Rigid internal fixation of mandible fractures is advocated as an effective means of providing undisturbed healing and immediate function. However, its application in the clinical setting has resulted in many technique-related failures. To determine the reasons for clinical failure and to help develop improved means of providing successful fixation, the results of plate application in the teaching laboratory were evaluated. Seventy-four surgeons taking the AO/Association for the Study of Internal Fixation (AO/ASIF) maxillofacial course in Davos, Switzerland and 56 surgeons taking the advanced AO/ASIF course in Naples, FL applied rigid internal fixation devices to a mandibular fracture model. Treatment was evaluated for anatomic morbidity and effectiveness. In Davos, 92 of 121 subcondylar, body, symphysis, and ramus fractures (76%) were treated effectively. This included 22 of 34 symphysis fractures (65%). In Naples, 11 of 28 symphyseal fractures (39%) were fixed effectively with lag screws without anatomic morbidity. Technique failure is a frequent event in the application of rigid internal fixation devices to mandible fractures. Lag screw fixation of symphyseal fractures had a particularly high rate of technique-related failure.