Clinical Efficacy Analysis Of Maxillary Microimplant Assisted Rapid Palatal Expansion Combined With Protraction In Skeletal Class Ⅲ Patients Of Different Ages

Objective To perform microimplant assisted rapid palatal expansion(MARPE)combined with facemask(FM)in skeletal Class Ⅲ patients and to compare and analyze the skeletal,dental and soft tissue changes in patients of different ages.The clinical outcomes of hyrax/FM and MARPE/FM were also compared.Methods Thirty-five cases(14 males,21 females)of skeletal Class Ⅲ patients with mean age(range from)were selected for this study from 2018 to 2023 at YaBoyi Dental Clinic.26 cases applied MARPE/FM treatment(aged 16.67±5.27 years,ranged from 11.0 to 28.49 years),and patients were divided into 4 groups:early adolescence(11-14 years),late adolescence(15-19 years),and adulthood(20-29 years).The other 9 patients applied hyrax/FM(11-14 years,mean age).Cephalometric lateral radiographs were taken before(T1)and after(T2)treatment for measurement and analysis of skeletal,dental and soft tissue indices.Statistical analysis was performed using SPSS software(version 25.0;IBM,Armon,NY).Results(1)Clinical changes of MARPE/FM treatment in patients of different ages1.skeletal changesSagittally,the amount of change in SNA was 1.35°,0.90°and 0.67° at different age group,respectively;the amount of change in A-VRP was 2.94 mm,1.61 mm and 0.73 mm,respectively.The amount of anterior displacement of the maxilla was smaller in adult patients aged 20-28 years compared with patients aged 11-15 years(A-VRP,P<0.01).There was no significant displacement of the mandible in patients aged 11-19 years,and the patients aged 20-28 years had a significant posterior shift of the mandible,which was significantly different than the other two groups(P<0.01).Vertically,there was a significant increase in mandibular length and lower facial vertical distance in the 11-14 year old group,but no significant posterior downward rotation of the mandible.However,there was no significant change in mandibular length,mandibular plane angle and facial vertical distance in the 15-19 year old group,except for a 0.49° decrease in SNB;The 20-28 year old group had a significant posterior downward rotation of the mandible and increasement in vertical distance.The ANB and Wits were improved in all groups with no statistically significant differences between the three groups.2.Dental changesThe actual mesial movement of the maxillary first molars increased by 1.09±1.25mm in the 11-14 year old group,but there was no obvious movement of the maxillary first molars in the other two groups,and no obvious extrusion of the maxillary first molars in the three groups(PP-SN,P<0.05).There was no significant change of overbite in all three groups,but the negative overjet was significantly corrected in all three groups.There were no statistical differences in dental changes among patients in the three age groups.3.soft tissue changesOnly patients<20 years old got a significant anterior movement of soft tissue A points.The chin was significantly posteriorly shifted in adult patients.The soft tissue A point anterior shift was smaller in the≥20 years old adult group than in the other two groups,and the soft tissue B and Pog points posterior shift was significantly larger than in the other two groups,with no significant difference between the two adolescent groups.(2)Comparison of the efficacy of MARPE/FM and Hyrax/FM in skeletal Class Ⅲ patients aged 11-14 yearsThe amount of increasement in SNA and A-VRP in the Hyrax/FM group was 1.67° and 3.51 mm,respectively,and the ANS moved forward and downward.The maxillary first molars had a extrusion of 2.14 mm and mesial displacement of 1.34mm.Skeletal effects,intermaxillary relationship adjustment,upper and lower anterior tooth inclination and soft tissue were similar in the MARPE/FM group compared to the Hyrax/FM group,with no differences found between the groups(P>0.05).The Hyrax/FM group showed a greater increase in mandibular length,maxillary first molar extrusion and vertical downward facial height compared to the MARPE/FM group.Conclusion1.Used from adolescents to adults,MARPE/FM produces significant skeletal effects,avoids dental side effects,and improves soft tissue lateral appearance.2.The effect of maxillary protraction with MARPE/FM treatment decreased with increasing age,and mandibular clockwise rotation and vertical face height increased.3.Similar skeletal effects were observed in early adolescent patients treated with MARPE/FM and Hyrax/FM.Better control of maxillary first molar extrusion and vertical face height was achieved with MARPE/FM compared to Hyrax/FM.