## 2 Materials and Methods
The working steps were the same as in Group 2, except that after applying the primer and using the air spray, a small amount of saliva was applied to the entire buccal surfaces of the group's specimens. The saliva was donated by one of the authors and applied by using a microbrush. The donor had been asked to clean their teeth well just before collecting the saliva [5]. Group 4: Fuji Ortho LC in capsules on etched and dry enamel. The specimens were first etched with 37% orthophosphoric acid for 15 s [11; 16; 18]. Then, the treated surfaces were rinsed thoroughly with the water spray for 15 s and air-dried with the oil-free spray for 20 s [18]. Fuji Ortho LC was applied to the bracket base. Then, the brackets were pressed evenly on the enamel surfaces, respecting the positioning bonding rules by localizing the center of the buccal surfaces [17]. In order to achieve the minimum adhesive thickness, the brackets were compressed over the tooth surface by putting a special blade in the slots. Excessive bonding material around the bracket base was then gently removed by using a common sealer. The light-curing was performed with the lamp Demetron LC. The specimens were light-cured from occlusal, gingival, mesial and distal aspects for 10 s each [18; 19]. Group 5: Fuji Ortho LC in capsules on etched enamel entirely moistened with distilled water before bonding. All the stages of the teeth preparation were similar to those in Group 4. The difference was that after being treated with orthophosphoric acid, washed and dried, the buccal surfaces of the teeth were moistened by using distilled water and a microbrush. Group 6: Fuji Ortho LC in capsules on etched enamel surfaces entirely moistened with saliva before bonding. All the stages of the teeth preparation were similar to those in Group 4. The only difference was that after being treated with orthophosphoric acid, washed and dried, the buccal surfaces of the teeth were moistened by using saliva donated by one of the authors and a microbrush in the same way as in Group 3 [5]. We used a universal testing machine (Model DDW-100, DTEC, Deity Testing Equipment Co., Ltd., Beijing, China) (Figure 2) to determine the force required to detach the brackets. For testing the bond strength, the bracket slot was positioned parallel to the horizontal plane and the surveyor blade was placed perpendicular to the bracket's base [18]. We tested the shear bond strength by applying an occlusal-cervical force to the bracket base, with a cross-head speed of 1 mm/min [5]. The force required to detach the brackets was expressed in megapascal (MPa) by using a common conversion from N/mm\({}^{2}\) to MPa [12], taking into account the dimension of the bracket base, i.e., 10.3 mm\({}^{2}\) (data obtained from the manufacturer--Dentaurum, Ispringen, Germany). Data resulting from the experimental investigation were verified to avoid outliers and considered for statistical analysis. The results are expressed as mean \(\pm\) standard deviation. For testing the normality of data, we used the Kolmogorov-Smirnov test. For the parametric data, we used Student's \(t\)-test. To compare all six groups together, we used the ANOVA test. The statistically significant level was \(p\) < 0.05.