Study On Forensic Identification For Digital Panoramic Tomography Of Chinese Group Finished Replacing Of Dentes Permanentes For Dentes Decidui

ObjectivesThis study is for the purpose of discussing of maxillary tooth image characters in the digital panoramic tomography of Chinese group who have finished the replacing of dentes permanentes for dentes decidui, improving and perfecting forensic odontology individual identification system, satisfying the needs of individual identification according to odontology in actual forensic medicine practices, and especially being able to provide a kind of basic theory with narrow logic and precise consequence and a sort of easy and convenient, rapid and effective, low-cost and feasible relatively method of forensic odontology individual identification for the corpse with it's name not being found, the broken body in the case, the bones of the dead, and people died in the mass disasters . The main purposes of this study can be concluded as:1. To define the observed indexes for forensic identification of the maxillary tooth image in the digital panoramic tomography of Chinese group who have finished the replacing of dentes permanentes for dentes decidui.2. To observe the distributing probabilities of the observed indexes in Chinese group who have finished the replacing of dentes permanentes for dentes decidui.3. To observe the coefficient of variation(CV)of the data from each observed index, and verify the identification capability of every observed index.4. To establish a method of individual identification for the digital panoramic tomography of Chinese group who have finished the replacing of dentes permanentes for dentes decidui.5. To establish an initial basic databank of the observed indexes in the digital panoramic tomography of Chinese group who have finished the replacing of dentes permanentes for dentes decidui.6. To provide a kind of theory with narrow logic and precise consequence and a sort of easy and convenient, rapid and effective, low-cost and feasible relatively method of forensic odontology individual identification for actual forensic medicine practices.MethodsCollect 120 digital panoramic tomographies of Chinese group who have finished the replacing of dentes permanentes for dentes decidui according to the including criteria. 14 maxillary teeth images in each of these 120 digital panoramic tomographies have been accurately measured and analyzed. And 10 observed indexes including 5 length indexes and 5 angle indexes have been selected for every maxillary tooth image. All of the observed indexes are measured by the software of efilm Workstation 2.1, and all of the datum from the observed indexes are disposed, counted and analyzed by the softwares of Microsoft Office Excel 2003 and the SPSS 13.0. In order to observe the effect of different surveyors'measuring and different shooting time, all of the datum from all observed indexes are analyzed statistically. Calculat the matching probability of two digital panoramic tomographies from the same body. Calculate the total probability of discrimination power(TDP)of all the useable observed indexes with the formular of TDP.Results1. The distributing probabilities of most datum from the observed indexes in Chinese group who have finished the replacing of dentes permanentes for dentes decidui are different. And 99.166 7% is the maximal probability, while the distributing probabilities of some datum from certain observed indexes in some divided and evaluated sections are rather low, and even 0.2. The CV of each observed index's data is not the same thing. That of the observed index S415 is maximal, 516.098 8%, andθ216 minimal , 3.116 73%.3. The statistics test results of the datum from 21 observed indexes , including S116, are provided with statistics significance and are not adapt to forensic individual identification and weeded with taking both of the factors of different surveyors'measuring and different shooting time into account, however, those of the rest of 95 observed indexes show that the factors of different surveyors'measuring and different shooting time can not affect the datum clearly.4. The matching probabilities of the sections which are divided and evaluated manually for two digital panoramic tomographies from the same body are different: the maximal one belongs to No.27353(女), is 98.947 368 42%, while the minimal is of No.025(男), is 89.473 684 21%;but all of them are higher than 89.473 684 21%. And the maximal matching probability of divided and evaluated section for two digital panoramic tomographies from different bodys is only 61.052 631 58%,much lower than 89.473 684 21%.5. The TDP of 95 observed indexes can reach 1030-1050.6. The probability of identification for 6 digital panoramic tomographies in the blind study among 30 achieves 100%, and the result is very satisfying.Conclusions1. The length index whose data is rather small is not adapt to being selected when you select length indexes observed. 2. The distributing probability of the data from each observed index of each tooth image in the different divided and evaluated section for Chinese group who have finished the replacing of dentes permanentes for dentes decidui are different.3. The CV of each observed index's data is not the same thing, and the DP of each observed index varies from one to another, also.4. The statistics test results of the datum from 21 observed indexes , including S116, are provided with statistics significance and not adapt to forensic individual identification and weeded because they are affected markedly by the factors of different surveyors'measuring and different shooting time, While the datum of the rest of 95 observed indexes are affected rarely by different researchers'measuring and different shooting time, are steady-going when measuring is repeated, and are adapt to forensic individual identification.5. Here are two methods for forensic individual identification for the digital panoramic tomography of Chinese group who have finished the replacing of dentes permanentes for dentes decidui. One is the method of matching probability of divided and evaluated sections, the other is the method of TDP of all the rest observed indexes.6. An initial basic databank of the observed indexes in the digital panoramic tomography of Chinese group who have finished the replacing of dentes permanentes for dentes decidui has been established.