## 4 Discussion  
The present study was designed to assess the ability of different powders to remove biofilm from contaminated titanium surfaces. To our best knowledge, this is the first study comparing the ability of six different powders in removing biofilm; therefore, it was designed as a pilot study to generate data to run a power analysis for the sample size calculation for future studies. Results from this study highlighted differences on biofilm removal capacity of the various employed powders. Surface characteristics, such as roughness in M and MRS discs, affected the biofilm removal capacity, which was achieved by different kinds of powders in all the cases, although with different percentages (e.g., 88.6 \(\pm\) 3.9% in M group 4 and 89.3 \(\pm\) 1.3% in MRS group 6). Treatments were followed by no relevant changes to the microscopic ultrastructure of the disc surfaces. In this study, MRS and M contaminated treated samples showed significantly reduced residual biofilm after all provided treatment modalities, compared to untreated portions of contaminated discs. No statistically significant difference was noted in the biofilm removal ability of the tested modalities in MRS samples, while in M samples, group 3 (\(p\)-Value 0.0395) and group 4 (\(p\)-Value 0.0121) were significantly more effective than group 2 in biofilm removal. However, it should be noted that all provided treatments on M surfaces reduced the fluorescence signal to a level equivalent to or lower than the level of signal obtained from pristine discs. A striking note to us was that distilled water was as effective in removing biofilm as all the other tested powders on both M and MRS surfaces. This finding could have been influenced by the fact that we tested a single micro-organism biofilm. Another influencing element could be the use of flat surface titanium discs, rather than screw-shaped implants. Both these factors could have influenced the ease of biofilm removal. Since this was a pilot study, we would recommend in future to repeat these treatments using a true multimicrobial biofilm on screw-shaped implants for more accurate and definitive outcomes. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Machined Discs**} & \multicolumn{2}{c}{**Moderately Rough Surface**} \\ \cline{2-5}
**Treatments** & **RMS Means \(\pm\) S.D.** & **Ra Means \(\pm\) S.D.** & **RMS Means \(\pm\) S.D.** & **Ra Means \(\pm\) S.D.** \\ \hline Group 1—before treatment & 1.40 \(\pm\) 0.31 & 1.10 \(\pm\) 0.23 & 3.22 \(\pm\) 0.21 & 2.45 \(\pm\) 0.35 \\ Group 1—after treatment & 1.60 \(\pm\) 0.34 & 1.30 \(\pm\) 0.22 & 3.01 \(\pm\) 0.46 & 2.30 \(\pm\) 0.45 \\ Group 2—before treatment & 3.01 \(\pm\) 0.44 & 2.47 \(\pm\) 0.31 & 2.52 \(\pm\) 0.40 & 1.95 \(\pm\) 0.41 \\ Group 2—after treatment & 3.14 \(\pm\) 0.29 & 2.60 \(\pm\) 0.35 & 2.55 \(\pm\) 0.37 & 1.99 \(\pm\) 0.22 \\ Group 3—before treatment & 2.01 \(\pm\) 0.30 & 1.61 \(\pm\) 0.33 & 2.44 \(\pm\) 0.47 & 1.89 \(\pm\) 0.21 \\ Group 3—after treatment & 2.04 \(\pm\) 0.37 & 1.67 \(\pm\) 0.32 & 2.42 \(\pm\) 0.39 & 1.88 \(\pm\) 0.38 \\ Group 4—before treatment & 2.04 \(\pm\) 0.29 & 1.57 \(\pm\) 0.41 & 2.73 \(\pm\) 0.18 & 2.13 \(\pm\) 0.23 \\ Group 4—after treatment & 2.14 \(\pm\) 0.37 & 1.70 \(\pm\) 0.3 & 2.77 \(\pm\) 0.32 & 2.17 \(\pm\) 0.25 \\ Group 5—before treatment & 2.30 \(\pm\) 0.44 & 1.86 \(\pm\) 0.43 & 3.38 \(\pm\) 0.25 & 2.57 \(\pm\) 0.15 \\ Group 5—after treatment & 2.49 \(\pm\) 0.37 & 2.02 \(\pm\) 0.39 & 3.40 \(\pm\) 0.31 & 2.59 \(\pm\) 0.21 \\ Group 6—before treatment & 2.75 \(\pm\) 0.21 & 2.22 \(\pm\) 0.26 & 2.71 \(\pm\) 0.28 & 2.10 \(\pm\) 0.39 \\ Group 6—after treatment & 2.60 \(\pm\) 0.29 & 2.10 \(\pm\) 0.33 & 2.48 \(\pm\) 0.41 & 1.96 \(\pm\) 0.15 \\ Group 7—before treatment & 1.72 \(\pm\) 0.42 & 1.07 \(\pm\) 0.31 & 3.19 \(\pm\) 0.37 & 2.42 \(\pm\) 0.22 \\ Group 7—after treatment & 1.60 \(\pm\) 0.39 & 0.93 \(\pm\) 0.37 & 2.96 \(\pm\) 0.33 & 2.23 \(\pm\) 0.29 \\ \hline \hline \end{tabular}
\end{table}