Comparative characteristics of angulometric parameters of teeth and dentitions in terms of personal identification

Angulometric teleroentgenographic characteristics of teeth were compared for 158 subjects. A computer technology of calculation and assessment of 47 angular (quantitative) parameters characterizing spatial position of the teeth and jaws is proposed. This complex of parameters can be used as an additional test in personal identification.     

数字全口牙位曲面体层片的法医学同一认定指标

目的采用颌面全口牙位曲面体层片,针对牙齿无病变者筛选简洁实用的法医学同一认定识别指标并进行编码、统计分析及评估。方法随机选取170例牙齿无病变者的颌面数字全口牙位曲面体层片进行观测．根据牙齿的生理变异特征和牙齿的排列特征分别筛选全口牙型和牙列型识别指标。按设计的编码标准对全口牙型、牙列型逐一编码,统计分析编码的多样性,以评估两类识别指标的应用价值。结果170例中共有74种全口牙型编码,多样性为43．53％：170例中共有129种牙列型编码,多样性为75．88％;170例同时进行全口牙型和牙列型编码．则共有150种全口牙型／牙列型编码,多样性为88．24％。结论全口牙型编码多样性较低,单独使用尚不能满足法医学同一认定的要求。牙列型编码的多样性比较高,具有一定的法医学同一认定价值。如果同时进行全口牙型和牙列型编码,多样性明显提高,有较高的法医学同一认定价值。     

Rationale of identification based on biological factors of the dentition

Dental traits in the nature of form and size of fissures, cusps, and pits often reflect genetic and phylogenetic interactions in growth and development that are common to other individuals and serve a useful purpose in identification.     

Personal identification by radiographic comparison of vascular groove patterns of the calvarium

A case of forensic identification utilizing the vascular grooves within the skull is presented. The case is unique in that the antemortem radiographs were from childhood, rendering useless the more standard points of comparison. Calvarial vascular grooves represent unique points of comparison when the only available premortem radiographs were obtained during childhood, especially when one is attempting to identify children (living or dead).     

Personal identification from human remains by mitochondrial DNA sequencing

The authors report four cases in which severely damaged human remains were identified by mitochondrial DNA (mtDNA) sequencing. Degraded DNA was extracted from highly adipoceratous tissues using the phenol-chloroform method and polymerase chain reaction amplified for sequencing of two hypervariable regions, hypervariable region 1 and hypervariable region 2, of mitochondrial DNA. They also sequenced these regions of blood samples that were obtained from the presumptive mother or sister of the human remains. The sequencing results were compared with each other and with the Anderson's sequence. It was concluded from the sequence data that a lower part of a body in case 1 and some organs in case 2 were from the same woman, and a human head in case 3 and a female body in case 4 were from the relative of a presumptive mother and a sister, respectively.     

Postmortem pink teeth. Histochemical identification of the causative pigment

The phenomenon of postmortem pink teeth has been reported in subjects who have died suddenly and unnaturally, and whose bodies have been subsequently exposed to a wet or moist environment. Ground and EDTA-decalcified sections of teeth of 21 corpses exhibiting postmortem pink-stained teeth were investigated for the identification of the responsible pigment. With histochemical methods and ultraviolet microscopy, the causative pigment was identified as undegraded hemoglobin. Staining from hemosiderin, bile and bile-related pigments, and porphyrins was ruled out. However, histochemical techniques are unable to reveal the form in which the hemoglobin occurred. The cause of death or time of death had no observable effect on the staining reactions for hemoglobin in the teeth.     

Assignment of a bite-mark on the victim's skin to the dentition of the perpetrator by means of anomalies in the number and position of the frontal teeth

This report is about a bite mark on the breast of a female corpse. The woman had been killed by ligature strangulation at the age of 76 years. The investigation of the dental casts of a suspected man showed some anomalies in the dentition and orthodontic variations. A comparison of the bite mark with these anomalies demonstrated the correspondence of several details. Consequently, the probability that the suspect was responsible for the bite mark was regarded as being very high. During the further investigations the suspect admitted the offence including the bite injury to the breast. The authors emphasize the importance of an exact photographic documentation as an indispensable prerequisite for an odontological comparison.     

