A Preliminary Research Study on the Cytotoxicity of Expired and Non-expired Composite Resins: In Vitro Study / Estudio preliminar in vitro de la citotoxicidad de resinas compuestas caducadas y no caducadas

Astracts Objective: Studies have focused on use of non-expired composites. Unfortunately some clinicians still use expired composite resins without considering their effects. The objective of this in vitro preliminary research was to investigate cytotoxicity of expired(6-months) and non-expired composite resins. Materials and methods: Expired (E) and non-expired (NE) samples of one bulk-fill (Tetric N-Ceram Bulk-fill (TNB), Ivoclar Vivadent), two nano-hybrid (Tetric N-Ceram (TN), Ivoclar Vivadent; Clearfil Majesty ES-2 (CM), Kuraray) composite resins were tested on L929 fibroblast cells. Medium covering cells was removed then plastic rings (2-mm height) were filled with non-polymerized composite resins, placed in direct contact with cells and polymerized with LED light curing unit (LCU). Three samples were prepared for each group. After polymerization, removed medium was added to the cells. Cells that were left without medium (WOM) and cells that were exposed to LCU were used as positive control groups. Cells without any treatment were used as negative control group (C). Cells were incubated with tested materials for 7-days to evaluate cytotoxicity. Cell viability was calculated by sulforhodamine B test as a percentage (%). One-way ANOVA and post-hoc Tukey tests were used for statistical analyses (p0.05), except between TN NE and TN E (p0.05). All experimental groups compared with C group showed statistically significant cytotoxicity (p<0.05). A statistically significant difference existed between LCU and C groups (p<0.05). Conclusions: In clinical practice, expired composite resins should never be used. Although a correlation was found between expiration dates of nano-hybrid composite resins and cell viability, opposite data were obtained for bulk- fill composite resin. Researches are still required to evaluate biocompatibility of bulk- fill composite resins at various thicknesses with current LCUs.

Resumen Objetivo: Los estudios se han concentrado en el uso de resinas compuestas no vencidos. Desafortunadamente, algunos clínicos aún usan resinas caducadas sin considerar sus efectos. El objetivo de este estudio preliminar in vitro fue investigar la citotoxicidad de resinas compuestas caducadas (6 meses) y no caducadas. Materiales y métodos: muestras caducadas (E) y no caducadas (NE) de una resina bulk-fill (Tetric N-Ceram Bulk-fill (TNB), Ivoclar Vivadent) y dos resinas nanohíbridas (Tetric N-Ceram (TN) Ivoclar Vivadent) (Clearfil Majesty ES-2 (CM), Kuraray), se probaron en células de fibroblastos L929. Se retiraron las células que cubrían el medio, luego se llenaron anillos de plástico (2 mm de altura) con resinas no polimerizadas, se colocaron en contacto directo con las células y se polimerizaron con una unidad de fotocurado LED (LCU). Se prepararon tres muestras para cada grupo. Después de la polimerización, se añadió el medio eliminado a las células. Las células que quedaron sin medio (WOM) y las células que se expusieron a LCU se usaron como grupos de control positivo. Las células sin ningún tratamiento se utilizaron como grupo de control negativo (C). Las células se incubaron con las resinas durante 7 días para evaluar la citotoxicidad. La viabilidad celular se calculó mediante la prueba de sulforodamina B como un porcentaje (%). ANOVA unidireccional y pruebas post-hoc de Tukey se utilizaron para los análisis estadísticos (p 0.05), excepto entre TN NE y TN E (p 0.05). Todos los grupos experimentales en comparación con el grupo C mostraron citotoxicidad estadísticamente significativa (p <0,05). Existió una diferencia estadísticamente significativa entre LCU y grupos C (p <0.05). Conclusiones: En la práctica clínica, las resinas compuestas caducadas nunca deben usarse. Aunque se encontró una correlación entre las fechas de vencimiento de las resinas compuestas nano-híbridas y la viabilidad celular, se obtuvieron datos opuestos para la resina bulk-fill. Se requieren nuevas investigaciones para evaluar la biocompatibilidad de las resinas bulk-fill en distintos espesores con las LCU actuales.

Cytotoxic, genotoxic and apoptotic effects of naringenin-oxime relative to naringenin on normal and cancer cell lines

Objective: To assess and compare the cytotoxic, genotoxic, apoptotic and reactive oxygen species (ROS) generating effects of naringenin (NG) and its new derived compound naringenin-oxime (NG-Ox) on MCF-7, HT-29, PC-12 cancer and L-929 normal cell lines. Methods: The cells were incubated with different doses of NG-Ox and NG (50–1 000 mmol/L) for 24 h. The cell viability was assessed based on ATP cell viability assay. Intracellular accumulation of ROS was determined using the fluorescent probes 2070-dichlorodihydrofluorescin diacetate. Genotoxic effects were evaluated by alkaline single cell gel electrophoresis assay (comet assay) and, the apoptotic effect was evaluated by acridine orange staining at below the IC50 levels. Results: Both NG-Ox and NG exhibited cytotoxic, genotoxic and apoptotic effects and resulted in increased ROS values in a dose-dependent manner. The effects were more pronounced on cancer cell lines. The cytotoxic, genotoxic and apoptotic effects of NG-Ox were higher than that of NG in all cell lines. Significant correlations were observed be-tween cell viability, DNA damage, apoptosis and ROS, in all cell lines exposed to either NG-Ox or NG. Conclusions: This study showed that both NG-Ox and NG possess cytotoxic, genotoxic and apoptotic activities through the production of ROS on cells, NG-Ox being the more effective one. Therefore, derived compound of NG might be used as antiproliferative agents for the treatment of cancer.