Rogério Nogueira de Oliveira

Avaliação de três métodos de extração de DNA de material parafinado para amplificação de DNA genômico pela técnica da PCR

Existem na literatura varios protocolos para extracao de DNA genomico a partir de material fixado em formol e embebido em parafina. A obtencao de DNA genomico e importante para realizacao de experimentos em biologia molecular, dentre eles a PCR. Este trabalho teve por objetivo otimizar a extracao de DNA genomico a partir de material fixado (hiperplasia fibrosa inflamatoria) e nao-fixado (mucosa bucal normal) em formol, comparando-se tres metodologias diferentes: fenol com digestao enzimatica, particulas de silica com e sem digestao enzimatica. Para amplificacao do DNA pela tecnica da PCR, utilizou-se iniciadores para o exon 7 da citoqueratina humana tipo 14. O sucesso da amplificacao foi verificado pela eletroforese do produto em gel de poliacrilamida 8% contendo glicerol 5% corado com prata. Obteve-se amplificacao do DNA genomico extraido com fenol/digestao enzimatica e com particulas de silica/digestao enzimatica, para ambos tecidos utilizados. O metodo padronizado tem potencial para auxiliar no diagnostico histopatologico, assim como no estudo retrospectivo de material de arquivo.There are several protocols reported in the literature for the extraction of genomic DNA from formalin-fixed paraffin-embedded samples. Genomic DNA is utilized in molecular analyses, including PCR. This study compares three different methods for the extraction of genomic DNA from formalin-fixed paraffin-embedded (inflammatory fibrous hyperplasia) and non-formalin-fixed (normal oral mucosa) samples: phenol with enzymatic digestion, and silica with and without enzymatic digestion. The amplification of DNA by means of the PCR technique was carried out with primers for the exon 7 of human keratin type 14. Amplicons were analyzed by means of electrophoresis in an 8% polyacrylamide gel with 5% glycerol, followed by silver-staining visualization. The phenol/enzymatic digestion and the silica/enzymatic digestion methods provided amplicons from both tissue samples. The method described is a potential aid in the establishment of the histopathologic diagnosis and in retrospective studies with archival paraffin-embedded samples.

Use of DNA technology in forensic dentistry

The established importance of Forensic Dentistry for human identification, mainly when there is little remaining material to perform such identification (e.g., in fires, explosions, decomposing bodies or skeletonized bodies), has led dentists working with forensic investigation to become more familiar with the new molecular biology techniques. The currently available DNA tests have high reliability and are accepted as legal proofs in courts. This article presents a literature review referring to the main studies on Forensic Dentistry that involve the use of DNA for human identification, and makes an overview of the evolution of this technology in the last years, highlighting the importance of molecular biology in forensic sciences.

Responsabilidade civil do cirurgião-dentista: a importância do assistente técnico

INTRODUCTION: The dentists liability can be understood as the criminal, civil, ethical and administrative obligation that they have in their professional exercise. Thus, when producing a harmful result to the patient, due to imprudence, ineptitude or recklessness, the dentists will be liable to the foreseen penalties on the Civil Code, where the compensation will be obligatory to satisfy the damage according to the reached consequence. In these types of processes, the involved parts will be able to contract a technical assistant to supply the respective lawyers about biological, technician and professional knowledge. AIM: This paper aim to report about the technical assistants importance, in the performance of each one of the involved parts in a civil process. CONCLUSION: It is necessary a major knowledge, by dentists, about legal and ethical aspects in the professional activity.

X-chromosome genetic variation in São Paulo State (Brazil) population

Abstract As data on X-chromosomal short tandem repeats (X-STRs) for the Brazilian population are scarse, the aim of this study was to determine the allele frequencies of five X-STRs (DXS6854, DXS7424, DXS101, DXS6808 and DXS7132) in the São Paulo State, Brazil. No deviations from the Hardy–Weinberg equilibrium were observed, with the exception of DXS101. The forensic efficiency parameters demonstrated that DXS101 was the most informative marker. Population comparisons revealed that the X-STR profile sampled in the state of São Paulo was more similar to European and African populations than Asiatic populations reported in this work.

