## 3 Results  
At 700\(\times\) magnification, it was possible to clearly see the enamel prisms on the surface of samples A, B, and O (Figure 5a-c, respectively). In contrast, no structures resembling prisms could be observed on the enamel surface of the area test of Group X (Figure 5d). Although prisms are visible in Figure 5a-c, the enamel surface and prisms appear different in the three images. In sample A, the prisms are evenly spaced and have open concave centers with well-defined peripheral prism outlines and their surfaces are also at the level of the tooth surface; this type of prism is referred as a \"well-defined prism\" in the text. In samples B and O, smoothly rounded prisms were observed; they are arranged uniformly on the surface with delineated prism outlines, and their surface is in the level with the tooth surface; this type of prism is referred to in the text as a \"shallow prism\". The enamel surface of sample X appeared with an amorphous layer. Each image covers an enamel area of 19,600 \(\upmu\)m\({}^{2}\).  
For each group, four surfaces were viewed under 54\(\times\) and 700\(\times\) magnification. Prisms' counting was carried out at 700\(\times\) magnification on each analyzed surface. The resulting prisms count on each examined surfaces was expressed as prisms count per surface in \(\upmu\)m\({}^{2}\). In Group A, the mean prism number on each surface examined was 7.2/1000 \(\upmu\)m\({}^{2}\) with a standard deviation of 0.72/1000 \(\upmu\)m\({}^{2}\). The Kolmogorov-Smirnov test for the surfaces of Group A showed a normal distribution of the number of prisms between analyzed surfaces, with D = 0.26 and \(p\) = 0.8. In Group B, the mean number of prisms measured by each analyzed surface was 8/1000 \(\upmu\)m\({}^{2}\), with a standard deviation of 0.96/1000 \(\upmu\)m\({}^{2}\). The  
Figure 4: This figure shows the images of the enamel surface of area test of Groups A, B, O, and X obtained by SEM) at 54\(\times\) magnification. The scale length was set at 500 \(\upmu\)m and the images represent an area of 2600 \(\upmu\)m \(\times\) 2000 \(\upmu\)m. Debris can be observed on the enamel surface of all the samples. Retzius striae with width ranging from 150 to 200 \(\upmu\)m were observed in samples from Groups A (**a**), B (**b**), and O (**c**), although they are less evident with respect to the sample from Group A (**a**). In sample X (**d**), no striae are observed and the enamel appears to be camouflaged by an amorphous layer.  
Kolmogorov-Smirnov test for the surfaces of Group B revealed a normal distribution of the number of prisms between the analyzed surfaces, with D = 0.16 and \(p\) = 0.99. In Group O, the mean number of prisms measured by each analyzed surface was 4.8/1000 \(\upmu\)m\({}^{2}\), with a standard deviation of 0.4/1000 \(\upmu\)m\({}^{2}\). The Kolmogorov-Smirnov test for the surfaces of group O showed a normal distribution of the number of prisms between the analyzed surfaces, with D = 0.21 and \(p\) = 0.94. Student's \(t\)-test with significance set at \(p\) = 0.01 revealed no significant difference between Group A and B with a \(p\) = 0.054, meaning that prism density was similar between Group A and B. Group O showed a significant decrease in prism density compared with Group A (\(p\) = 0.0027) and Group B (\(p\) = 0.0009). Statistical analysis was also performed with RM one-way ANOVA test, where F = 458, \(p\) < 0.0001 with Geisser-Greenhouse's epsilon correction: 0.6846 and R: 0.9892.