The University Münster model surgery system for Orthognathic surgery. Part I – The idea behind

Former intraoperative measurement of the average height of the LeFort I osteotomy plane relative to the molar occlusal plane allow to construct a virtual osteotomy plane in the lateral cephalogram. This is the basis for the development of the Axis Orbital Marker Lines System (AO-MLS).The AO-MLS is presented graphically, and in detail, with construction guidelines. The system could be integrated into various lateral cephalometric analysis- and surgical prediction schemes. It forms the basis for a standardized transfer of the 2D planning to the 3D planning in the articulator, and vice versa. This procedure makes it possible to generate surgical planning protocols based on the model surgery, which represent the dislocations in the proximity of the real osteotomy planes.The Axis Orbital Marker Lines System (software component) in conjunction with the University Münster Model Surgery System (hardware system) increases the predictability of model operations in orthognathic surgery.Our approach for diagnosis and treatment planning complies to international standards for Combined Surgical Orthodontic Treatment [1-8].The diagnostic procedure comprises modified standard procedures of collecting the patient’s medical history, comprehensive clinical examinations, facial analysis using a custom-designed form for a concise clinical documentation (Figure 1), taking impression for plaster models, x-rays, and customized analysis- and documentation procedures, developed from international analysis- and documentation procedures combined with our own measurement modifications.The psycho-social status of the patient is being assessed preliminarily by means of a psychological screening interview (PSI) [9-12], following a “traffic-light”- approach: a positive status comprises mainly of answers which are highlighted in green, whereas the indication for a more detailed psychological evaluation is given by answers mainly from the red highlighted spectrum.Figure 2 shows this color-coded scree