**Author details**

3 to 5) and employ a two-flap technique (Case 4). The two cases not meeting the criteria include the harvesting of a free iliac bone flap (Case 1) and a vascularised iliac bone flap (Case 2). Indeed, the latter cases were simpler with respect to the literature criteria and compared with Cases 3, 4 and 5. However, our experience was that the CAD/CAM technique facilitated finding and harvesting bone segments that closely duplicated the shape of the natural mandible in even less complex cases of osseous reconstruction. Without the CAD/CAM technique and cutting guides, surgery might have required further trimming and blurring of the osseous transplant without improving accuracy. At worst, it might have resulted in unnecessary

However, the latter case was the only one in which compromises were necessary with respect to the accuracy of the anterolateral junction of the osseous transplant and the residual man‐ dibular bone. Besides, the discrepancy between virtual planning and the actual finding was within the scope of a reported distance between the real and virtual osteotomies of 1.30 ± 0.59 mm [1]. Retrospectively, the source of this error is difficult to detect. Possible reasons for this inaccuracy are purely hypothetical, including movement artefacts during CT scans, metallic artefacts from filled teeth, too much play of the oscillating saw in the slots of the cutting guides, calculation errors, or simply being unfamiliar with a new method. Further studies are war‐

While performing surgery with CAD/CAM devices, we experienced in Cases 2 and 3 an additional helpful aspect. After we resected the aforementioned mandibular part in Case 2, including parts of the ascending ramus, the condyle-bearing stump rotated clockwise as a result of contraction of the temporal muscle tendon. Hand-setting alone would have resulted in considerable bias when repositioning the condlye. However, by seamlessly insetting the osseous transplant, we were able to replace the condyle exactly in its initial position without further effort. Accordingly in Case 3, initial findings showed that the ascending rami were pathologically rotated medially and the condyles laterally. During virtual planning, the rotated parts were derotated and the segmented fibula flap was planned for the new position. Within the inset of the prepared fibula we achieved the planned derotation of the condyles by setting the residual mandibular stumps and fibula in a strictly axial and seamless bone-to-bone contact. Hence, the outcomes of these cases suggest that the CAD/CAM technique presents both the opportunity to accurately reconstruct osseous parts of the maxillofacial region and to

Our case report has fulfilled the challenge in the literature to improve upon traditional shaping methods, especially to justify the added costs [4, 10]. Furthermore, our report suggests that the possible applications of CAD/CAM techniques have not yet to be exhausted. At the current state of the art, we believe that the application of CAD/CAM techniques for osseous recon‐ struction in the field of maxillofacial surgery should not be restricted to obviously complex

scarifying of the ASIS in Case1 with further comorbidity.

744 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

ranted to clarify these hypotheses.

solve arising or existing pathological conditions.

**5. Conclusion**

reconstructions.

Jan Rustemeyer

Department of Oral and Maxillofacial Surgery, Plastic Operations, Klinikum Bremen-Mitte,

School of Medicine of the University of Göttingen, Bremen, Germany