Radiographic evaluation of teeth subjected to high temperatures: experimental study to aid identification processes

The radiographic evaluation of dental remains represents a significant aspect in the forensic identification process, particularly after an exposure to fire. The aim of this "in vitro" study was to evaluate the radiographic features of unrestored, endodontically treated and restored teeth after exposure to an experimental range of high temperatures. Ninety human teeth were divided into two groups: (1) unrestored teeth, as a control group and (2) teeth endodontically treated (condensation technique) and restored with amalgam or composite fillings. Before testing the high temperatures, periapical radiographs of all teeth were performed. The tests of exposure to heat were carried out in an oven for six different temperatures (200, 400, 600, 800, 1000 and 1100 degrees C (392, 752, 1112, 1472, 1832, 2012 degrees F)). After each exposure, periapical radiographs of all the teeth were taken. The radiographic appearance of all the teeth before and after the thermal stresses were evaluated and the differences were recorded. The results of the radiographic examination showed that a number of significant radiographic details were conserved: the composite fillings were in place maintaining the shape till 600 degrees C (1112 degrees F), the amalgam fillings were in place maintaining the shape till 1000 degrees C (1832 degrees F) and the endodontic treatments were recognisable till 1100 degrees C (2012 degrees F).     

Studies of dentition abnormalities in children of the Republic of Armenia for the purpose of personality identification

This paper reports the results of investigations carried out to elucidate the frequency and the structure of various forms of abnormalities of dentition among the children of the preschool and school age in the Republic of Armenia. These data may be of help for the forensic medical personality identification especially for the expertise of unrecognized corpses. Moreover, these data provide an indirect picture of the prevalence of abnormalities of dentition among the adult population of the country. Specifically they may sometimes be used to identify the ethnic and/or racial background of a person.     

Barefoot impressions--a preliminary study of identification characteristics and population frequency of their morphological features

Footprint impressions of 107 male adults ranging in age from 19 to 67 years were recorded and examined. Included in this study were foot impressions from a pair of monozygotic twins as well. The impressions were recorded and converted into a set of indices which essentially are width-versus-length ratios of prominent features of the human foot. These indices were then correlated to yield probability values for use in this study and for comparison to data published by previous investigators Qamra, Abbott, Lovejoy, Cassidy, and Robbins. Friction ridge minutae were not considered in this study. Crease marks, well impressions, and toe step measurements were considered, but not incorporated in the probability values, because of the unique aspect of these features and the inability, at present, to convert these features to mathematical indices. These features do, however, introduce a subjective nature to the analysis scheme. This study uses the combined index probabilities of foot impressions so that the data generated can be used to assign a given probability that a particular foot impression, even without clear definable individual features, can be linked to the person who made the impression.     

用于法医学同一认定的额窦CT编码

目的 使用头颅CT图像重建冠状位鼻骨切面研究额窦观测指标,以编制特异的识别编码.方法 通过距离数值量和形态学描述对额窦CT图像进行分析.额窦同一认定识别编码为:右侧额窦部分隔数,形态一额窦中间隔位置,形态一左侧额窦部分隔数,形态;右侧额窦上缘弓形弯曲数(右侧最高峰位置,最低峰位置)-左侧额窦上缘弓形弯曲数(左侧最高峰位...     

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。     

STR复合扩增及荧光检测技术在个体识别中的应用

目的 :使用 310型遗传分析仪对D3S1358等 10个位点进行基因型检测并应用于法医物证学个体识别案件。方法 :用PCR复合扩增结合四色荧光检测技术对样本DNA进行基因分型。结果 :常见物证检材可成功地得到检验。结论 :这些位点适用于法医物证学个体识别。     

Numerical classification of curvilinear structures for the identification of pistol barrels

This paper demonstrates a numerical pattern recognition method applied to curvilinear image structures. These structures are extracted from physical cross-sections of cast internal pistol barrel surfaces. Variations in structure arise from gun design and manufacturing method providing a basis for discrimination and identification. Binarised curvilinear land transition images are processed with fast Fourier transform on which principal component analysis is performed. One-way analysis of variance (95% confidence interval) concludes significant differentiation between 11 barrel manufacturers when calculating weighted Euclidean distance between any trio of land transitions and an average land transition for each barrel in the database. The proposed methodology is therefore a promising novel approach for the classification and identification of firearms.     

Personal identification by the comparison of facial profiles: testing the reliability of a high-resolution 3D-2D comparison model

Identification from video surveillance systems is frequently requested in forensic practice. The "3D-2D" comparison has proven to be reliable in assessing identification but still requires standardization; this study concerns the validation of the 3D-2D profile comparison. The 3D models of the faces of five individuals were compared with photographs from the same subjects as well as from another 45 individuals. The difference in area and distance between maxima (glabella, tip of nose, fore point of upper and lower lips, pogonion) and minima points (selion, subnasale, stomion, suprapogonion) were measured. The highest difference in area between the 3D model and the 2D image was between 43 and 133 mm(2) in the five matches, always greater than 157 mm(2) in mismatches; the mean distance between the points was greater than 1.96 mm in mismatches, <1.9 mm in five matches (p < 0.05). These results indicate that this difference in areas may point toward a manner of distinguishing "correct" from "incorrect" matches.     

