The relevance of taurodontism in forensic dental age estimation.

Taurodontism is a dental morphological anomaly characterized by enlarged pulp cavities repositioned towards the apical region of the tooth, coupled with shortened root structures. Molars are commonly affected by this alteration. Certain populations exhibit up to 48% prevalences for this dental alteration, underscoring its significance in dental age estimation (DAE). In the field of DAE, an individual's chronological age is inferred from specific dental features, frequently employed within the forensic context. The effect of taurodontism on the features of DAE is an unanswered issue. The influence of taurodontism on eruption, mineralization, radiographic visibility of root canals, and radiographic visibility of the periodontal ligament space in mandibular third molars- some of the established criteria for DAE as examples-is currently not systematically examined. Some common staging scales for the dental features of DAE cannot technically be applied to taurodontic teeth. Additionally, given the association of taurodontism with syndromes affecting tooth development, caution is warranted in age assessment procedures. Notably, taurodontic teeth may serve as indicators of syndromes influencing skeletal development, further emphasizing the relevance of taurodontism in forensic age assessment. Presumably taurodontic teeth were included in reference data to some extent due to their partially high prevalence in the past, whereby the influence of taurodontism has been statistically absorbed within the overall spread of the features. Future studies should compare the temporal course of these tooth characteristics in affected and unaffected teeth. Subsequent initiatives should focus on raising awareness among forensic dentists regarding taurodontism, necessitating in-depth exploration of the subject.

Studying eruption patterns of mandibular third molars for forensic age assessment: Introducing current reference data from a population of black South Africans.

INTRODUCTION: Evaluation of the eruption of mandibular third molars in orthopantomograms (OPGs) is a method of forensic age assessment. The objective of our study was to provide valid reference data for this trait within a population of black South Africans. The study was guided by the criteria for reference studies in age assessment. MATERIALS AND METHODS: A study population from Pretoria, South Africa comprising 670 OPGs obtained from 338 black females and 332 black males aged between 15.00 and 25.97 years was analysed. All OPGs were performed for medical indication during the period from 2011 to 2022 and were retrospectively evaluated. From the 670 OPGs, a total of 1021 mandibular third molars were evaluated. The assessment of mandibular third molars was conducted using the staging scale presented by Olze et al. in 2012. Two experienced dentists evaluated the OPGs independently of each other. If the two examiners diverged in their assessments, a consensus stage was assigned. RESULTS: As expected, the mean, median and minimal age increased with higher stages for both teeth and both sexes. The minimum age recorded for stage D, indicating complete tooth eruption, was 15.79 years in females and 16.62 years in males. CONCLUSION: As it is the case for previous reference studies in other countries, placing exclusive reliance on the evaluation of mandibular third molar eruption is inadequate for ascertaining the age of majority among Black South Africans. Future studies need to examine if our results are transferable to other countries in Sub-Saharan Africa.

The "hypopigmented" bitemark: a clinical and histologic appraisal.

So-called "hypopigmented" bitemark patterns, commonly seen but not limited to dark skinned individuals, can be of value in forensic investigations. The process of aging bitemarks observed on skin is controversial and without guidelines. This report analyzes tissue obtained from the site of a hypopigmented bitemark using special histochemical stains for the identification of melanin pigment, and a panel of immunohistochemical markers to aid in the aging process. Histologic evaluation clearly showed that cellular changes in the hypopigmented area were indicative of wound healing that had taken place over a period of time. This validates the hypothesis that a hypopigmented bitemark is an indication of a wound inflicted some days previously. These findings have value in forensic investigations, particularly in cases of suspected long-term physical abuse.

A systematic review of 3D scanners and computer assisted analyzes of bite marks: searching for improved analysis methods during the Covid-19 pandemic.

The global Covid-19 pandemic has forced forensic dentists to improve infection control methods. This search investigated the practical utilization of different 3D scanners to record and to analyze bite marks in the skin- and inanimate objects with this aim in mind. A systematic review of the literature using keywords like "human bite mark", "bite mark analyzes", "3D analyzes", "3D scanning", "forensic odontology", and "forensic dentistry" was performed in three scientific databases: MEDLINEOvid®, Pubmed® and Google Scholar. The initial search yielded 263 full-text articles, of which 15 were considered eligible and current within the last 10 years. 3D scanners and computer-assisted human bite mark analyzes showed potential advantages and can be effectively used in forensic odontology on skin and inanimate objects. These technologies minimize the number of people being exposed to pathogens, simplify the chain of evidence, facilitate immediate information exchange between the team members and enable the virtual presentation of the expert witnesses in a court of law.

