A comparison of treatment effectiveness between clear aligner and fixed appliance therapies

Align technology has developed greatly over past few years. Patients tended to prefer clear aligners over conventional brackets because of the superior comfort and esthetics, while the effectiveness of clear aligners was still controversial. The aim of this systematic review was to verify whether the treatment effectiveness of clear aligners was similar to the conventional fixed appliances.

A comprehensive search of the Pubmed, Web of Science, Embase, Scopus, and Cochrane Central Register of Controlled Clinical Trials Register databases for studies published through to August 20, 2018 was conducted. Comparative clinical studies assessing the effectiveness of clear aligners compared with braces were included.

Eight papers were included in this study. Two of the included papers were randomized controlled trials and six were cohort studies. Clear aligners might not be as effective as braces in producing adequate occlusal contacts, controlling teeth torque, increasing transverse width and retention. While no statistically significant difference was found between two groups in Objective Grading System score (WMD = 8.38, 95% CI [- 0.17, 16.93]; P = 0.05). On the other hand, patients treated with clear aligners had a statistically significant shorter treatment duration than with braces (WMD = - 6.31, 95% CI [- 8.37, - 4.24]; P < 0.001).

Both clear aligners and braces were effective in treating malocclusion. Clear aligners had advantage in segmented movement of teeth and shortened treatment duration, but were not as effective as braces in producing adequate occlusal contacts, controlling teeth torque, and retention.