Age estimation: the state of the art in relation to the specific demands of forensic practise.

Age estimation in cadavers, human remains and living individuals may clarify issues with significant legal and social ramifications for individuals as well as for the community. In such cases methods for estimating age should fulfil the following specific demands: (1) they must have been presented to the scientific community, as a rule by publication in peer-reviewed journals, (2) clear information concerning accuracy of age estimation by the method should be available, (3) the methods need to be sufficiently accurate and (4) in cases of age estimation in living individuals principles of medical ethics and legal regulations have to be considered. We have identified and summarized the methods that essentially fulfil these specific demands. In childhood and adolescence morphological methods based on the radiological examination of dental and skeletal development are to be recommended. In adulthood, the accuracy of most morphological methods is much reduced. Here a biochemical method based on aspartic acid racemization in dentine provides the most accurate estimates of age, followed by special morphological dental and skeletal methods. The choice of method has to take account of the individual circumstances of each case. Most methods require either the consultation of specialised and trained scientists or an adequate calibration by the "user". Very few attempts have been made to find common standardisation, calibration and evaluation procedures or to develop means of quality assurance for methods of age estimation. Efforts in these directions are necessary to guarantee quality standards and adequate answers to the important legal and social issue of age estimation in forensic medicine.

A review of the methodological aspects of aspartic acid racemization analysis for use in forensic science.

Accurate age determination of adult cadavers and human remains is a key requirement in forensic practice. The current morphological methods lack accuracy and precision, require specialist training and are costly. The use of aspartic acid racemization (AAR) in human dentine provides a simple, cost-effective solution and the method can achieve accuracies of +/- 3 years at best. Currently, there are differences in AAR methodology between laboratories which produce different results on the rate of racemization in teeth. These inconsistencies must be resolved if the technique is to be successfully applied to age determinations in forensic cases. This paper reviews the differences in protocol which have been used, discusses how each method will affect the results obtained from AAR analysis and gives recommendations for optimization of the methological protocol as a first step towards international standardization.

On denture marking.

During the last decades in Sweden dentures have been permanently marked with a stainless steel metal band incorporated into the acrylic and containing the patient's birth date, a special number, and "S" for Sweden. The last recommendation issued by the National Board of Health and Welfare states that "the patients shall always be offered denture marking and be informed about the benefit thereof. Denture marking is not permitted if the patient refuses it". Requirements for denture markers have been that they should be biologically inert (when incorporated into the denture), not be expensive, be easy to inscribe, be possible to retrieve after an accident, and survive elevated temperatures for a reasonable time under normal circumstances. Although the frequency of edentulousness has decreased in recent years due to the improvement in oral health there remains a need to address the issue of marking of complete dentures, because there is a large variation in the oral status of populations in different countries. Given that only one marked denture can reveal the identity of a deceased person when all other methods fail to do so, makes it worthwhile. Furthermore, denture marking is important in long-term care facilities. We have investigated the issue of denture marking in Europe and in the United States. The results from the European survey show that denture marking is, to our knowledge regulated by law only in Sweden and Iceland. In the US denture marking is so far mandatory in 21 states while New York State requires dentures to be marked if the patient requests it and several other states impose the obligation to mark dentures on long-term care facilities. Since there is no international consensus regarding the issue of denture marking it is important to address it. A survey from the Nordic countries has shown that if denture marking was in general use, the contribution to the establishment of identity by forensic odontology in cases of fire would increase by about 10%. This means that about 25 more individuals could have been identified if their dentures were marked. Increased international collaboration is needed to solve the issue of denture marking for clinical and forensic purposes.

Tooth wear and temporomandibular joint morphology in a skull material from the 17th century.

Skeletal remnants from the skulls of 69 subjects from the 17th century have been studied focusing on TMJ morphology and tooth wear. Several of the skulls were damaged and altogether 68 condyles and 28 temporal components of the TMJ, and 97 dentate jaws could be examined. Tooth wear was extensive and most of the first molars in both jaws had lost most of their occlusal morphology. This is remarkable with respect to the fact that the great majority of the subjects had died before the age of 35 years, according to the age determination performed. The TMJs showed frequent remodelling but only rarely deformative changes. The frequent observation of a broken up compact bone layer on the condyle was interpreted as a post-mortem artefact. The results indicate adaptive response of the TMJs to the probably heavy masticatory function but do not support the suggested relationship between tooth wear and TMJ osteoarthrosis.

Dental condition and identification marking of dentures in homes for the elderly in Göteborg, Sweden.