Validation of Roberts' method using root canal width patterns as a mandibular maturity marker in determining the 18-year threshold.

The South African Bill of Rights and the Children's Act define a 'child' as a person under the age of 18 years. The age of 18 years is therefore significant for legal purposes in South Africa. The third molar is an important indicator in determining the 18-year threshold. Human biological growth markers are accepted indicators of a subject attaining the age of 18 years. A recent study by Roberts et al. suggested that the relative width of the distal root canals (RCW) of the lower left permanent molars (Fédération Dentaire Internationale notation 36, 37 and 38) as visualised on dental panoramic radiographs can be used as such a growth marker. This study aimed to validate this human biological growth marker in both black and white populations living in South Africa according to Roberts' method. The findings of this validation study were in agreement with this method which showed that individuals with Demirjian stage H left molars and category RCW-C were indeed over the 18-year threshold. Important aspects regarding the rationality and application of Roberts' method are discussed. The authors conclude that this method should not be used in isolation but as an adjunct with other age estimation methods.

Are animals shrinking due to climate change? Temperature-mediated selection on body mass in mountain wagtails.

Climate change appears to affect body size of animals whose optimal size in part depends on temperature. However, attribution of observed body size changes to climate change requires an understanding of the selective pressures acting on body size under different temperatures. We examined the link between temperature and body mass in a population of mountain wagtails (Motacilla clara) in KwaZulu-Natal, South Africa, between 1976 and 1999, where temperature increased by 0.18 [Formula: see text]C. The wagtails became lighter by 0.035 g per year. Partitioning this trend, we found that only a small part of the effect (0.009 g/year) was due to individuals losing weight and a large part (0.027 g/year) was due to lighter individuals replacing heavier ones. Only the latter component was statistically significant. Apparently, the wagtails were reacting to selection for reduced weight. Examining survival, we found that selection was temperature-mediated, i.e., lighter individuals survived better under high temperatures, whereas heavier individuals survived better under low temperatures. Our results thus support the hypothesis that temperature drove the decline in body mass in this wagtail population and provides one of the first demonstrations of the selective forces underlying such trends.

Tongue position and its relation to the cause of death and sequential stages of body decomposition observed during 608 forensic post-mortems.

The purpose of this study was to document tongue position and its relation to the cause of death and sequential stages of body decomposition, as observed during the routine forensic pathological examination of bodies. The sample of 608 included all bodies examined by the first and third authors during the period April 2016 to September 2016. Tongue position was recorded in all cases where position of the tongue could be visually determined. The condition of the body was recorded as follows: fresh flaccid, fresh with rigor mortis, early decomposition, and advanced decomposition. The cause of death was recorded where known. The results showed that 86% of all bodies examined did not show a protruded tongue and that 92.8% of the bodies were in a state of fresh rigor mortis. The study also showed that tongue protrusion was more prevalent in certain causes of death, namely, hanging, burning, and drowning, but was never absolute. The authors believe that due to the low numbers of bodies presenting with protruded tongues, this phenomenon has previously been overlooked, the significance thereof underestimated, and the pathophysiology and pathomorphology never fully investigated.

Age estimation based on Willems method versus new country-specific method in South African black children.

AIM: The aims of our study were to develop new maturity scores for dental age estimation in South African black children according to the Willems method, which was developed based on Belgian Caucasian (BC) reference data (Willems et al. J Forensic Sci 46(4):893-895, 2001), and to compare age prediction performance of both methods. SUBJECTS AND METHODS: A total of 986 panoramic radiographs of healthy South African black (SAB) children (493 males and 493 females) in the age range of 4.14 to 14.99 years (mean age 10.06 years) were selected for obtaining developmental staging scores (according to Demirjian et al. Hum Biol 45(2):211-227, 1973). Willems BC methodology was applied to develop new country-specific maturity scores (Willems SAB). Age prediction performance of Willems BC and Willems SAB was compared. RESULTS: On average, Willems BC renders acceptable results with an overestimation of chronological age of 0.06 years (SD 0.88 years) in SAB children. Compared to Willems SAB, the overall mean absolute error was slightly higher with Willems BC (0.62 and 0.68 years, respectively), but this was not significant in males. Also, the root mean squared error was marginally higher in Willems BC. CONCLUSION: The new age prediction method developed in South African black children was found to be better compared to Willems BC, although the difference seems to be small and clinically not relevant, especially in males.

