Evaluation of the effect of different polishing systems on color change, surface roughness and bacterial adhesion of universal composites with high color adaptation capability

Objective: The aim of this study was to evaluate the effects of different polishing systems on discoloration, surface roughness and bacterial adhesion of universal chromatic composites. Method: In the study, a total of 208 samples were prepared, 52 of each of Brilliant EverGlow, Clearfil Majesty Esthetic, Neo Spectra ST HV and Omnichroma composites. The samples in each composite group were randomly divided into 4 subgroups (n=13) according to the polishing systems (Mylar Strip, OneGloss, OptiDisc and Clearfil Twist Dia) and 1 sample from each subgroup was used to be examined in scanning electron microscope (SEM) after the polishing systems were applied. Color values were measured by spectrophotometer and roughness was measured by mechanical profilometer. In the bacterial adhesion experiment, the samples were soaked in saliva for 1 hour for pellicle formation, a suspension containing Streptococcus mutans was added and incubated at 37°C for 24 hours. Following the experimental steps, 50 µl of medium was inoculated for each sample and incubated at 37°C with CO2 for 24 hours. After incubation, the colonies formed were counted and calculated as colony forming units per milliliter (cfu/ml). Then, the samples were stained with coffee for 12 days, measurements were made after polishing and after the staining procedure, and and the color change was calculated with the CIEDE2000 formula. Results: Clearfil Majesty Esthetic was the composite with the least discoloration. In all composite groups, Mylar Strip group had the highest discoloration, while there was no significant difference between OneGloss, OptiDisc and Clearfil Twist Dia polishing systems. Omnichroma was the composite with the least surface roughness. In the bacterial adhesion findings, the highest values were observed in the Mylar Strip groups for all composites, and a significant positive correlation was found between surface roughness and bacterial adhesion values only in the Mylar Strip group of Omnichroma. No significant correlation was found between surface roughness values and ΔE00 for all groups. Conclusion: The ΔE00 values of all groups in the study were higher than the clinically acceptable threshold level of ΔE00=1.8. Roughness values were less than 0.2 µm in all groups. Bacterial adhesion values were affected by the composite material and polishing system. Keywords: bacterial adhesion, universal composite, polishing system.