The Role of Cytometry for Male Fertility Assessment in Toxicology

Infertility is nowadays a major concern, affecting approximately 8–12% of the couples and the male factor accounts for about 50% of the cases. Occupational and/or environmental exposure to heavy metals and other pollutants is the main cause of male infertility. Lead, cadmium and chromium are heavy metals widely used in industry and quite persistent in the environment, raising major concerns over the possible effects on the reproductive health of workers and the general population. Sperm DNA integrity is essential for the accurate transmission of paternal genetic information, and normal sperm chromatin structure is important for sperm fertilizing ability. Flow cytometry can be to characterize multiple physical characteristics of the population of spermatozoa in the sperm, including sperm concentration, viability, mitochondrial mass and function, acrosome integrity, capacitation, membrane fluidity, DNA content and status, etc. This chapter elucidates the role of cytometry in the study of male fertility under toxicological insult by pollutants such as chromium, cadmium and lead. Some representative examples are presented using in vivo studies with rodents. In addition, complementary techniques to cytometry and future perspectives will be mentioned in an interdisciplinary point of view to gain knowledge on this subject

Influence Of Post-thickness And Material On The Fracture Strength Of Teeth With Reduced Coronal Structure

Purpose: To evaluate the fracture strength of endodontically treated teeth with reduced coronal structure reinforced with glass-fiber posts and cast posts and core (nickel-chromium alloy) with different thickness. Materials and Methods: Forty maxillary central incisors were sectioned at 1 mm of the cementoenamel junction and endodontically treated. The teeth were divided into four groups (n = 10) and restored with cast post and core and glass-fiber posts with diameters of 1.5 mm and 1.1 mm. The fracture strength was evaluated using a Universal Testing Machine (Instron 1144) at 45° of angulation. The results were submitted to analysis of variance two-way and Tukey′s test ( P < 0.05). The failure mode was also evaluated. Results: Cast post and core were statistically superior to the glass-fiber posts with the self-post diameter ( P = 0.001). When the self-post material was considered, no significant difference was observed between the two post-diameters ( P = 0.749). The glass-fiber post-groups presented more fractures in the cervical third than the cast post and core groups. Conclusion: Teeth restored with cast post and cores present higher fracture strength than those reinforced with glass-fiber posts. An increased post-thickness does not increase the fracture strength. 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