Effect Of Co-Cr Alloy Soaked In Organosilicon Quaternary Ammonium Salt On Adherence Of Candida Albicans

Objective: To investigate the anti-adhesion of Co-Cr alloy after treated with organosilicon quaternary ammonium salt(Si-QAC)and the long-term anti-adhesion of the treated Co-Cr alloy was calculated through thermal cycling test.Methods:1.174 Co-Cr alloy specimens with 10 mm × 10 mm × 1mm were prepared.Randomly selected 144 Co-Cr alloy specimens.After grinding with metallographic sandpaper,ultrasonic shock cleaning and sterilizing were carried out.The specimens were randomly divided into six groups with different concentrations.Five of which were soaked in different concentrations of organosilicon quaternary ammonium salt(Si-QAC)at 1%,5%,10%,30% and 60% respectively,and one was soaked in distilled water as a control.Each group was further divided into four groups with different treatment time(30min,60 min,120min and 240min).After processing,rinse,blow dry,put specimens into the electrothermal blast thermostatic drying box in order to form film.2.The anti-adhesion experiment: The treated specimens were placed in 1640 liquid medium containing Candida albicans for 48 hours under constant temperature.Then the specimens were removed and washed.Then put them into the sterile 1640 medium to oscillate 1min by oscillator.Turbid data were recorded by turbidimeter.3.The long-term anti-adhesion experiment: Selected 30 Co-Cr alloy specimens.After grinding with metallographic sandpaper,ultrasonic shock cleaning and sterilizing were carried out.The specimens were divided into G,H,I,J,K five groups,the first four groups of specimens were soaked in 5% Si-QAC for 120min(it was concluded that the best processing combination in anti-adhesion experiment),fifth groups was only degreased and sterilized.The first four groups were thermocycling test respectively,and then took them out respectively after 0 times,2500 times,5000 times,10000 times,the last one with distilled water soaking.Then add with Candida albicans bacteria suspension for 48 h under constant temperature,and then the specimens were removed and washed.Then put them into the sterile 1640 medium to oscillate 1min by oscillator.Turbid data were recorded by turbidimeter.Results:1.The anti-adhesion experiment:Analysed the six groups' variance,different concentrations significantly affected the adherence of Candida albicans(F=52.571 P<0.01),and the processing time had no effect on the adherence of Candia albicans(F=2.124 P=0.101>0.05).There was an interaction between the two factors(F=2.260 P=0.008<0.01).S-N-K test for multiple comparisons six groups,there was no difference between the group A,group C,group D and group E,and the rest were differences between the two groups(P<0.05).The results showed that Co-Cr alloy with Si-QAC had anti – adhesion.Within a certain range,the anti-adhesion increased first and then decreased with increasing concentration.When the concentration was 5%,the anti-adhesion effect was obvious.Further analysis showed that when the concentration was 5%,the turbidity value decreased first and then increased with the prolongation of treatment time.When the treatment time was 120 min,the turbidity value was the lowest.Therefore,the most appropriate treatment concentration was 5% with a most suitable time of 120 min.2.The long-term anti-adhesion experiment:The data of the five experimental groups belonged to normal distribution and variance equal(P=0.133>0.1),so choosed Dunnett-t for test,that was comparing each experimental group with control group K.The results showed that there was significant difference between the experimental groups and group K.Further analysis of S-N-K test for experimental groups data,there was no difference between the group G and group H,and the rest were differences between the two groups(P<0.05).It is indicated that the number of thermal cycling has an influence on the anti-adhesion of Co-Cr alloys pecimens,and 10000-thermocycled Co-Cr still exhibited significant reduction of microbial adherence.Conclusion:The following conclusions can be obtained for this experimental condition:1.After soaking with Si-QAC,the Co-Cr alloy has anti-adhesion to the Candida albicans,and the most appropriate treatment concentration was 5% with a most suitable time of 120 min.2.After soaking in 5% Si-QAC for 120 min,the anti-adhesion property of the Co-Cr alloy may maintain for one year.