The Effects of the Refugee Crisis on Age Estimation Analysis over the Past 10 Years: A 16-Country Survey.

Dental age estimation (AE) tests are routinely done on living and deceased persons. There is anecdotal evidence suggesting an increase in age estimations due to the refugee crisis. Our aim is to determine the reasons and methods for performing dental AE tests in both living and deceased individuals. Global trends in AE over the past 10 years were also investigated. A database of all forensic laboratories was obtained and an electronic questionnaire was sent to all of them. The questionnaire was self-developed and included questions on the reasons for performing AE tests, the preferred methods used in living and deceased individuals, and the people/organizations who requested these AE tests. The number of tests performed annually varied between 0 and 500 and the majority were on asylum seekers, refugees, and for adoption cases. Most units used multiple techniques to determine the age among the living, but seldom used more than three techniques for the deceased. The majority of tests were requested by coroners and the legal fraternity. There has been an increase in the number of dental AEs carried out and this has been mostly due to asylum seekers and refugees. The most common techniques for the living were variations of Demirjian's technique while country specific techniques were used for the deceased.

An analysis of dental intercanine distance for use in court cases involving bite marks.

High levels of crime in South Africa and the resulting court cases requiring bite mark evidence have necessitated continuous research into the prevalence and interrelationship of recognisable dental features present in bite marks. This study represents the largest data set of descriptive statistics related to intercanine distance, in which the means, standard deviations, medians and interquartile ranges across four racial groups were determined. Intercanine distances were also statistically weighted by determining the common, uncommon and very uncommon values for each of the racial groups. The results of this research show that we can consider any maxillary intercanine distance more than 24.1 mm and less than 43.0 mm to represent a human bite mark. Black males had the largest mean (average) intercanine distance of 36.33 mm (standard deviation 2.49 mm) and white females the smallest mean intercanine distance of 33.4 mm (standard deviation 2.13 mm). The analyses showed statistically significant differences between the mean intercanine distances of different race and gender groupings. The authors do not advocate trying to determine the race or gender from intercanine distances determined, but rather the relevance of the intercanine distances in the specific race and gender groupings. This study makes a meaningful scientific contribution to the presentation of bite mark evidence at a time when subjective opinions need to be replaced with scientific data.

Tongue protrusion as an indicator of vital burning.

In the forensic assessment of burned bodies, the question of whether the victim was exposed to the fire before or after death is of crucial importance. Several external signs have been used in the past to indicate heat exposure prior to the death of the victim but these did not include tongue protrusion. The internal signs of heat exposure are generally regarded as much more important than those observed externally. No one factor has been found to be totally reliable. This study found a statistically significant dependence between tongue protrusion and presence of soot in the respiratory tract and stomach, the latter being a good indicator of vital burning. The results of this study confirm that tongue protrusion can be used as an additional indicator of vital burning.

The individualisation of a dog bite mark: a case study highlighting the bite mark analysis, with emphasis on differences between dog and human bite marks.

A person who keeps or controls a dog in his own interest is liable "without fault" should that dog cause harm to any person. By owning a dog, man welcomes into his home a beast that preserves much of its primordial self, and is capable of inflicting a fatal bite wound. The courts may require the forensic expert to identify which specific dog caused the damage or fatal bite in an effort to establish the owner/controller of the animal. Very little has been published on the individualisation of dog bite marks, the procedures to be followed when confronted with usable bite marks and the range of analysis techniques available. The authors advocate a multidisciplinary approach, and utilise a case study to demonstrate the protocol to be followed when analysing a dog bite mark. The paper also highlights differences between human and dog inflicted bites. The authors warn against over interpretation of poor quality bite marks and a final conclusion of absolute certainty.

