Comparative study on the effect of ethnicity on wisdom tooth eruption.

The current knowledge base for evaluating the influence of ethnic origin on wisdom tooth eruption is still inadequate. We therefore analyzed and compared the chronology of wisdom tooth eruption in three ethnic populations-German, Japanese, and black South African-based on evidence from 2,482 conventional orthopantomograms. The investigated German population ranked in the middle in terms of the age of wisdom tooth eruption. The black South African population was the fastest and the Japanese population the slowest in terms of reaching the respective eruption stages. Population-specific reference data should be used when evaluating wisdom tooth eruption for the purpose of forensic age estimation.

Studies on the progress of third-molar mineralisation in a Black African population.

The forensic determination of the age of living people has become increasingly important in recent years. With regard to the relevant age group, the radiographic assessment of third-molar mineralisation is of particular importance. So far, the influence of geographic origin on the mineralisation rate has been insufficiently analysed. The paper is based on a total of 595 conventional orthopantomograms of 474 male and 121 female Black Africans aged between 10 and 26 years for whom dates of birth were known. The mineralisation status of third molars was evaluated based on Demirjian's classification of stages [Demirjian et al., 1973. A new system of dental age assessment. Hum. Biol. 45, 221-227]. This study presents the means and standard deviations, median values and the lower and upper quartiles separately for both sexes for the mineralisation stages D-H. Statistically significant differences between the upper and lower jaws were observed in males examined with regard to their attaining the stage F. Mandibular teeth developed 0.8 years earlier than maxillary teeth. Significant sex-specific differences were found with regard to the age at which tooth 38 reached the stage G. In females, tooth 38 reached stage G 1.5 years earlier than in males. In comparison to White probands, the Black African sample showed a tendency to achieve the mineralisation stages earlier. We would recommend using population-specific standards for age determination purposes.

Retrospective investigation of dental records used in forensic identification cases.

The purpose of this paper was to investigate the standard of dental record keeping from a sample of forensic records retrieved from the Department of Oral Pathology and Oral Biology, School of Dentistry, University of Pretoria. Forty of the most recent cases in which ante-mortem information was required, were analysed. From the investigation it was clear that dentists did not comply with the requirements pertaining to dental charting and record keeping. A recommended code of abbreviations is proposed for use by dentists. It is concluded that until such time as charting is reinstituted as a legal requirement by the Health Professional Council of South Africa, dentists would not routinely chart their patients' dental status.

Bungled bite mark evidence collection: a proposed protocol for the prevention thereof.

In recent years, several bite mark cases referred to our department could not be adequately analysed due to poor evidence collection. This has highlighted the fact that police officers, forensic pathologists and dental practitioners do not have access to the information required to collect, record, duplicate, store and transport the relevant evidence correctly. This article highlights several case studies in which evidence collection was bungled. A protocol is proposed that should eliminate this problem.

Comparison of bitemarks left in foodstuffs with models of the suspects' dentitions as a means of identifying a perpetrator.

In a recent court case, a comparison was made between an impression of marks left in cheese at a murder scene and a set of study models of one of the suspects. The court was reluctant to accept the validity of the pattern-associated comparison that was used in the identification. This study compared marks made in cheese, butter and cooked potato with study models taken from volunteers. Pattern-associated comparison was the method used. Eighty pair-wise comparisons were made by two odontologists. The examiners correctly identified all the true matches from among the eighty comparisons as well as selecting the dental models for which there were no corresponding silicone impressions. In the absence of identifiable fingerprints or DNA samples, the method can be employed for matching left in foodstuffs to the dentitions of suspects.

Morphology of the deciduous tusk (tush) of the African elephant (Loxodonta africana).

The tusk of the African elephant is preceded by a deciduous tooth generally known as the tush. Tushes from nine elephant fetuses and six calves younger than 1 year were exposed by dissection and described morphologically. All tushes consisted of a crown, root and pulpal cavity, the formation of which is completed soon after birth. They reached a maximum length of 5 cm, appeared not to erupt through the skin and were pushed aside and resorbed during enlargement of the distally located primordium of the tusk. Dental enamel, which covered the crown, could easily be removed and consisted of rods with an interwoven arrangement; the dentine-enamel junction was flat. Cellular cementum extended for variable distances over the crown and the dentine was tubular in nature. Although the tush apparently has no function, it provides the anlage and orientation for the development of its permanent successor.

Comparative review of bitemark cases from Pretoria, South Africa.

Bitemark evidence has become more scientifically based and is currently widely accepted in the legal process. Bitemarks can be inflicted by humans or animals on humans, animals and a variety of inanimate objects and can be found on any part of the body, with their quality and appearance being influenced by a variety of factors. The purpose of this study was to record the experiences with bitemark cases presented to forensic odontologists at the University of Pretoria from 1983-1993 and to compare them with trends and findings elsewhere. Sixteen cases are presented, of which 14 were bitemarks inflicted by humans and two by dogs. Thirteen cases occurred in human tissues, three in inanimate objects. Of the bitemarks in human skin, most were present on the arms, followed by the face, thorax and back. Bitemarks over the entire body were seen in the two victims bitten by dogs. The male:female ratio was 4:1 and in 46% of cases single marks were present while the rest were multiple. Eight of the victims had been assaulted. Two cases were associated with sexual behaviour (rape), two were inflicted by dogs, and the circumstances surrounding one case were unknown. A variety of factors complicated the investigations. The major factors responsible for disqualifying bitemarks as evidence included mutilation, removal of tissues, inexperience of officials involved and multiple bitemarks. The results of the study confirm the importance of bitemarks as forensic evidence. Humans are the primary victims with the arm being the anatomical site most often involved. Inexperience on the part of the investigating officers and other officials in the handling of these cases strongly emphasises the need for proper training and education of these personnel.

The nutritional composition of South African eggs.

Samples of hens' eggs produced throughout South Africa during the winter and summer of 1990 were analysed for nutrient content to obtain representative values for inclusion in food tables intended for local use. Proximate analyses and vitamin, mineral, fatty acid and amino acid determinations were carried out on all the samples. When the analysed values obtained for whole eggs, egg yolks and egg whites were compared with values listed in the Research Institute for Nutritional Diseases food tables, a number of differences were found. With regard to the inclusion of eggs in diets in general, the cholesterol content of whole eggs was found to be 23.5% lower and the total fat and saturated fatty acid contents 9% and 10% lower, respectively, than the listed values. The eggs were found to be rich sources of protein of animal origin, all the essential amino acids, thiamine, riboflavin, pantothenic and folic acids, vitamin B12, biotin, vitamin D3, vitamin E and phosphorus. Eggs are readily available and inexpensive and should be included in the diets of young children, adolescents, pregnant and breastfeeding women, adults, the elderly and particularly those of all ages who are undernourished.

Diagnosis of oral precancer and cancer.

The early diagnosis of oral cancer and precancer is important because oral cancer is usually well advanced at the time of diagnosis, having spread to regional lymph nodes in a substantial percentage of cases. The earlier the diagnosis is made, the better the prognosis. Several diagnostic methods that are used, such as stomatoscopy, toluidine blue staining, oral exfoliative cytology, histopathological examination and other more advanced diagnostic procedures, are discussed.