Dental fluorescence: Potential forensic use

In cases of identification of bones, skeletal segments or isolated bones, searching for biotypologic diagnostic data to estimate an individuals age enables comparing these data with those of missing individuals. Enamel, dentin and pulp undergo remarkable changes during an individuals life. The enamel becomes more mineralized, smoother and thinner, and deteriorates because of physiological and pathological factors. Dental pulp decreases in volume due to the deposition of secondary dentin; thus, the dentin becomes thicker with time. In natural teeth, the fluorescence phenomenon occurs in dentin and enamel and changes in those tissues may alter the expression of the natural tooth color. The aim of this study was to assess the correlation between age and teeth fluorescence for individuals from different age groups. The sample consisted of 66 randomly selected Brazilians of both genders aged 7-63 years old. They were divided into 6 groups: Group 1 - aged 7-12 years, Group 2 - aged 13-20 years, Group 3 - aged 21-30 years, Group 4 - aged 31-40 years, Group 5 - aged 41-50 years and Group 6 - aged between 51 and 63 years. Upper right or left central incisors were used for the study. Restored and aesthetic rehabilitated teeth were excluded from the sample. The measurement of tooth fluorescence was carried out via computer analysis of digital images using the software ScanWhite DMC/Darwin Systems - Brazil. It was observed that dental fluorescence decreases when comparing the age groups 21-30, 31-40, 41-50 and 51-63 years. The results also showed that there is a statistically significant difference between the groups 41-50 years and 21-30 years (p=0.005) and also among the group 51-63 years and all other groups (p<0.005). It can be concluded that dental fluorescence is correlated with age and has a similar and stable behavior from 7 to 20 years of age. It reaches its maximum expected value at the age of 26.5 years and thereafter decreases.

Validation of a physical anthropology methodology using mandibles for gender estimation in a Brazilian population

UNLABELLED Validation studies of physical anthropology methods in the different population groups are extremely important, especially in cases in which the population variations may cause problems in the identification of a native individual by the application of norms developed for different communities. OBJECTIVE This study aimed to estimate the gender of skeletons by application of the method of Oliveira, et al. (1995), previously used in a population sample from Northeast Brazil. MATERIAL AND METHODS The accuracy of this method was assessed for a population from Southeast Brazil and validated by statistical tests. The method used two mandibular measurements, namely the bigonial distance and the mandibular ramus height. The sample was composed of 66 skulls and the method was applied by two examiners. The results were statistically analyzed by the paired t test, logistic discriminant analysis and logistic regression. RESULTS The results demonstrated that the application of the method of Oliveira, et al. (1995) in this population achieved very different outcomes between genders, with 100% for females and only 11% for males, which may be explained by ethnic differences. However, statistical adjustment of measurement data for the population analyzed allowed accuracy of 76.47% for males and 78.13% for females, with the creation of a new discriminant formula. CONCLUSION It was concluded that methods involving physical anthropology present high rate of accuracy for human identification, easy application, low cost and simplicity; however, the methodologies must be validated for the different populations due to differences in ethnic patterns, which are directly related to the phenotypic aspects. In this specific case, the method of Oliveira, et al. (1995) presented good accuracy and may be used for gender estimation in Brazil in two geographic regions, namely Northeast and Southeast; however, for other regions of the country (North, Central West and South), previous methodological adjustment is recommended as demonstrated in this study.

Pericial analysis of a dental element found inside food used for human consumption.

The field of forensic dentistry embodies the human identification in a lot of conditions. A case is described when a tooth-like object was found in a pork sausage. A lawsuit was filed against the food company and the possible dental element was analysed. The tests used to analyze the case were: scanning electronic microscopic exam, radiographic exam and compared anatomy. The results confirmed that the object found in the sausage pack was a dental element from an adult pig; which had the potential for problems like asphyxia or contamination. The case illustrates one facet of forensic dentistry in Brazil.

