Initial osteoblast functions on a type of near β-type titanium alloys surfaces modified by the double glow plasma nitriding technology / 中华口腔医学杂志

Objective@#To evaluate the adhesion, proliferation, alkaline phosphatase (ALP) activity and the expression of osteogenesis-related genes and osteoprotegerin (OPG)/receptor activator of NF-κB ligand (RANKL) of osteoblast-like cells on a type of near β-type titanium alloys (Ti-5Zr-3Sn-5Mo-15Nb, TLM) surfaces modified by the double glow plasma nitriding technology, and to investigate the effect of the modified surfaces on the initial functions of osteoblast-like cells. @*Methods@#The surfaces of TLM were modified by the double glow plasma nitriding technology. TLM surfaces without modification were used as control. Cell morphology was observed with scanning electron microscopy (SEM). Methyl thiazolyl tetrazolium (MTT) method was used to measure cell proliferation. Cell ALP activity was evaluated by using reagent kits. The mRNA expression of Runt-related transcription factor-2 (RUNX2), typeⅠcollagen alpha 1 chain (COLⅠ α1) and OPG/RANKL were examined by quantitative real-time PCR(qRT-PCR). @*Results@#Four hour following cell alture, cells on modified surfaces extend filopodia and intercellular junction was tight. Three days later, cell proliferation (0.277±0.007) was significantly higher than that in control group (0.249±0.004) (P<0.01). After two weeks, ALP activity on TLM modified layer (173.6±1.89) was significantly higher than that on unmodified TLM (162.6±2.4) (P<0.01). The mRNA expression of osteoblast marker RUNX2, COLⅠα1 were stronger than that in control group (P<0.05). The expression of OPG mRNA was higher than that in control group (P<0.01), and RANKL mRNA expression was significantly lower than that in control group (P<0.05). @*Conclusions@#The TLM surface modified by the double glow plasma nitriding technology has a positive effect on osteoblasts initial adhesion, proliferation and differentiation, and it can also improve expression of OPG mRNA and has an inhibitory effect on RANKL mRNA expression of osteoblasts.

Influência da composição dos gases durante a modificação da superfície por plasma na adesão de células primárias da polpa dental / Influence of the composition of gases during plasma surface modification on adhesion of primary cells from dental pulp

Amostras de titânio foram nitretadas por plasma usando duas composições gasosas: 80%H2-20%N2 e 20%H2-80%N2 e as propriedades físicas químicas desse tratamento foram estudas, bem como sua resposta biológica quando submetidas à cultura de células primárias da polpa dentária. Análise por difração de raios X indicam a formação de TiN nas duas amostras nitretadas ao contrário da superfície não nitretada que continha apenas a fase Ti-α. Verificaram-se modificações na dureza, topografia e molhabilidade dessas amostras quando comparadas às amostras não nitretadas. A adesão celular nessas amostras indica que o tratamento aumenta seu valor sendo superior para amostras tratadas em maior concentração de hidrogênio.

Samples of titanium were nitrided using plasma and a composition of two gases: 80% H2-20% N2 and 20% H2-80% N2. The influence of these treatments on their physical chemical properties and biological response when subjected to the primary cell culture of dental pulp were studied. Analyses by X-ray diffraction indicate the formation of TiN in both nitrided samples in contrast to the non-nitrided surface samples that contained only the Ti-α phase. Changes in hardness, topography and wettability of these samples compared to non-nitrided samples were found as well. Finally, the analysis of cell’s adhesion in these samples indicate that treatment increases its value being higher for samples treated at higher hydrogen concentration.