Evaluation of miniscrew-supported rapid maxillary expansion in adolescents: A prospective randomized clinical trial

Abstract

Objectives:: To evaluate and compare the dental and skeletal changes with conventional and miniscrew-supported maxillary expansion appliances in adolescents.

Materials and methods:: Forty patients were divided into two groups, with one group receiving a tooth-borne expander and the other group receiving an expander supported by four miniscrews (bone-borne). Multiplanar coronal and axial slices obtained from cone-beam computed tomography images were used to measure the changes in transverse skeletal widths, buccal bone thickness, tooth inclination, and root length. Paired t-tests and independent-sample t-tests were used to compare the two expansion methods.

Results:: Bone-borne expansion increased the maxillary suture opening more than 2.5 times than tooth-borne expansion both anteriorly and posteriorly. Between the maxillary first premolars, sutural expansion accounted for 28% and 70% of the total transverse width increase in the tooth-borne and bone-borne expander groups, respectively. Similarly, 26% and 68% of the total expansion was of skeletal nature in the tooth-borne and bone-borne expander groups between the maxillary first molars. The pattern of expansion was variable, with most of the patients in both groups demonstrating a triangular-shaped sutural opening that was wider anteriorly. Subjects in the conventional group experienced significantly more buccal bone reduction and greater buccal inclination of the teeth. No significant differences were observed for root length measurements between the two groups.

Conclusion:: Use of bone-borne expansion in the adolescent population increased the extent of skeletal changes in the range of 1.5 to 2.8 times that of tooth-borne expansion and did not result in any dental side effects.

Keywords: Dentoskeletal changes; Hyrax; Miniscrew-supported expansion; RME.

Figure 1.

Pre- (a) and postexpansion (b) occlusal photographs of a patient from the miniscrew-supported (bone-borne) RME group. Pre- (c) and postexpansion (d) occlusal photographs of a patient from the conventional RME group.

Figure 2.

Nasal cavity width measurement performed on the nasal floor between the maxillary first premolars (NCWP) and maxillary first molars (NCWM).

Figure 3.

The widest intercortical distance of the incisive foramen as measured perpendicular to the intermaxillary suture (IFW). Intermaxillary suture width measured between the right and left cortical border at the anteroposterior position of maxillary first premolars (SWP) and first molars (SWM).

Figure 4.

Buccal width measurements obtained at the level of the maxillary first premolar bifurcation (PBW) and maxillary first molar trifurcation (MBW). Buccolingual inclinations of the maxillary first premolars (PBLI) and first molars (MBLI) measured using the inclinations of the buccal and mesiobuccal roots, respectively, to the horizontal plane projected from the nasal floor.

Figure 5.

Individual length measurements made for maxillary first premolar buccal (PBRL) and lingual (PLRL), and maxillary first molar mesial-buccal (MMBRL), distal-buccal (MDBRL), and palatal (MPRL) roots from the cusp tip to the apex.