Phonetic Damage Related to Unilateral Functional Inhibition of the Lingual Nerve

PURPOSE The aim of this study was to analyze the effects of unilateral functional inhibition of the lingual nerve in phonetic function by perceptual and acoustic analyses of speech, which was recorded before and after neurosensory modification of the lingual nerve, and a comparison of results of these evaluations with a subjects self-perception. PATIENTS AND METHODS The sample consisted of 10 volunteers who had the lingual nerve of the right side anesthetized. The analyzed recordings consisted of terms directly dependent on the tongue for production. In the perceptual analysis, pitch and loudness behaviors were observed, in addition to coarticulation and intelligibility. The acoustic analysis of 5 vowels and sibilant /s/ was realized. A questionnaire about the discomfort level in speech production was applied. RESULTS Perceptual/auditive and acoustic parameters showed no significant differences. Although 3 informants declared some kind of discomfort related to speech production, they presented no acoustic or perceptual modification in sound quality. CONCLUSIONS Although inhibition of sensory function of the lingual nerve generated considerable annoyance, there was no specific damage to phonetic function in the group under study, because no differences were observed in the quality of the speech of subjects after applying anesthesia to the lingual nerve.

Avaliação do grau de conhecimento do cirurgião-dentista a respeito das manchas de sangue no contexto forense

Objetivo: o presente trabalho buscou verificar o grau de conhecimento do cirurgiao-dentista sobre aspectos relacionados ao efeito forense do sangue cenografico em diferentes superficies, bem como confirmar a reprodutibilidade de modelos de manchas propostos por Simonin¹ (1966), variando ângulos de incidencia e superficies. Metodos: a amostra foi constituida por cirurgioes-dentistas dos cursos de atualizacao e especializacao da Escola de Aperfeicoamento Profissional da Associacao Brasileira de Odontologia, Porto Alegre, RS. Para a realizacao da pesquisa, foram criados quatro tipos de manchas de sangue teatral com morfologias diferentes (“esfregaco”, “poca” ou “contato”, “escorrimento” e “espargimento”) em superficies de papel (folha A4) e outras seis manchas variando a angulacao (45o e 90o) em tres superficies distintas (jeans, pano e papel). Apos, os componentes da amostra avaliaram as imagens. As respostas foram tabuladas e analisadas estatisticamente. Resultados: sobre a composicao das manchas, 53,2% (n=33) dos pesquisados acertaram a questao. Em relacao a classificacao das manchas, o tipo esfregaco obteve um escore de acertos de 82,3% (n=51) e a angulagem que mais atingiu respostas corretas foi de 90 graus, com 69,3% (n= 43). Conclusao: foi possivel concluir que, embora a maioria dos pesquisados tivessem conhecimentos parciais em relacao ao tema proposto, desconhecem que a pericia em vestigios como manchas ou liquidos oriundos da cavidade bucal ou nela presentes e uma das areas de competencia para atuacao do especialista em Odontologia Legal.

Como justificar a ausência de dano estético? Relato de perícia civil odontológica

Introducao: A perda do patrimonio estetico da pessoa e entendida como a alteracao da complexa imagem que podemos perceber por qualquer dos sentidos, tambem definida como qualquer irregularidade fisica ou alteracao corporal externa, visivel e permanente que pressuponha fealdade ostensiva ao visualizar o ofendido. O valor dessas indenizacoes tem sido fixado por arbitramento dos magistrados, com base no laudo pericial e de acordo com as circunstâncias do caso, ja que nao existe, ainda, dispositivo legal estabelecendo parâmetros objetivos a respeito. Objetivo: O presente trabalho objetiva relatar um caso pericial em que foi aplicada uma metodologia que permite objetivar a impressao e o impacto do prejuizo estetico proposta por Plana (2010), mostrando as razoes pelas quais nao houve dano estetico. Relato de Caso: apresentou-se uma pericia civil onde foi solicitada a avaliacao de danos esteticos em um periciado masculino de 68 anos, o qual relatou uma queda em um estabelecimento comercial. No trauma, verificou-se um ferimento corto contuso no labio inferior e, posteriormente, atraves de imagens radiograficas, a fratura de dentes. Foi mostrada a comparacao do avaliado antes e depois do trauma e verificada e ausencia de dano estetico. Discussao: a utilizacao de parâmetros objetivaveis pelos peritos e assistentes tecnicos na valoracao do dano estetico sao fundamentais para responder, justificar e esclarecer adequadamente a justica. O cirurgiao-dentista, quando investido no papel de avaliador, deve se encontrar atualizado sobre as abordagens existentes, realizar uma descricao pormenorizada e padronizada das lesoes, bem como estar atento para indicar uma visao completa da pessoa a autoridade requisitante, uma vez que nem toda sequela decorrente de trauma remetera a dano estetico com possibilidade de valoracao e indenizacao.