title: Evaluation of a Novel Computer Color Matching System Based on the Improved Back-Propagation Neural Network Model.
abstract: OBJECTIVE
  To explore the feasibility of a novel computer color-matching (CCM) system based on the improved back-propagation neural network (BPNN) model by comparing it with the traditional visual method.
  
  
  METHODS
  Forty-three metal-ceramic specimens were fabricated by proportionally mixing porcelain powders. Thirty-nine specimens were randomly selected to train the BPNN model, while the remaining four specimens were used to test and calibrate the model. A CCM system based on the improved BPNN model was constructed using MATLAB software. A comparison of the novel CCM system and the traditional visual method was conducted by evaluating the color reproduction results of 10 maxillary central incisors. Metal-ceramic specimens were fabricated using two color reproduction approaches. Color distributions (L*, a*, and b*) of the target teeth and of the corresponding metal-ceramic specimens were measured using a spectroradiometer. Color differences (ΔE) and color distributions (ΔL*, Δa*, and Δb*) between the teeth and their corresponding specimens were calculated.
  
  
  RESULTS
  The average ΔE value of the CCM system was 1.89 ± 0.75, which was lower than that of the visual approach (3.54 ± 1.11, p < 0.01). With respect to color distributions, substantial differences were found between the two color-matching systems, except for ΔL* (p > 0.05).
  
  
  CONCLUSIONS
  The novel CCM system produced greater accuracy in color reproduction within the given color space than the traditional visual approach.
authors.affiliation: School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Jiaqiang
authors.initials: J
authors.lastname: Wei
authors.affiliation: School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Mengdong
authors.initials: M
authors.lastname: Peng
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Yining
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D003776:Dental Porcelain; D017266:Dental Prosthesis; D017267:Dental Prosthesis Design / Q000379:methods*; D005260:Female; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology; D008297:Male; D016571:Neural Networks, Computer; D017797:Prosthesis Coloring / Q000379:methods*; D055815:Young Adult
chemical_list: D003776:Dental Porcelain
keywords: Computer color matching; back-propagation neural network; color difference; metal-ceramic restoration