Published online Feb 26, 2023. doi: 10.12998/wjcc.v11.i6.1299
Peer-review started: October 21, 2022
First decision: December 13, 2022
Revised: January 3, 2023
Accepted: February 8, 2023
Article in press: February 8, 2023
Published online: February 26, 2023
Processing time: 126 Days and 5.9 Hours
Mandibular retraction is the main etiological mechanism of class II malocclusion in China and the subsequent distal molar relationship can cause functional discomfort in mastication, breathing and the temporomandibular joint. The use of mandibular advancement (MA) devices has recently emerged as an adolescent mandibular retraction treatment; however, current studies regarding the effect thereof are relatively few, and there is lack of sufficient clinical support.
To investigate the clinical effect of invisalign MA on the treatment of mandibular retraction in adolescents.
This study included 30 adolescent patients who underwent treatment with the MA appliances from December 2017 to June 2021. The lateral cephalometric data before and after treatment were collected and imported into Dolphin Imaging software. The changes were measured by linear measurement superimposed with lateral cephalometric trajectory based on the Pancherz technology.
There was no significant difference in the length and position of maxilla before and after the treatment. The position of the mandible moved 3.13 mm, the length increased 4.14 mm, the mandibular ramus length increased 4.09 mm, the body length increased 4.25 mm, and the position of the condyle moved 1.03 mm forward after treatment. Additionally, changes in the incisor sagittal position and labial inclination were observed. The position of the upper incisor point moved back 1.33 mm, without statistical difference, the inclination and tooth angle decreased by 3.44° and 4.06°, respectively; the position of the lower incisor point was moved 2.98 mm, and the inclination and tooth angle increased by 2.62° and 1.23°, respectively. Furthermore, changes in the incisor overjet and molar relationship were seen. Overjet decreased by 4.31 mm, of which 1.78 mm was due to dental factors, accounting for 41.3% of the effect as opposed to 58.7% due to skeletal factors. Molar relationship improved 3.87 mm, with 1.34 mm due to dental factors, and dental and skeletal factors were accounted for 34.6% and 65.4% of the effect, respectively.
For adolescent patients with mandible retraction, invisalign MA can effectively promote the mandible growth, and it was proven to be mainly due to skeletal effects.
Core Tip: This study aimed to investigate the clinical effect of invisalign mandibular advancement (MA) in the treatment of mandibular retraction in adolescents. In addition to the conventional cephalometric analysis method, Pancherz analysis was used to separate the skeletal and dental effects. The results of this study show that invisalign MA can effectively promote the adolescent mandible growth, improve the incisor overjet and molar relationship, and it was proven to be mainly due to skeletal effects.