Assessment of the effectiveness of invisible aligners compared with conventional appliance in aesthetic and functional orthodontic treatment: A systematic review.

To seek scientific evidence to support the effectiveness of invisible aligners, in the aesthetic and functional aspects, compared with that of conventional braces. An electronic search was performed with a complementary grey literature search for in vivo research. No language restrictions were applied. Scopus, PubMed, Web of Science, Cochrane, ClinicalTrials and GreyLiterature databases were used. Studies were first selected by title and abstract; those potentially eligible were read in full. Non-randomized studies were assessed for risk of bias using the tools Methodological Index for Non-randomized Studies (MINORS) and Cochrane Collaboration Common Scheme for Bias as a function of the presence of randomization. The search found 559 studies, of which 55 were potentially eligible. A total of 4 articles were included in this systematic literature review: three non-randomized controlled studies and one randomized controlled study, three with low risk of bias (RoB) and one with moderate RoB. Three studies showed time of correction of dental crowding shorter or equal to that of the control group and only one study showed less time of correction using conventional braces. Invisible aligners were deficient with respect to anterior/posterior and vertical corrections compared with fixed orthodontic appliances. Invisible aligners are effective in promoting dental alignment, but present clinical limitations in relation to the conventional system.