Stella Martin-de-las-Heras

Comparison of simulated human dermal bitemarks possessing three-dimensional attributes to suspected biters using a proprietary three-dimensional comparison

The infliction of a bite is a four-dimensional space-time event that is ideally analyzed with three-dimensional (3-D) technology. Comparison of 2-D images (photographs) of a bitemark with a 3-D replica of a suspects dentition is challenging. The authors present a technique that produces 3-D images of indented marks and dentitions for comparisons. Study models and corresponding dental-wax bites were digitized by 3-D scanning, and comparison overlays were generated using DentalPrint software. The effectiveness of the method was analyzed by determining the area under receiver operating characteristic (ROC) curve and the sensitivity, specificity and 95% confidence interval (CI) for each cut-off point. An area under the ROC curve of 0.953 (SE=0.029; 95% CI=0.893-0.985) and high sensitivity and specificity values were obtained for 104 comparisons made by an expert examiner, who correctly identified 92.3% of matching dentitions and 98.7% of non-matching dentitions. This technique can be considered a highly accurate method of bitemark analysis, although indentations must be present in the injury, limiting the cases that can be resolved. A comparative study of the same dentitions using 2-D bitemark photography confirmed the superiority of the new approach.

The utility of dental patterns in forensic dentistry

The comparison of antemortem and postmortem dental patterns, which reflect a combination of dental states, can be quantified for human identification. However, the utility derived from the uniqueness of these patterns is limited by variations in oral health status related to population, age, and birth cohort. We analyzed dental pattern diversity from reference datasets that documented differences in oral health. Our analysis was based on full dentitions and partial dentitions available in forensic situations. To analyze the diversity of dental patterns, data from 3166 adults were extracted from the last 3 contemporary Spanish National Oral Health Examination Surveys, corresponding to the years 1993, 2000, and 2005. Each survey comprised 2 adult age groups (35-44 years and 65-74 years), therefore six datasets were available for our study. Our six samples showed substantial variability in oral health status (caries history) and dental code distribution, not only between age groups within the same survey year, but also between different survey years for the same age group. To test the overall diversity of dental patterns in each datasets, pairwise comparisons were performed and the total number of pattern matches was generated. We calculated total and conditional diversity (excluding individuals in whom all teeth were classified as unrestored or missing) for each forensic situation. To test the homogeneity of diversity estimates among the six datasets we used a random effect model that requires a parameter estimate together with its standard error. Total diversity values were low and heterogeneous. However, conditional diversities were high and homogeneous, which allowed all data to be pooled into a single database. Once data were pooled, high combined diversity values (above 0.99) were obtained for each forensic situation. This indicates their usefulness for forensic purposes. We conclude that the conditional diversity value derived from dental patterns is a potentially valuable tool with broad applicability for human identification.

Intimate partner violence against Spanish pregnant women: application of two screening instruments to assess prevalence and associated factors.

To investigate the prevalence of intimate partner violence in Spanish women during the 12 months prior to delivery and to identify associated risk factors using two screening instruments.

A quantitative method for comparing human dentition with tooth marks using three-dimensional technology and geometric morphometric analysis

Abstract Objective. To develop a quantitative method to compare 3D overlays from dental casts with experimental bitemarks by using geometric morphometric analysis. Materials and methods. Thirteen upper and lower dental casts and corresponding simulated bitemarks were 3D-scanned to generate comparison overlays with DentalPrint software©. This study considered the inter-canine distance and four incisal angles. A matrix was created to compare all possible combinations of matches and non-matches between models and bites, i.e. 169 combinations (13 models × 13 bites), of which 13 were true matches. For each combination, the percentage difference was calculated between the variables in the model and the same variables in the bitemark. Logistic regression was used to obtain a predictive model (algorithm) for a match, calculating the discriminative values (area under the ROC curve, sensitivity and specificity) for each measure and for the logistic model. Results. Statistically significant discriminative power was found for all single (angle or distance) and combined (logistic model) variables, with lower 95% CI limits > 0.50 for areas under the ROC curves and sensitivity/specificity values > 50% in both maxilla and mandible. Conclusions. This quantitative method has sufficient discriminative power to be utilized in forensic cases.

Unintended pregnancy and intimate partner violence around pregnancy in a population-based study

BACKGROUND Intimate partner violence (IPV) and unintended pregnancy are public health issues that can affect the health and well-being of women and their children. However, the relationship between IPV and womens ability to control their fertility has not been adequately explored. AIM To investigate the association between unintended pregnancy and emotional or physical violence perpetrated by partners around pregnancy. METHODS A population-based study was undertaken, recruiting women (n=779) at the hospital obstetric departments and gathering social and family data. IPV was diagnosed by using the Index of Spouse Abuse (ISA). Data were gathered by trained midwives in 15 public hospitals in southern Spain and multivariate logistic regression analysis was performed. FINDINGS The pregnancy was reported to be unintended by 118 (15.1%) of the study population. Unintended pregnancy was significantly associated with: physical and/or emotional IPV around pregnancy, age, marital status, cohabitation, educational level, and employment status. After adjusting for socio-demographic characteristics, emotional IPV around pregnancy was significantly associated with an unintended pregnancy (AOR=2.5; 95% CI=1.5-4.3). Being in a non-committed relationship was a risk factor (AOR=3.5; 95% CI=1.8-6.1) and being in employment a protective factor (AOR=0.4; 95% CI=0.2-0.8) for an unintended pregnancy. CONCLUSION Women who report an unintended pregnancy may be experiencing emotional IPV. The risk of emotional IPV is higher if women reporting an unintended pregnancy are in a committed relationship, married, or in employment. A better understanding of the relationship between unintended pregnancy and violence can aid midwives about potential reproductive health risk factors associated with abuse.

