Evaluation of structured training in osteotomy and splitting for BSSO using a 3D-printed mandibular model / Leonhard Gerich, Yao Li, Oliver-Costin Vladu, Moritz Bregenzer, Kunpeng Xie, Jan Egger, Rainer Röhrig, Frank Hölzle, Behrus Hinrichs-Puladi, Ashkan Rashad