, non-significant differences on the periodontal status of adolescents undergoing orthodontic treatment with either conventional or self-ligating brackets were detected.The periodontal status of adolescents undergoing orthodontic treatment is of considerable importance. The synthesis of the available evidence on oral hygiene related factors will provide insights to best clinical practice during the course of orthodontic treatment.