Abstract: Objective　 To obtain the theoretical condyle distance (TCoD) which was applied to determine the width of the mandible in mandibular reduction and reconstruction through three-dimensional measurement and analysis of jaw anatomical landmarks. Methods　 The archived CBCT images of 100 cases of normal jaws were imported into mimics to establish jaw model. Then 6 bony landmarks were marked, and 12 linear and angular variables were measured. The data were statistically analyzed via Spss software to obtain parameters for mandibular reduction and reconstruction. The feasibility was verified by a retrospective analysis of 10 cases of mandibular fracture. And it was used to guide 1 case of mandibular fracture reduction in the clinic. Results　 The discrepancy in angle variables of different genders and individuals was usually smaller than the length variable, and the COV in ramus height and gonial angle was the largest. However, there was a high degree of consistency between fossa distance (FoD) and condyle distance (CoD). The FoD was equal to CoD (P＞0.05) in patients under 50 years old. There was a linear relationship between fossa distance (FoD) and condyle distance (CoD) (P＜0.05), so patients above 50 years old could obtain the TCoD through correction. Through retrospective analysis of 10 fracture patients, compared with FoD, the theoretical condyle distance was closer to the postoperative condyle distance. On an edentulous patient with a comminuted mandibular fracture, preoperative virtual surgery was performed. The reduction and reconstruction of the mandible was guided and verified via TCoD, and satisfactory results were obtained. Conclusions　 TCoD can be used as an ideal parameter for determining the width of the mandible.

Key words: theoretical condyle distance, digital technology, mandible width, mandibular comminuted fracture