Accuracy of 3D Scanners in Tooth Mark Analysis

The objective of this study was to compare the accuracy of contact and laser 3D scanners in tooth mark analysis. Ten dental casts were scanned with both 3D scanners. Seven linear measurements were made from the 3D images of dental casts and biting edges generated with DentalPrint© software (University of Granada, Granada, Spain). The uncertainty value for contact 3D scanning was 0.833 for the upper dental cast and 0.660 mm for the lower cast; similar uncertainty values were found for 3D‐laser scanning. Slightly higher uncertainty values were obtained for the 3D biting edges generated. The uncertainty values for single measurements ranged from 0.1 to 0.3 mm with the exception of the intercanine distance, in which higher values were obtained. Knowledge of the error rate in the 3D scanning of dental casts and biting edges is especially relevant to be applied in practical forensic cases.

Spectrophotometric analysis of color changes in teeth incinerated at increasing temperatures

Color changes produced by histological alterations in burned teeth can provide conclusive forensic information on the temperature of exposure. The objective was to correlate heat-induced color changes in incinerated teeth with increases in temperature (to 1200°C). Spectrophotometry was used to measure lightness, chromaticity (a* and b*), whiteness, and yellowness in 80 teeth heated at temperatures of 100, 200, 400, 600, 800, 1000, or 1200°C for 60 min. Chromaticity a* was reduced at 100°C and lightness at 200 and 400°C, while chromaticity b* and yellowness were reduced at 400 and 600°C. Higher temperatures (800, 1000, and 1200°C) produced progressive increases in lightness and whiteness but reductions in chromaticity b* and yellowness. The accuracy of color values to determine the temperature of exposure was determined by Receiver Operating Characteristic analysis. High accuracy was shown by lightness, chromaticity b* and yellowness values for temperatures between 800° and 1200°C, by whiteness for temperatures of 1000° and 1200°C, and by lightness for temperatures of 200° and 400°C, with sensitivity and specificity values ranging from 90% to 100%. According to these results, colorimetric analysis of incinerated teeth can be used to estimate the temperature of exposure with high accuracy, with lightness being the most useful variable.

Validity of a dichotomous expert response in bitemark analysis using 3-D technology

Despite efforts to quantify bitemark evidence, comparison procedures remain subjective and yield different degrees of certainty. Our aim was to study the effectiveness of a comparison procedure requiring a dichotomous response by the expert. We compared overlays from 3-D images of dental casts and bite impressions, obtained using DentalPrint(©) software. Receiver operating characteristic (ROC) analysis was performed on the results of 104 comparisons, finding an area under the ROC curve of 0.955 (standard error=0.029; 95% CI, 0.896-0.986), sensitivity of 92.3% (95% CI, 74.8-98.8) and specificity of 98.7% (95% CI, 93.0-99.8). According to these findings, this bitemark analysis procedure is highly accurate, although study limitations are discussed, placing these results in context. The main advantage of the dichotomous decision model is that it can be more easily understood, facilitating course of justice. Further research is warranted to explore the potential of this approach as an alternative to diagnostic decisions based on certainty levels.

Bite Mark Analysis in Foodstuffs and Inanimate Objects and the Underlying Proofs for Validity and Judicial Acceptance

Even though one of the first bite mark cases was Doyle v. State in 1954 (a bitten cheese case), the research has focused on bite marks inflicted in human skin. As published Papers, Case Reports, or Technical Notes can constitute precedents which are relied upon in making the legal arguments and a considerable amount of case law exists in this area, we present a systematic review on bite mark analysis in foodstuffs and inanimate objects and their underlying proofs for validity and judicial acceptance according to Daubert rulings. Results showed that there is vulnerability in these procedures, and it is essential to demand for focus scrutiny on the known error rates when such evidence is presented in trials. These kinds of bite marks are well documented; however, there has been little research in this field knowing that the protocols of analysis and comparison are the responsibility of the forensic odontologists.

Spectrophotometric dental colour measurement to assess age in living adults

The aim of this study was to evaluate the usefulness of spectrometrically measured colour parameters of teeth for age estimation in living adults. A total of 329 teeth were selected (162 upper central incisors and 167 upper canines) from 52 men and 50 women aged between 20 and 86 years. Colour measurements were performed in vivo on the vestibular surface of the teeth using a portable contact Spectro-color device. Colorimetric variables (L*, a*, b*), chromaticity coordinates (x, y, z), and indexes of whiteness (WIC, Z%, WI) and yellowness (YI) were calculated. The accuracy of colour values to estimate the age was determined by Receiver Operating Characteristic analysis. A more powerful age discrimination was obtained with upper incisors than with upper canines. Areas under the ROC curve ranged from 0.7 to 0.8 for all dental colour parameters measured in upper central incisors except for the variables L* and Z%, with sensitivity values ranging from 56% to 93% and specificity values from 38% to 92%. We conclude that spectrophotometric dental colour measurement may be an objective and useful tool to estimate age and meets medical ethical standards for application in living adults. However, further research is needed to study the effect of ethnicity and other factors on tooth colour.