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Resumen Introducción: El Bisfenol A (BPA) es un producto químico al que los seres humanos están expuestos ampliamente por la vía oral, inhalación y transdérmica. Justificación: Dada la importancia de la patología oncológica que puede estar asociada a exposición a este químico, resulta imprescindible comprender mejor sus posibles mecanismos de acción asociados a carcinogénesis. Objetivo General: Investigar el mecanismo carcinogénico asociado a la exposición a BPA. Resultados: Aunque la mayoría de las investigaciones se han orientado hacia el efecto disruptor endocrino, con la limitante que los estudios in vivo son realizados en animales, existen estudios recientes que muestran su posible efecto carcinogénico en tejidos humanos. Sin embargo, se requiere más investigación sobre el papel del BPA de dosis baja (como ocurre en condiciones ambientales normales) y su efecto en la regulación de los cambios globales de expresión génica y las alteraciones epigenéticas en las células, que permitan establecer vínculos con carcinogénesis; esta revisión demuestra que los estudios realizados hasta la fecha señalan varios factores que pueden estar involucrados, como efectos mutagénicos que incluyen cambios en la transcripción génica y enzimáticos que promueven la proliferación celular limitando la apoptosis y favorecen la angiogénesis y migración de células tumorales. Conclusión: Si bien en la actualidad se reconoce que la célula cancerígena adquiere características patológicas que le ayudan a sobrevivir en el organismo, estas características obedecen a mecanismos moleculares genéticos y epigéneticos, muchos de los cuales han sido descritos para el caso de la exposición humana al BPA.

Abstract Introduction: Bisphenol A (BPA) is a chemical to which humans are extensively exposed orally, inhaled and transdermally. Justification: Given the importance of the oncological pathology that may be associated with exposure to this chemical, it is essential to better understand its possible mechanisms of action associated with carcinogenesis. Objective: To investigate the carcinogenic mechanism associated with BPA exposure. Results: Although the majority of investigations have been oriented towards the endocrine disrupting effect, with the limitation that in vivo studies are carried out in animals, recent studies have shown that they can be carcinogenic in human tissues. However, more research is required on the role of low-dose BPA (as occurs under normal environmental conditions) and its effect on the regulation of global changes in gene expression and epigenetic alterations in cells, which allow establishing links with carcinogenesis; this review shows that the studies carried out to date point to several factors that may be involved, such as mutagenic effects that include changes in gene transcription and enzymes that promote cell proliferation, limiting apoptosis and promoting angiogenesis and migration of tumor cells. Conclusion: Although it is currently recognized that the cancer cell acquires pathological characteristics that help it to survive in the organism, these characteristics are due to genetic and epigenetic molecular mechanisms, many of which have been described for the case of human exposure to BPA.

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ABSTRACT This study was conducted to find out the ameliorative properties of Tribulus terristeris L (TT) on BPA induced spermatotoxicity in male albino rats. Mature male albino rats were divided into five groups, Group A was taken as control for comparison group, whereas the other four groups namely B(vehicle control), C (toxic), D (preventive control) and Group E (amelioration group) received distilled water, olive oil, BPA, TT, and (TT + BPA) respectively. Macroscopic results revealed decreased body weight of rats, weight of testes, and the relative tissue weight index (RTWI) in BPA induced group. Hormonal (testosterone) assay results revealed the decreased values of BPA treated group. Microscopic examination of testis of BPA treated rats showed reduction in leydig cells, decreased diameter of seminiferous tubules and low values of Johnsen's scoring. Histological examination showed discontinuity and irregularity of basement membrane and sloughing of the germinal cell linage. Group E showed the body weights of rats, weight of testes, RTWI, and increased, while reduced level of testosterone, reduced number of Leydig cells, decreased diameter of seminiferous tubules and low values of Johnsen's scoring were restored near to normal. These results demonstrate that TT might be beneficial in combating the spermatotoxicity, induced by BPA.

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OBJECTIVE: As resin-modified glass-ionomer cement (RMGIC) is an adhesive material, its association to dentin bonding agents (DBAs) was previously proposed. This study investigated the adjunctive behavior of an RMGIC with etch-and-rinse bonding systems under in situ/ex vivo cariogenic challenge. METHOD AND MATERIALS: Bovine enamel blocks (3 3 3 3 2 mm) were randomly assigned to group VP, Vitremer + its own primer (3M ESPE); group VSB, Vitremer + Single Bond (3M ESPE); and group VPB, Vitremer + Prime and Bond 2.1 (Dentsply). Two blocks of each group were randomly placed in an acrylic palatal appliance, so each appliance included six blocks. Volunteers (n = 10) wore these appliances according to given instructions to promote a sucrose challenge eight times/day for 15 days. After this period, the blocks were removed from the devices and cleaned, and demineralization was assessed through longitudinal microhardness analysis (Knoop indenter, 25 g/5 s). Data were submitted to three-way ANOVA and Tukey test (P < .05). RESULTS: No treatment was able to completely avoid demineralization. All materials showed a statistically significant difference in mineral loss when the microhardness on the outer enamel was compared with deeper regions (P < .05). CONCLUSION: Association of the tested RMGICs with etch-and-rinse DBAs did not seem to be more beneficial against caries than the conventional treatment with RMGIC.

