牙齿异常者颌面数字全景片同一认定指标及其编码

目的系统筛选颌面影像法医学同一认定的识别指标，制定全口牙型识别指标编码。方法随机选取620例有牙齿治疗史者、150例牙齿有病变无治疗史者的数字全口牙位曲面体层片进行观测，根据牙齿的生理变异、病理改变和治疗特征筛选全口牙型识别指标，并按设计的编码标准和原则对其全口牙型逐一编码，最后分别统计两组全口牙型的多样性以评估其价值。结果620例牙齿有治疗史者中共有619种全口牙型编码，全口牙型多样性为99．84％；150例牙齿有病变无治疗史者中共有146种全口牙型编码，全口牙型多样性为97．33％。结论选出的全口牙型识别指标对牙齿异常者进行法医学同一认定具有实际应用价值。     

颌面数字X线片的法医学同一认定

目的探讨颌面数字X线片(DigitalRadiology,DR)的全口牙型32位编码和测量6项骨性指标的变化特征,评估其在法医学同一认定的价值。方法随机选取颌面DR全景片300例,按设计的编码标准和原则对其全口牙型逐一编码,分析编码的多样性;随机选取颌面DR侧位片100例,由口腔放射科医生和培训过的法医研究生各一人对6项骨性指标(N-S,N-Me,Cd-Gn,Cd-Go,NP-SN,MP-SN)进行准确测量,计算指标的变异系数(CV),并对两人测量结果的一致性进行相关分析。结果(1)300例个人全口牙型编码,总体多样性为75%;牙齿有病变或治疗组的多样性为99.53%;(2)颌面DR侧位片中6项指标变异系数较大;(3)两次测量结果的相关系数均接近1,表明所选指标的测量结果稳定,有高度一致性。结论颌面DR全景片全口牙型32位编码和颌面DR侧位片中6项骨性指标可用于同一认定。     

X线头影侧位片同一认定指标的建立

目的探究口腔颌面X线头影侧位片的形态学分型,对识别指标进行数字编码,构建法医学同一认定体系。方法选取200例成年人口腔颌面的X线头影侧位片,通过SNA角、SNB角的相互关系及后面高与前面高比值,对颌面骨骼形态进行矢状向垂直向的综合分型,同时筛选出反映颌面特征的8个测量指标进行数字编码。结果依据矢状向、垂直向及8个测量指标构建的编码系统,其多样性较大,为99.5%。MP-FH和Y轴角的变异系数较大,同一认定价值较高。S-Ar-Go、Ar-Go-Me、MP-FH、1—-MP角、Y轴角、1—-SN角、1—-1—角各级别构成比间性别差异有统计学意义。结论利用头颅侧位片矢状向及垂直向分型并结合所选取的8项定量识别指标进行识别编码的方法,为法医同一认定提供了新思路。     

中国汉族成人颅骨CT片同一认定方法的研究

目的建立对中国汉族成人颅骨CT片进行同一认定的方法。方法按照纳入标准收集100例中国汉族成人颅骨CT片，对确定的识别指标进行观察和测量，对各指标的观测结果进行分类编码，然后按观测顺序编制特异的12位颅骨CT片识别编码。运用SPSS13．0统计学软件对所得数据进行各指标年龄和性别差异的统计学分析，利用个人识别能力公式计算单个指标和总体指标的个人识别能力。结果12项识别指标中有6个指标存在男女性别差异；12项指标累计个人识别能力可达到99．9997997％。结论本文确定中国汉族成人颅骨CT片12项观测指标，利用指标分类编码法可进行中国汉族成人颅骨CT片的同一认定。     

