Background and Objectives: To compare the oral-health-related quality of life (OHRQoL) outcomes between patients treated with modified Ni-Ti spring-based alignment appliances or conventional fixed appliances using the Oral Health Impact Profile 14 (OHIP-14), as well as the levels of satisfaction with the appliance appearance, treatment progress, and outcomes. Materials and Methods: Thirty-six patients (11 males, 25 females) were randomly divided into two groups: either the modified aligner appliance with Ni-Ti springs group (MAA) or the traditional fixed appliances group (FA). The allocation ratio was 1:1, and the randomization process was carried out by an independent investigator not involved in this study. Mild crowding cases were included in this study. The OHRQoL of patients was evaluated using the short-form Oral Health Impact Profile (OHIP-14) at five time points: before the treatment commencement (T0); 2 weeks (T1), 1 month (T2), and 2 months (T3) after the treatment initiation; and post-treatment (T4). The visual analog scale (VAS) was used to evaluate the patient satisfaction. Blinding was performed only during the outcomes assessment. Results: This randomized controlled trial had no dropouts, and the demographic characteristics of the groups were comparable. The MAA group experienced significantly greater functional limitations compared with the FA group at all three evaluation time points (T1, T2, and T3), as evidenced by the statistically significant p-values (p = 0.004, p = 0.001, and p < 0.001, respectively). The psychological disability in the MAA group was significantly lower than in the FA group at both T2 (p = 0.005) and T3 (p = 0.003). The patient satisfaction with the appliance appearance was significantly higher in the MAA group than in the FA group (p = 0.002). Conclusions: The OHRQoL improved in both the modified aligner appliance with Ni-Ti springs and fixed appliance groups after the treatment. Moreover, the functional limitations during the treatment were less severe in the FA group, while the psychological disability was lower, and the patient satisfaction with the appliance appearance was higher in the MAA group.