Tore Solheim

Age estimation of adults from dental radiographs

Previous studies have shown that with advancing age the size of the dental pulp cavity is reduced as a result of secondary dentine deposit, so that measurements of this reduction can be used as an indicator of age. The aim of the present study was to find a method which could be used to estimate the chronological age of an adult from measurements of the size of the pulp on full mouth dental radiographs. The material consisted of periapical radiographs from 100 dental patients who had attended the clinics of the Dental Faculty in Oslo. The radiographs of six types of teeth from each jaw were measured: maxillary central and lateral incisors and second premolars, and mandibular lateral incisors, canines and first premolars. To compensate for differences in magnification and angulation on the radiographs, the following ratios were calculated: pulp/root length, pulp/tooth length, tooth/root length and pulp/root width at three different levels. Statistical analyses showed that Pearsons correlation coefficient between age and the different ratios for each type of tooth was significant, except for the ratio between tooth and root length, which was, therefore, excluded from further analysis. Principal component analyses were performed on all ratios, followed by regression analyses with age as dependent variable and the principal components as independent variables. The principal component analyses showed that only the two first of them had significant influence on age, and a good and easily calculated approximation to the first component was found to be the mean of all the ratios. A good approximation to the second principal component was found to be the difference between the mean of two width ratios and the mean of two length ratios, and these approximations of the first and second principal components were chosen as predictors in regression analyses with age as the dependent variable. The coefficient of determination (r2) for the estimation was strongest when the ratios of the six teeth were included (r2 = 0.76) and weakest when measurements from the mandibular canines alone were included (r2 = 0.56). Measurement on dental radiographs may be a non-invasive technique for estimating the age of adults, both living and dead, in forensic work and in archaeological studies, but the method ought to be tested on an independent sample.

Evaluation of the radiographic visibility of the root pulp in the lower third molars for the purpose of forensic age estimation in living individuals

The question of whether an individual has reached the age of 18 is of crucial importance in forensic age estimation practice. In some countries, the age threshold of 21xa0years is relevant as well. A completed mineralization of third molars is not a sufficient criterion for a diagnosis of a minimum age of 18xa0years with the required probability. In a material of 1,198 orthopantomograms from 629 females and 569 males aged between 15 and 40xa0years, the visibility of the root pulp of fully mineralized lower third molars was evaluated according to stages 0, 1, 2, and 3. In females, stage 0 was first noticed at age 17.2xa0years, in males at age 17.6xa0years. In either sex, the earliest observation of stage 1 was between 21.0 and 22.4xa0years. Stage 2 was first achieved by males between 22.3 and 22.7xa0years, by females between 23.4 and 24.7xa0years. The occurrence of stage 3 was first found in both sexes between 25.1 and 25.9xa0years. These findings indicate that for stage 0, an age below 18xa0years cannot be excluded. However, for stage 1, the examined individual must be over 18xa0years of age and most probably over 21xa0years of age. For stages 2 and 3, the age can safely be stated to be over 21xa0years of age. This method may be a powerful tool for forensic dentists in age estimation in asylum and criminal proceedings.

Human Dental Age Estimation by Calculation of Pulp–Tooth Volume Ratios Yielded on Clinically Acquired Cone Beam Computed Tomography Images of Monoradicular Teeth†

Abstract:u2002 Secondary dentine is responsible for a decrease in the volume of the dental pulp cavity with aging. The aim of this study is to evaluate a human dental age estimation method based on the ratio between the volume of the pulp and the volume of its corresponding tooth, calculated on clinically taken cone beam computed tomography (CBCT) images from monoradicular teeth. On the 3D images of 111 clinically obtained CBCT images (Scanora®3D dental cone beam unit) of 57 female and 54 male patients ranging in age between 10 and 65u2003years, the pulp–tooth volume ratio of 64 incisors, 32 canines, and 15 premolars was calculated with Simplant® Pro software. A linear regression model was fit with age as dependent variable and ratio as predictor, allowing for interactions of specific gender or tooth type. The obtained pulp–tooth volume ratios were the strongest related to age on incisors.

