فهرست نشریات علمی دسترسی آزاد ایران

Aim Orthodontic relapse after alignment remains a major clinical concern. This study aimed to evaluate whether adjunctive low-intensity ultrasound could reduce the rate of orthodontic relapse and improve post-treatment stability compared with no intervention.Methods In this quasi-experimental clinical trial, 39 patients (mean age 19.3 ± 5.7 years) with Class I malocclusion and severe dental crowding were enrolled after completion of alignment. Participants were randomly allocated to an ultrasound group (n = 20) or a control group (n = 19). The ultrasound group received therapeutic ultrasound (EME, Pesaro, Italy) at 1 MHz, 100 mW/cm², 20% duty cycle (200 μs on/800 μs off; 1000 cycles/s), for 10 min/session over 10 sessions. In both groups, archwires were then removed for 2 months; the control group received no additional intervention. Dental casts were obtained at archwire removal (baseline) and after 2 months. Outcomes were inter-canine width, inter-molar width, arch length, arch circumference, and modified Little’s irregularity index. Analyses used Chi-square, independent t-test, and paired t-test with .Results All 39 participants were included in the analyses. Over 2 months, between-group differences in changes of inter-canine width, inter-molar width, arch length, arch circumference, and modified Little’s irregularity index were not statistically significant (P > 0.05). In both groups, modified Little’s irregularity index differed significantly between the maxilla and mandible (ultrasound: P = 0.025; control: P = 0.002). Within-group analysis showed a significant reduction in mandibular arch circumference in the ultrasound group (P = 0.007) and a significant increase in maxillary arch circumference in the control group (P = 0.018).Conclusion Under the conditions of this trial, low-intensity ultrasound did not reduce orthodontic relapse in the maxilla or mandible during the 2-month post-alignment period.