RESUMEN
Studies regarding cytotoxic effects attributed to the use of adhesive bonding agents on pulp tissue are not conclusive. To point out whether these materials are safe for clinical use, in vivo exposure of dental pulp to adhesive bonding agents was simulated using an experimental setup in which Human Dental Pulp Stem Cells (hDPSC) are exposed to the action of two kinds of adhesives: self-etching adhesives and two-step bonding agents through a dentine barrier. Cytotoxic effects on these cells were evaluated by MTT assay protocol and fluorescence microscopy, and their results were contrasted to those obtained through Raman spectra taken on single hDPSCs. Overall, no significant cytotoxic effects were observed by combining all the techniques, and cell viability close to 90% was achieved for a dentine barrier of at least 1 mm thick. Moreover, Raman spectroscopy was able to detect structural DNA damage in some dental pulp cells when exposed to two-step bonding agents, suggesting that this technique could be considered a complementary tool with the potential to evaluate cell toxicity beyond cell viability.
Asunto(s)
Supervivencia Celular , Pulpa Dental , Recubrimientos Dentinarios , Espectrometría Raman , Células Madre , Humanos , Pulpa Dental/citología , Pulpa Dental/efectos de los fármacos , Células Madre/efectos de los fármacos , Recubrimientos Dentinarios/toxicidad , Supervivencia Celular/efectos de los fármacos , Microscopía Fluorescente , Células CultivadasRESUMEN
Abstract Studies regarding cytotoxic effects attributed to the use of adhesive bonding agents on pulp tissue are not conclusive. To point out whether these materials are safe for clinical use, in vivo exposure of dental pulp to adhesive bonding agents was simulated using an experimental setup in which Human Dental Pulp Stem Cells (hDPSC) are exposed to the action of two kinds of adhesives: self-etching adhesives and two-step bonding agents through a dentine barrier. Cytotoxic effects on these cells were evaluated by MTT assay protocol and fluorescence microscopy, and their results were contrasted to those obtained through Raman spectra taken on single hDPSCs. Overall, no significant cytotoxic effects were observed by combining all the techniques, and cell viability close to 90% was achieved for a dentine barrier of at least 1 mm thick. Moreover, Raman spectroscopy was able to detect structural DNA damage in some dental pulp cells when exposed to two-step bonding agents, suggesting that this technique could be considered a complementary tool with the potential to evaluate cell toxicity beyond cell viability.
Resumo Os estudos sobre os efeitos citotóxicos atribuídos ao uso de agentes de união adesivo no tecido pulpar não são conclusivos. Para determinar se esses materiais são seguros para uso clínico, a exposição in vivo da polpa dentária a agentes de união adesiva foi simulada por meio de uma configuração experimental na qual as células-tronco da polpa dentária humana (hDPSC) são expostas à ação de dois tipos de adesivos: adesivos autocondicionantes e agentes de união de duas etapas por meio de uma barreira de dentina. Os efeitos citotóxicos nessas células foram avaliados pelo protocolo de ensaio MTT e microscopia de fluorescência, e seus resultados foram contrastados com os obtidos por meio de espectros Raman obtidos em hDPSCs individuais. De modo geral, não foram observados efeitos citotóxicos significativos com a combinação de todas as técnicas, e a viabilidade celular próxima a 90% foi obtida para uma barreira de dentina de pelo menos 1 mm de espessura. Além disso, a espectroscopia Raman foi capaz de detectar danos estruturais ao DNA em algumas células da polpa dentária quando expostas a agentes de colagem de duas etapas, sugerindo que essa técnica poderia ser considerada uma ferramenta complementar com potencial para avaliar a toxicidade celular além da viabilidade celular.