Assessment of the radiographic visibility of the periodontal ligament in the lower third molars for the purpose of forensic age estimation in living individuals

The main criterion for dental age estimation in living individuals is the mineralisation of third molars. However, the mineralisation of third molars can be completed before the forensically relevant age of 18xa0years has been attained. In a material of 1,198 orthopantomograms from 629 females and 569 males aged between 15 and 40xa0years, the radiographic visibility of the periodontal membrane of fully mineralised third molars was assessed according to stages 0, 1, 2 and 3. Stage 0 first appeared at the age of 17.2xa0years in females and at the age of 17.6xa0years in males. Stage 1 was first achieved by females between 18.9 and 20.0xa0years and by males between 20.1 and 20.2xa0years. The earliest appearance of stage 2 was between 22.5 and 23.1xa0years in females and at 22.3xa0years in males. The occurrence of stage 3 was first found between 24.6 and 25.2xa0years in females and between 25.4 and 26.2xa0years in males. If stage 1 is determined, it is, therefore, possible to prove that an individual has already attained the legally relevant age of 18xa0years. For stages 2 and 3, it can be stated beyond reasonable doubt that a person is over 21xa0years of age.

EVALUATION OF PREPARATION, STAINING AND MICROSCOPIC TECHNIQUES FOR COUNTING INCREMENTAL LINES IN CEMENTUM OF HUMAN TEETH

Apposition of cementum occurs in phases resulting in two types of layers with different optical and staining properties that can be observed by light microscopy. Narrow, dark staining incremental lines are separated by wider bands of pale staining cementum. The distance from one line to the next represents a yearly increment deposit of cementum in many mammals, and counting these lines has been used routinely to estimate the age of the animals. Incremental lines in cementum have also been observed in sections of human teeth, and the object of the present investigation was to examine a number of methods for preparing and staining them for counting. Longitudinal and transverse sections, either ground or decalcified, were cut from formalin fixed human dental roots, paraffin embedded or frozen, and stained using several techniques. The cementum was investigated using conventional light, fluorescence, polarized light, confocal laser scanning, interference contrast, phase contrast, and scanning electron microscopy. Incremental lines in the cementum could be observed in ground sections and, following decalcification, in both frozen and paraffin embedded sections. Toluidine blue, cresyl violet, hematoxylin, or periodic acid Schiff (PAS) stained incremental lines allowing differentiation by conventional light microscopy. Contrast was best using fluorescence microscopy and excitation by green light since the stained cemental bands, but not the incremental lines, fluoresced after staining with cresyl violet, PAS or hematoxylin and eosin. The results with other microscopic techniques were unsatisfactory. Since incremental lines are not destroyed by acids and stain differently than the remaining cementum, it is likely that they possess an organic structure which differs from the cementum. Incremental lines in human dental cementum could be observed best using decalcified sections stained with cresyl violet excited by green light.

An Integrated Technique for the Analysis of Skin Bite Marks

Abstract: 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

ABSTRACT: 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 suspects 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 Allens 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.

Human papillomavirus subtypes in oral lesions compared to healthy oral mucosa

BACKGROUNDnHuman papillomaviruses (HPV) are involved in the etiology of cervix cancer, but it is still unclear whether they play a role in related oral lesions.nnnOBJECTIVESnThe presence of HPV in oral leukoplakia biopsies (n=50) and oral squamous carcinoma biopsies (n=50) was compared to normal oral mucosa swabs (n=50) for the purpose of indicating a possible etiological role for the virus.nnnSTUDY DESIGNnDNA was extracted from tissue biopsies and from mucosa swabs of control samples. Nested PCR was performed with primers targeting conserved sequences within the capsid gene L1. PCR products were sequenced to identify the HPV genotype.nnnRESULTnThe results reveal a profile of low-risk HPV genotypes in oral leukoplakia similar to that in healthy controls, while HPV was less frequently observed in oral squamous carcinoma.nnnCONCLUSIONSnHPV does not seem to represent an important causal factor for the development of oral leukoplakia or oral squamous carcinoma.