RESUMEN
Despite its proven cytotoxicity, poly-methyl methacrylate (PMMA) resin is one of the most frequently and extensively used materials in dental practice. This study hypothesized that an anti-oxidant amino acid, N-acetyl cysteine (NAC), has the potential to detoxify this material. Ten percent of the rat dental pulp cells were viable when cultured on the PMMA resin for 24 hours, while over 70% of the cells were viable on the NAC-added resin. Nearly all suppressed alkaline phosphatase activity, matrix mineralizing capability, and odontoblastic gene expression, such as dentin sialoprotein, on the untreated control resin was recovered by NAC in a concentration-dependent manner. A Ca/P ratio of 1.65 was found in the extracellular matrix of cultures on NAC-added resin, while that in the untreated resin culture was 0.70. The addition of NAC to PMMA resin significantly ameliorated its cytotoxicity to the dental pulp cells and restored their odontoblast-like cell phenotype to a biologically significant degree.
Asunto(s)
Acetilcisteína/farmacología , Antioxidantes/farmacología , Pulpa Dental/efectos de los fármacos , Depuradores de Radicales Libres/farmacología , Polimetil Metacrilato/toxicidad , Acetilcisteína/administración & dosificación , Fosfatasa Alcalina/antagonistas & inhibidores , Fosfatasa Alcalina/efectos de los fármacos , Animales , Antioxidantes/administración & dosificación , Apoptosis/efectos de los fármacos , Biotransformación , Calcificación Fisiológica/efectos de los fármacos , Calcio/análisis , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Colágeno Tipo I/antagonistas & inhibidores , Colágeno Tipo I/efectos de los fármacos , Pulpa Dental/citología , Relación Dosis-Respuesta a Droga , Matriz Extracelular/química , Matriz Extracelular/efectos de los fármacos , Proteínas de la Matriz Extracelular , Depuradores de Radicales Libres/administración & dosificación , Masculino , Odontoblastos/efectos de los fármacos , Fosfoproteínas/antagonistas & inhibidores , Fosfoproteínas/efectos de los fármacos , Fósforo/análisis , Precursores de Proteínas/antagonistas & inhibidores , Precursores de Proteínas/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , SialoglicoproteínasRESUMEN
The application of implant therapy is still limited, because of various risk factors and the long healing time required for bone-titanium integration. This study explores the potential for osseointegration engineering with dental pulp cells (DPCs) by testing a hypothesis that DPCs generate mineralized tissue on titanium. DPCs extracted from rat incisors positive for CD44, alkaline phosphatase activity, and mineralizing capability were cultured on polystyrene and on machined and dual-acid-etched (DAE) titanium. Tissue cultured on titanium with a Ca/P ratio of 1.4 exhibited plate-like morphology, while that on the polystyrene exhibited fibrous and punctate structures. Tissues cultured on titanium were harder than those on polystyrene, 1.5 times on the machined and 3 times on the DAE. Collagen I, osteopontin, and osteocalcin genes were up-regulated on titanium, especially the DAE surface. In conclusion, DPCs showing some characteristics of the previously identified dental pulp stem cells can generate mineralized tissue on titanium via the osteoblastic phenotype, which can be enhanced by titanium surface roughness.