Evaluation of Regular Market Ethyl Cyanoacrylate Cytotoxicity for Human Gingival Fibroblasts and Osteoblasts.

Background: The aim of this study was to evaluate the cytotoxicity of cyanoacrylate adhesives in an indirect contact assay in human gingival fibroblast (FGH) and oral osteoblasts (GO) lineages. Methods: Cover glasses were glued with adhesives following the ISO 10993-2012 protocol. The groups were: C (control with cells and regular Dulbecco Modified Eagle Medium; LC (liquid ethyl-cyanoacrylate); GC (ethyl-cyanoacrylate gel); EGC (easy gel [ethyl-cyanoacrylate]); and D (Dermabond [octyl-cyanoacrylate]). Each cell linage was plated in the sixth passage using 104 cells. Cell viability was measured by the MTT test at 24, 48, 72, and 96 hours. Data were analyzed by two-way analysis of variance complemented by the Tukey test, with p < 0.05 being significant. Results: Dermabond stimulated osteoblast viability at 72 h (p < 0.05). All other groups were similar to the control cells (p > 0.05). For the fibroblasts, there was no difference in the groups, including the control except that EGC was cytotoxic for these cells (p < 0.05). Conclusions: Ethyl-cyanoacrylate gel and liquid forms available on the general chemical market were not cytotoxic for oral osteoblasts and fibroblasts in most cases. However, the easy gel form was cytotoxic for fibroblasts.

Low intensity lasers differently induce primary human osteoblast proliferation and differentiation.

Among various compounds used in research and clinic for degenerative bone diseases, low level laser therapy (LLLT), comprising low level lasers (LLL) and light emitting diodes (LEDs), has been investigated regarding its effects on bone metabolism. They have specific wavelengths but in general act as a cellular biomodulator, and as a therapeutic agent, rebalancing and normalizing their activity. However, they are not standardized yet, since their parameters of use are relevant for the effects and mechanisms of action. Therefore, the aim of this study was to compare the influence of two spectrums of LLL and LED phototherapy, at the same energy densities (10 and 50J/cm(2)), on human osteoblasts proliferation and differentiation. The involvement of ERK signaling on proliferation was also investigated by evaluating its activation during proliferation under different phototherapies by western blotting and CFSE-based osteoblast proliferation was measured in a presence or absence of the ERK-specific inhibitor. Osteogenic differentiation was evaluated through in vitro mineralization and gene expression of type I collagen (COL1A1) and osteonectin (SPARC) by Real Time- PCR. Increases in viable cells and proliferation were obtained after irradiation, regardless of LLLT type. However, only red at 10J/cm(2) and infrared at both doses, but not LED, induced ERK1/2 activation. In the presence of ERK inhibitor, the LLL-induced proliferation was prevented. In addition, while COL1A1 gene expression was upregulated by red laser, SPARC does so by infrared stimulation. However, LED, at both doses, increased both COL1A1 and SPARC expression. All LLLT increased mineralization, dependent on the dose and time. Thus, LLL and LED differently modulated the metabolism of human osteoblasts, increasing proliferation by mechanism dependent or not of ERK signaling activation and osteogenic differentiation markers.