医学影像资料法医学同一认定30例分析

目的探讨医学影像资料法医学同一认定的鉴定原则、思路及方法。方法总结华西法医学鉴定中心1992—2012年受理的30例医学影像资料同一认定案例,对影像资料数量、种类,鉴定利用的识别点及其类型、间隔进行回顾性统计分析。结果胸部X线片为最常见的鉴定资料类型。利用的识别点共有33处、6种类型,包括：自身惟一性特征、骨骼自身结构的变异或发育畸形、疾病或退行性变、创伤后病理变化、医疗后果和正常形态的多处一致。结论影像资料常规审查是案件受理前提之一,同一认定时结合资料类型、投照部位及案情特点选择相应识别点,自身惟一性识别点最佳,多种类型识别点联合使用,识别点多处表现一致得出肯定结论者可应用于鉴定实践。     

利用腭皱特征进行同一认定的指标体系构建

目的根据腭皱的形态图特征,进行口腔腭皱在法医学同一认定的指标体系构建。方法收集100例成年人腭皱模型,依据腭皱的形状、数量、位置分布等特征对腭皱形态图进行全面系统的编码。编码顺序采用英文字母按照先右侧再左侧,先前部再后部的顺序编码,并且右、左侧编码以破折号连接。最后依据编码,统计分析腭皱形态分布特征。结果 100例腭皱形态图中,个体间未见完全一致者,每个个体不论男性与女性均表现有独特的腭皱形态图;且同一个体左右侧单条腭皱的形态及分布亦不同。波浪形腭皱所占比例最大（23.03%）,三分叉形出现比例最小（0.74%）,不同性别的波浪形及曲线形腭皱所占比例均较大,女性波浪形（22.7%）及曲线形（18.28%）;男性波浪形（24.11%）及曲线形（21.43%）。结论口腔腭皱法医学同一认定的指标体系构建,将为法医学的同一认定提供一种新的方法。     

人牙咬痕同一认定数字化分析的盲法评定

目的评定人牙咬痕同一认定数字化分析方法的精确性。方法 采用数字化分析法对人牙咬痕及8名“疑犯”牙列模型进行双盲法分析实验,用Photoshop 5.5将获得的咬痕扫描图像生成overlay,用AutoCAD Rl4工程测量软件分析各项参数,比较人牙咬痕和“疑犯”牙列参数的匹配性。结果人牙咬痕及“疑犯”牙列模型数据化分析的各项参数分析结果一致。结论对于试验性咬痕,数字化分析是一种可行的认定方法,对法医学实践具有可行性及良好的应用前景。     

根据数字全颌曲面断层片进行个体识别研究

目的建立中国恒乳牙交替完全人群数字全颌曲面断层片的同一认定方法。方法对120例中国恒乳牙交替完全人群的数字全颌曲面断层片进行测量和分析,对每颗牙齿的影像分别选取5个长度性指标和5个角度性指标,运用efilm workstation 2.1软件进行测量,SPSS 13.0软件对数据进行处理和统计。结果各观测指标的测量值在分段赋值区段里的分布概率有所不同,最大可达99.166 7%。两张同源数字全颌曲面断层片之间的分段赋值匹配概率最高为98.947 368 42%,最低为89.473 684 21%。结论所建立分段赋值匹配概率同一认定法经盲测验证,效果较好,该方法可为个体识别提供参考。     

耳廓的同一认定研究

目的研究耳廓观测指标的变化特征,提出利用耳廓特征识别点进行个体同一认定的研究方法,为法医学个体识别,及对视频图片中的个体进行同一认定,提供一种科学、准确、简便易行的方法。方法通过对19岁至22岁的汉族成人拍摄耳廓侧位图像,选取148人照片中的相应指标进行观测,数据收集,经SPSS统计软件处理,分析各种因素对测量结果的影响,计算出各指标识别能力及两批照片各指标之间的差值,最终得出各指标差值的参考值范围。结果 10项观测指标经统计检验分析,最终保留6项指标,重复测量结果稳定。各指标的变异系数相差不大,结果稳定可靠。结论通过制定6项观测指标差值的参考范围,确定指标是否同一,最终认定照片中耳廓是否属于同一个体的方法准确可行。     

颅脑CT片同一认定初探

法医学是一门应用医学,它随着基础医学及临床医学的发展而发展,同时又对后二者起着一定的导向作用.近年来,电子计算机体层摄影,(Computed tomography,CT)作为一种临床诊断新技术已在国内不断地普及、推广,因而对两张或两张以上的CT片进行同一认定(个人识别)已作为     

