Cytotoxicity of dental alginates / Citotoxicidade de alginatos odontológicos

Purpose: To evaluate the cytotoxicity of dental alginate (irreversible hydrocolloid), which is widely used as an impression material in Dentistry. Methods: Four dental products were assessed: J (Jeltrate Traditional), ALG (Alga Gel), PG (Printer Gel), and AVG (Ava Gel). Three control groups were used: positive (C+) cell detergent Tween 80, negative (C-) PBS, and control of cells (CC - no exposure of cells to any substance). Disk-shaped specimens were immersed in Eagle minimum essential. The supernatants were collected after 24, 48, 72, and 168 hours (7 days) for analysis of the toxicity to L929 fibroblast cells after 24-h incubation. Viable cells stained with 0.01% neutral red dye were counted using a spectrophotometer. Data were analyzed by ANOVA and Tukey's test (α=0.05).Results: Significant differences in number of viable cells were found between the alginate groups and C- or CC (P<0.05). The group J showed the highest cytotoxicity level followed by PG, ALG, and AVG. Conclusion: All dental alginates tested showed some cytotoxic response from fibroblasts.

Objetivo: Avaliar a citotoxicidade de alginatos (hidrocolóide irreversível) de uso odontológico, os quais são a categoria de material de moldagem mais utilizada em Odontologia. Metodologia: Foram avaliadas quatro marcas de alginato: grupo J (Jeltrate Tradicional), ALG (Alga Gel), PG (Printer Gel) e AVG (Ava Gel). Utilizaram-se 3 grupos controle: positivo (C+) com detergente celular Tween 80, negativo (C-) com PBS, e controle de célula (CC), onde as células não foram expostas a nenhum material. Espécimes em forma de disco foram imersos em meio mínimo essencial Eagle. O sobrenadante foi coletado 24, 48, 72 e 168 horas (7 dias) para análise de toxicidade para fibroblastos L929 após 24 h de incubação. As células viáveis foram coradas com corante vermelho neutro a 0,01%, fixadas e contadas em espectrofotômetro. Os dados foram analisados por ANOVA e teste de Tukey (α=0,05). Resultados: Houve diferença significativa do número de células viáveis entre os alginatos e os grupos C- ou CC (P<0,05). O grupo J apresentou a maior citotoxicidade, sendo seguido por PG, ALG e AVG. Conclusões: Pode-se concluir que todos os alginatos testados mostraram resposta citotóxica para fibroblastos.

Culture of osteoblasts by serial explant culture and comparison of their characteristics / 北京大学学报(医学版)

Objective:To Investigate a simple, economical and efficient method of primary osteoblast culture and compare their characteristics. Methods:Primary osteoblasts of 1 st -4 th series explant culture from calvarial bones of neonatal Sprague Dawley rats,were collected and osteoblasts shape, mitosis, proliferation, ALP activity and immunohistological expression of osteocalcin and BMP 2 observed. Results:No difference was found in cell shape, spread, conflunce, ALP activity as well as immunohistological stain of osteocalcin and BMP 2 of the osteoblasts, which had been harvested from the 1 st -4 th series explant cultures of Sprague Dawley rats. Conclusion:Series explant culture can harvest the same kind of osteoblasts as the explant culture, and more osteoblasts can be obtained at a single time. It saves money and time and is easy to manipulate.