The Effect of Polishing and Glazing Procedure on Streptococcus Mutans Adhesion of Three CAD/CAM Ceramics (in vitro)

Polish and glaze are 2 methods to decrease roughness and bacterial adhesion to the ceramic surfaces. This in vitro study assessed the effect of polish and glaze on the bacterial adhesion of 3 ceramics.

In this in vitro trial, samples of zirconia-reinforced lithium silicate, lithium disilicate and monolithic zirconia ceramic specimens were milled by CAD/CAM device from the blocks and sintered in the oven. The specimens were polished, glazed or remained intact with no preparations as a control group. The specimens' surface roughness were assessed by a profilometer followed by exposing to streptococcus mutans bacterium. The bacterium suspension were inoculated in wells containing tryptic soy broth + 0.2% glucose and ceramic specimens were placed into the wells. The plates were incubated for 48 hours at 37C° to form biofilms on the specimens. After washing, biofilm fix and ethanol removal, 1ml 0.4% crystal violet dye were added. The dye was removed and after washing, 1mm 30% acetic acid was added and 200 µl of the wells containing were transferred to a 96-well plate.The observations of streptococcus mutans adhesion to ceramic specimens were done by SEM.  Two-way analysis of variance was used for evaluation of ceramic type and preparation effects and one-way variance and tukey tests were used for intragroup evaluations.

In the Zolid ceramics, significantly higher bacterial adhesion were noted in the glazed than polished specimens (p=0.005). In the glazed specimens, significantly higher bacterial adhesion were noted in the Zolid ceramic than Suprinity (p=0.01) or IPS.Emax (p=0.009) ceramics.

Then, the surface preparation method showed significant effect on the bacterial adhesion only in Zolid ceramic. Except to polished Zolid ceramics, all ceramics and preparation techniques showed bacterial adhesion.