## 3 Results  
The obtained mean values of nanomechanical parameters in all groups are presented in Table 1.  
(1) Sq: surface roughness  
The roughness parameter analysis showed that  
* the highest roughness occurred after etching the surface and was on average 36 nm,
* the resin-coated surface showed roughness of 5.4 nm and was only slightly (but statistically significantly, \(p<0.05\)) less rough than the intact enamel, where the roughness was 8.3 nm and
* the roughness in the group of teeth with cleaned enamel was 7.0 nm and was lower than in the intact enamel group and similar to the resin-coated enamel group. These differences were statistically significant (\(p<0.05\)).  
The results of the above analysis are presented graphically in Figure 2.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multirow{2}{*}{
\begin{tabular}{c} **Sq** \\ **[nm]** \\ \end{tabular} } & **ISAD** & **Sk** & **Spk** & **Svk** & **Ym** & **FAm** \\  & & **[**\%**]** & **[**nm**]** & **[**nm**]** & **[**nm**]** & **[**nm**]** & **[**MPa**]** & **[**nN**]** \\ \hline
1 & 8.3(1.7) & 8.0(3.5) & 19.6(3.6) & 7.1(2.9) & 10.2(2.5) & 510(110) & 1.13(0.24) \\ \hline
2 & 36(12) & 51(21) & 85(25) & 34(15) & 45(17) & 550(200) & 1.26(0.20) \\ \hline
3 & 5.4(2.2) & 3.4(3.4) & 13.5(7.4) & 13(11) & 8.0(5.6) & 520(160) & 1.65(0.36) \\ \hline
4 & 7.0(2.1) & 3.2(1.3) & 15.4(5.3) & 7.2(4.2) & 7.7(6.3) & 610(130) & 1.89(0.32) \\ \hline \hline \end{tabular}  
* Sq: surface roughness—root mean square surface roughness; ISAD: Image Surface Area Difference—surface development (the ratio of the area spanned by the samples (triangulated) to the area of a flat surface with the same side length); Ym: mean Young’s modulus—Young’s pseudo-modulus of elasticity averaged over the image; Fam: mean adhesion force—the force of attraction between the scanning blade and the surface averaged over the image; Sk: core—the central part of the surface responsible for load transmission.  
\end{table}
Table 1: Mean values of nanomechanical parameters in groups 1, 2, 3, 4.  
Figure 1: Visualization of topography, Mean Young’s modulus and adhesion in atomic force microscopy.  
(2) Ym: mean Young's modulus--pseudo-modulus of elasticity  
Emanuel etching and its cleaning of the resin are the steps of the orthodontic abutment bonding procedure, which significantly increase the elasticity coefficient.  
The mean value of the pseudo-modulus of elasticity is shown in Figure 3.  
The Young's pseudo-modulus is the largest after enamel etching and has a mean value of 350-750 MPa; after enamel cleaning, it is 500-750 MPa (\(p<0.05\)).  
The pseudo-modulus in the intact enamel is on average 400-620 MPa; after using the resin, it is 350-650 MPa.  
(3) Fam: mean adhesion force--the force of attraction between the scanning blade and the surface averaged over the image are presented in Figure 4.  
Figure 3: Graph of the averaged Young’s pseudo-modulus of elasticity. The black dot means mean value.  
Figure 2: Surface roughness and development averaged over the samples (N: intact, W: etched, Z: resin, O: cleaned).  
The samples with the intact enamel show an adhesion strength of 0.9-1.3 Fadh (nN) and the samples with the etched enamel show a force of 1.0-1.5 Fadh (nN), whereas the samples from groups 3 and 4 show a greater range of adhesion: 1.25-2.0 Fadh (nN) and 1.5-2.25 Fadh (nN), respectively.  
(4) Surface development  
The graph in Figure 5 correlates with Figure 1, which results from the direct relationship between the surface roughness (height amplitude) and the thickness of the individual components. The strong effect of etching on exposing the porous surface structure is again confirmed.