Denture marking is of crucial importance especially in homes for the elderly where dentures could be misplaced, particularly during cleaning by staff where there is a chance of loss or mix-up. Recent research regarding denture marking in homes for the elderly shows that only about 50% of the dentures were marked and that the issue should receive attention. The aim of this study was to investigate the number of subjects with natural teeth and the number of edentulous subjects in homes for the elderly in Göteborg, Sweden. The results of the present work show that only about 35% of the complete dentures were ID-marked. Thus, even if the number of complete denture wearers is few, in Sweden presently there are predictions that dentures will become more common in the future, and also in other parts of the world owing to the socio-economic conditions of today and likely in the future.

Denture identification: a new band material and the Swedish ID-band revisited.

The Swedish-developed ID-band has become the internationally accepted method for marking dentures and the Federation Dentaire International (FDI) has put its stamp of approval on the system, but recent research has indicated that the materials used for the metal bands are not resistant to the temperatures the material might be exposed to during fire. In this article, a new group of materials (nickel aluminides) is shown to have a unique combination of mechanical strength, ductility, microstructural high temperature stability and high temperature oxidation resistance in both oxidising and carbonising atmospheres, that make the material suitable for denture marking.

Denture marking: a questionnaire for patients and dentists.

It has been recommended by the Swedish National Board of Health and Welfare (NBHW) (SOSFS[M] 1986:25) since the 1960s that all patients should be offered the opportunity to have their dentures marked. The Swedish ID-band has become the international standard and the FDI-accepted denture marking system. Recent research from our group has shown that only about 50% of the dentures in homes for elderly were marked. Since this is not acceptable the aim of this study was to investigate the opinions regarding denture marking among dentists, dentate patients and edentulous patients. The results from this study are based on the answers from 79 dentists. Most dentists made 2-5 dentures a year and in only four cases had they experienced unmarked dentures returning from the dental technician. Most of the patients were satisfied with their dentures but sixteen were not. According to the patients their dentist did not ask for permission to mark in 76% of cases and the dentists stated that they did not ask for the patients' opinion about marking in 65% of cases. One of the conclusions from this investigation indicates that the dentists are responsible for the lack of marking of the dentures. Previous studies have shown that denture marking can be crucial in identification of deceased persons and that clinical experience shows that denture marking is important especially in institutions where the recommendations of the NBHW should be stressed.

Frequency of edentulism and identification marking of removable dentures in long-term care units.

There were two aims of this study. First, the frequency of edentulism and denture wearers among 464 residents in long-term units in Göteborg, Sweden, was evaluated. Second, the dentures were examined to determine whether they were marked correctly for identification. Of the subjects, 46% were edentulous in both jaws, and 13% in one jaw. Among complete denture wearers, 47% of the patients had at least one identification-marked denture. Removable partial dentures, worn by 26 subjects, were marked to a lesser extent (32%). Since there are many edentulous people among the elderly in most parts of the world we suggest that removable dentures are marked with the patient's name or identification number.

Dental conditions and temporomandibular joints in an early mesolithic bog man.

In 1994 parts of a human skeleton were found in the county of Västergötland, Sweden. The remains were probably from a man and estimated according to 14C dating to be about 9800 years old, i.e. from the Early Mesolithic Period. As such old finds are rare and the skull was well preserved a more detailed description is presented in this paper. The facial skeleton was robust and the face shape was rectangular. The remaining teeth, one maxillary and 10 mandibular teeth, exhibited no caries but extensive occlusal wear which in some teeth had exposed the pulp and led to periapical osteitis. Besides these teeth the 4 maxillary incisors and the two canines and one incisor in the mandible had been lost post-mortem, probably because of severe marginal bone loss. Both temporomandibular joints showed remodelling, one also osteoarthrotic changes. The observations are discussed with respect to masticatory function and some background factors.

Accuracy in identification of implant treated patients by use of intraoral radiographs.

This study aimed at investigating the accuracy of seven forensic odontologists (FO) and seven police officers (PO) in determining person identity using comparable intraoral radiographs from implant treated patients, and evaluating the different characteristics used for identification. The investigation was based on 34 edentulous patients, from 26 of whom a matched pair of radiographs was constructed in such a way that one, taken after insertion of an implant supported prosthesis in the anterior part of the mandible, was regarded as the antemortem radiograph, while another picture from a later follow-up examination served as the postmortem x-ray. From each of the remaining eight patients similar radiographs were selected so that four antemortem and four postmortem ones were obtained. These eight radiographs were also paired but did not match. There were thus 30 pairs of radiographs. A classification of the 26 matched pairs regarding degree of ease (easy, moderate, difficult) in combining the radiographs, using as parameters the design of the implants, shape of the abutments, shape of the bridges and bony anatomy of the jaws was established. The total number of errors made by the FO were higher (26) than those made by the PO (18) (one PO combined all 26 matching radiographs correctly) and 12 of the 26 matchable cases were correctly paired by all observers. The design of the fixed prostheses was the most often used characteristic in the exercise.

Denture marking. Clinical and technical aspects.

