Effect of 5 Popular Disinfection Methods on Microflora of Laboratory: Customized Implant Abutments

To compare the efficacy of 5 different decontamination methods of titanium abutments and to assess their possible effects on surface roughness of titanium.

Micrococcus luteus, Acinetobacter baumannii, Enterococcus faecalis, and Candida albicans were cocultured to form a multispecies biofilm on 18 titanium discs. In another group, Bacillus subtilis, a spore-forming species, was cultivated on another set of 18 titanium discs. Each group was further divided into 5 test groups: high-pressure steam cleaning (4 Mpa, 5 seconds), NaOCl (1% active chlorine, 5 minutes), H2O2 (3%, 5 minutes), GaAlAs laser (810 nm, CW, 1 W, 400-μm fiber, 1-mm distance, 1 minute), Er:YAG laser (2940 nm, pulse mode, 100 mJ, 10 Hz, 230-μm noncontact handpiece, 4-mm distance, 50/50% air/water, 1 minute), and a control group of no treatment. After each decontamination procedure, the remaining microbial load was reported as colony-forming unit/disc. To evaluate the effect of each treatment on titanium discs, surface roughness parameters including Sa, Sq, Ssk, Sku, Sal, and Sdr were measured at 6 points of each disc using an atomic force microscope.

Complete disinfection was achieved using high-pressure steam, NaOCl, H2O2, and Er:YAG laser. GaAlAs laser was able to reduce microbial count over 90%. Sa and Sq parameters were only increased significantly in diluted NaOCl group in comparison with control group, whereas Sdr was increased significantly in both absolute and diluted NaOCl groups.

All the methods could decontaminate machined titanium surfaces, although complete microbial elimination was not achieved by diode laser. None of the treatments altered surface roughness significantly, except for sodium hypochlorite (NaOCl).