A study of multiple bitemarks inflicted in human skin by a single dentition using geometric morphometric analysis

Criticisms of the forensic discipline of bitemark analysis state that the range of distortion in the shape of bitemark impressions in skin has not been scientifically established. No systematic statistical studies exist that explore this problem. As a preliminary investigation of this issue, a single dentition was mounted in a mechanical apparatus and used to create 89 bitemarks in human cadaver skin, both parallel and perpendicular to tension lines. Impressions of the same dentition were also created in wax. 2D scanned images of the biting dentition were obtained. Locations of incisal edges of all 6 anterior teeth as well as the midpoint of the canine were captured as landmarks in all specimens. This set of landmark data was then studied using established geometric morphometric methods. All specimen shapes were compared using Procrustes superimposition methods, and by a variation of Procrustes superimposition which preserves scale information. Match criteria were established by examining the range of variation produced by repeated measurements of the dentition for each class of specimen. The bitemarks were also compared to a population of 411 digitally scanned dentitions, again using the match criteria. Results showed that bitemarks in wax had lower measurement error than scanned images of the dentition, and both were substantially lower than measurement error as recorded in skin. None of the 89 bitemarks matched the measured shape of the biting dentition or bitemarks in wax, within the repeated measurements error level, despite the fact that all bitemarks were produced by this dentition. Comparison of the bitemarks to the collection of 411 dentitions showed that the closest match to the bitemarks was not always the same dentition that produced the bitemarks. Examination of Procrustes plots of matched shapes showed non-overlapping distributions of measurements of bitemarks in skin, wax, and the dentition. All had statistically significant differences in mean shape. Principal component analysis (PCA) and canonical variates analysis (CVA) both showed clear segregation of the three types of data. The patterns of variance revealed by PCA showed several distinct patterns produced by skin distortion; alteration of relative arch width, and varying displacement of non-aligned teeth in the dentition. These initial results indicate that when multiple suspects possess similar dentitions, bitemark analysis should be approached with caution.     

马和人股骨碎片组织形态学结构特征及其鉴别

目的研究成体马和成年人的股骨组织形态学结构,分析其组织学特征,建立人与马之间的种属鉴别方法。方法取来源于尸体检验的成人右股骨中段约4cm,同时收集马的右腿股骨,取中段约4cm,脱钙后制作成厚约25μm的骨组织切片,在光学显微镜下观察,将显微镜下的图像录入电脑,选取25项指标进行逐步判别分析。结果马和人在哈氏系统数量、哈氏系统直径等13个指标上具有显著差异,用这些指标建立种属判别数学模型,经盲测检验,二者的判别率可达99.6%。结论马和人的股骨组织学结构具有明显的种属特征,建立的判别方程可以有效地鉴别马和人的股骨碎片。     

丛状骨和骨单位带的种属特征及法医学应用价值

目的 探讨丛状骨和骨单位带的种属特征及其法医学应用价值。方法 人及猪、牛、羊、狗长骨中段横切磨片35张，在光学显微镜下观察骨组织中丛状骨和骨单位带的形态学特征。结果 丛状骨和骨单位带在猪、牛、羊、狗的密质骨中广泛存在，人骨组织中几乎不见；同种动物不同个体之间骨组织学结构也存在差异。结论 观察丛状骨和骨单位带是根据人骨鉴别种属的重要排除指标。     

Establishing personal identification based on specific patterns of missing,filled, and unrestored teeth

The primary goal of this research is to examine the overall utility of nonradiographic dental records for the establishment of individual identifications. It was found that even without radiographic lines of comparison, charts and notes that accurately detail a missing individual's antemortem dental condition can be essential for establishing an identification. Based on an analysis of two large datasets, individual dental patterns were determined to be generally unique, or at least very uncommon. Through this type of empirical comparison, it is possible to establish a strong, quantifiable association with a missing individual. The results of this research indicate that a definitive number of points of concordance do not need to be established in dental identification cases. Each case must be assessed individually. The critical factor is to remove subjective judgment calls from dental comparisons. This research has proposed a new method of empirical comparison that allows forensic odontologists to derive objective frequency information regarding the occurrence of specific dental patterns in the general population. The method is similar to that used for mtDNA casework, and a computer program (OdontoSearch) has been developed to make the technique accessible. It was found that even a small number of common dental characteristics may produce a very rare dental pattern, a point that may be counterintuitive to many forensic odontologists.