Age estimation from anterior cervical vertebral ring apophysis ossification in South Africans.

Age estimation in living individuals around the age of 18 years remains a difficult challenge. In this study, the anterior inferior vertebral ring apophysis development of cervical vertebrae C2, C3, and C4 of 496 white and 478 black South African individuals aged between 15 and 22 years was assessed from cephalometric radiographs. Apophysis development was scored according to a four-stage scoring system. Ancestry and sex differences in apophysis maturation were assessed and likelihood values determined for individuals in each population group being 18 years, based on developmental stages. Regression equations were developed for each ancestry and sex group. The results indicated that the median ages for attainment of stages 0, 1, and 2 were below the 18-year threshold for all ancestry and sex groups. Additionally, WSA males and BSA females attained stage 3 for C2, and WSA females attained stage 3 for C2, C3, and C4, below the 18-year threshold. The presence of stage 0 for black and white males in all three observed vertebrae and stage 1 for black males for C2, C3, and C4, white females for C2 and C3, and white males for C4 indicates an age below 18 years (with a 95% or higher probability). The results indicate that anterior inferior apophysis ossification stages of C2, C3, and C4 can be used as a reliable indicator to determine the likelihood of being 18 years of age at a 95% confidence index level. Apophysis development provides a valuable addition to the methods that can be used to assess age in the adolescent years.

Estimating age and the probability of being at least 18 years of age using third molars: a comparison between Black and White individuals living in South Africa.

Third molar development of 705 White and 563 Black South African individuals aged between 15 and 25 years was assessed from panoramic radiographs obtained from the School of Dentistry, University of Pretoria, South Africa. The maxillary and mandibular left third molars were scored according to a ten-stage scoring system. Ancestry and sex differences in dental maturity were assessed, and the likelihood of an individual being 18 years of age was determined for each developmental stage. Statistically significant differences were noted among ancestry groups for most developmental stages, with South African Black individuals consistently maturing earlier than the White individuals. Statistically significant differences were noted among sex groups for some of the stages, mostly those near the final stages of root development. The results indicate that male third molars completed their development faster than that of females. The likelihood of an individual being 18 years of age based on the third molar development stage for the maxilla and mandible on its own was also determined. Combined likelihood results, for the maxillary and mandibular left third molars for stage H, increased the likelihood of being 18 years to 95% for all the studied ancestry and sex groups.

Estimating age in black South African children.

Forensic dentists are frequently required to determine the age at death of unidentified skeletons, or to age live individuals who have no record/documentation of their chronological age. In order to be of the greatest value, the method used should have the lowest possible standard deviation and be validated for the individual's specific population group. The method most frequently used in Forensic Dentistry for the estimation of age in children, was described by Demirjian et al. The maturity standards determined were based on samples of French Canadian origin and it has been recommended by several authors that correction factors be incorporated when applying this method to different population groups. The current research was carried out on a sample of 838 black South African children. A new model for age estimation in the said population was developed, to accurately determine the chronological age from dental development. A sample of 604 black South African children was used to test the validity of the method described by Demirjian.

A pilot study to determine the effects of skin contact on two commonly used dental impression materials.

Impression materials used in the analysis of bite marks are required to maintain their stability and integrity for extended periods. It has been observed that certain impressions taken of skin lose their properties with time, becoming sticky and unusable as evidence. The objective of this study was to investigate the onset of "stickiness" in two commonly used dental impression materials when brought into contact with skin. The two materials tested were Impregum and President. They were syringed into glass rings positioned on the upper arms of 28 volunteers. Changes in stickiness were monitored over a four-month period using a tensile testing machine. A metal plunger was lowered onto the impression material and then retracted measuring the adhesive force of the material to the lower surface of the plunger. Over the research period 17 of the 28 rings of Impregum became sticky and changed colour from purple to turquoise. The remaining 11 Impregum samples, all the President samples and all control samples remained unchanged over the 120 day period. The results of this study show that certain factors present in or on skin are responsible for the loss of surface integrity of Impregum. The factors responsible for these changes have not been established.

Concepts to elucidate the pattern-associated analysis of tooth marks in court.

Increased awareness by crime scene detectives has led to a rise in number of bite mark associated cases appearing before the South African courts. This has led to an increased number of dentists being subpoenaed to give forensic evidence. The purpose of this paper was to elucidate the presentation of evidence in pattern associated tooth mark analysis. Three aspects are discussed. They are the basic principle of pattern association, the effects of limited shrinkage and distortion on the pattern of the tooth marks, and finally how to overcome the difficulties that court personnel experience in visualising bite marks. The author has applied these basic concepts over the past six years. Judges and defence advocates have been able to understand the simple concepts and apply them to the more complex issues before them. The concepts described should be familiar to all dentists and forensic odontologists giving tooth mark evidence in the high court. They will assist in explaining all aspects of pattern association to the legal fraternity and aid in the presentation of the evidence. Their strength is in their simplicity.

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 microscope identification of a cheese bitemark: a case report.

Police investigating the murder of a farmer recovered a piece of cheese containing bite- marks. The local dental practitioner used white plaster to make casts of the bitemarks in the cheese and also of the teeth of three suspects. The cheese specimen was retained by the police and seven months later the case was referred to the Forensic Odontology Unit at the University of Pretoria where a silicone rubber cast of the bitemarks in the cheese was made. A lack of concordant features present in a conventional pattern-associated comparison was overcome with the aid of a Leica DMC comparison microscope. Individual features observed under 6.3x magnification aided in the positive identification of the suspect, who when confronted with the evidence, admitted guilt at his first court appearance.

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.

An inclusion technique for marking dentures.

The importance of placing identification markers in dentures is well documented and this paper describes a simple and inexpensive technique for doing it. Twenty marked upper acrylic simulated dentures and 20 controls (unlabelled) were constructed in a standardized mould. Clear laminated labels were produced in a P-touch 300 electronic lettering system and contained both the patient's identification number and suffix ZA (international code for South Africa). The markings were both clear and aesthetically acceptable. Strength tests were carried out to establish the effect of the mark with the result that no significant difference (p70.05) was demonstrated. The routine marking of all dentures by this method is advocated.

The prevalence of oral pathoses in a private dental practice: a 30 month survey.

The purpose of this study was to determine the prevalence of oral lesions in a private dental practice, which treats a broad spectrum of patients from both urban and rural areas. All oral lesions were documented over a 30 month period in a research programme, which formed part of the normal patient treatment plan. The lesions were analysed according to the prevalence of the lesions, race, age and gender distribution, and the ratio of lesions diagnosed by the practitioner compared with those presented for treatment by the patients. A total of 8418 patients were examined and 151 pathological lesions were diagnosed, representing 46 different conditions. The commonest conditions were fluorosis (11 per cent of lesions) and geographic tongue (11 per cent of lesions seen). Twenty conditions (47.8 per cent) were seen only once. The male:female ratio was 1.17:1. A total of 74 per cent of the lesions were seen in patients between the 2nd and the 5th decades and 25 per cent in the 4th decade. Patients seeking treatment suffered from conditions such as fluorosis causing aesthetic problems. On the other hand premalignant lesions such as leukoplakia and life threatening diseases were usually detected by the dentist, which stresses the importance of a thorough clinical examination of all patients. Fluorosis documented in 17 patients in this study, led to analysis of drinking water in the Dennilton area, which was found to contain toxic levels of fluoride.