# Surface Morphology Changes of Bleached Dental Ceramics
## 3 Results
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{5}{c}{**Surface Roughness, nm**} \\ \hline \hline \multirow{2}{*}{**Dental Ceramic**} & \multirow{2}{*}{**Before Bleaching**} & \multirow{2}{*}{**Treated with 16\% CP**} & \multirow{2}{*}{**Treated with 6\%**} & \multirow{2}{*}{**Treated with 6\% HP**} \\  & & & & **HP + LED** \\ \hline \multirow{2}{*}{**Polished lithium**} & R\({}_{\text{a1}}\) = 11.39 \(\pm\) 3.36 & R\({}_{\text{a2}}\) = 10.22 \(\pm\) 1.84 & R\({}_{\text{a2}}\) = 16.39 \(\pm\) 8.44 & R\({}_{\text{a2}}\) = 37.17 \(\pm\) 19.92 \\ \cline{2-5}
**disilicate** & R\({}_{\text{q1}}\) = 16.24 \(\pm\) 5.65 & R\({}_{\text{q2}}\) = 12.84 \(\pm\) 2.39 & R\({}_{\text{q2}}\) = 23.23 \(\pm\) 13.20 & R\({}_{\text{q}}\) = 50.69 \(\pm\) 26.49 \\ \hline \multirow{2}{*}{**Glazed lithium**} & R\({}_{\text{a1}}\) = 12.36 \(\pm\) 2.76 & R\({}_{\text{a2}}\) = 9.82 \(\pm\) 4.44 & R\({}_{\text{a2}}\) = 16.55 \(\pm\) 8.46 & R\({}_{\text{a2}}\) = 13.43 \(\pm\) 4.98 \\ \cline{2-5}
**disilicate** & R\({}_{\text{q1}}\) = 17.91 \(\pm\) 4.85 & R\({}_{\text{q2}}\) = 12.39 \(\pm\) 5.42 & R\({}_{\text{q}}\) = 22.74 \(\pm\) 11.69 & R\({}_{\text{q2}}\) = 18.19 \(\pm\) 6.18 \\ \hline \multirow{2}{*}{**Polished leucite-reinforced glass ceramic**} & R\({}_{\text{a1}}\) = 13.15 \(\pm\) 5.13 & R\({}_{\text{a2}}\) = 9.12 \(\pm\) 2.17 & R\({}_{\text{a2}}\) = 25.68 \(\pm\) 14.40 & R\({}_{\text{a2}}\) = 22.89 \(\pm\) 14.30 \\ \cline{2-5}
**glase ceramic** & R\({}_{\text{q1}}\) = 17.68 \(\pm\) 6.72 & R\({}_{\text{q2}}\) = 11.72 \(\pm\) 2.72 & R\({}_{\text{q}}\) = 38.49 \(\pm\) 22.08 & R\({}_{\text{q2}}\) = 32.34 \(\pm\) 11.52 \\ \hline \multirow{2}{*}{**Glazed leucite-reinforced glass ceramic**} & R\({}_{\text{a1}}\) = 10.84 \(\pm\) 4.50 & R\({}_{\text{a2}}\) = 9.20 \(\pm\) 2.16 & R\({}_{\text{a2}}\) = 11.33 \(\pm\) 4.91 & R\({}_{\text{a2}}\) = 21.76 \(\pm\) 11.99 \\ \cline{2-5}
**glase ceramic** & R\({}_{\text{q1}}\) = 14.95 \(\pm\) 7.29 & R\({}_{\text{q2}}\) = 11.88 \(\pm\) 2.84 & R\({}_{\text{q}}\) = 17.67 \(\pm\) 8.88 & R\({}_{\text{q2}}\) = 32.97 \(\pm\) 19.76 \\ \hline \multirow{2}{*}{**Polished zirconium dioxide**} & R\({}_{\text{a1}}\) = 7.47 \(\pm\) 4.41 & R\({}_{\text{a2}}\) = 9.50 \(\pm\) 2.22 & R\({}_{\text{a2}}\) = 14.44 \(\pm\) 5.36 & R\({}_{\text{a2}}\) = 18.83 \(\pm\) 10.95 \\ \cline{2-5}
**dioxide** & R\({}_{\text{q1}}\) = 10.07 \(\pm\) 6.31 & R\({}_{\text{q2}}\) = 12.63 \(\pm\) 3.46 & R\({}_{\text{q}}\) = 21.60 \(\pm\) 13.97 & R\({}_{\text{q2}}\) = 25.29 \(\pm\) 13.96 \\ \hline \multirow{2}{*}{**Glazed zirconium dioxide**} & R\({}_{\text{a1}}\) = 9.33 \(\pm\) 3.45 & R\({}_{\text{a2}}\) = 12.26 \(\pm\) 3.06 & R\({}_{\text{q2}}\) = 13.57 \(\pm\) 3.84 & R\({}_{\text{q2}}\) = 20.92 \(\pm\) 15.11 \\ \cline{2-5}
**glase oxide** & R\({}_{\text{q1}}\) = 12.40 \(\pm\) 4.63 & R\({}_{\text{q2}}\) = 15.91 \(\pm\) 3.82 & R\({}_{\text{q}}\) = 18.67 \(\pm\) 4.21 & R\({}_{\text{q2}}\) = 27.72 \(\pm\) 19.32 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Mean surface roughness values of dental ceramics before and after bleaching with different bleaching agents. Figure 2: Statistical evaluation of the bleaching agent impact on the polished surface roughness of the treated ceramic samples. Since teeth whitening is a common aesthetic improving procedure, the results of surface morphology and roughness changes of dental ceramics caused by application of different bleaching agents were additionally compared with the results of colour changes of the same samples observed after bleaching. The details of the colour difference assessment procedure and some results could be found in our previous publication [27]. In this paper we have provided just a summary of colour difference evaluation results of all of the investigated samples. The results of colour changes of bleached dental ceramics with indicated NBS criteria are shown in Table 4.  
The results of the performed statistical analysis of colour changes of samples due to the bleaching are provided in Figure 3.