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PURPOSE: This study evaluated the postoperative sensitivity of posterior Class I composite resin restorations, restored with a self-etching or a total-etch one-bottle adhesive system. MATERIALS AND METHODS: One hundred four restorations were replaced by one clinician in 52 patients. Each patient received two restorations. After cavity preparations were completed under rubber-dam isolation, they were restored using Clearfil SE Bond or Single Bond and a resin-based restorative material (Filtek Z250). Sensitivity was evaluated at 0 and 7 days and 6 months using cold stimuli, and recorded using a visual analogue scale. If sensitivity was experienced on day 7, patients were also contacted on days 14 and 30 to assess the degree of sensitivity. The scores were analyzed as nonparametric data by means of the Friedman and Wilcoxon tests. RESULTS: No statistically significant differences in sensitivity were found between the two adhesives systems at days 0 and 7 or at 6 months. No spontaneous postoperative sensitivity was reported. CONCLUSIONS: The adhesives systems used in this study showed no differences in postoperative sensitivity, and did not show spontaneous sensitivity after 6 months.

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Because the risk of dental caries increases with the use of orthodontic appliances and its control cannot depend only on the patient's self-care, this study evaluated the effect of a glass ionomer cement on reducing enamel demineralization around orthodontic brackets. Fourteen orthodontic patients were randomly divided into 2 groups of 7; they received 23 brackets fitted to their premolars, bonded with either Concise (3M Dental Products, St Paul, Minn), a composite resin (control group), or Fuji Ortho LC (GC America, Chicago, Ill), a resin-modified glass ionomer cement (experimental group). The volunteers lived in a city that has fluoridated water, but they did not use fluoridated dentifrices during the study. After 30 days, the teeth were extracted and longitudinally sectioned; in the enamel around the brackets, demineralization was assessed by cross-sectional microhardness. The determinations were made at the bracket edge cementing limits, and at occlusal and cervical points 100 and 200 microm away from them. In all of these positions, indentations were made at depths from 10 to 90 microm from enamel surface. Analysis of variance showed statistically significant effects for position, material, depth, and their interactions (P<.05). The Tukey test showed that the glass ionomer cement was statistically more efficient than the control, reducing enamel demineralization in all analyses (P<.05). The use of glass ionomer cement for bonding can be encouraged because it decreases the development of caries around orthodontic brackets.

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The vascular changes in the subcutaneous connective tissue of rats induced by dentin bonding systems (one step) was studied and compared to those induced by saline solution (negative control) and Furacin (positive control), during the exudative phase of the inflammatory process. Twenty mg/kg of Evan's blue were injected intravenously in the vein of the rats' penises; 0.1 ml of each substance tested was inoculated in the subcutaneous tissue. After a 3 hour period the animals were sacrificed and their skins were excised and punched out with a standard steel 2.5 cm in diameter. The specimens were immediately immersed in 8 ml of formamide and taken to a double boiler for 72 hours at 37 C, to remove the dye. The liquid containing the overflowed dye was filtered, analyzed in the spectrophotometer (620 nm) and classified according to the criteria established by Nagem-Filho, Pereira (1976). After statistical analysis, the irritative potential of the substances was ranked as follows: Furacin (severe) > Single Bond and Bond 1 (moderate - no significant differences between the dentin bonding systems tested) > saline solution (not significant as regards the irritation degree).

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The vascular changes in the subcutaneous connective tissue of rats induced by dentin bonding systems (one step) was studied and compared to those induced by saline solution (negative control) and Furacin (positive control), during the exudative phase of the inflammatory process. Twenty mg/kg of Evan's blue were injected intravenously in the vein of the rats' penises; 0.1 ml of each substance tested was inoculated in the subcutaneous tissue. After a 3 hour period the animals were sacrificed and their skins were excised and punched out with a standard steel 2.5 cm in diameter. The specimens were immediately immersed in 8 ml of formamide and taken to a double boiler for 72 hours at 37ºC, to remove the dye. The liquid containing the overflowed dye was filtered, analyzed in the spectrophotometer (620 nm) and classified according to the criteria established by Nagem-Filho, Pereira (1976). After statistical analysis, the irritative potential of the substances was ranked as follows: Furacin (severe) > Single Bond and Bond 1 (moderate - no significant differences between the dentin bonding systems tested) > saline solution (not significant as regards the irritation degree)

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