| Objective: To investigate the antimicrobial ability of pure titanium in vitro when pre-soaked with organosilicon quaternary ammonium salt.Methods:1 Test specimen fabricationAfter polished medical pure titanium plate,cut it into 10×10×1 mm by cutting mathine, and then polished it with 600 mesh metallographic sandpaper under the running water, each surface 50 times to ensure that the roughness is consistent.2 Antibiotic treatmentRandomly choose 144 pieces pure titanium specimens, put them into 95% ethanol and sterilized distilled water successively for 30 min ultrasonic vibration, and then sterilized under high temperature and pressure.Divided the pure titanium specimens into six groups randomly, Five of which were soaked with organic silicon quaternary ammonium salt solution with different concentrations of 1%, 5%, 10%, 30%, 60% respectively, and one was treated by distilled water as control. Each group was further divided into four according to different treatment time(30, 60, 120, and 240mins).Took them out of the solution and rinsed 10 min with terilized distilled water immediately, then took out again, put them in the aseptic cell culture plate with 24 hole after drying at room temperature.3 The preparation of bacterial suspensionAfter ATCC 90028 standard candida albicans strains recovered, diluted with 1640 liquid medium to 0.5M, adjusting by turbidity comparator.4 The antibacterial experimentsEach specimen was soaked with 1ml bacterial suspension in the calorstat under 37℃for 24 hours. Then took out and swing washed the floating bacteria with sterilized distilled water. and put them into the 3ml sterilized 1640 liquid medium to oscillate 1 min by oscillator. Then transferred the liquid medium to turbidimetric tube, after mixing, recorded the data with turbidimeter, one 1640 liquid medium as blank control group.5 Inspection of long-acting antibacterial experimentsSelect 30 pure titanium specimens, divided into GHIJK 5 groups randomly, the fist four groups of specimens were soaked with 1% silicone quaternary ammonium salt solution for 120 mins after degreasing and sterilization( it was concluded that the best processing combination in antibacterial experiments),the last one was just degreased and sterilized. The first four groups of specimens were separately soaked in the thermostatic water bath under 5℃and 55℃ for 30 s, and then took them out respectively after 0 times, 2500 times, 5000 times, 10000 times, the last one with sterilized distilled water instead of thermal cycling. Then put each specimen into 1ml bacteria suspension of 0.5m for 24 hours under constant temperature, and then rinsed them with 3 ml new medium to oscillate for 1 min. Then transfer the liquid medium to the turbidimetric tube, after mixing, recorded the data with turbidimeter, one 1640 liquid medium as blank control group.6 Data analysisThe data was analysed by using SPSS21.0 software factorial design was applied with analysis of variance, the mean was compared by Dunnett-t test, when P<0.05 for difference was statistically significant.Results:1 The results of antimicrobial propertiesAnalysed the 6 groups’ variance, according to the level that alpha equals 0.05, different concentrations significantly affected the growth of candida albicans(P<0.05), but the processing time did not(P>0.05). There was an interaction between concentration and processing time(P<0.05). For the concentration factor, S-N-K multiple comparison method showed that higher concentration had better antimicrobial ability, but no significant differences were found between the group 1% and 5%, and between the group 10%, 30% and 60%. It proved that pure titanium with silicone treated has antibacterial properties, Further compareing ABCDE five groups with F group(control group) have significant differences,1% treat concentration can be endowed pure titanium with antimicrobial properties.The turbidity value changed with a tendency of up-down-up following the extension of time,and the lowest value appeared in 120 min. So the most appropriate treatment concentration was 1% with a most suitable time of 120 mins.2 The results of long-acting antimicrobial propertiesAfter normality test and F test for the data of five groups, it was found that the data belongs to the normal distribution and variance equal(P>0.1).So choose Dunnett-t for test, that was comparing each group with control group K.According to alpha equals 0.05’s level, there were significant differences(P<0.05)between group G, H, I and group K; while there was no significant difference(P>0.05) between group J and group K. We considered that hot and cold cycling times have influence on the antibacterial properties of pure titanium specimen, pure titanium specimen treated with silicone quaternary ammonium salt still possess antimicrobial properties after 5000 hot and cold cycling.Conclusion: After soaking with the organosilicon quaternary ammonium salt solution, the pure titanium can maintain long-acting antibacterial properties, and the most appropriate treatment concentration was 1% with a most suitable time of 120 mins. |
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