Associated postmortem dental findings as an aid to personal identification.

The use of the unique features of the human dentition to aid in personal identification is well accepted within the forensic field. Indeed, despite advances in DNA and other identification methodologies, comparative dental identifications still play a major role in identifying the victims of violence, disaster or other misfortune. The classic comparative dental identification employs the use of postmortem and antemortem dental records (principally written notes and radiographs) to determine similarities and exclude discrepancies. In many cases the tentative identification of the individual is unknown and therefore antemortem records cannot be located. In such a situation a dental profile of the individual is developed to aid the search for the individual's identity. With such a profile a forensic odontologist can identify and report indicators for age at time of death, race (within the four major ethnic groups) and sex. In addition to these parameters the forensic dentist may be able to give more insight into the individual. This paper outlines, for the non-expert, some of the additional personal information that can be derived from the teeth of the deceased, and which may assist in their ultimate identification.     

Significance of the recent extraction to the postmortem dental identification: a case study

This case report illustrates the significance of the partially healed extraction site to the postmortem dental identification process. It presents the remains of two individuals with documented extractions--one, 6 1/2 months prior to death, the second, only three weeks prior to death. These photographs, compiled with others, can be used as a guideline for the forensic scientist who seldom has the opportunity to study skeletonized remains.     

Decision-making concepts in postmortem identification

Concepts of the decision-making process in mass casualty identification are discussed. The importance of the correct data type, the correct data format, and the appropriate decision paths are emphasized. Also discussed are the hidden dangers in the use of changeable physical characteristics for sorting factors. A suggested decision process for use in postmortem identification is outlined, along with its application to computer-assisted identifications.     

Design and use of a computer-assisted postmortem identification system

The organization and rationale for the design of a computer-assisted postmortem identification system are discussed along with results of the use of this system in extensive simulation trials on a database of 578 records. The selectivity of dental characteristics is so great that any individual with 4 or more characteristics (either fillings or missing teeth), can be separated from a group of 578 people for final verification of the identity match. The effects of errors in the database are discussed and the actual effects of different error rates on identification are shown. Error rates of up to 30% have only small effects on the ability of the system to pick out correct identity matches. The system is presently implemented on a portable microcomputer, a representative desktop computer, and a large minicomputer. The present efforts include statistical analysis of an enlarged database and testing of a data acquisition system to allow the building of a large identification database (25 000 records) in a quick and economical manner.     

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.     

Shadow positioning technique: a method for postmortem identification

Radiology is increasingly being used as a means of postmortem identification. We have devised a shadow positioning technique by which a postmortem radiograph of a skeletal part can exactly duplicate an antemortem radiograph, thus, faciliating identification by comparison of the antemortem and postmortem radiographs. The antemortem radiograph can be of any skeletal part and taken in any position.     

The significance of postmortem radiographs in infants

The radiographs of 108 infants were analyzed prospectively before autopsy to correlate radiographic findings with those found at the postmortem examination. There was poor correlation between radiographs and autopsy findings when pulmonary pathology was present, and there was no gut pathology when radiographs revealed portal venous air. The radiographs were most helpful when either bony abnormalities (that is, fractures or congenital abnormalities) or free air were found before autopsy.     

Dental identification by comparison of antemortem and postmortem dental radiographs: influence of operator qualifications and cognitive bias

Dental forensic identifications based on comparison of antemortem and postmortem radiographs provide effective and reliable evidence. There are no standardized procedures for assessing similarities between different types of dental radiographs (e.g. orthopantomograms, bitewings, and periapical radiographs), and the operator's subjective judgment can considerably affect identification. The purpose of this study is to evaluate the potential influence of experts' qualifications, training, and cognitive bias on the accuracy of identification. Seventy-eight differently qualified and experienced experts underwent an identification test. The expert sample was composed of 10 specialists in emergency care (ER), 10 specialists in legal medicine (ML), 20 pregraduate dental students (STU), 12 dentists (DENT), 20 dentists educated in forensic odontology (DENT-TRA), and 6 experienced forensic odontologists (FOR). The simulated cases required participants to assess the possible matching of 42 postmortem intraoral radiographs with 16 antemortem panoramic radiographs. Accuracy and specificity for the different operator groups were as follows: ER, 0.76-0.70; ML, 0.76-0.88; STU, 0.89-0.82; DENT, 0.87-0.97; DENT-TRA, 0.88-0.92; and FOR, 0.97-1. As evidenced by high rates of accuracy and repeatability, the most experienced forensic odontologist consistently outperformed operators less or differently educated and trained, especially for difficult cases. In our sample, the dentists who received additional education in forensic odontology did not necessarily perform better than dentists who had not received this additional education. Some cognitive bias, mainly the so-called observer effect, emerged as a possible source of outcome variability among the operator groups.     

