Treatment Strategy for Condyle/Ramus Deficiency Using 3D Virtual Surgery and CAD/CAM Technologies; Total Joint Replacement or Inverted-L Osteotomy.

OBJECTIVE: To introduce a guideline for selecting proper surgical modalities for correction of skeletal Class II malocclusion with moderate-to-severe vertical height deficiency (VHD) of the condyle/ramus complex (CRC) using bimaxillary surgery in conjunction with total joint replacement (TJR) or inverted-L osteotomy (ILO) assisted by 3D virtual surgical planning and CAD/CAM technologies. CASES: Four cases of severe skeletal Class II patients with moderate-to-severe VHD of CRC were presented. They underwent bimaxillary surgery using Le Fort I osteotomy in the maxilla and TJR or ILO in the mandible, with the help of virtual surgical planning (VSP) and computer-aided design/computer-aided manufacturing (CAD/CAM)-printed surgical guides and osteosynthesis plates. Guidelines are as follows: (1) if a patient has a moderate degree of VHD and the function of the temporomandibular joint (TMJ) is normal, ILO would be preferred for vertical elongation of the ramus; (2) if a patient has congenitally small condyle or severe condylar resorption, TJR would be preferred to resolve severe VHD of CRC; and (3) when a patient has a metal allergy, foreign body reaction or anatomic limitations (ie, thin cranial base cortex for fossa fixation), ILO would be a better option than TJR. RESULTS: TJR or ILO using VSP and CAD/CAM-printed surgical guides, wafers, and customized plates can provide a proper selection of the surgical plan, accurate transfer of surgical plans to actual surgical procedures, and esthetic improvement of the facial profile. CONCLUSION: This guideline based on the degree of VHD and functional aspects of CRC might help clinicians to select effective surgical modality for correction of skeletal Class II malocclusion with moderate-to-severe VHD of CRC.

Metastasis of Renal Cell Carcinoma to the Mandible.

Renal cell carcinoma (RCC) is the most common tumor of the kidney. Although RCC often metastasizes to other organs, metastasis to the head and neck region is rare, and metastasis to the mandible is very unusual. Given the fact that metastasis of primary neoplasms is not always predictable, it is essential to rule out metastatic carcinoma in jaw lesions. We herein report a rare presentation of metastasis of RCC to the mandible, in which the metastatic lesion in the oral cavity was found first, followed by the primary lesion, in a 22-year-old girl who suffered from pain in the left temporomandibular joint on mouth opening and hypoesthesia of the left chin, left lower lip, and left lower gum.

Maxillary Total Elongation Surgery using 3D Virtual Surgery, CAD/CAM and 3D Printing Technology: Surgical Convenience and Accuracy.

After Le Fort I osteotomy was first performed by von Langernbeck in 1859, there has been many improvements since. Research on and development of Le Fort I osteotomy procedure has shown downward movement of the maxilla to exhibit lowest stability and accuracy. However, maxillary downgraft movement is necessary in orthognathic patients with insufficient vertical length of the maxilla, but fixation of the maxilla after elongation is often very inaccurate. In this study, the authors utilized 3D virtual surgery, CAD/CAM-assisted 3D printing technology to overcome such limitations of maxillary total elongation. In addition, accuracy at 7 different landmarks from superimposition of virtual simulation data and postoperative Cone-beam computed tomography (CBCT) data were measured. Although posterior maxilla exhibited bigger range of errors, an error of <1 mm was measured at all 7 landmarks. Operation time was greatly shortened with cutting guides and customized plates. Although this study is a single-case study, this study shows increased accuracy and efficacy from application of 3D virtual surgery, CAD/CAM, and 3D printing technology.