Comparison Of Surface Properties And Bacterial Adhesion Of PEEK Treated By Three Polishing Suites

Background and ObjectivePolyetheretherketone(PEEK)has been widely used in the field of oral cavity due to its good biocompatibility,excellent mechanical properties and good processability,including planting,repair,orthodontic and so on.When PEEK is used as a prosthesis,it needs to be adjusted and ground,resulting in its larger roughness.Previous studies have confirmed that materials with larger roughness can cause increased bacterial adhesion,thereby inducing a series of oral diseases,and thus require chair-side polishing.It has been found that polishing can affect the surface properties of the repair material,such as roughness and hardness,while aging can destroy the stability of the material and cause changes in the surface properties of the material.At present,there are a wide variety of polishing sets available for clinical selection,and few studies have been conducted on the selection of PEEK polishing sets and the changes in surface properties of PEEK after polishing and aging.Therefore,in this experiment,the surface roughness,contact angle,vickers hardness,surface morphology and bacterial adhesion of PEEK polished by three clinically commonly used polishing sets are compared,and the surface roughness,contact angle,vickers hardness and surface morphology of the polished PEEK test piece are measured after cold and heat cycle aging,so as to evaluate the polishing effect of three clinically commonly used polishing sets on PEEK and the stability after polishing,and screen out the set with better polishing effect to guide the selection of clinical doctors.Methods1.PEEK was prepared using CAD/CAM technology as a disk test piece with a diameter of 10.0 mm and a thickness of 2.0 mm.2.The test pieces were divided into four groups:group A(control group),group B(EVE group),group C(SHOFU group),group D(Tob group),All the three groups were polished with different polishing sets,but no treatment was given to group A.3.The contact angle of the polished PEEK was measured by a contact angle meter,the surface roughness was measured by a white light interferometer,and the surface morphology was observed by a scanning electron microscope.The Vickers hardness was measured by a Vickers hardness meter.4.Streptococcus mutans was resuscitated and cultured.The streptococcus mutans suspension was inoculated on the surface of each group of polyetheretherketone(PEEK)test pieces,and cultured under anaerobic condition for 24 h at 37℃.The adhesion of bacteria Observation of polyetheretherketone surface by microscope Scanning electron microscope.The plate colony count method and the optical density detection value of CCK8 were used to determine the amount of bacterial adhesion on the surface.5.PEEK specimens were put into a cold-heat cycle machine at the temperature of 5℃and 55℃,for 5000 times of cold-heat cycle aging.6.The contact angle of aged PEEK specimens was measured by a contact angle meter,and the surface roughness was measured by a white light interferometer.The surface morphology was observed by a scanning electron microscope,and the Vickers hardness was measured by a Vickers hardness meter.7.SPSS26.0 software was used for statistical analysis of the experimental results.Results1.Surface roughness Ra and Rz values Results:Ra and Rz values of group B,group C and group D increased successively before and after aging,and EVE had statistical difference compared with those of SHOFU group and Tob group(P<0.05);There was no significant difference between SHOFU group and Tob group(P>0.05).The two roughness parameters Ra and Rz of the control group were the largest in the four groups,and there was a statistical difference with PEEK after polishing set treatment(P<0.05).The values of Ra and Rz after aging showed an increasing trend,and there was a statistical significance(P<0.05)for different polishing sets,cold and heat cycles and the interaction between the two.2.Contact angle results:The contact angle values before and after aging were not statistically significant by one-way ANOVA,and the interaction between different polishing sets and cold and heat cycles was not statistically significant by multi-factor ANOVA and paired sample t test(P=0.72).3.SEM observation results:Before and after aging,it was shown that the surface of the alloy in group A was the roughest,that in group B was the smoothest,and that C and D were in the range,without significant difference.Wide and deep scratches and dense pit-shaped defects were observed on the surface of Group A before aging,and the number and density of pit-shaped defects were increased and more dense after aging.A small number of deep scratches were observed on the surfaces of the specimens in Group C and Group D before aging,and pit-like defects were occasionally observed.After aging,the pit-like defects in Group C and Group D increased and the scratches deepened.Before aging,the surface of the test piece in Group B was the smoothest,with the least defects.A small number of thinner and shallower scratches were observed,and even deeper scratches were observed.After aging,the scratches deepened and the number increased.The scanning electron microscopy of bacterial adhesion showed that the group A had the most bacterial adhesion,which was mainly distributed around the pit-shaped defects.Group B had the least bacterial adhesion and scattered distribution.Groups C and D were located in the middle,and distributed more evenly,most of them around the scratches.4.Vickers hardness test results:The Vickers hardness values before and after aging were not statistically significant through one-way analysis of variance,and the multi-factor analysis of variance and paired sample t test showed that there was no statistical significance in the interaction between different polishing sets and cold and heat cycles(P=0.946).5.Bacterial adhesion test results:The bacterial adhesion values of EVE group,SHOFU group and Tob group gradually increased,and EVE group had statistical difference as compared with SHOFU group and Tob group(P<0.05).There was no significant difference between SHOFU group and Tob group(P>0.05).Among them,the bacterial adhesion value in the control group was the most among the four groups,with statistical differences as compared with the other three groups(P<0.05).ConclusionThe polishing effects of EVE,SHOFU and Tob are different.In this experiment,EVE is the best one,which has the smallest roughness and the smallest bacteria adhesion after polishing.Moreover,the three kinds of polishing sets have no significant effect on the mechanical properties and surface free energy.