Biofilm formation on metal alloys and coatings, zirconia, and hydroxyapatite as implant materials in vivo.

OBJECTIVES: Composition of implant material and its surface structure is decisive for oral biofilm accumulation. This study investigated biofilm formation on eight different materials. MATERIALS AND METHODS: Eighteen healthy subjects wore intraoral splints fitted with two sets of eight materials for 24 h: zirconia [ZrO(2) ]; silver-gold-palladium [AgAuPd]; titanium zirconium [TiZr]; Pagalinor [PA]; hydroxyapatite [HA]; silver-platinum [AgPt]; titanium aluminum niobium [TAN]; titanium grade4 [TiGr4]. Total biomass was stained by safranin to assess plaque accumulation while conventional culturing (CFU) was conducted to investigate viable parts of the biofilm. Cell viability of human gingival fibroblasts (HGF-1) was assessed in vitro. Statistical evaluation was performed with linear mixed-effects models to compare materials (geometric mean ratios, 95% CI), with the level of significance set at a = .05. RESULTS: Less biofilm mass and CFU were found on noble metal alloys (AgPt, AgAuPd, and PA). Compared to AgPt, PA had 2.7-times higher biofilm mass value, AgAuPd was 3.9-times, TiGr4 was 4.1-times, TiZr was 5.9-times, TAN was 7.7-times, HA was 7.8-times, and ZrO(2) was 9.1-times higher (each p < .001). Similarly, CFU data were significantly lower on AgPt, AgAuPd had 4.1-times higher CFU values, PA was 8.9-times, TiGr4 was 11.2-times, HA was 12.5-times, TiZr was 13.3-times, TAN was 16.9-times, and ZrO(2) was 18.5-times higher (each p < .001). HGF-1 viability varied between 47 +/- 24.5% (HA) and 94.4 +/- 24.6% (PA). CONCLUSION: Noble alloys are considered as beneficial materials for the transmucosal part of oral implants, as less biofilm mass, lower bacterial counts, and greater cell viability were detected than on titanium- or zirconia-based materials.