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A new approach for the analysis of facial growth and age estimation: Iris ratio

The study of facial growth is explored in many fields of science, including anatomy, genetics, and forensics. In the field of forensics, it acts as a valuable tool for combating child pornography. The present research proposes a new method, based on relative measurements and fixed references of the human face—specifically considering measurements of the diameter of the iris (iris ratio)—for the analysis of facial growth in association with age in children and sub-adults. The experimental sample consisted of digital photographs of 1000 Brazilian subjects, aged between 6 and 22 years, distributed equally by sex and divided into five specific age groups (6, 10, 14, 18, and 22 year olds ± one month). The software package SAFF-2D® (Forensic Facial Analysis System, Brazilian Federal Police, Brazil) was used for positioning 11 landmarks on the images. Ten measurements were calculated and used as fixed references to evaluate the growth of the other measurements for each age group, as well the accumulated growth (6–22 years old). The Intraclass Correlation Coefficient (ICC) was applied for the evaluation of intra-examiner and inter-examiner reliability within a specific set of images. Pearson’s Correlation Coefficient was used to assess the association between each measurement taken and the respective age groups. ANOVA and Post-hoc Tukey tests were used to search for statistical differences between the age groups. The outcomes indicated that facial structures grow with different timing in children and adolescents. Moreover, the growth allometry expressed in this study may be used to understand what structures have more or less proportional variation in function for the age ranges studied. The diameter of the iris was found to be the most stable measurement compared to the others and represented the best cephalometric measurement as a fixed reference for facial growth ratios (or indices). The method described shows promising potential for forensic applications, especially as part of the armamentarium against crimes involving child pornography and child abuse.

Dental anthropology of a Brazilian sample: Frequency of nonmetric traits

Dental elements are valuable tools in a study of ancient populations and species, and key-features for human identification; among the dental anthropology field, nonmetric traits, standardized by ASUDAS, are closely related to ancestry. This study aimed to analyze the frequency of six nonmetric traits in a sample from Southeast Brazil, composed by 130 dental casts from individuals aged between 18 and 30, without foreign parents or grandparents. A single examiner observed the presence or absence of shoveling, Carabellis cusp, fifth cusp, 3-cusped UM2, sixth cusp, and 4-cusped LM2. The frequencies obtained were different from the ones shown by other researches to Amerindian and South American samples, and related to European and sub-Saharan frequencies, showing the influence of this groups in the current Brazilian population. Sexual dimorphism was found in the frequencies of Carabellis cusp, 3-cusped UM2, and sixth cusp.

Use of the Chronological Dental Mineralization Table of Nicodemo, Moraes and Medici Filho (1974) to Estimate Age by Undergraduate Dentistry Students

Objective: To evaluate the agreement and applicability of the Chronological Dental Mineralization Table of Nicodemo, Moraes and Medici Filho (1974) to estimate age held by undergraduate Dentistry students at the Federal University of Paraiba. Material and Methods: Field research applied with a sample of 50 students according to inclusion and exclusion criteria. Sequentially, 3 panoramic radiographs were exposed (actual age known only by teachers), and students were instructed to interpret them from the selection of 2-4 teeth under formation. Data were analyzed using SPSS software (Statistical Package for Social Sciences), version 20.0, adopting significance level of 5%. Results: Most students chose 3 teeth, with percentages of 56.0% (n = 28); 38.0% (n = 19) and 58.0% (n = 29) for radiographs 1, 2 and 3, respectively. Teeth selected with greater frequency were: 47 (20.1%, n = 33) and 45 (19.5%, n = 32) - radiography 1; 38 (22.7%, n = 32) and 18 (13.4%, n = 19) - radiography 2; and 47 (17.9%; n = 26) and 36 (13.7%; n = 20) - radiography 3. The agreement between estimated and actual ages was 60.0% for radiography 1, 12.0% for radiography 2 and 32.0% for radiography 3. Age was underestimated in 40.0% (n = 20) and 88.0% (n = 44) in radiographs 1 and 2, respectively. Overestimation of the actual age occurred only in radiography 3 (68.0%; n = 34). The linear regression analysis revealed that it is possible to estimate the actual age from the maximum age stipulated by training students with 88.1% success rate. Conclusion: The method is applicable; however, the correlation between estimated and actual ages varied considerably among radiographs, and maximum estimated values were closer to the actual age than minimum values.