Pain Intensity and Oral Health-Related Quality of Life in Orthodontic Treatment: An Umbrella Review Comparing Clear Aligners and Fixed Appliances

Background and objectives: Clear aligner therapy is becoming more popular than fixed appliance therapy in orthodontic treatment due to its comfort and aesthetic benefits. However, little is known regarding its differential impact on pain perception and oral health-related quality of life. This umbrella review aimed to compare pain levels and oral health-related quality of life (OHRQoL) between clear aligner therapy and fixed appliance therapy. Materials and Methods: An electronic search was performed in PubMed, Embase, Cochrane, Web of Science, Scopus, and Google Scholar without any restrictions until March 2025. We included systematic reviews that evaluated pain or OHRQoL in clear aligner therapy compared to fixed appliance therapy. The risk of bias was assessed using the AMSTAR-2. Certainty of evidence was rated using GRADE. Quantitative data were synthesized through meta-meta-analyses, and findings were qualitatively summarized. Results: After removing duplicates, exclusion by title and abstract, and full text screening, seven systematic reviews met the inclusion criteria. Four of them had meta-analyses, and the remaining three were without meta-analyses. From Day 1 to Day 7, clear aligner therapy was associated with lower pain scores (mean difference: −0.46 to −1.04; I²=0%) and better OHRQoL at Week 1 (SMD: -1.80), Month 1 (SMD: -1.46), and Month 6 (SMD: -1.45). Qualitative synthesis mostly aligned with the general patterns but noted some inconsistencies in pain perception. Conclusion: Clear Aligners reduce pain during the first few days of treatment and improve short-term OHRQoL compared to fixed appliances. This is probably due to using forces over time and less mucosal damage. Nonetheless, the low quality, significant overlap, and low redundancy of the included reviews deeply undermine these conclusions. More robust findings from longitudinal studies that are independent of one another are needed to establish and analyze the long-term clinical consequences of these claims.