title: Novel method of fabricating individual trays for maxillectomy patients by computer-aided design and rapid prototyping.
abstract: OBJECTIVE
  Making impressions for maxillectomy patients is an essential but difficult task. This study developed a novel method to fabricate individual trays by computer-aided design (CAD) and rapid prototyping (RP) to simplify the process and enhance patient safety.
  
  
  METHODS
  Five unilateral maxillectomy patients were recruited for this study. For each patient, a computed tomography (CT) scan was taken. Based on the 3D surface reconstruction of the target area, an individual tray was manufactured by CAD/RP. With a conventional custom tray as control, two final impressions were made using the different types of tray for each patient. The trays were sectioned, and in each section the thickness of the material was measured at six evenly distributed points. Descriptive statistics and paired t-test were used to examine the difference of the impression thickness. SAS 9.3 was applied in the statistical analysis. Afterwards, all casts were then optically 3D scanned and compared digitally to evaluate the feasibility of this method.
  
  
  RESULTS
  Impressions of all five maxillectomy patients were successfully made with individual trays fabricated by CAD/RP and traditional trays. The descriptive statistics of impression thickness measurement showed slightly more uneven results in the traditional trays, but no statistical significance was shown. A 3D digital comparison showed acceptable discrepancies within 1 mm in the majority of cast areas. The largest difference of 3 mm was observed in the buccal wall of the defective areas. Moderate deviations of 1 to 2 mm were detected in the buccal and labial vestibular groove areas.
  
  
  CONCLUSIONS
  This study confirmed the feasibility of a novel method of fabricating individual trays by CAD/RP. Impressions made by individual trays manufactured using CAD/RP had a uniform thickness, with an acceptable level of accuracy compared to those made through conventional processes.
authors: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
authors: Zhi
authors: Z
authors: Huang
authors: Xin-zhi
authors: XZ
authors: Wang
authors: Yue-Zhong
authors: YZ
authors: Hou
mesh_terms: D017076:Computer-Aided Design; D003760:Dental Impression Materials / Q000494:pharmacology; D003761:Dental Impression Technique / Q000295:instrumentation*; D003813:Dentistry / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008422:Materials Testing; D008437:Maxilla / Q000601:surgery*
chemical_list: D003760:Dental Impression Materials
keywords: Clinical application; feasibility; impression technique; maxillofacial prosthesis