The influence of ZnO content in YSZ-ZnO composite ceramics on bacterial growth and cell behaviour for the prevention of peri-implant inflammation.

OBJECTIVES: Peri-implantitis is a significant complication in dental implant therapy and arises primarily from bacterial colonization. Current preventive strategies show limited long-term efficacy. This study evaluated antibacterial properties and biocompatibility of yttria-stabilized zirconia-zinc oxide (YSZ-ZnO) composite ceramics as implant abutment material for peri-implantitis prevention. METHODS: Nine ZnO/YSZ ratios (10-90-90-10 at%), and controls (100 % ZnO, 100 % YSZ, and titanium) were synthesized. Analyses included microstructure and composition by scanning electron microscopy and energy dispersive X-ray spectroscopy, and surface roughness with an Alicona Infinite Focus Variation microscope. Antibacterial properties were assessed against Porphyromonas gingivalis and cell viability of immortalized human gingival fibroblasts (iHGF) was evaluated using the CCK8 assay. Statistical analysis was performed using one-way ANOVA with post-hoc tests (P = 0.05). RESULTS: Samples with ZnO > 40 % showed larger inhibition zones than Ti and YSZ (P < 0.05). No CFUs were observed with >/= 60 % ZnO, while controls showed bacterial growth. Cell viability assays revealed no significant differences between YSZ and 60 % ZnO (P > 0.05), but higher ZnO concentrations reduced viability. Mean roughness (Ra) values ranged from 0.13 mum (66.6 % ZnO) to 0.58 mum (100 % ZnO). SIGNIFICANCE: YSZ-ZnO composites could reduce peri-implantitis by inhibiting bacterial colonization. The 60 % ZnO composition exhibited strong antibacterial properties and biocompatibility, suggesting potential solution for improving implant success rates, especially in high-risk patients. Further research is needed to explore long-term stability and interactions with other bacteria.