Influence Of Surface Roughness On Gold Alloy And Ni-Gr-Ti Alloy On Adhesion Bacteria

Objective : This experiment develops more efficiently polishing proceedings through observing the surface roughness of gold alloy and Ni-Gr-Ti alloy which are polished in various degrees and adhesive relationship of streptococcus mutans and actinomyces viscosus. It also provides a principle basis for clinical applications.Methods:Making 24 specimens of gold alloy and Ni-Gr-Ti alloy respectively in the same standard, dividing them into 4 groups randomly, polishing them according to the regular procedures of mental-full-crown and adding one procedure successively in each group; measuring the Ra value by the surface roughometer; and then placing the specimens into the nurturing fluid of streptococcus mutans and actinomyces viscosus which is under 80%N₂,10% H₂,10%CO₂,37℃,in order to nurture them for 48 hours or 72 hours separately. Count in CFU /ml after dilution of multiple proportions.Results:Measuring the Ra value by the surface roughnessr, we know: (1) To every kind of alloy specimen in one group, there is significantly difference in the value of Ra experiencing different polishing procedures(P<0.05), and to different alloy, there is no difference in the Ra value(P>0.05); (2) From the linear correlation analysis, we know: the surface roughness of gold alloy and titanium alloy has the linear correlation with the amount of streptococcus mutans and viscosus's bacteria adhesion; the latter one reduces with the lessening of the former one;(3) There is also a difference among the alloy groups experiencing different polishing procedures with less significantly difference between the third and fourth group(P>0.05) and relatively marked difference between the other two(P<0.05).(4) To gold alloy and Ni-Gr-Ti alloy with the same Ra value, the amount of the bacteria adhesion has zero difference in statistics.Conclution:(1)For the same alloys,Ra value and the amount of bacteria adhesion have positive correlation, and the amount of bacteria adhesion, with surface roughness reduced.We should attach importance to polishing in clinical.; (2)To the evaluation of polishing procedure, the application of hard rubber wheels is the key steps in bacterial adhesion,but the amount of bacteria adhesion is the least.So we should give strict and sophisticated polishing procedures before prosthesis enter into the mouth; (3)Polished sophisticated gold and Ni-Gr-Ti alloy have no marked influence on the early bacteria adherison.