Effect of clear aligners and Z-spring appliance on anterior crossbite correction and quality of life in the mixed dentition: a randomized clinical trial.

Objectives: To compare the efficacy of clear aligners and Z-spring (ZS) appliances in treating dental anterior crossbite (AC) during the mixed dentition period.

Materials and methods: Thirty patients (7-12 years) with Angle Class I occlusion and isolated pseudo-Class III AC were randomly assigned to clear aligners (Group A, n = 15) or ZS appliances (Group B, n = 15). Outcomes were evaluated based on duration, cephalometric changes, model analysis, and oral health-related quality of life (OHRQoL), assessed using the Child Oral Health Impact Profile-Short Form-19 (COHIP-SF-19).

Results: AC was successfully corrected in all patients. Treatment duration was significantly shorter in Group B (48.4 ± 27 days) than in Group A (96.3 ± 22.7 days) (P < .05). U1-NA angle increased by 5.9° and overjet by 4 mm in Group A; in Group B, U1-NA increased by 7.7° and overjet by 4.2 mm (P < .01). Intergroup cephalometric changes (ΔT1-T0) were not significant (P > .05). In Group A, incisal and gingival arch depths increased significantly (2.6 mm and 1.17 mm, respectively; P < .001), whereas no significant changes occurred in Group B (P > .05). COHIP-SF-19 scores were comparable (P > .05).

Conclusion: Clear aligners and ZS appliances were effective in treating dental AC, achieving normal overjet relationships. However, ZS appliances may cause greater tipping, whereas clear aligners facilitate tipping, alignment, and bodily movement. Treatments demonstrated comparable effects on OHRQoL of children. This study provides a foundation for future research on different appliances for managing AC in the mixed dentition.