Objective To evaluate the clinical effectiveness of computer-aided surgery system and 3Dprinting(CASS-3DP)in reconstruction of oral and maxillofacial defects(OMDs). Methods Twenty patients with OMDs scheduled for repair and reconstruction surgery were equally randomized to computer-aided surgery group(C-A group)and traditional surgery group(T-S group).A conventional maxillofacial reconstruction was applied in T-S group,and in C-A group,a mandibular focus and image model was created using CASS-3DP,pre-bendin...