OBJECTIVE: Sustainability is a prominent topic in modern-day society, with a trend toward reducing environmental impact. The growing amount of plastics and the release of greenhouse gases during waste management raise concerns. This study compares the environmental burden of clear aligners- and self-ligating metal brackets (fixed appliances) to identify the production phase where improvements could best reduce impact. METHODS: A simplified fast-track life cycle impact assessment (LCIA) was performed for four illustrative patient cases (two aligner, two fixed appliances). Data were derived from the Industrial Design & Engineering Materials open access database (Idemat, 2024) and manufacturer specifications. Environmental indicators were carbon footprint (kg CO2-eq), cumulative energy demand megajoules (MJ), and total ReCiPe score Points (Pt). RESULTS: Clear aligners show a higher environmental impact in all categories. Mean carbon footprint for clear aligners ranged from 20.58 to 24.75 kg CO2 and 0.22 kg CO2 in fixed appliance treatment. The Total ReCiPe ranges 0.54-0.66 Pt) for clear aligners compared with 0.01 Pt in treatment with self-ligating metal brackets. These results should be interpreted cautiously, as they may overestimate true magnitudes. LIMITATIONS: This study used a simplified LCIA, incorporating assumptions substantiated by research whenever possible. CONCLUSIONS: Within the limitations of a small sample size and a simplified model, fixed appliance treatment showed a lower environmental impact than clear aligners. The results are exploratory and require validation through larger, clinically based studies incorporating sensitivity analyses and multi-source datasets. The "materials" phase seems a key contributor, stimulating environmentally conscious decision making.
Heezen et al. (2026) studied this question.