The diversity of dental patterns in the orthopantomography and its significance in human identification

The primary aim of this study was to evaluate the utility of orthopantomography for human identification. Three hundred orthopantomograms were randomly selected from those stored at Dental Hospital of Yonsei University in Seoul. Dental patterns observed in the orthopantomograms were converted into eight codes and their diversity was calculated. The diversity of dental patterns in the orthopantomogram data was 99.92% for full dentition and the diversity of mandible (99.28%) was slightly higher value than that of maxilla (98.22%). In the case of molars and premolars in both jaws, the diversity values ranged from 92.13% to 96.04%. It was founded that orthopantomography is a valuable means of personal identification not only based on full dentition but also when only the posterior teeth are available. The present study indicates that orthopantomography is excellent means of forensic identification.     

中国汉族6-18周岁男性牙齿生长发育的年龄研究

目的研究牙齿钙化程度与年龄的关系,建立利用牙齿钙化程度推断中国汉族6～18周岁男性年龄的办程。方法通过对6568名6～18周岁汉族男性全口曲面断层影像上牙齿的钙化程度进行评分;将分级值及其对应年龄输入SPSS软件进行分析,建立推断年龄的方程模型;从研究样本外随机抽取已知年龄的样本160例进行卣测,,结果同名牙齿钙化评分值侧别间秩合检验结果P〉0．05;下颌左侧恒牙钙化评分值与年龄相关分析结果r值均存0．7以上,下颌同名牙间相关系数r均在0．9以上;所建回归模型拟合优度R^2=0．828,估计值标准误为1．23岁;阿测平均洪差为0．423±0．269岁。结论本研究所建立的方法准确可靠,可用于中国汉族6～18周岁男性人群的年龄推断。     

Root Morphology and Anatomical Patterns in Forensic Dental Identification: A Comparison of Computer‐Aided Identification with Traditional Forensic Dental Identification*

Abstract: An online forensic dental identification exercise was conducted involving 24 antemortem–postmortem (AM–PM) dental radiograph pairs from actual forensic identification cases. Images had been digitally cropped to remove coronal tooth structure and dental restorations. Volunteer forensic odontologists were passively recruited to compare the AM–PM dental radiographs online and conclude identification status using the guidelines for identification from the American Board of Forensic Odontology. The mean accuracy rate for identification was 86.0% (standard deviation 9.2%). The same radiograph pairs were compared using a digital imaging software algorithm, which generated a normalized coefficient of similarity for each pair. Twenty of the radiograph pairs generated a mean accuracy of 85.0%. Four of the pairs could not be used to generate a coefficient of similarity. Receiver operator curve and area under the curve statistical analysis confirmed good discrimination abilities of both methods (online exercise = 0.978; UT‐ID index = 0.923) and Spearman’s rank correlation coefficient analysis (0.683) indicated good correlation between the results of both methods. Computer‐aided dental identification allows for an objective comparison of AM–PM radiographs and can be a useful tool to support a forensic dental identification conclusion.     

Ultraviolet illumination as an adjunctive aid in dental inspection

Tooth-colored resin fillings have become increasingly popular as restorative materials. Their presence in the dentition presents a challenge to the clinician and the forensic odontologist, as detection of the fillings can be difficult both visually and radiographically. As they necessarily form part of the unique dentition of an individual, recognition of the resins is important for forensic identification. Alternative light sources have been used with success in various fields of forensic science. In recent years small LED flashlights emitting at specific wavelengths in the ultraviolet light (UV) range have been developed. Their low cost, small size, and ready availability makes their use practical in both forensic dental inspection and clinical settings. UV inspection is of interest because enamel, dentin and dental materials all have differing fluorescent properties when illuminated by UV light. It was one goal of this research to quantitatively assess the fluorescence properties of modern restorative resins in order to predict their behavior during inspection using UV illumination. The second goal was to demonstrate practical use of UV in dental inspection with examples of how different materials fluoresce. Quantitative measurements were obtained for optical emission wavelength and intensity for 15 modern resins using a spectrophotometer. Results indicated that resin brands fluoresce at different wavelengths and with varying intensities. Practical use and comparison of the flashlights revealed that the most useful excitation wavelengths for resin detection were in the UVA range (365 and 380 nm). Porcelain restorations and composite resin fillings exhibited different responses to these two wavelengths and thus use of both is recommended for forensic dental inspection.     

