## 4 Discussion
Moreover, the acid etching of the enamel surfaces was analyzed in order to increase the SBS of multibracket appliances; however, no variations were shown on the lingual surfaces after preconditioning with laser and sandblasting [18]. On the other hand, a successful adhesion procedure between the enamel surface and the inner surface of multibracket appliances was achieved by etching with 37% orthophosphoric acid for 10 s, increasing significantly the SBS in comparison with self-etching adhesion procedures [19]. Therefore, the SBS value could vary depending on the cement used. [PERSON] et al. obtained statistically significant differences in the SBS values of brackets cemented with glass-ionomer-modified cement compared with samples cemented with composite resin (\(p\) = 0.007) or light-activated composite resin (\(p\) = 0.001). However, they did not obtain significant differences in the SBS values between the composite resin study groups (\(p\) = 0.290). These results could be due to the fact that the glass-ionomer-modified group was etched with 10% acrylic acid, while in the composite groups, 37% orthophosphoric acid was used [20]. Moreover, [PERSON] et al. studied the differences in the SBS values between composite resin, a light-cured composite, and self-etched and concluded that the SBS value could vary over time until debonding in all the materials used [21]. Nevertheless, the contact area between the multibracket appliances and the enamel surface has not been found to influence the SBS of mesh-backed multibracket appliances; hence, the mesh area of multibracket appliances is smaller nowadays [22]. However, the mesh design of the multibracket appliances has been shown to significantly affect the SBS. [PERSON] et al. compared different mesh designs and reported that a single mesh crossing the base diagonally of multibracket appliances showed the highest SBS values [5]. In addition, [PERSON] et al. showed that SBS values increased 24% after 24 h of bonding, and rebonded multibracket appliances also showed higher SBS values than multibracket appliances bonded for the first time [23]. In addition, [PERSON] et al. showed a statistically significantly higher SBS associated with premolars with lingual multibracket appliances adapted to the lingual enamel surface compared with a buccal multibracket appliance adapted to the buccal enamel surface, but lingual enamel surfaces were more susceptible to fracture and detachment than buccal enamel surfaces when vertical shear forces were applied [24]. However, [PERSON] et al. did not report statistical bond failure between lingual and buccal multibracket appliances despite there being significant differences in the extent and design of both techniques [25]. Additionally, the adhesive remnant index (ARI) has been used to analyze the SBS and, hence, the remaining cement over the enamel surface after multibracket appliance debonding, and the calcium remnant index (CRI) has also been used to evaluate the cement remnants over multibracket appliance mesh after multibracket appliance debonding [8,9]. [PERSON] et al. reported a 15% higher debonding strength in buccal multibracket appliances (\(p\) < 0.05) compared with lingual multibracket appliances. However, a significantly higher ARI score (\(p\) < 0.002) was found in the lingual surface of teeth submitted to lingual multibracket appliance therapy (2.0 \(\pm\) 1.3) compared with the buccal surfaces of teeth submitted to buccal multibracket appliance therapy (1.6 \(\pm\) 1.5). Additionally, a higher CRI score (\(p\) < 0.005) was also found in the mesh of lingual multibracket appliance therapy (1.7 \(\pm\) 1.4) compared with the mesh of buccal multibracket appliance therapy (1.1 \(\pm\) 1.5) [4]. These results do not agree with the findings obtained in the present study. The main reason for these discrepancies could be related to the fact that in the [PERSON] et al. study, they used the same buccal brackets (Victory, 3M-Unitek) for both sides: Buccal and lingual.