Sagittal And Vertical Effects Of Aligners Vs. Acrylic Splint Expander

To assess and compare the sagittal and vertical treatment effects of Invisalign First and acrylic splint expanders in mixed dentition patients with transverse maxillary deficiency. Sixty subjects were included after propensity score matching (PSM), and were equally divided into three groups: the acrylic splint expander (Splint) group (n=20), the Invisalign First (First) group (n=20), and the Natural Growth (Natural) group (n=20). Lateral cephalograms were acquired before the initiation of treatment (T0) and at a minimum of one year after treatment (T1). Sixteen cephalometric variables were assessed to detect differences within and between groups from T0 to T1. Intra-group analyses were conducted using paired t-tests, while inter-group comparisons were performed using analysis of variance (ANOVA). Statistical significance was set at p < 0.05. In all groups, a significant increase (p < 0.05) were observed in ANS-Me, N-Me, and S-Go during the T1-T0 period. In the Splint group, ANB and NA-PogA significantly decreased (p < 0.05), whereas SNB significantly increased (p < 0.05). In the First group, both overjet and overbite significantly decreased (p < 0.05), with a greater reduction observed compared to the other two groups (p < 0.05). 1. Both First and Splint therapy were effective in controlling clockwise rotation of mandible to some extent compared to the Natural group. 2. First therapy resulted in a greater reduction of overjet and overbite. 3. Splint therapy led to a reduction in profile convexity.