The successful reconstruction of mandibular and maxillary defects using a free bone block requires a precisely fitting preformation of the interponent. The problem of poor fit of iliac crest grafts with unaesthetic results, insufficient fixation zone and oversizing with a correspondingly large defect of the donor site is countered by the construction of an individual drill template for the removal of an ideally shaped bone fragment for the defect situation. With the segmentation software Mimics (Materialise, Leuven, Belgium), the DVT of the patient is evaluated and processed. The region of interest is converted into a three-dimensional model. In the area of the bone defect, the construction of an ideally adapted three-dimensional body is performed layer by layer. The outline of the interponent is used to construct a template. The outer dimensions of the outline are extended to make room for the placement of a milling cutter. By using the 3D visualisation of radiological data sets and suitable software, patient-specific solutions for the reconstruction of mandibular and maxillary defects can be simulated and realised on the computer. The virtual planning can be produced promptly in-house and cost-efficiently on one's own printer. Substance defects after traumas, malformations, or tumors can thus be reconstructed safely and effectively using individualised templates, the duration of surgery can be shortened, and the morbidity rate can be significantly reduced compared to free iliac crest removal. Keywords: Innovation, 3D print, in-house workflow, jaw reconstruction, cutting guide