Residual extracellular polymeric substances (EPS) detected by fluorescence microscopy on dental implants after different decontamination

Since the existing used detecting techniques were unable to distinguish the types of extracellular polymeric substances (EPS) components (polysaccharides, proteins, and nucleic acids et al.), it is needy to apply more targeted methods to detect the residual EPS components on decontaminated dental implants. Herein we aimed to assess whether fluorescence microscopy method was feasible for detecting residual EPS components on decontaminated dental implants. Six clinical-retrieved dental implants suffered severe peri-implantitis were collected, and also Staphylococcus aureus (S. aureus) cultured titanium discs were prepared. Before and after decontamination (Er:YAG laser, air-abrasive, and citric acid), corresponding fluorochrome stains were used to label polysaccharides, proteins, and nucleic acids on the samples for identification and then observed under confocal laser scanning microscopy (CLSM). Besides, scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) detection techniques were also used. The results showed that fluorescent signals of EPS components are strong before decontamination and decreased after treatments, indicating that the intensity can roughly reflect the amounts. This preliminary study proved that EPS-stained fluorescence microscopy was feasible as a detection tool of choice for implant decontamination outcome evaluation. However, further study incorporating large sample size and quantified data should be carried out.