Positioning control of the upper incisors in orthognathic surgery. Pre-operative planning with the Model Positioning Device and intra-operative application of the Sandwich Splint.

In orthognathic surgery a three-dimensional positioning of the maxilla is possible by means of the Le Fort I osteotomy and subsequent maxillary movement. In treatment planning and at the time of surgery it is very important to achieve an exact positioning of the upper incisors in relation to the upper lip and the rest of the skull. The Model Positioning Device described here allows three-dimensional positioning of the upper incisors in one- or two-jaw surgery. The reference plane is the upper surface of the upper part of a semi-individually adjustable articulator. The application of the Sandwich Splint enables the three-dimensional positioning of the maxilla in relation to the rest of the skull. The Sandwich Splint ensures that the vertical position of the mandible in relation to the rest of the skull above the osteotomy plane is exactly reproducible in the pre- and post-operative situation in both model surgery and at time of surgery. To this mandibular position the maxilla is positioned in three dimensions, as preplanned. The vertical dimension, which is identically reproducible before and after surgery is measured with a caliper. After surgery the mandible can be rotated into the planned new intercuspidation.