title: Artificial Neural Networks as a powerful numerical tool to classify specific features of a tooth based on 3D scan data.
abstract: Chairside manufacturing based on digital image acquisition is gainingincreasing importance in dentistry. For the standardized application of these methods, it is paramount to have highly automated digital workflows that can process acquired 3D image data of dental surfaces. Artificial Neural Networks (ANNs) arenumerical methods primarily used to mimic the complex networks of neural connections in the natural brain. Our hypothesis is that an ANNcan be developed that is capable of classifying dental cusps with sufficient accuracy. This bears enormous potential for an application in chairside manufacturing workflows in the dental field, as it closes the gap between digital acquisition of dental geometries and modern computer-aided manufacturing techniques.Three-dimensional surface scans of dental casts representing natural full dental arches were transformed to range image data. These data were processed using an automated algorithm to detect candidates for tooth cusps according to salient geometrical features. These candidates were classified following common dental terminology and used as training data for a tailored ANN.For the actual cusp feature description, two different approaches were developed and applied to the available data: The first uses the relative location of the detected cusps as input data and the second method directly takes the image information given in the range images. In addition, a combination of both was implemented and investigated.Both approaches showed high performance with correct classifications of 93.3% and 93.5%, respectively, with improvements by the combination shown to be minor.This article presents for the first time a fully automated method for the classification of teeththat could be confirmed to work with sufficient precision to exhibit the potential for its use in clinical practice,which is a prerequisite for automated computer-aided planning of prosthetic treatments with subsequent automated chairside manufacturing.
authors.affiliation: Department of Dental Materials and Biomaterials Research, RWTH Aachen University Hospital, Aachen, Germany. Electronic address: sraith@ukaachen.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Raith
authors.affiliation: Department of Dental Materials and Biomaterials Research, RWTH Aachen University Hospital, Aachen, Germany.
authors.forename: Eric Per
authors.initials: EP
authors.lastname: Vogel
authors.affiliation: Department of Dental Materials and Biomaterials Research, RWTH Aachen University Hospital, Aachen, Germany.
authors.forename: Naeema
authors.initials: N
authors.lastname: Anees
authors.affiliation: Department of Prosthodontics, Dental School, Ludwig-Maximilians University Munich, Munich, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Keul
authors.affiliation: Department of Prosthodontics, Dental School, Ludwig-Maximilians University Munich, Munich, Germany.
authors.forename: Jan-Frederik
authors.initials: JF
authors.lastname: Güth
authors.affiliation: Department of Prosthodontics, Dental School, Ludwig-Maximilians University Munich, Munich, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Edelhoff
authors.affiliation: Department of Dental Materials and Biomaterials Research, RWTH Aachen University Hospital, Aachen, Germany.
authors.forename: Horst
authors.initials: H
authors.lastname: Fischer
mesh_terms: D000465:Algorithms; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000145:classification / Q000379:methods*; D000069550:Machine Learning; D003765:Models, Dental; D016571:Neural Networks, Computer; D014070:Tooth / Q000000981:diagnostic imaging*
keywords: 3D surface scan; Artificial Neural Networks; Digital dentistry; Image analysis; Machine learning