External apical root resorption (EARR) is a common irreversible effect of the orthodontic treatment, and the influence of appliance type remains debated. The study objective was to compare the extent of EARR in patients treated with clear aligners (CAs) and fixed appliances (FAs). Sixty-eight patients were treated with either CAs (n=34) or FAs (n=34). Standardized radiographs or CBCT scans were obtained before and after treatment to measure incisor root length changes and classify resorption using the Malmgren system. Both modalities produced EARR; however, resorption was significantly lower in the CA group (0.54 ± 0.29 mm) than in the FA one (1.12 ± 0.43 mm; p < 0.001). Central incisors showed significantly greater resorption with fixed appliances, while lateral incisors exhibited no significant differences. Mild resorption predominated in the CA group. Clear aligners were associated with reduced EARR compared with fixed appliances, suggesting a lower biological impact on root structures. Keywords: external apical root resorption, clear aligners, fixed appliances, orthodontic treatment, radiographic assessment.