title: Accuracy of medical models made by additive manufacturing (rapid manufacturing).
abstract: BACKGROUND
  Additive manufacturing (AM) is being increasingly used for producing medical models. The accuracy of these models varies between different materials, AM technologies and machine runs.
  
  
  OBJECTIVE
  To determine the accuracy of selective laser sintering (SLS), three-dimensional printing (3DP) and PolyJet technologies in the production of medical models.
  
  
  METHODS
  3D skull models: "original", "moderate" and "worse". SLS, 3DP and PolyJet models, and a coordinate measuring machine (CMM).
  
  
  METHODS
  Measuring balls designed for measurements were attached to each 3D model. Skull models were manufactured using SLS, 3DP and PolyJet. The midpoints of the balls were determined using CMM. The distances between these points were calculated and compared with the 3D model.
  
  
  RESULTS
  The dimensional error for the PolyJet was 0.18 ± 0.12% (first measurement) and 0.18 ± 0.13% (second measurement), for SLS 0.79 ± 0.26% (first model) and 0.80 ± 0.32% (second model), and for 3DP 0.67 ± 0.43% (original model, first measurement) and 0.69 ± 0.44% (original model, second measurement), 0.38 ± 0.22% (moderate model) and 0.55 ± 0.37% (worse model). Repeatability of the measurement method was 0.12% for the PolyJet and 0.08% for the 3DP.
  
  
  CONCLUSIONS
  A novel measuring technique was developed and its repeatability was found to be good. The accuracy of the PolyJet was higher when compared with SLS or 3DP.
authors: Aalto University, School of Science, Department of Industrial Engineering and Management, BIT Research Centre (Head: Dr. Jouni Partanen), P.O. Box 15500, FI-00076 Aalto, Espoo, Finland. Electronic address: mika.salmi@aalto.fi.
authors: Mika
authors: M
authors: Salmi
authors: Kaija-Stiina
authors: KS
authors: Paloheimo
authors: Jukka
authors: J
authors: Tuomi
authors: Jan
authors: J
authors: Wolff
authors: Antti
authors: A
authors: Mäkitie
mesh_terms: D000465:Algorithms; D002508:Cephalometry / Q000706:statistics & numerical data; D017076:Computer-Aided Design / Q000706:statistics & numerical data*; D005147:Facial Bones / Q000033:anatomy & histology*; D057918:Fiducial Markers; D006358:Hot Temperature; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data; D007834:Lasers; D008953:Models, Anatomic; D011327:Printing / Q000706:statistics & numerical data; D012886:Skull / Q000033:anatomy & histology*; D012984:Software / Q000706:statistics & numerical data
keywords: Craniofacial; Precision; Preoperative models; Rapid prototyping