Forensic exploration of endodontic cements: Unveiling macroscopic and radiographic changes under high temperatures.

OBJECTIVE: To evaluate macroscopically and radiographically the behavior of four endodontic sealers submitted to high temperatures, with forensic purposes. METHODS: Sixty-four lower anterior teeth were included. All teeth were endodontically treated, and simulation of external cervical resorption (ECR) was performed. Half of the sample was filled with AH-Plus™ cement and had ECR sealed with Bio-C-Repair™. The other 32 teeth were filled with Bio-C-Sealer™ cement and had their respective ECR sealed with MTA-Repair™. Then, all teeth were introduced into a bovine bone block to simulate the alveolar bone. The teeth were submitted to incineration at temperatures of 600, 800, 1000, and 1140 °C. All teeth were radiographed before and after incineration. The pre-and post-incineration radiopacity of cements and dentin were evaluated using the ImageJ™ software and compared using a t-test for paired samples. RESULTS: It was possible to confirm color change and appearance of cracks in the tissues and dental materials tested, varying according to the temperature. Radiographically, it was observed that the dental crowns completely detached at 1000 ° and 1140 °C, and, only at 1140 °C, the roots showed cracks. Regarding the radiopacity, there was a significant difference in the shades of gray in AH-Plus™ when subjected to 1000 ° and 1140 °C, and at 600 ° and 1000 °C in Bio-C-Sealer™. In Bio-C-Repair™ and MTA-Repair™, a difference was observed at 600 ° and 1140 °C. CONCLUSIONS: There were macroscopic and radiographic alterations of the materials. This data is important in Forensic Dentistry and may contribute to identifying carbonized victims.

Photoperiod and testosterone modulate growth and melanogenesis of s91 murine melanoma.

In vivo and in vitro assays were performed with S91 murine melanoma cells aiming to investigate the effects of testosterone and photoperiod on tumor growth and melanogenesis (tyrosinase activity). In vivo assays were performed by inducing melanoma tumors in castrated mice receiving increasing concentrations of testosterone and submitted to varying photoperiod regimens. The results demonstrated that the increase of melanin content was higher in animals submitted to the longest days, thus demonstrating the importance of photoperiod length in melanin synthesis. Increase in tumor growth and protein content was observed in testosterone-treated animals submitted to 12L:12D; in testosterone-treated animals submitted to 4L:20D and 20L:4D tumor growth was significantly smaller. In S91 cultured cells, testosterone increased cell proliferation and reduced tyrosinase activity in a dose-dependent manner. Radioactive binding assays demonstrated that the hormone was acting through low affinity testosterone receptors, since the presence of aromatase inhibitor did not affect the binding assay in a statistically significant way, and all the in vitro experiments were performed in the presence of the inhibitor. Our in vivo data added to the in vitro results corroborate the hypothesis that S91 melanoma cells directly respond to testosterone and that this effect is modulated by light.