Bacterial Adhesion and Biofilm Formation on Monolithic Zirconia

Objectives: Monolithic zirconia and glass ceramics are increasingly used in implant dentistry. Screw retained ceramic crowns can be fixed directly on implants or by cementing them first on titanium bases. However, little scientific research is available on bacterial adhesion and biofilm formation on ceramic implant crown materials or on the cements used to attach the full-contour crowns on titanium bases.
Methods: Four different groups of materials (10x10x2 mm³) were investigated: (1) IPS e.max CAD by Ivoclar Vivadent (control), (2) Prettau Anterior by Zirkonzahn, (3) Katana by Noritake, and (4) Multilink hybrid abutment cement by Ivoclar Vivadent. All materials were prepared and polished according to manufacturers’ instruction. The investigated surfaces (n=5 per material) were incubated at +37°C in a suspension of Streptococcus mutans (S. mutans) for 30min for bacterial adhesion and 48h for biofilm formation. The amounts of S. mutans were determined by counting the colony-forming units. Statistical analysis was performed using one-way ANOVA and post-hoc Tukey’s tests (p<0.05).
Results: For bacterial adhesion test, the ranking from lowest to highest was: IPS e.max = Prettau Anterior < Multilink Hybrid Abutment cement < Katana (p<0.05). While for bacterial biofilm formation no statistically significant differences among the investigated surfaces were found.
Conclusions: Bacterial adhesion on monolithic zirconia is brand dependent. Neither glass ceramic nor resin cement favor biofilm formation.