| Objective To measure the related indicators of neonatal mandibular.On the one hand,it provides basic data for the study of mandibular position and morphology of normal newborns;On the other hand,it can provide data support for the diagnose,evaluation,and treatment of Pierre Robin sequence.Methods The first step,we collected the CT data of normal neonates at Nanjing Children’s Hospital Affiliated to Nanjing Medical University from January 2013 to January 2019.The date must include maxilla and mandible,and neonates have no craniomaxillofacial related malformation.The data were exported in DICOM format.In the second step the data were imported into the MIMICS 21.0 to reconstruct the data in a three-dimensional model,then the model is used to measure the measurement items.Specific measurement items:(1)Measurement angle α: The CT data of the child was read by the software and reconstructed in 3D model.We observe the 3D model,to find the left and right gonion(LGo,RGo)and the menton(Me)were determined,and the angle measurement tool of the software was used to appoint Me as the apex,and the sides were separated by the gonion on both sides as angle α.(2)Measure the distance between the left and right gonion: Reuse the distance measurement tool of the software to measure the distance between the bilateral gonion as a.(3)Measure the distance from the Me to the line between LGo and RGo: Connect the LGo and RGo as line on the 3D model,then measure the distance between Me and line as b.(4)Measure Upper and lower jaw distance: Find the median sagittal view and measure the distance c between the foremost point of the upper jaw and the foremost point of the lower jaw.The measurement results were imported into the SPSS software for statistical analysis.Results Specific measurement results:(1)angle α: 86.34 ± 8.58 °.(2)distance a: 63.63 ± 6.83 mm.(3)distance b: 31.99 ± 3.70 mm.(4)distance c: 2.28 ± 1.04 mm.Among all the indicators above,there was no statistical difference in gender factors.Conclusions In this study,132 neonates were collected and 117 patients Meet the inclusion criteria.There were 69 males and 48 females.The indicators α,a,b,and c have no statistically differences between the male and female,so they were combined to obtain the normal reference value: angle α: 86.34±8.58°;distance a: 63.63 ± 6.83 mm;distance b: 31.99±3.70mm;distance c: 2.28 ± 1.04 mm. |
