## 3 Results  
After the washing process, the surface aspects of the specimens of each group were photographed using FE-SEM. For the IPA-D group, which had a relatively short washing time, it could be observed that suspensions remained on the surface of the specimen, and groups A and B, which had a relatively long washing time of 10 min, contained relatively few foreign substances (Figure 1). Surface roughness was measured with a nano surface 3D optical profiler, and Ra (\(\upmu\)m) values were 1.27 \(\pm\) 0.23 \(\upmu\)m for group IPA-D, 1.55 \(\pm\) 0.60 \(\upmu\)m for group IPA-1, 1.47 \(\pm\) 0.91 \(\upmu\)m for group IPA-10, and 1.86 \(\pm\) 0.83 \(\upmu\)m for group TPM-10. Between the four groups, no statistically significant difference was found (Figure 2). As for the contact angle, the results of the TPM-10 group (43.26 \(\pm\) 0.15\({}^{\circ}\)) were statistically more significant than those of the IPA-D group (67.74 \(\pm\) 1.96\({}^{\circ}\)), IPA-1 group (64.58 \(\pm\) 1.29\({}^{\circ}\)), and IPA-10 group (63.92 \(\pm\) 0.07\({}^{\circ}\)). TPM-10 group has a very small contact angle (\(p<0.05\)), indicating that this surface is the most hydrophilic (Figures 3 and 4). In the case of surface energy, the TPM-10 group (125.8 \(\pm\) 0.13 mN/m) had the highest energy compared with the IPA-D group (100.4 \(\pm\) 2.31 mN/m), the IPA-1 group (104.0 \(\pm\) 1.48 mN/m), and the IPA-10 group (104.8 \(\pm\) 0.07 mN/m), and the difference was determined to be statistically significant (\(p<0.05\)) (Figure 5).  
Figure 1: FE-SEM images at 1.0 K magnification after washing the surface of the specimen (**A**) IPA-D group: IPA dipping, (**B**) IPA-1 group: IPA washing for 1 min, (**C**) IPA-10 group: IPA washing for 10 min, (**D**) TPM-10 group: TPM washing for 10 min.  
Figure 3: Contact angle of the water droplet on the surface. (**A**) IAP-D group; (**B**) IAP-1 group; (**C**) IAP-10 group; (**D**) TPM-10 group.  
Figure 2: Surface roughness according to different washing conditions.  
The amount of residual monomers was measured using a Fourier infrared spectrometer (PerkinElmer, Waltham, MA, USA). From this, the amount of residual monomers could be evaluated quantitatively. Due to the substituted alkenes, the residual monomers were calculated from the peak at the 1637 cm\({}^{-1}\)[15, 16, 17]. The FTIR equation was used to evaluate the DOC by referencing the result of uncured state [18]. By comparing the DOC for each resin, the groups washed for a long time such as the IPA-10 and TPM-10 groups were determined to be approximately 37% and 47%, respectively. The short washing time for the IPA-D group and the IPA-1 group resulted in a DOC of 27-32%. In particular, the TPM-10 group showed the highest DOC (46-50%), and the statistical significance was confirmed between the four groups (\(p\) < 0.05) (Figure 6). Flexural strength was 131.46 \(\pm\) 25.97 MPa for group IPA-D, 133.07 \(\pm\) 19.37 MPa for group IPA-1, 114.56 \(\pm\) 20.54 MPa for group IPA-10, and 114.64 \(\pm\) 26.76 MPa for group TPM-10. Overall, the four groups showed a value of about 110-130 MPa. For the groups lacking washing, such as the IPA-D and IPA-1 groups, the flexural strength was slightly higher, but there was no statistically significant difference (Figure 7).  
Figure 4: Contact angle for different washing conditions: * significant difference at \(p\) < 0.05.  
Figure 5: Adhesion energy according to different washing conditions: * significant difference at \(p\) < 0.05.