Restoration of the temporal defect using laser stereolithography technique.

Temporalis muscle flaps have been widely used for covering tissue defects after resection of tumors in the oral cavity, orbit, or cranial base.1,2 The advantages of this procedure include the reliability of the vascular pedicle, versatility in application, and a donor site almost free of dysfunction. The most common sequelae occurring in the donor site is a depression posterior to the lateral orbital rim, which may be aesthetically objectionable. The defect may be easily camouflaged by hair styling.3 The resulting style may, however, be awkward or insufficient for effective concealment, especially for men. Concealing the defect with implantable material is recommended in most situations when a large portion of the muscle is used.1,2,4 The most common material used is acrylic bone cement, a chemically cured methylmethacrylate that is extensively used in orthopedics and in craniofacial surgery. It is well tolerated by tissue, unresorbable, and moldable to conform to the size and shape of the defect before set.4 Traditionally, the cement was put onto the temporal defect during its dough stage and molded manually to restore the original contour. Although this method seemed to work, there were concerns regarding the safety of applying the curing acrylic to tissue directly. Deaths had been reported to be associated with the use of bone cement in immobilization of joint prosthesis.5 In addition, this method was inaccurate and the aesthetic results might vary. We herein proposed an indirect method using laser stereolithography technique to fabricate the acrylic implant for the temporal defect. Laser stereolithography (LSL) was introduced in the early 1990s. It was a technique of rapid prototyping originally developed for manufacturing industrial products. The sectional 3-dimensional data are fed into the stereolithography apparatus computer, which directs the laser to draw selectively on the liquid resin and subsequently solidifies it. The platform supporting the object then sinks and submerges the solid layer into the liquid and then raises it to guarantee another smear layer of liquid on the previously hardened resin. The laser traces the next layer and the dipping process repeats itself, resulting in fusion of all slices. The time for constructing the 3-dimensional model varies with the shortest dimensions of the individual model. In contrast to the milling computer-assisted manufacturing, this technique has the capability of producing objects with undercuts and internal cavities and therefore is more suitable to make anatomic models.6 By using smaller-pixel resolution in the computed tomography (CT) images, the LSL models thus formed can be used as very accurate replicas of complex anatomic structures.7 Application of biomodeling in the craniomaxillofacial region serves multiple purposes.8-10 The deformities or disease status of certain cases could be better shown by the models. Operative procedures could be simulated on the models with much greater accuracy. Implants or surgical templates, if indicated, could be preformed on the models before the real operation. Fabrication of the augmentation implants typically involved direct molding or carving techniques on the medical models. *Chief, Division of Oral and Maxillofacial Surgery, Department of Dentistry, National Cheng Kung University Hospital, Taiwan, ROC. †Associate Professor, Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan, ROC. ‡Attending Staff, Division of Oral and Maxillofacial Surgery, Department of Dentistry, National Cheng Kung University Hospital, Taiwan, ROC. §Attending Staff, Division of Oral and Maxillofacial Surgery, Department of Dentistry, National Cheng Kung University Hospital, Taiwan, ROC. Address correspondence and reprint requests to Dr Wong: Division of Oral and Maxillofacial Surgery and Department of Dentistry, National Cheng Kung University Hospital, 138 Sheng-Li Rd, Tainan City, Taiwan, ROC; e-mail: z8308032@email.ncku.edu.tw © 2002 American Association of Oral and Maxillofacial Surgeons 0278-2391/02/6011-0025$35.00/0 doi:10.1053/joms.2002.35755