## 4 Discussion  
The results revealed that adult patients with unilateral scissors bite showed asymmetric characteristics in the mandible. The alveolar, condylar process, mandibular ramus, mandibular body, and chin units tended to be the most affected region. Only the coronoid process and mandibular angle showed no significant differences. To analyze whether the position of the premolar scissors bite tooth influenced the results, we compared the first premolar scissors bite, second premolar scissors bite, and two premolars scissors bite. However, no statistically significant difference was found among them (\(p>0.05\)). Moreover, the matching percentage of the entire mandible was lower than each of the functional units. In this study, a lower matching percentage meant a more significant asymmetry. The higher matching percentages of the units represented relatively small changes. If all these small changes made by each functional unit were added up, there would be a more significant effect on the entire mandible. Possible reasons will be discussed to explain the results. Previous studies have reported that occlusal disturbances have been considered the cause of mandibular asymmetry. Unilateral scissors bite malocclusion can make a cart to the occlusal plane [4]. The occlusal disturbances and functional lateral displacement can lead to dysfunctional jaw movement, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Mandibular Units** & **Study Group** & **Control Group** & **Significance** \\ \hline Mandibular ramus & 62.52 \(\pm\) 11.00 & 68.60 \(\pm\) 7.56 & ** \\ Mandibular angle & 69.16 \(\pm\) 12.39 & 71.44 \(\pm\) 10.07 & NS \\ Condylar process & 62.78 \(\pm\) 13.56 & 67.58 \(\pm\) 10.32 & * \\ Coracoid process & 87.03 \(\pm\) 6.99 & 89.73 \(\pm\) 7.68 & NS \\ Alveolar process & 67.00 \(\pm\) 12.68 & 73.83 \(\pm\) 8.88 & ** \\ Mandibular body & 66.62 \(\pm\) 9.44 & 72.37 \(\pm\) 8.69 & ** \\ Chin & 80.75 \(\pm\) 9.86 & 85.23 \(\pm\) 6.80 & ** \\ \hline \hline \end{tabular} \(p\) values were based on the independent t-test. The level of significance was set at 0.05. NS = no significance; \({}^{*}=p<0.05\); \({}^{**}=p<0.01\).  
\end{table} 
Table 1: Matching percentages of the mandibular functional units. Figure 8: Surface deviation analysis of mandibles. The map showed the difference between the original mandible model and the mirrored mandible model. The tolerance range was set at 0.5 mm. skeletal mandibular deviation, and asymmetry in the condylar position, affecting the mandibular growth and development [17; 18; 19]. In addition, unilateral scissors bite may cause an imbalance between the muscles. The scissors bite teeth do not have the normal chewing function, and only the non-locked posterior teeth can be used. The chewing function is weakened, and the chewing efficiency is reduced, affecting the mandibular lateral movement and growth [20; 21; 22]. The jaw closing muscles' surface electromyographic activities (SEMG) during centric maximal voluntary clenching (MVC) of patients with unilateral scissors bite have been studied. Compared with non-scissors bite, lower SEMG values for masseter, fewer contacts, and lower biting force distribution were found on the scissors bite side [23]. Also reported in another study, [PERSON] et al. demonstrated the reduced contact of unilateral posterior scissors bite. They suggested that scissors bite malocclusion is associated with the masticatory chewing pattern and muscle activity, such as masseter and temporalis [1]. Furthermore, bones and muscles are in close crosstalk; a better understanding of the relationship between craniofacial deformities and muscles helps understand the relationship between malocclusion and mandible deformities [24; 25]. [PERSON] et al. revealed that experimental removal of the masseter muscle during the growing period in rats induced atrophic changes and shortening of the whole mandible [26]. The mandibular condyle plays a vital role in bone remodeling and mandibular development [27]. Our study used the 3D distance mapping technique to evaluate.