The three-dimensional characteristic of mandibular growth in children with mixed dentition
1.Department of Orthodontic, Hospital of Stomatology, Wenzhou Medical University, Wenzhou, 325027; 2.Department of Stomatology, Yuxi Hospital of Traditional Chinese Medicine, Yuxi, 653100; 3.Department of Orthodontic, Hospital of Stomatology, Nanjing Medical University, Nanjing, 210029
PAN Sisi1,WANG Xin2,DAI Weiwei1, et al. The three-dimensional characteristic of mandibular growth in children with mixed dentition[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2014, 44(10): 712-717.
Abstract：Objective: To analyze the three-dimensional characteristics of mandibular growth of the children with mixed dentition by Cone Beam Computed Tomography and discuss the whole trend of mandibular growth. Methods: Cone Beam Computed Tomography scans were performed in 140 subjects from 6 to 12 years old with mixed dentition. CT images were constructed into 3D model using medical image processing software Dolphin Imaging 11.0. Fifteen linear and six angular measurements including mandibular length, mandibular width, etc, were positioned through MPR method and analyzed by SPSS 17.0. Results: Transverse comparison in 6~8 years old for early age group of 60 cases with 9~12 years old for late age group of 80 cases, the measured values were significantly increased in the late age group, including the left mandibular length [(7.29±0.7) mm], the right mandibular length [(8.00±0.9) mm], the condyle spacing [(3.29±0.8) mm], coronoid spacing [(4.76±0.7) mm], sigmoid notch spacing [(5.11±0.6) mm], mandibular angle spacing [(4.83±0.7) mm], mental foramen spacing [(1.65±0.4) mm], mental foramen mesial buccal point spacing [(1.16±0.4) mm], mental foramen distal buccal point spacing [(2.39±0.4) mm], mental foramen distal tongue point spacing [(1.42±0.6) mm], the left corpus length [(5.80±0.8) mm], the right corpus length [(6.95±0.7) mm], the left ramus height [(4.40±0.5) mm], the right ramus height [(4.33±0.6) mm], left mandibular angle [(3.75±0.4) º], right mandibular angle [(5.18±0.3) º], condylar strength [(0.62±0.28) º], coracoid strength [(0.68±0.3) º] and sigmoid notch strength [(0.59±0.27) º] significantly (P<0.05). The inner side of mental foramen mesial almost unchanged and mandibular angle strength increased [(0.32±0.4) º], both had no significant difference (P>0.05). Conclusion: Mandibular dimensions are increased in the late age group (except mental foramen mesial tongue point width), the increase in different parts of mandibular are different. The change of mandibular width from the former show a trend of increase, mandibular width of mental foramen area in nearly increase is mainly caused by bone hyperplasia in the outside of mandibular. The trend of mandibular growth is downward, forward and outward.