大鼠死后不同时间肌肉酶组织化学观察

为了研究死后不同时间酶组织化学发迹和死亡时间的关系。方法 用ＨＥ、ＰＴＡＨ和酶组织化学洒色法,对列在鼠尸僵时肌肉的横纹和酶活性改变进行观察。结果 发现死后２－４ｈ横纹模糊,６ｈ后变清楚可持续至２４ｈ,琥珀酸脱氢酶（ＳＤＨ）和辅酶Ⅰ黄递酶（ＮＡＤＨＤ）变化较小,至死后２４ｈ,两岂纤维的酶活性 较强;细胞色素氧化酶（ＣＣＯ）活性下降较明显,至死后２４ｈ,Ⅱ型纤维的酶活性几乎完全消失。结论 肌纤维结构的     

大鼠死后不同时间肌肉酶组织化学观察

目的　为了研究死后不同时间酶组织化学改变和死亡时间的关系。方法　用ＨＥ、ＰＴＡＨ 和酶组织化学染色法,对死后大鼠尸僵形成时肌肉的横纹和酶活性改变进行观察。结果　发现死后２ ～４ｈ 横纹模糊,６ｈ 后变清楚,可持续至２４ｈ 。琥珀酸脱氢酶（ＳＤＨ） 和辅酶Ⅰ黄递酶（ＮＡＤＨＤ） 变化较小,至死后２４ｈ,两种肌纤维的酶活性均较强;细胞色素氧化酶（ＣＣＯ） 活性下降较明显,至死后２４ｈ ,Ⅱ型纤维的酶活性几乎完全消失。结论　肌纤维结构的变化以及酶活性的变化可以用作推测死后经过时间     

Differences in morphological age-related dental changes depending on postmortem interval.

Morphological methods for age estimation from teeth have been developed and applied to samples without taking the postmortem interval into consideration. We studied differences in morphological age-related changes between fresh extracted teeth and teeth from human skeletal remains in order to develop appropriate dental age estimation methods according to the time after death. Forty-three permanent teeth from dental patients were compared to 37 teeth obtained from human skeletal remains with a postmortem interval from 21 to 37 years. Morphological age-related changes were investigated by measuring variables on intact and half-sectioned teeth. A new computer assisted image analysis procedure to avoid subjectivity was developed to measure variables in sectioned specimens. Dental color, translucency length, attrition, cementum apposition, and secondary dentin showed higher values in teeth from human skeletal remains than in fresh extracted teeth. Variables obtained by morphometric analysis of computer-generated images (tooth length, tooth width, root length, and root area) showed higher values in fresh extracted teeth than in teeth from skeletal remains. The postmortem interval affects age-related morphological changes, and therefore different methods should be used for teeth of unknown postmortem interval.     

The gander disaster: dental identification in a military tragedy

The authors record the contributions of dentistry to the identification of victims of one of the most significant disasters in aviation and U.S. military history--the December 1985 crash of a DC-8 charter airliner near Gander, Newfoundland (now known as Newfoundland and Labrador), Canada, which killed 248 Army personnel and 8 crewmembers. Most of the dental records of the military victims were destroyed in the crash, and, as a result, this loss hampered dental identification. Nevertheless, dental identification was the primary means of identification for many because a very high percentage of the bodies were severely burned and fragmented. Many phases of the U.S. identification efforts have been reported, but the dental-investigation aspects have been mentioned only in passing. Therefore, this article documents the dental team's organization, methodology, and a variety of remarkable problems that the team encountered.     

