The mineralization of third molars has been used repeatedly as a method of forensic age estimation. However, this procedure is of little use beyond age 18, especially to determinate if an individual is older than 21 years of age; thus, the development of new approaches is essential. The visibility of the periodontal ligament has been suggested for this purpose. The aim of this work was to determine the usefulness of this methodology in a Portuguese population. Periodontal ligament visibility was assessed in the lower third molars, using a sample of 487 orthopantomograms, 228 of which belonging to females and 259 to males, from a Portuguese population aged 17 to 31 years. A classification of four stages based on the visual phenomenon of disappearance of the periodontal ligament of fully mineralized third molars was used. For each stage, median, variance, minimal and maximal age were assessed. The relationship between age and stage of periodontal ligament had a statistical significance for both sexes. In this population, stage 3 can be used to state that a male person is over 21 years-old; for females, another marker should be used. This technique can be useful for determining age over 21, particularly in males. Differences between studies are evident, suggesting that specific population standards should be used when applying this technique. Key words:Forensic sciences, forensic odontology, age estimation, third molar, periodontal ligament.

Micronuclei (MN) are abnormal nuclear structures that arise in dividing cells due to chromosomal breakage or chromosome mis-segregation, and their evaluation in oral exfoliated cells may constitute a reliable and noninvasive, cancer biomarker method. Therefore, it is crucial to assess whether different aspects of oral health can induce micronuclear formation. Because chronic periodontal disease is a prevalent inflammatory condition that may lead to reactive oxygen species generation and DNA damage, the aim of this study was to characterize the frequency of micronuclei according to the periodontal status. For this purpose, we analyzed oral exfoliated cells of 30 patients matched by age and sex (15 control patients with healthy periodontum to mild periodontitis and 15 patients with moderate to severe periodontitis). Our results indicated a 2.3-fold increase in MN basal levels in patients with moderate to severe periodontitis compared to the control patients (P < 0.001), suggesting that the periodontal status may affect MN reference levels

Traditionally, dental identification techniques are used to establish identity or assist in reconstructing an individual's biological profile. However, other aspects of identity, namely socioeconomic status (SES), can be estimated through teeth. This work aims to evaluate the influence of SES on third molar agenesis in a Portuguese population. X-rays from 448 subjects (223 belonging to a high and 225 to a low socioeconomic status) were assessed and demographic data (age, sex) and dental history were registered. Frequencies and associations between the variables were analyzed using the chi-square test. For each group, differences between third molar agenesis were studied using the Wilcoxon test. The significance level was 5%. X-rays displaying at least one agenesis were more common in females (in both SES groups). Differences between socioeconomic status were found in female subjects' upper right and lower left third molars, with a higher frequency of agenesis in the lower SES group. Agenesis of lower third molars displayed fluctuant asymmetry in both groups, whereas agenesis of upper third molars was also present in the lower SES group. These results suggest that socioeconomic status can affect third molar agenesis prevalence, and fluctuant asymmetry seems more prevalent in the lower SES, as it affects all third molars.

In vitro cytotoxicity testing of dental acrylic resins is fundamental to establish clinical safety limits, requiring suitable cell models that closely simulate physiological processes. This study's main aim is to evaluate the viability of an untransformed human gingival fibroblast cell line, as an oral cell model for acrylic resin cytotoxicity tests. For this purpose, cell viability was compared to a control cell line (Chinese hamster lung fibroblast), following exposure to increasing concentrations of methyl methacrylate and formaldehyde (acrylic resins’ leachable compounds). Additionally, because of the volatile nature of these compounds and their harmful effects on the respiratory tract, a human fetal lung fibroblast line was also tested. Two-way ANOVA of generated data (p<0.05) showed that all cell types are significantly affected in a dose dependent manner by these chemicals. Further characterization of the human gingival fibroblast line shall be addressed in future biocompatibility studies