| ObjectivesObjectives: To explore the three-dimensional characteristic differences of the cranial-facial and dental arch in children with different types of malocclusion in the mixed dentition stage.MethodsMethods: 180 subjects aged 8 to 12 years old were selected from the Department of pediatric dentistry in Stomatological Hospital of Chongqing Medical University,and they were assigned to three groups: class I relation group(60 cases),class II malocclusion group(60 cases)and the class III malocclusion group(60 cases).The comparative analysis of the 3D data from cephalometric and digital model measurements between groups was carried out.ResultsResults: The class II subjects presented smaller SNB angle(74.60±3.13 vs.77.33±3.74,P=0.00)and mandibular length(Cond-Pog)(90.20±4.72 vs.92.90±5.44,P=0.00),larger SNA angle(81.42±3.13 vs.79.77±5.39,P=0.03),Y axis angle(67.45±3.99 vs.64.72±6.82,P=0.00)and inferior front tooth inclination(IMand-ML)(96.93±5.48 vs.93.13±6.53,P=0.00)than the class I group.The upper posterior maxillary width(UPMW)(31.17±2.33 vs.32.36±5.19,P=0.07)in the class II group was narrower than the class III group.The class III subjects showed a decrement in the SNA angle(76.00±4.21 vs.79.77±5.39,P=0.00),maxillary length(ANS-PNS)(38.53±3.63 vs.42.60±2.90,P=0.00),the upper total arch length(UTAL)(24.37±2.68 vs.25.68±2.24,P=0.00),anterior cranial base length(N-S)(57.12±3.05 vs.58.67±3.10,P=0.01),facial height(N-Me)(99.70±4.91 vs.101.77±5.78,P=0.03),Y-axis(62.50±4.22 vs.64.72±6.82,P=0.02),and the IMand-ML angle(85.17±6.81 vs.93.13±6.53,P=0.00)compared to the class I group.The class III malocclusion showed a more forward mandibular position(S-Co)(13.92±2.57 vs.15.15±2.79,P=0.01).ConclusionConclusions: The morphological features of the cranio-facial bone and dental arch are different between different types of malocclusions during the mixed-dentition period.The main clinical manifestations for class II malocclusion are smaller mandibular length,lip tilted lower front teeth,and a narrowing UPMW,presenting a steeper or sharper palatal vault,and for the class III malocclusion are shorter maxillary length,N-S,UTAL and facial height,advanced mandibular position,and tongue tilted lower front teeth.The results provide reference for early identification and correction of skeletal and dental developmental abnormalities in children with malocclusion. |
