Objective: Assess and evaluate the different indicators of oral health and quality of life (OHRQoL) among patients treated with clear aligners (CAs) versus those treated with conventional fixed orthodontics (FAs).
Methods: An electronic search was performed on 3 databases: WOS, Scopus and Embase. Randomized and non randomized control trials, cross-sectional, prospective cohort and retrospective trials were included. Quality was  assessed with ROB and ROBINS-I. Meta-analyses were performed with random effects models, estimating the standardized non-standardized mean differences, Odds Ratio and Risk Ratio as the measure of effect. The effect on time was determined using a meta-regression model.
Results: 31 articles were included in the qualitative synthesis and 17 in the meta-analysis. CAs had a significantly lower negative impact on QoL, with an "important" effect size, while the influence of time was not significant. Periodontal indicators PI, GI, PD, BOP show significantly better values in patients treated with CAs, with moderate to large effect sizes. PI and GI with a significant tendency to improve over time. In microbiological indicators, CAs present a lower biofilm mass, without differences in the percentage of patients with high counts of S. Mutans and Lactobacilli bacteria. The risk of WSL onset is 10 times lower in carriers of CAs.
Conclusions: Patients wearing CAs show better periodontal indicators, less risk of white spot development, less biofilm mass and a better quality of life than patients with FAs.

Keywords: Removable, Tooth movement, Orthodontic treatment