The Study Of Three-Dimensional Cephalometric Measurement And Analysis Of Hard Tissue In Skeletal Malocclusion Patients

Purpose:(1)Through Three-dimensional reconstruction of13cases CT data of the patients underwent orthognathic surgery in the hospital from2009to2012, to master the method of a three-dimensional reconstruction of Cranial facial hard tissues. Using Multiplanar Reformation (MPR) and Surface Rendering (SRS) technology to establish a set of easy to master, and the high degree of Repeatability3D measurement of craniofacial method. Two researchers mark the same13patients’ CT(including Preoperative and postoperative) repeated for different three time. and use statistical analysis in coordinate values to evaluate the landmarks repeatability and stability.(3) By customizing the " Malocclusion analysis " and conforming to it. we made the maxillofacial three-dimensional measurement and evaluation and two-dimensional measurement and evaluation respectively.besides, we make a comparison between the three-dimensional evaluation methods and the traditional two-dimensional cephalometric method to illustrate the superiority of three-dimensional measurement method.Methods:(1)We analyzed the patient’s (Ranging in age from19to33.9male among them. Average age of23years old, and4female. Average age of26years old) CT dates (save by DICOM format) who underwent orthognathic surgery in Affiliated Stomatological Hospital of Guangxi Medical University for skeletal Deformity from2008to2012and Met the requirements of this study, and made hard tissue of patients with three-dimensional reconstructed by MINICS software (version10.1).(2)Though the study and mark of Preoperative and postoperative CT dates including cephalometric and lateral radiographs of patients who with skeletal Deformity and undergo the Orthognathic surgery in Affiliated Stomatological Hospital of Guangxi Medical University in the past5year. We developed27three-dimensional positioning requirements of hard tissue markers, CT-shooting image dot (ie, the space in the CT probe the lower left corner) for the Centre Point. Then Using Minics (version10.1) software to complete the establishment of three-dimensional coordinate point for three times. And Marking and measuring established indicators by two researchers at different times on the same patient data. Besides, we Making ICC (Intra Class Correlation) analysize during the researchers, in order to evaluate the reproducibility of the calibration points.(3)By Using MIMICS software、customizing the " Malocclusion analysis " and conforming to it, we measured the established indicators from26CT data in different time, concluded that rangeability of each index Preoperative and postoperative. By Using CASSOS Software to make positive and lateral Cephalometric Analysis. And using "Malocclusion analysis" analysis method to evaluate the changes in amplitude of indicators before and after orthognathic surgery. Obtained and calculate the correlation coefficient, finally making Comparison between three-dimensional measurement and evaluation system and two-dimensional measurement and evaluation system.Result:(1) We succeed in reconstructing Three-dimensional model of the craniofacial based on CT data in patients with CD. The model resolution meet the basic requirements for clinical diagnose and research.(2) Calibration marked successfully by using Multiplanar Reformation (MPR) and Surface Rendering (SR) technology. All signs point repeatability are believable.(P>0.05), intra class correlation=0.925, Inter class correlation=0.923。(3) In addition to (∠SNA)、(ANS-N)、(Rh-ANS)、(ANS-Me/N-Me)、(Co-Go/Ag-Me)、(CoL-CoR)、(N-Pg)、(Go-S/N-Me)、(U6L-U6R/L6L-L6R)、(ZL1-FH), Other parameters differences were statistically significant (P<0.05).Conclusion:(1) We succeed in reconstructing Three-dimensional model of the craniofacial based on CT data in patients with CD. Used PC to complete the work that needs for large workstations to complete in the past.The model resolution meet the basic requirements for clinical diagnose and research.(2) Calibration marked successfully by using Multiplanar Reformation (MPR) and Surface Rendering (SR) technology. All signs point repeatability are believable. Repeatedly designated the difference between lmm to meet the need for clinical diagnosis;(3) Three-dimensional reconstruction with high repeatability, the visualization of the simulation maps can be very convenient designated, Three-dimensional measurements are more convenient and repeatable,Not easily interferenced by The surrounding tissue than Two-dimensional measurements. and be suitable for use in the clinical work.