Differential Benefit of Two Different Tooth-Borne Rapid Maxillary Expansion Appliances in Female Subjects

Abstract

Objective: The aim of the present study was to evaluate the effects of tooth-borne acrylic-bonded rapid maxillary expansion (RME) appliances with or without the anterior teeth anchorage on the skeletal and dentoalveolar structures, as well as soft tissues.

Methods: This study included 44 patients who were treated with two different tooth-borne bonded acrylic RME appliances. Lateral cephalometric radiographs were taken before the treatment (T0) and in the post-retention (T1) phase of the RME treatment. The posterior-bonded RME appliance group and full-bonded RME appliance group were created as the two different groups of treatment. The following statistical analyses were performed: intra- and inter-group comparisons were made using the paired t-test, Wilcoxon test, independent t-test, and Mann-Whitney U-test for normal and non-normal distribution data.

Results: Significant increases were observed in R1-A, R1-ANS, R1-U1, R1-AR, R1-St, R1-Li, and R1-Pn in both groups. R1-PNS, R1-Ls, R1-Sn, and R1-B' were found to be significantly larger at T1 than at T0 in the posterior-bonded RME appliance group. R2-A, R2-ANS, R2-L1, R2-A', and R2-Pn were significantly larger at T1 than at T0 in the full-bonded RME appliance group. The R2-A' was significantly different between the groups.

Conclusion: The soft tissue A point appears to be the most important differing matter between the two different RME appliances, and a full acrylic-bonded RME appliance may be beneficial for subjects with a maxillary retrognathic profile.

Keywords: Rapid maxillary expansion; growing subjects; soft tissue profile; tooth-borne expander.

Figure 1. a, b

Posterior acrylic-bonded tooth-borne RME (Group1) (a); full acrylic-bonded tooth-borne RME (Group2) (b)

Figure 2

Reference line, landmarks, and measurements SNA(°)(1), SNB(°)(2), ANB(°)(3), SN-GoGN(°)(4), R1-A(mm)(5), R1-ANS(mm)(6), R1-PNS(mm)(7), R2-A(mm)(8), R2-ANS(mm)(9), R2-PNS(mm)(10), R1-U1(mm)(11), R2-U1(mm)(12), R1-Ar(mm)(13), R2-Ar(mm)(14), R1-L1(mm)(15), R2-L1(mm)(16), R1-Ls(mm)(17), R1-St(mm)(18), R1-Sn(mm)(19), R1-A′(mm)(20), R1-B′(mm)(21), R1-Li(mm)(22), R1-Pn(mm)(23), R2-Ls(mm)(24), R2-St(mm)(25), R2-Sn(mm)(26), R2-A′(mm)(27), R2-B′(mm)(28), R2-Li(mm)(29), R2-Pn(mm)(30), NLA(°)(31)