The goal of this study was to determine whether complications during the intervention can be forseen with an exact diagnosis. We therefore evaluated preoperative roentgenograms and analyzed the course of the operative intervention. Numerous additional pathologic findings, presented in diagrams, were identified on the orthopantomogram. Bent roots of third molars projecting into mandibular canal, for example, present certain problems. Intraoperative problems can be recognized on preoperative roentgenograms of the operative field without their being completely excluded; the preoperative roentgenogram therefore is necessary to limit complications.