Background: It has been hypothesized that zirconia might have a reduced bacterial adhesion compared with titanium; however, results from experimental studies are rather controversial. The aim of the present study is to compare biofilm formation on zirconia and titanium implant surfaces using an in vitro three‐species biofilm and human plaque samples.Methods: Experimental disks made of titanium (Ti) or zirconia (ZrO₂) with a machined (M) or a sandblasted (SLA) and acid‐etched (ZLA) surface topography were produced. An in vitro three‐species biofilm or human plaque samples were applied for bacterial adhesion to each type of disk, which after 72 hours of incubation was assessed using an anaerobic flow chamber model.Results: Zirconia showed a statistically significant reduction in three‐species biofilm thickness compared with titanium (ZrO₂‐M: 8.41 μm; ZrO₂‐ZLA: 17.47 μm; Ti‐M: 13.12 μm; Ti‐SLA: 21.97 μm); however, no differences were found regarding three‐species‐biofilm mass and metabolism. Human plaque analysis showed optical density values of 0.06 and 0.08 for ZrO₂‐M and ZrO₂‐ZLA, and values of 0.1 and 0.13 for Ti‐M and Ti‐SLA, respectively; indicating a statistically significant reduction in human biofilm mass on zirconia compared with titanium. Additionally, zirconia revealed a statistically significant reduction in human plaque thickness (ZrO₂‐M: 9.04 μm; ZrO₂‐ZLA: 13.83 μm; Ti‐M: 13.42 μm; Ti‐SLA: 21.3 μm) but a similar human plaque metabolism compared with titanium.Conclusion: Zirconia implant surfaces showed a statistically significant reduction in human plaque biofilm formation after 72 hours of incubation in an experimental anaerobic flow chamber model compared with titanium implant surfaces.

The purpose of this study was to investigate a three-species in vitro biofilm with peri-implantitis-related bacteria for its variability and metaboli

The mechanism of action of adjuvant antibiotic therapy in the treatment of peri-implantitis is not well understood. The aim of this study is to investigate antibiotic susceptibility of an in vitro biofilm by isothermal microcalorimetry (IMC). Titanium disks containing a 72-hour three-species biofilm (Streptococcus sanguinis DSM20068, Fusobacterium nucleatum ATCC10953, and Porphyromonas gingivalis DSM20709) were placed in a series of IMC ampoules with nutrient agar supplemented with increasing concentrations of amoxicillin, metronidazole, or their combination and incubated anaerobically for 10 days. Lag time and maximum growth rate were determined from continuous heat-flow recordings of metabolic activity. To validate the IMC biofilm results, adherent S. sanguinis and P. gingivalis were incubated anaerobically in medium supplemented with antibiotics at 37°C for 24 hours, and their vitality was determined by live/dead staining, conventional culturing, and IMC. In all biofilm samples incubated with antibiotics, a prolonged lag phase was observed compared with controls (P <0.05). Maximum growth rate was significantly lower for samples treated with either amoxicillin or metronidazole compared with controls (P <0.05). Combining the antibiotics did not improve this effect. Concentrations exceeding 10 times the minimum inhibitory concentration completely inhibited the growth of adherent S. sanguinis and P. gingivalis, whereas lower concentrations resulted in only a delay in the lag phase. A poor correlation was observed between live/dead staining and conventional culturing. IMC gives new evidence about antibiotic effects on oral biofilms and is more informative than conventional culture and live/dead assays. The combination of antibiotics was found to be more efficient than metronidazole alone; however, only minor differences in growth inhibition were detected compared with amoxicillin alone.

Objectives: To determine whether the surface treatment of zirconia affects biofilm formation in an in vitro three‐species biofilm model and in situ.Material and methods: Zirconia surfaces considered for the transmucosal portion of a zirconia implant were compared with polished pure titanium grade 4 (Tp). Disks 13 mm in diameter of either polished (Zp), polished and heat‐treated (Zpt), machined (Zm), machined and heat‐treated (Zmt) and sandblasted, etched and heat‐treated (Z14) zirconia were fabricated. Surface roughness and wettability of specimens was measured. Biofilm formation was evaluated by safranin staining and scanning electron microscopy (SEM) using a three‐species model, and intraorally with 16 volunteers carrying oral splints in two independent experiments. Relative biofilm formation was compared with Kruskal–Wallis followed by Bonferroni post hoc test (α = 0.05).Results: In vitro biofilm formation with optical density values on Zp (0.14 ± 0.01), Zpt (0.14 ± 0.02), Zm (0.13 ± 0.01) and Zmt (0.13 ± 0.01) was significantly lower than on Tp (0.21 ± 0.05) and Z14 (0.20 ± 0.04) (p < .05). In situ biofilm formation was significantly higher on Z14 (0.56 ± 0.45) (p < .05), while no significant differences in optical density were observed among Zp (0.25 ± 0.20), Zm (0.36 ± 0.34) and Tp (0.28 ± 0.22). SEM analysis supported quantitative findings.Conclusions: In the in vitro, three‐species biofilm model differences in material and surface roughness affected biofilm formation. In situ biofilm formation was mainly affected by the surface roughness of the specimens. Polishing of zirconia is recommended to reduce biofilm formation, while heat treatment has no significant effect.