Positive Dental Identification Using Tooth Anatomy and Digital Superimposition

Dental identification of unknown human remains continues to be a relevant and reliable adjunct to forensic investigations. The advent of genomic and mitochondrial DNA procedures has not displaced the practical use of dental and related osseous structures remaining after destructive incidents that can render human remains unrecognizable, severely burned, and fragmented. The ability to conclusively identify victims of accident and homicide is based on the availability of antemortem records containing substantial and unambiguous proof of dental and related osseous characteristics. This case report documents the use of digital comparative analysis of antemortem dental models and postmortem dentition, to determine a dental identification. Images of dental models were digitally analyzed using Adobe Photoshop^TM software. Individual tooth anatomy was compared between the antemortem and postmortem images. Digital superimposition techniques were also used for the comparison. With the absence of antemortem radiographs, this method proved useful to reach a positive identification in this case.     

Antemortem dental records: attitudes and practices of forensic dentists

This study was designed to provide insight concerning the attitudes and practices of forensic dentists regarding antemortem dental records reviewed for purposes of dental identification. Forensic dentists were invited to participate in a 10 item survey. The majority of the respondents reported a considerable amount of experience in dental identifications of the deceased. Sixty-six percent reported having suspected dental negligence or fraud in their antemortem record reviews. Only 17% believe that a forensic dentist should report suspected dental negligence, while 31% agree that dental fraud should be reported. Their response to additional issues addressed in the study suggests diversity in the practices and attitudes of forensic dentists in the use of antemortem dental records. In conclusion, opening a dialogue among practicing forensic dentists may lead to a standardized set of recommendations by the appropriate societies in the forensic dental community.     

Identification through X-ray fluorescence analysis of dental restorative resin materials: a comprehensive study of noncremated, cremated, and processed-cremated individuals

Tooth-colored restorative materials are increasingly being placed in the practice of modern dentistry, replacing traditional materials such as amalgam. Many restorative resins have distinct elemental compositions that allow identification of brand. Not only are resins classifiable by elemental content, but they also survive extreme conditions such as cremation. This is of significance to the forensic odontologist because resin uniqueness adds another level of certainty in victim identification, especially when traditional means are exhausted. In this three-part study, unique combinations of resins were placed in six human cadavers (total 70 restorations). Simulated ante-mortem dental records were created. In a blind experiment, a portable X-ray fluorescence (XRF) unit was used to locate and identify the resin brands placed in the dentition. The technique was successful in location and brand identification of 53 of the restorations, which was sufficient to enable positive victim identification among the study group. This part of the experiment demonstrated the utility of portable XRF in detection and analysis of restorative materials for victim identification in field or morgue settings. Identification of individuals after cremation is a more difficult task, as the dentition is altered by shrinkage and fragmentation, and may not be comparable with a dental chart. Identification of processed cremains is a much greater challenge, as comminution obliterates all structural relationships. Under both circumstances, it is the nonbiological artifacts that aid in identification. Restorative resin fillings can survive these conditions, and can still be named by brand utilizing elemental analysis. In a continuation of the study, the cadavers were cremated in a cremation retort under standard mortuary conditions. XRF was again used to analyze retrieved resins and to identify the individuals based on restorative materials known to exist from dental records. The cremains were then processed and the analysis was repeated to determine whether restorative resins could be found under this extreme condition. Under both circumstances, sufficient surviving resin material was found to distinguish positively each individual in the study group. This study showed the utility of XRF as an analytical tool for forensic odontology and also the significance of the role of restorative resins in victim identification, even after cremation.