The frequency of edentulousness has decreased in recent years due to the improvement in oral health. However, there is still a need to address the issue of denture marking for social and legal reasons because the oral status of populations varies in different countries and the wearing of complete dentures will be a fact for the foreseeable future. Given that only one marked denture can tell us the identity of a decreased when all other methods fail makes it a worthwhile exercise. The marking of dentures is not regulated by law in Sweden, but it is recommended by the Swedish Board of Health and Welfare (SOSFS[M]1986), that all patients should be offered the opportunity to have their dentures marked, which they may refuse. In Sweden, the dental laboratories report that they mark all dentures. The Swedish ID-Band has become the international standard and FDI accepted denture marking system, but recent research has indicated that this metal band is not resistant to very high temperatures. Since there is no international consensus regarding the matter we suggest that new materials should be explored.

Artefacts caused by dental filling materials in MR imaging.

An investigation regarding possible artefacts from dental filling materials in MR imaging is presented including 9 types of such materials from various manufacturers. Freshly extracted teeth were prepared and the filling materials were handled according to manufacturers' instructions. The teeth were encapsulated into a gel phantom based on de-ionized water, Ni (NO3)2 and polysaccharide agarose powder. The investigation was performed with a standard head coil and a 1.5 T MR unit. Images acquired with various combinations of parameters from different sequences were visually analysed regarding possible artefacts. The investigation showed that only one of the materials caused significant artefacts. The gel phantom was found to be a valuable means for examination of artefacts from small samples, and can be recommended as a standard technique for this purpose.

The paradental cyst a clinicopathologic study of 26 cases.

This retrospective study describes the clinical, radiographic and histological features of 26 paradental cysts. These cysts comprised 0.9% of the 2700 cases of jaw cysts diagnosed in 9 years. The true incidence is, however, probably greater since many cases are misdiagnosed. The cysts occurred in relation to partly or fully erupted teeth and were all located in the mandible. An equal sex distribution was found and clinical symptoms in the form of swelling was the main finding especially for the paradental cysts located in the first and second molar area. The radiographic characteristics of the paradental cysts were found to be rather variable. The borders of the cysts adjacent and distal to the third molars were more distinct than the borders of the cysts in the first and second molar area. Histologically, all the cysts were lined by a nonkeratinized stratified squamous epithelium with edema and migration of neutrophils through the epithelium. In most cases, the epithelium was markedly hyperplastic. The connective tissue wall was infiltrated by neutrophils, lymphocytes and plasma cells.

Inter-examiner variation in the assessment of age-related factors in teeth.

Inter-observer variations in the registration of dental age-related characteristics have not previously been studied. Examination and registration were made by 6 dentists with varying experience in age estimation. A total of 13 age-related dental characteristics in 30 teeth extracted from adults were assessed macroscopically, by stereomicroscope and from radiographs. The measurements were analysed in a microcomputer, using the SPSS/PC+ statistical package. The results showed that, except for the score on surface roughness, significant differences were found between some of the observers for all types of measurements, when a paired t-test analysis was made. The correlation coefficients between the observers varied and were rather weak for the surface roughness score. The study revealed systematic differences among the observers as well as differences in interpreting the definitions of the scores for the different parameters. Thus age estimation using statistical methods is seen to be dependent upon the experience of the individual observer and interpretation. Care should therefore be taken not to rely too much upon the results of an odontological age estimation. The possible implications of these results for forensic work are also discussed.

Odontological identification of fire victims--potentialities and limitations.

A retrospective study was performed to analyse the power of odontological evidence in burn victims. The material comprised 292 single fire cases registered at 4 centers of forensic odontology in Scandinavia (DK: Aarhus, Copenhagen; N: Oslo; S: Goteborg) covering a 10-year period. Filed antemortem (am) and postmortem (pm) data were critically reviewed and registered. New systems for classification of the degree of injuries to the teeth and jaws and of the quality of dental records were developed. Matching dental am-pm units/features were recorded using the tooth as unit. Units were scored as either ordinary or extraordinary if the frequency of occurrence in a Danish reference population was > or = 10% or < 10%, respectively. The ID conclusion of a single case was classified into one of the categories: no conclusion, ID possible, ID probable or ID established, depending on the number of ordinary/extraordinary matching units. All age groups were represented. Most fatal burns occurred in house fires (62%) and there was a preponderance of males (71%). Detailed written records supplied by single or by systematic radiographs were available in 71% of cases. About 50% of burn victims were classified into the no-injury group and approximately 25% of cases showed injuries to the anterior teeth only. The number and complexity of dental restorations increased with age. The dental examination was a powerful tool in identification of burn victims. Thus, dental identity (ID) was established in 61% of burn victims and dental evidence assisted the identification in another 31% (ID possible 19%; ID probable 12%).(ABSTRACT TRUNCATED AT 250 WORDS)

Quality evaluation of 10 years patient records in forensic odontology.

