The effects of maxillary protraction on soft and hard tissue in patients with cleft lip and palate in the mixed dentition period

Objective To study the three-dimensional changes of soft and hard tissue in male patients with unilateral non-syndromic cleft lip and palate in the mixed dentition period before and after maxillary protraction. Methods Twenty male patients with unilateral non-syndromic cleft lip and palate in the mixed dentition period treated by maxillary anterior traction in the Department of Orthodontics of Affiliated Stomatological Hospital of Nanjing Medical University were selected (average age (10.6±1.23) years old). Cone beam CT was taken before and after treatment. Dolphin 3D 11.95 software was used for three-dimensional measurement and analysis. SPSS 25.0 software package was used for statistical analysis. The self-controlled paired t test was used to compare the changes in soft and hard tissues of male patients with unilateral cleft lip and palate before and after treatment. The changes in the anterior displacement of the ANS point, the anterior displacement of point A, and the posterior displacement of point B were tested using the one-sample t test. Results The sagittal skeletal changes were significantly increased in ∠SNA (P<0.01), ∠ANB (P<0.01), Y axis (P<0.05), the forward displacement of ANS point(P<0.01)and A point(P<0.01)and the backward displacement of B point (P<0.01), but ∠SNB(P<0.05) was decreased significantly. The vertical skeletal changes showed that ∠MP-FH(P<0.01), ∠MP-SN (P<0.05) and the distance of ANS-Me(P<0.05)were increased significantly, but ∠SN-PP(P<0.01)was decreased significantly. The dental changes including ∠U1-NA(P<0.01), the distance of U1-NA(P<0.01), ∠U1-SN(P<0.01), overjet and the Wits were increased significantly, but ∠ L1-NB(P<0.01), the distance of L1-NB(P<0.01)and ∠L1-MP(P<0.01)were decreased significantly. The changes of soft tissue including ∠S-Ns-Sn(P<0.01), ∠Sn-Ns-Bs(P<0.01), the distance of UL-EP(P<0.01)and LL-UL(P<0.01)were increased significantly. Conclusion After the treatment of maxillary protraction, the forward growth of maxilla will be possibly promoted on patients with cleft lip and palate in the peak of growth timing, as well as the intermaxillary relationship and soft tissue profile, but the side effects should be paid attention to.