Study on soft tissue changes of angle class Ⅱ division Ⅰ mandibular retraction patients during mixed dental period with MRC functional correction / 口腔疾病防治

ABSTRACT

Objective @#To observe the changes of soft tissue in patients with Angle class Ⅱ division Ⅰ malocclusion during mixed dentition treated with MRC functional appliance.@* Methods @# Twenty patients with Class Ⅱ division Ⅰ malocclusion of Angle were treated with functional MRC. The facial features before and after treatment were measured by software and the results were analyzed statistically. @*Results@#The patients′soft tissue profiles were improved significantly before and after treatment, The OE-Prn-Pos angle, OE-N′-B′ angle, OE-N′-Pos angle, OE-Prn-N′angle, Cm-Sn-UL angle, and N′-Sn-Pos angle increased significantly (P < 0.05). The OE-Sn-UL angle, and Sn-N′-B′ angle decreased significantly (P < 0.05); the distance between the lateral soft tissue line and the middle Sn-H line, UL-E line and LL-E line were significantly different (P < 0.05). The distances were all reduced, and the difference was statistically significant (P < 0.05).@* Conclusion @#The application of an MRC functional appliance can improve the relationship among nasolabial soft tissue, upper and lower lip soft tissue, and chin-lip soft tissue, thus improving the protrusion profile of patients.