Clear Aligner Attachments: A Scoping Review

This scoping review aimed to map the available evidence on clear aligner attachments, summarise key themes and identify gaps to inform clinical practice and future research. This review was registered in the Open Science Framework database. A systematic search was conducted across PubMed, Scopus, Web of Science and Embase databases in accordance with PRISMA-ScR guidelines. The search strategy was systematically constructed using Boolean operators to capture the core literature related to clear aligners and attachments. Searches were conducted up to 30 August 2025. Studies focusing on attachments in clear aligner therapy published between 1 January 2005 and 30 August 2025 were included without restrictions on study design, except narrative reviews. Both primary studies and secondary studies (systematic reviews) were eligible and mapped in this scoping review. Data were systematically charted using a standardised form capturing key variables including study design, year of publication, country of origin, research objectives and outcomes relevant to clear aligner attachments. A total of 115 studies were finally included. In vitro studies predominated, representing 72.1% of the total. Most research was conducted in China and Turkey, with a total of 23 countries represented. The United States, China, Australia and Italy led in international research collaborations. A noticeable increase in publications was observed from 2020 onward, reaching a high point in 2025. Five major thematic areas were identified: Biomechanics and tooth movement, bonding and debonding, attachment materials, patient-reported outcomes and adverse effects, and aligner retention. Evidence was concentrated in biomechanics and bonding/material studies, whereas patient-reported outcomes (comfort/acceptability) and safety-related aspects (e.g., material elution/exposure) were relatively underexplored. Current evidence on clear aligner attachments is mostly in vitro-based, leaving its actual clinical effectiveness unclear. More clinical, multicentre and standardised studies are needed to strengthen and unify our understanding of clear aligner attachments.