## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Unit** & **Odds Ratio** & \begin{tabular}{c} **Lower** \\ **95\% CI** \\ \end{tabular} & \begin{tabular}{c} **Upper** \\ **95\% CI** \\ \end{tabular} & \
\begin{tabular}{c} **\(p\) Value** \\ \end{tabular} \\ \hline Sex &
\begin{tabular}{c} Male \\ Female \\ \end{tabular} & 0.996 & 0.610 & 1.63 & 0.986 \\ FHR & \% & 0.965 & 0.920 & 1.01 & 0.140 \\ D/MP & mm & 0.777 & 0.706 & 0.856 & 0.000 *** \\ SNMP & \(\circ\) & 1.02 & 0.978 & 1.06 & 0.397 \\ PPMP & \(\circ\) & 1.0 & 0.966 & 1.05 & 0.813 \\ ANB & \(\circ\) & 1.050 & 0.938 & 1.17 & 0.403 \\ J-J/Ag-Ag & \% & 1.010 & 0.957 & 1.07 & 0.686 \\ ratio & \% & \(\circ\) & 0.001. & & \\ \hline \hline \end{tabular} Simple logistic regression. *** \(p<0.001\).  
\end{table} 
Table 7: Comparison of odds ratio according to the clinical variables. second molars [8]. Considering the mean D7 MP measured in our study was 13.44 mm, the distal roots of the mandibular second molars appear to be located close to the mylohyoid line. Overall, these findings suggest that second molars are more likely to be a problem than first molars during distalization or intrusion of the mandibular posterior teeth. The distance between the mandibular molar roots and lingual cortical bone was shorter in all areas in the hyperdivergent group than in the hypodivergent group in this study. This finding may be due to (1) differences in mandibular morphology according to the vertical facial pattern and (2) reduced molar eruption because of insufficient mandibular forward rotation. [PERSON] et al. reported that the mandibular buccal width in the upper third of the mandibular molar was thinner in hyperdivergent patients [16]. It is thought that the thin mandibular buccal width in patients with a hyperdivergent facial shape affected the contact between the mandibular molar roots and lingual cortical bone. Furthermore, differences in the eruption of posterior teeth according to the mandibular rotation pattern also seem to be related to the proximity between roots and lingual cortical bone. Patients with a hyperdivergent facial pattern show reduced forward rotation of the mandible according to growth and rather backward rotation compared to those with a hypodivergent facial pattern [22]. This limits the eruption of the posterior teeth, which may lead to relative proximity between the mandibular molar roots and lingual cortical bone. In general, given the same conditions, hyperdivergent patients have relatively retracted chins which leads to an increased protrusion of their lips. In these patients, distalization and intrusion of the entire dentition are required to improve the unesthetic facial profile,  
Figure 5: CBCT multiplanar reconstruction images showing contacts between distal roots of mandibular second molars and the lingual cortical bone. (**A**) axial view, (**B**) coronal view. and these types of movements may be restricted by the root-cortical bone relationship. Therefore, it is necessary to check whether there is sufficient space between the mandibular molar roots and lingual cortical bone through CT when treating hyperdivergent patients. If the space is insufficient, extraction may be necessary. The distance between the mandibular molar roots and lingual cortical bone was closest in mandibular second molars, and similarly, contact between the mandibular molar roots and lingual cortical bone was observed mostly in mandibular second molars (Table 5). [PERSON] et al. reported that 35.3% of mandibular second molar roots were in contact with the lingual cortical bone in a study of skeletal Class I patients with normovergent facial patterns [2]. In our study, in agreement with these findings we also observed that 34.5% (100 out of 290) of the mandibular second molar roots were in contact with the lingual cortical bone. The mandibular second molar roots were in contact with the lingual cortical bone in 23.6% (17 out of 72), 36.3% (58 out of 160), and 43.1% (25 out of 58) of hypodivergent, normovergent, and hyperdivergent groups, respectively.