The application of affine transformations in matching distorted forensic samples with a common origin.

The practice of forensic odontology regularly requires the forensic dental expert to establish a degree of concordance between two objects, one or both of which have undergone minimal degrees of warping, shrinkage and distortion collectively described as deformations. These comparisons can be between the suspect's or victim's dentition and bite marks on inanimate objects/skin, two radiological images, palatal rugae patterns, dental arches, lip prints and other unique scenarios which are presented in forensic odontological cases. This paper will define the mathematical concept of affine transformation as it pertains to forensic matters and explains how it can be applied to a case study involving pattern deformations. Although the deformation of the evidence may be minimal in extent, it creates a measure of uncertainty when expert evidence is given in court cases. Any metric discrepancy caused by deformation of the evidence will necessitate the application of pattern association and negate the use of metric analysis. It has been shown that a pattern association analysis of evidence will not be affected by minimal amounts of deformation. The mathematical limits of these deformations which will significantly affect the comparisons have not yet been determined. In the case study presented the deformations were considered minimal and thus explainable by a pattern association analysis. The mathematical concepts will empower the expert to explain to a court of law how two samples which were not a perfect match, could in fact be deformed equivalents of common origin.

Reconstruction of deformed bite marks using affine transformations.

Bite marks inflicted on animate and inanimate objects will undergo a certain degree of deformation. This fact remains one of the biggest stumbling blocks when analyzing evidence for court presentation. It has been demonstrated that the reliability of pattern association analysis will not be affected by minimal degrees of warping, shrinkage, and distortion. In this study, affine transformations were applied to bite marks to establish if minimal distortions would affect the mathematically determined relationships of the defined features. In a real case study, it was then tested whether the distorted bite mark matched the dentition of the perpetrator by applying an affine transformation. This was confirmed to be the case. Affine transformations will thus not affect the relationships of the individual features found in bite marks. The numerical calculations validate the reliability of pattern association analysis in the presence of minimal amounts of warping, shrinkage, and distortion.

The challenges and effects of globalisation on forensic dentistry.

This paper deals with the challenges faced by forensic dentists in a world in which globalisation has become a reality. People travelling across the globe on a daily basis become victims of violent crime, terrorist attacks, human displacement, natural and man made disasters. This has forced colleagues in the profession to participate in joint operations exposing inadequacies which need urgent attention. Forensic dentists practise in isolation creating their own rules and regulations oblivious to the greater global community. No international protocols exist for the many procedures practised by the profession. Possible solutions to the complex problems are offered. These include co-operation with colleagues around the globe while striving for the highest levels of quality control, standardisation, reliability, impartiality, reproducibility and ethical accountability.

An integrated technique for the analysis of skin bite marks.

The high number of murder, rape, and child abuse cases in South Africa has led to increased numbers of bite mark cases being heard in high courts. Objective analysis to match perpetrators to bite marks at crime scenes must be able to withstand vigorous cross-examination to be of value in conviction of perpetrators. An analysis technique is described in four stages, namely determination of the mark to be a human bite mark, pattern association analysis, metric analysis and comparison with the population data, and illustrated by a real case study. New and accepted techniques are combined to determine the likelihood ratio of guilt expressed as one of a range of conclusions described in the paper. Each stage of the analysis adds to the confirmation (or rejection) of concordance between the dental features present on the victim and the dentition of the suspect. The results illustrate identification to a high degree of certainty.

A technique to capture, analyze, and quantify anterior teeth rotations for application in court cases involving tooth marks.

Anterior teeth within the human dentition have a specific numerical rotation value. Bite marks show an array of angled indentations, abrasions, microlacerations, and contusions. These marks generally represent the incisal surfaces of the suspect's dentition reflecting the rotation values of the teeth in the dental arch. This study described a method for capturing and analyzing anterior dental rotations. The rotations of individual anterior teeth within the study population were categorized as common, uncommon, and very uncommon according to Allen's classification. In the absence of a large number of incisal patterns present in a bite mark, a single but heavily weighted tooth rotation could be of equal discriminatory potential to several common rotation values. No prevalence studies quantifying individual tooth rotations are available. The measurement of each individual tooth rotation together with its individual discrimination potential will enhance the evaluation of the concordant features observed in bite marks.