## 3 Results  
Eighteen patients underwent segmental mandibular resection between December 2015 and November 2017. Three patients were excluded because of a lack of MRI data. Fifteen patients who fulfilled the inclusion criteria consisted of 10 men and five women with a mean age of 60 years (range 31-79 years). Thirteen patients presented with a primary tumor (three patients with ameloblastoma, nine patients with squamous cell carcinoma, and one patient with osteosarcoma), and two patients presented with osteoradionecrosis of the mandible (Table 1). The median follow-up was 28 months (Table 2). Both the surgical guides and prebent plates fit well on the mandible in all cases. No patient needed modification of the preoperative surgical planning of mandibular resection intraoperatively. The operations of all cases were uneventful, and no complications were observed during surgery or the follow-up period (Table 2). In all 15 patients, disease-free bone margins were confirmed by histopathology. However, in one patient, a positive margin was identified in the soft tissue that was very close to the skull base. Fourteen patients included in this study survived without recurrence. One patient had a distant metastasis in the lung during the follow-up and died (Patient 11). Volumes of conventional resection simulation and tailor-made resection simulation were 49,468.66 \(\pm\) 14,007.96 mm\({}^{3}\) and 52,610.01 \(\pm\) 13,755.33 mm\({}^{3}\), and surfaces were 20,927.38 \(\pm\) 4471.70 mm\({}^{2}\) and 22,356.49 \(\pm\) 4185.73 mm\({}^{2}\), respectively. Between the two kinds of simulations, both volume and surface were statistically significant (\(p<0.001\)) (Table 3). Mandibular dentition was partially preserved in six patients, and canines were preserved in five patients. Twelve of 15 patients showed changes in the defect classification with preservation of the mandibular inferior border (Table 2). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Patient No.**} & \multirow{2}{*}{**Sex**} & \multirow{2}{*}{**Age (Years)**} & \multirow{2}{*}{**Diagnosis**} & \multicolumn{3}{c}{**Method of Reconstruction**} \\ \cline{5-6}  & & & & **Microvascular Free Flap** & **Fixation Method** \\ \hline
1 & M & 37 & Ameloblastoma & FFF & Miniplates \\
2 & F & 52 & SCC & FFF & Miniplates \\
3 & F & 56 & ORN & FFF & R-plate \\
4 & M & 63 & ORN & FFF & Miniplates \\
5 & F & 44 & Ameloblastoma & DCIA & R-plate \\
6 & M & 56 & SCC & FFF & Miniplates \\
7 & M & 62 & SCC & DCIA & Miniplates \\
8 & M & 78 & Osteosarcoma & FFF & R-plate \\
9 & M & 31 & Ameloblastoma & FFF & R-plate \\
10 & M & 79 & SCC & FFF & R-plate \\
11 & F & 74 & SCC & FFF & R-plate \\
12 & F & 75 & SCC & FFF & Miniplates \\
13 & M & 60 & SCC & FFF & R-plate \\
14 & M & 70 & SCC & FFF & R-plate \\
15 & M & 65 & SCC & FFF & R-plate \\ \hline Total & 10 men & Mean (SD) & & & \\ n = 15 & 5 women & 60.13 (14.55) & & & \\ \hline \hline \end{tabular} Abbreviations: F, female; M, male; ORN, osteoradinecrosis; SCC, squamous cell carcinoma; FFF, fibula free flap; DCIA, deep circumflex iliac artery bone flap; R-plate, reconstruction plate; SD, standard deviation; no., number.  
\end{table} 
Table 1: Patient demographic and clinical data.