Reconstruction of root morphology in skeletonized remains with postmortem dental loss.

A reversible technique is presented in which the root morphology of missing teeth in skeletonized human remains can be reconstructed for the purpose of radiographic comparison and postmortem identification. In this technique, which is based upon pilot studies with skeletonized mandibles of archival remains, the alveolar socket walls are sealed with a coat of cyanoacrylate cement and injected with a mixture of vinyl polysiloxane and barium sulfate. Radiographs are produced with the radiopaque mixture in place, which highlights the antemortem morphology of the roots. Subsequently, the impression material is removed, resulting in no gross alteration of the evidence. The radiographs made with this technique, as well as the impressions, can be stored for later use at a trial or pending the discovery of antemortem dental evidence.     

Use of prostate specific antigen in the identification of semen in postmortem cases

Over the past 20 years, the use of prostate specific antigen (PSA) as evidence of the presence of semen in forensic cases has been well established. In this study, we compared a commercially available immunoradiometric assay (IRMA) for the identification of PSA with the identification of spermatozoa in swabs obtained from the vagina of deceased females. There was agreement between the 2 methods in 67 of the 80 cases (84%), including 18 cases where both the PSA was positive and sperm were observed microscopically. The remaining cases had 1 positive result and 1 negative result. We concluded that although there was substantial agreement between the presence of sperm and a positive PSA, there were enough discrepancies between the 2 methods (16%) to justify the use of both methodologies, if possible, to make the determination of sexual activity prior to death.     

牙髓细胞DNA含量与死后经过时间的相关性

目的探讨死后不同环境温度下离体牙的牙髓细胞平均DNA含量变化与死后时间(PM I)的相关性。方法采用细胞图像分析系统(PIPS-2020),测定离体即刻至15d牙齿在低温环境(10~15℃)和高温(30~35℃)环境下牙髓细胞DNA含量变化值,并对其数据进行统计学分析。结果在不同的环境温度下,牙髓细胞DNA降解的速度有所不同,温度的升高有加速牙髓细胞DNA降解的趋势,且DNA降解存在一个平台期。低温组牙髓细胞平均DNA含量与PM I之间的相关系数r=0.953,相关指数R2=0.917;高温组的相关系数r=0.991,相关指数R2=0.971。结论牙髓细胞平均DNA含量与PM I之间具有高度相关性,测定牙髓细胞的DNA变化情况对推断3d(高温环境)或6d(低温环境)后的PM I有参考价值。     

流产的病因及其法医学鉴定中应注意的问题

流产的病因复杂多样,常见的原因有:遗传基因的异常、免疫疾病、内分泌异常、精子异常等。其他如感染、生殖器官疾病、全身性疾病、环境因素、外伤及其精神刺激与手术等也会导致流产。在法医学鉴定中,对于外伤后流产应排除非外伤性流产因素后,才能认定外伤性流产。     

International disaster identification report. Investigative and dental aspects

This meeting, held in October 1980 in Apeldoorn, Netherlands, was a very serious effort to begin international cooperation in a much needed area: disaster investigation and identification. Under the leadership of Col. Arie van den Bos of the Royal Police of the Netherlands, the work was accomplished with representatives and observers from many major countries represented. Efforts were made to solve the enigma of international cooperation. A plane crash of an airline of a major country in a distant country can be properly investigated only with the cooperation of the carrier and the country in which the tragedy occurred. The International Academy of Legal Medicine and Social Medicine devoted a 3-day program to the study of this problem during their last international meeting in Lyon, France, and it will be discussed further in Vienna in 1982 under the leadership of Prof. Wilhelm Holczabek. The experience of Norwegian investigators is mentioned as an example of the type of problems encountered with foreign nationals involved in a crash in the country, or a disaster involving a ship or a oil platform where foreign nationals are working, or in a tragedy such as the propylene explosion in Tarragona, Spain, which resulted in more than 200 tourists from many countries dying in the fire, many bodies burned beyond recognition.