What finite element models teach us about clear aligners: a PRISMA-ScR-aligned scoping review of biomechanics across different types of tooth movements (2020–2025)

To map and synthesise finite element analysis (FEA) evidence on clear aligner biomechanics and to address the research question: which design variables (attachments, auxiliary mechanics, activation vectors, and staging) most consistently influence the predicted displacement pattern (tipping vs translation) across movement types? A PRISMA-ScR-guided search of PubMed, Scopus, Web of Science, and Google Scholar identified English-language FEA studies published from January 2020 to December 2025. Two reviewers independently and in duplicate, screened records against a predefined eligibility criteria. Further, extracted data on study design and modelling parameters. Owing to the heterogeneity of the included studies, findings were synthesised descriptively according to movement categories. The review protocol was registered on the Open Science Framework (OSF) platform. Fifty-one studies met the inclusion criteria. Most simulations showed that aligners alone predominantly produced crown tipping and reciprocal movements, whereas predictable translation required engineered couples. In distalisation, third-molar interferences, various attachment configurations, and vertical vectors influenced movement efficiency, while precision-cut elastics and skeletal anchorage enhanced anchorage control. For torque/buccal translation and expansion, bilateral or bevelled rectangular attachments with limited torque overcorrection improved root control, while larger step sizes increased tipping. Premolar derotation outcomes improved with attachments and small per-stage rotational increments modelled in the FEA of the included studies. In extraction mechanics, canine-step modulation (around 0.25 mm) and controlled anterior spacing improved incisor torque and intrusion. Evidence mapping analysis indicated that while FEA literature provides robust parametric guidance on design variables, it currently lacks sufficient empirical validation and mechanistic realism for direct clinical translation without independent verification. FEA synthesised literature revealed convergent, movement-specific biomechanical trends; however, translating these predominantly static simulations into prescriptive clinical guidance should be approached with caution, given the limited time-dependent modelling, representation of biological remodelling, and external validation across included studies.