*Corresponding author: Cristiana Palmela Pereira, Faculty of Dentistry, Portuguese National Institute of Legal Medicine and Forensic Sciences, University of Lisbon, Portugal, Tel: +351 218811819; E-mail: cristiana.pereira@fmd.ul.pt Citation: Abrantes C, Santos R, Pestana D, Pereira CP (2015) Application of Dental Morphological Characteristics for Medical-Legal Identification: Sexual Diagnosis in a Portuguese Population. J Forensic Leg Investig Sci 1: 001. Received: June 12, 2015; Accepted: July 11, 2015; Published: July 27, 2015 Introduction Diagnosis of gender is a signifcant step in reconstructive postmortem profling of medico-legal personal identifcation [1]. Sex classifcation is a complicated procedure, especially in scenarios of severe mutilation or advanced decomposition, where bodies are damaged beyond recognition and also in cases of non-adult skulls whose sexual characteristics have not yet been developed. In these circumstances, teeth can play an important role as a source of sex information [2,3]. In humans, although only two biological sexes exist, sex diferentiation through morphological methods is difcult [2,4,5]. However, the examination of skeleton and dental morphological features represents a method that may help to build the biological profle of an unknown individual, serving as alternative and complementary elements useful in sex discrimination [6-10]. Even though dental sexual dimorphism has been mostly studied by means of odontometric analysis, tooth morphology also represents a valid qualitative method for its study [11-14]. Te investigations in dental morphology context seek to observe record, analyze and understand the behavior of the expression (frequency, variability and degree of expression) of the coronary and radicular morphological characteristics of human teeth. Tese dental traits can take diferent phenotypic presentations of dental enamel, whose expression is thought to be regulated by the genome of an individual and population during odontogenes is; these can appear in forms of positive structures (such as cusps) or negative (as grooves and depressions). Tese distinct features or traits have the potential to be present or not in a specifc location, occur in one or several individuals within the same population group and, when present, exhibit variable degrees of expression while having both a conservative and a dynamic evolution [15-19]. So far, there are over 100 coronary and radicular dental traits recognized in the human dentition. Te excelling analysis method of these features reported in the literature is the ASUDAS method developed at the Department of Anthropology of the Arizona State University. Tis observational method provides a scoring system to classify the degree of expression of dental morphological variants allowing to evaluate them beyond the dichotomy presence or absence [13,20]. Objectives Te main purpose of this experimental study was to test the possibility of a correct sexual diagnosis using a qualitative method, namely through the analysis of dental morphological traits. Tis identifcation procedure of forensic character was carried out on a sample of the Portuguese population gathered at the School of Dentistry, University of Lisbon. About 16 Non-metric Dental Crown Traits (NDCT) were investigated on 24 permanent teeth resulting in multiple experimental hypotheses (66) to be tested. Pereira CP, et al., J Forensic Leg Investig Sci 2015, 1: 001 DOI: 10.24966/FLIS-733X/100001 HSOA Journal of Forensic, Legal & Investigative Sciences Research Article Abstract The main purpose of this work is to investigate the application of dental morphological features as a potential qualitative method of sex classifcation in medico-legal identifcation. The classifcation of 16 non-metric dental traits was performed by ASUDAS (Arizona State University Dental Anthropology System) method. The traits displayed exclusively by the crowns of permanent teeth were analyzed on dental casts of a Portuguese population sample consisting of 53 male and 57 female individuals. No signifcant differences (p<0.05) were found between males and females for all investigated traits, except for the dental tubercle of tooth 13, for the metaconule of tooth 27 and the canine distal accessory ridge of teeth 33 and 43. Based on the method applied, tooth 43 has proven to be the most dimorphic among the Portuguese population. Further, a gender classifcation model using signifcant different traits between both sexes of the teeth 13, 27 and 43 was developed, and it proved to have a reasonable gender classifcation reliability (with 76.4 percent of correct classifcation, Cox & Snell’s pseudo R 2 equals to 0.344 and Nagelkerke’s pseudo R 2 equals to 0.458) although with a signifcant probability of misclassifcation. Keywords: Gender classifcation model; Gender identifcation; Medico-legal identifcation; Non-metric dental crown traits; Permanent dentition; Portuguese population Catarina Abrantes 1 , Rui Santos 2,5 , Dinis Pestana 3,5 and Cristiana Palmela Pereira 4,5 * 1 Faculty of Dentistry, University of Lisbon, Portugal 2 Department of Mathematics, School of Technology and Management, Polytechnic Institute of Leiria, Portugal 3 Department of Statistics and Operation Research, Faculty of Sciences, University of Lisbon, Portugal 4 Faculty of Dentistry, Portuguese National Institute of Legal Medicine and Forensic Sciences, University of Lisbon, Portugal 5 Centre of Statistics and Applications, University of Lisbon (CEAUL), Portugal Application of Dental Mor- phological Characteristics for Medical-Legal Identification: Sexual Diagnosis in a Portu- guese Population