Adhesion of Streptococcus Mutans to Zirconia, Enamel, IPS Empress II, Noble Alloy and Base-metal: An In-Vitro Comparative Study

Introduction: With increased usage of restorative materials, dentists are more concerned in choosing a suitable material with lower adhesion of pathogens like streptococci. This comparative in vitro study aimed to compare adhesion of streptococcus mutans to zirconia, IPS Empress II, noble alloy, and base-metal. Materials and Methods: In this descriptive study, 50 specimens (5 mm diameter disk with 1 mm thickness) were prepared (10 for each material; zirconia, enamel, IPS Empress II, noble alloy, and base-metal). Enamel was used as reference. The specimens were covered by artificial saliva and bacterial suspension. Scanning electron microscope and culturing the specimens in blood agar was used for evaluating bacterial adhesion. The collected data were analyzed by ANOVA and post-hoc Tukey test. Results: There was a significant difference in adhesion among study groups (P<0.001). The least amount of adhesion was observed in zirconia group (28±6.32), followed by enamel (48.2±8.4), IPS Empress II (50.6±6.99), noble (76±4.9) and base-metal (106.4±9.44). There was no significant difference in surface roughness among study groups. Conclusion: Zirconia showed the lowest bacterial adhesion in comparison to other restorative materials. Therefore, the findings of the present study highlight the fact that restorative ceramics, including zirconia is a better choice in patients with poor oral hygiene and those susceptible to periodontal disease.