Efficacy of clear aligners in treating crowded dentition in early permanent teeth by moving the upper and lower molars far

Objective To evaluate the clinical efficacy of clear aligner for crowded dentition in early permanent teeth by moving the upper and lower molars far. Methods A total of 36 adolescent patients with Class Ⅰ Angle malocclusion admitted in our department from March 2017 to August 2023 were enrolled, and they were 17 males and 19 females, and at a mean age of 13.20±0.53 years. Clear aligner was applied to push the upper and lower molars backward to obtain a neat dentition. Lateral cephalometric X-ray film before and after treatment was measured, and paired t-test was used to compare the cephalometric measurements before and after treatment. Results The average course of treatment was 21.2 months. Overbite, overjet and molar relationship were turned to normal after treatment, and the soft tissue profile was maintained. Analysis of relevant cephalometric items showed that the Ptm-U6 distance was decreased by 2.89±1.22 mm, and the Go-L6 distance was decreased by 2.61±1.07 mm after treatment, with significant differences (P < 0.01). While, there were no statistically differences in UL-EP, LL-EP, NLA and FCA before and after treatment. Conclusion With reasonable treatment target and good tooth movement design, clear aligner can effectively move the upper and lower molar distally to correct moderate dentition congestion in early permanent teeth, and meanwhile the patients' profile is maintained.