{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T15:58:50Z","timestamp":1792079930580,"version":"4.4.0"},"reference-count":35,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T00:00:00Z","timestamp":1780531200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: The impact of orthodontic appliances on oral health-related quality of life (OHRQoL) has gained increasing attention, particularly in relation to patient-centered outcomes. Clear aligners (CAs) are often perceived as more comfortable than fixed appliances (FAs), although evidence remains limited and heterogeneous. This systematic review and meta-analysis aimed to compare the effects of CAs and FAs on OHRQoL in patients with Angle class I malocclusion and to further evaluate the reliability of the findings using trial sequential analysis (TSA). Materials and Methods: This review followed PRISMA guidelines and was registered in PROSPERO (CRD420251051003). A comprehensive search of PubMed, Scopus, Web of Science, Embase, and Cochrane CENTRAL was conducted. Only randomized controlled trials comparing CAs and FAs and reporting OHRQoL outcomes (OHIP-14) were included. Random-effects meta-analyses were performed on early changes in OHRQoL. TSA was applied to control for type I and II errors and to evaluate the sufficiency of the cumulative evidence. Results: Two randomized controlled trials (n = 74) were included in the quantitative synthesis. Both treatments were associated with a transient deterioration in OHRQoL after appliance placement. Meta-analysis showed statistically significant improvements favoring CAs in psychological discomfort (p = 0.007) and psychological disability (p &lt; 0.001), while no significant differences were observed for other domains or for overall OHRQoL. Exploratory TSA suggested an early signal in favor of psychological outcomes, with the cumulative Z-curve crossing the monitoring boundary; however, given the very small number of included trials, these findings should be regarded as preliminary and hypothesis-generating rather than confirmatory. In contrast, for most other outcomes, the required information size was not reached and results remained inconclusive. For handicap, TSA suggested that a clinically relevant difference is unlikely. Conclusions: Clear aligners may provide a modest short-term advantage over fixed appliances in psychological aspects of OHRQoL, while no consistent differences are observed in physical or overall domains, based on very limited evidence. TSA suggests a preliminary signal in psychological outcomes but highlights insufficient evidence for most other domains. These results should be interpreted with caution, and further high-quality randomized trials are needed.<\/jats:p>","DOI":"10.3390\/medicina62061090","type":"journal-article","created":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T11:52:30Z","timestamp":1780573950000},"page":"1090","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Comparative Impact of Clear Aligners and Traditional Fixed Appliances on Oral Health-Related Quality of Life: A Systematic Review and Meta-Analysis"],"prefix":"10.3390","volume":"62","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-3188-5016","authenticated-orcid":false,"given":"Elisabetta","family":"Lalli","sequence":"first","affiliation":[{"name":"Department of Surgical Sciences, Postgraduate School in Orthodontics, University of Cagliari, 09124 Cagliari, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-1945-5809","authenticated-orcid":false,"given":"Elena","family":"Caramaschi","sequence":"additional","affiliation":[{"name":"Department of Surgical Sciences, Postgraduate School in Orthodontics, University of Cagliari, 09124 Cagliari, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Agnese","family":"Nieri","sequence":"additional","affiliation":[{"name":"Department of Surgical Sciences, Postgraduate School in Orthodontics, University of Cagliari, 09124 Cagliari, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sara","family":"Vitale","sequence":"additional","affiliation":[{"name":"Department of Surgical Sciences, Postgraduate School in Orthodontics, University of Cagliari, 09124 Cagliari, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maurizio","family":"Ledda","sequence":"additional","affiliation":[{"name":"Department of Surgical Sciences, Postgraduate School in Orthodontics, University of Cagliari, 09124 Cagliari, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-9773-6088","authenticated-orcid":false,"given":"Giulia","family":"Porcu","sequence":"additional","affiliation":[{"name":"Department of Surgical Sciences, Postgraduate School in Orthodontics, University of Cagliari, 09124 Cagliari, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pier Luigi","family":"Delogu","sequence":"additional","affiliation":[{"name":"Department of Surgical Sciences, Postgraduate School in Orthodontics, University of Cagliari, 09124 Cagliari, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-3315-0112","authenticated-orcid":false,"given":"Alessio","family":"Verdecchia","sequence":"additional","affiliation":[{"name":"Department of Surgical Sciences, Postgraduate School in Orthodontics, University of Cagliari, 09124 Cagliari, Italy"},{"name":"Orthodontics Division, Instituto Asturiano de Odontologia, Universidad de Oviedo, 33006 Oviedo, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4563-9804","authenticated-orcid":false,"given":"Enrico","family":"Spinas","sequence":"additional","affiliation":[{"name":"Department of Surgical Sciences, Postgraduate School in Orthodontics, University of Cagliari, 09124 Cagliari, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Kaklamanos, E.G., Makrygiannakis, M.A., and Athanasiou, A.E. 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