In forensic odontology, accurate detailed and complete recording of ante-mortem information is essential as the basis for odontological identification. Earlier studies on malpractice cases in Sweden indicated that the quality of the recording procedure was not always acceptable. Therefore, the aim of this retrospective study was to investigate the quality of ante-mortem records and its possible implications for identification work. All forensic odontology cases referred to the Department of Forensic Medicine in Göteborg between 1983 and 1992 were studied with regard to the instructions for dental records from the National Board of Health and Welfare. Information on dental characteristics, normal anatomical findings and restorative treatment was complete in 43 (68%) of the cases, incomplete in 17 (27%) and missing in 3 (5%). Registration of previous therapy was missing in about 75 (94%) of the records. It was possible to identify patient radiographs in only 16 of the 40 records where radiographs were available. In spite of this, the inaccuracies in the records did not seem to hamper the identification procedures in this study which could be explained by the character of the cases and the availability of medical and circumstantial information.

Odontogenic myxoma--a radiographic study of 21 tumours.

Radiological features of 21 odontogenic myxomas found in 14 women and 7 men were analysed. Ten of the tumors were unilocular and 11 were multilocular. Unilocular lesions were mostly located in the anterior and multilocular in the posterior areas of the jaws. Intralesional trabeculation was seen in all multilocular but only in 3 unilocular lesions. Because radiological appearance of myxoma may be essentially similar with many other lesions of the jaws careful radiological examination is mandatory for planning of proper treatment.

Accuracy of dental registrations in forensic odontology among dentists and dental students.

In forensic odontology, registration of dental characteristics is crucial in the identification procedure. It has been found that the most common errors made are incorrect registration of restorations and confusion about premolars and molars in both jaws. In an earlier study, dental students were observers and the charting was made without radiographs. However, in practical forensic work dentists make the registrations and radiographs are usually available. In this investigation eight dental students and eight dentists made registrations on ten excised macerated jaws with the aid of radiographs. The mean number of errors for each jaw for the students and the dentist was 4 and 3 respectively. The most common error among the dentists was incorrect registration of restorations, while errors on registrations of missing teeth were most common among the students. Even though the material in this study was limited, the results indicate the importance of re-examining of postmortem findings before the comparison with the antemortem data is done. Additionally, the forensic work should be performed by specialists.

Quality assessment of lateral cephalograms amongst radiologists and orthodontists.

This study investigated technical errors in the production of lateral cephalograms necessitating a retake and the extent to which the retake, as ordered by the radiologist, actually produced a gain in quality as assessed by the orthodontist. All the rejected lateral cephalograms taken at the Department of Oral Radiology over a period of 1 year were saved, and 20 such radiographs and their approved counterparts were then studied. Ten orthodontists were asked to decide whether the radiographs were acceptable or not and to provide reasons for those judged unacceptable. Considerable variation was found between the 10 orthodontists in the rate of acceptance of the radiographs. One orthodontist accepted only 13, while another accepted 37 out of the 40 radiographs. The main cause for rejection by the orthodontists of the radiologically approved films was: patients positioning error, and for the rejected: poor (or no) intercuspation. The results show large discrepancies between the radiologists and the orthodontists in quality criteria for cephalometric radiographs, as well as large interindividual variations among the orthodontists. In half of the cases, the radiologists ordered retakes that, according to the orthodontists, were not necessary.

Medico-legal aspects of postmortem pink teeth.

While the phenomenon of pink teeth has been known since 1829, when it was first described by Bell, its application in forensic medicine has been limited. Recently, however, attention was again focused on pink teeth in legal cases. The medico-legal implication was the use of pink teeth as a possible means of evaluating the cause of death. Pink teeth can occur during life and postmortem. Except for very few and poorly documented exceptions, they develop earliest after 1 to 2 weeks postmortem. Their chemical analogy is seepage of hemoglobin or it's derivates into the dentinal tubules. Prerequisites are hyperemia/congestion and erythrocyte extravasation of the pulp capillaries, furthermore autolysis and a humid milieu. Therefore, they are most often associated with water immersion. The intensity of characteristics varies between different cases and also between different teeth in an individual case. Since the ante-mortem prerequisites are non-specific and can be replaced by certain postmortem conditions, there exist until now no specific correlation to the cause of death. The phenomenon is very often seen in victims of drowning where the head usually lies in a head-down position. From this it can be assumed that pink teeth even if not identical to postmortem lividity can, at least to some extent, be considered as analogous. Since, there is no obvious connection between the occurrence of pink teeth and the cause of death, it may be concluded that pink teeth are not pathognomonic for a specific cause of death and this is therefore an unspecific phenomenon.