## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Variables**} & \multicolumn{4}{c}{**Bonding Failure**} & \multicolumn{4}{c}{**Position Failure**} & \multicolumn{4}{c}{**Total Re-Bonding**} \\ \cline{2-13}  & **Estimate** & **95\% CI** & \(p\)**-Value** & **Estimate** & **95\% CI** & \(p\)**-Value** & **Estimate** & **95\% CI** & \(p\)**-Value** \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Sex \\ Age \\ \end{tabular} } & Male & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 \\  & Female & \(-\)0.28 & \(-\)0.51 & \(-\)0.05 & 0.0150 * & \(-\)0.62 & \(-\)0.93 & \(-\)0.30 & 0.001 ** & \(-\)0.39 & \(-\)0.58 & \(-\)0.21 & \(<\)0.0001 ** \\  & \(<\)20 years & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 \\  & \(>\)20 years & \(-\)0.49 & \(-\)0.70 & \(-\)0.28 & \(<\)0.0001 ** & \(-\)0.79 & \(-\)1.10 & \(-\)0.48 & \(<\)0.001 ** & \(-\)0.58 & \(-\)0.76 & \(-\)0.41 & \(<\)0.0001 ** \\ Skeletal & I & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & \\ classification & II & 0.04 & \(-\)0.20 & 0.28 & 0.7675 & 0.09 & \(-\)0.25 & 0.44 & 0.5988 & 0.05 & \(-\)0.14 & 0.25 & 0.5860 \\  & III & 0.18 & \(-\)0.09 & 0.45 & 0.2012 & 0.19 & \(-\)0.19 & 0.58 & 0.3295 & 0.18 & \(-\)0.04 & 0.40 & 0.1119 \\  & Hyperdivergency & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 \\  & Normdivergency & \(-\)0.30 & \(-\)0.58 & \(-\)0.08 & 0.0807 ** & 0.01 & \(-\)0.37 & 0.40 & 0.9446 & \(-\)0.23 & \(-\)0.43 & \(-\)0.02 & 0.0322 * \\  & Hypdivergency & \(-\)0.30 & \(-\)0.60 & \(-\)0.01 & 0.0439 * & 0.14 & \(-\)0.29 & 0.58 & 0.5133 & \(-\)0.16 & \(-\)0.40 & 0.08 & 0.1882 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Multiple linear regression analysis with dependent variables of sex, age, skeletal classification, and skeletal divergency. error (7.55%) and bonding failure (15.09%). In this study, BF (15.09%) was the main reason for the total bracket re-bonding rate compared to PE (7.55%). The BF rates between the maxilla and mandible were significantly different (\(p<0.05\)). Mandibular teeth showed a higher BF rate than maxillary teeth and were concentrated in the anterior teeth (Table 2). This was impressive because it suggested that the position most prone to bracket bonding failure was the anterior mandibular teeth. [PERSON], et al. reported similar results [17]. It is speculated to be related to bite depth, arch wire force, movement of surrounding tissues, and excessive salivation. Bite depth has been reported to directly affect the bracket bonding failure rate, and more bracket failures occur in patients with deep bites than in those with an average or open bite [18], and the addition of bite blocks could effectively reduce the bonding failure rate [19]. The orthodontic arch wire moves the tooth by generating force through wire deformation, and bracket bonding failure occurs when the wire force exceeds the shear bond strength of the adhesive. Severe crowding is common in the lower anterior teeth, and the archive deforms to a greater extent and exerts more force on the lower anterior brackets, eventually causing bracket-bonding failure. Most failed brackets were reported for leveling and alignment stage (0.016\" NiTi) wires [19]. Furthermore, the mandibular anterior teeth are covered by the lower lip and close to the tongue on the lingual side. Unexpected movement of soft tissues around the anterior teeth affects bracket bonding. The sublingual gland duct orifice is located on the lingual side of the lower anterior teeth, and excessive salivation would contaminate the bonding interface. The study found that saliva contamination can significantly reduce the shear bond strength of brackets bonded with hydrophobic bond systems [19].