| Objective:Ricketts analysis is an analysis method proposed by Ricketts for the relationship among teeth,jaws and soft tissues.It can predict the direction and amount of facial growth and development,make treatment plans and predict treatment outcomes.Discrepancy index(DI)was used to quantify the complexity of malocclusion and evaluate the treatment effect by measuring 12 measurement indexes including dental plaster casts,panoramic radiographs and lateral cephalograms.The aim of this study is to evaluate the early treatment effect of maxillary protraction during growth and development using Ricketts analysis and asymmetry index.Methods:26 children who attended the Department of Pediatric Dentistry at Jilin University Stomatology Hospital from 2019 to 2022,were at peak or pre-growth and were diagnosed with a skeletal Class Ⅲ were selected for the study.Cephalometric analysis and growth prediction were performed on the lateral cephalometric films of the patients before and after orthodontic treatment,and the DI index score was performed on 13 of the cases with intact plaster models hosted.The pre-correction,post-correction and growth prediction measurements and each score are marked as T0,T1 and T’,respectively.The efficacy of maxillary protraction was evaluated using SPSS 27.0 for comparative analysis of T’,T1 and T0,T1,respectively.Results:1.After orthodontic treatment the maxillary parameters A-NPog(P1<0.001,P2<0.001),FH-NA(P1=0.001)and SNA(P1<0.001)increased significantly.FH-PP decreased(P1=0.042,P2=0.007).2.Mandibular parameters ANS-Xi-Pm(P1=0.014),FH-MP(P1=0.006,P2=0.011)and SN-MP(P1=0.018)increased.FH-NPog(P1=0.010,P2<0.001),NBa-Pt Gn(P1=0.018,P2<0.001),Dc-Xi-Pm(P1=0.002,P2=0.002)and SNB(P1<0.001)significantly reduced.3.ANB(P1 < 0.001)was significantly greater.4.OJ(P1 < 0.001,P2 < 0.001)increased,UI-APog(mm)and UI-APog(°)increased(P1 < 0.001,P2 < 0.001).LI-APog(mm)(P1 < 0.001,P2 = 0.001)and LI-APog(°)decreased(P1 = 0.002,P2 = 0.025).UI-LI(P1 < 0.001,P2<0.001)decreased.5.The soft tissue parameter LL-EP(P1=0.006,P2=0.006)significantly increased.6.DI scores for OJ(P < 0.001),crowding(P < 0.001),occlusion(P < 0.001)and lingual posterior crossbite(P < 0.001)scores significantly decreased.Lateral open bite(P =0.044)scores increased.No statistically significant changes in ANB,SN-MP and IMPA scores;total DI scores decreased by 11.31 points(p<0.001).Conclusions:1.After rapid maxillary expansion combined with face mask protraction in skeletal Class Ⅲ patients at the peak of growth,the growth of the maxilla is facilitated by the forward movement,the forward growth of the mandible is inhibited,the sagittal relationship of the jaws is significantly improved.96.2% of the patients had labial inclination of the upper anterior teeth and 84.6% of the patients had lingual inclination of the lower anterior teeth.The crossbite of the anterior teeth was corrected,normal overjet and overbite were obtained,the mesial relationship of the posterior teeth was improved.And the concave soft tissue profile was significantly improved.2.After rapid maxillary expansion combined with face mask protraction,the maxilla rotated counterclockwise and the mandible rotated clockwise.65.4% of the patients had increased lower height.3.Rapid maxillary expansion can correct posterior teeth crossbite,obtain space for patients with dentition crowding in mixed dentition,and simplify secondary orthodontic treatment.4.DI can be used in the scoring items to rate the outcome of RME/FM in skeletal Class Ⅲ patients. |
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