title: In vivo study of pixel grey-measurement in digital subtraction radiography for monitoring caries remineralization.
abstract: OBJECTIVE
  The aim of this study was to evaluate the performance of a quantitative method, based on pixel grey value measurements, for monitoring caries remineralization.
  
  
  METHODS
  Proximal radiographs of 11 patients (61 enamel caries lesions) were taken both before and after a 2 month remineralization protocol. Radiographs were digitized and for each area a follow-up image was subtracted from a baseline image. A quantitative analysis was undertaken using ImageTool software (University of Texas Health Science Center, San Antonio, TX). For each caries lesion diagnosed, a mean pixel value was obtained in digital subtraction radiographs (SR) using a scale ranging from 0-255 grey values. To identify caries status after the remineralization protocol, a subjective analysis of SR was undertaken by 6 radiologists who graded the lesions as demineralized (n = 10), unchanged (n = 34) or remineralized (n = 17).
  
  
  RESULTS
  There was a statistically significant difference between the mean pixel values for demineralized (112.1+/-14.4), unchanged (127.3+/-12.3) and remineralized (137.5+/-13.8) lesions.
  
  
  CONCLUSIONS
  It was concluded that the status of proximal caries lesions after remineralization therapy can be assessed by pixel grey measurements in SR and may constitute a suitable complementary method for monitoring the results of remineralization protocol in clinical practice.
authors.affiliation: School of Dentistry, Federal University of Goiás, Goiânia, Brazil.
authors.forename: L S
authors.initials: LS
authors.lastname: Carneiro
authors.forename: C A
authors.initials: CA
authors.lastname: Nunes
authors.forename: M A
authors.initials: MA
authors.lastname: Silva
authors.forename: C R
authors.initials: CR
authors.lastname: Leles
authors.forename: E F
authors.initials: EF
authors.lastname: Mendonça
mesh_terms: D000134:Acid Etching, Dental; D000149:Acidulated Phosphate Fluoride / Q000627:therapeutic use; D000293:Adolescent; D000328:Adult; D017607:Aluminum Compounds / Q000627:therapeutic use; D002327:Cariostatic Agents / Q000627:therapeutic use; D003731:Dental Caries / Q000000981:diagnostic imaging* / Q000628:therapy; D003743:Dental Enamel / Q000000981:diagnostic imaging; D003777:Dental Prophylaxis; D003804:Dentin / Q000000981:diagnostic imaging; D005260:Female; D005460:Fluorides, Topical / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D009566:Nitrates / Q000627:therapeutic use; D011856:Radiographic Image Enhancement / Q000379:methods*; D016300:Radiography, Bitewing; D012984:Software; D013382:Subtraction Technique; D014089:Tooth Remineralization; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D017607:Aluminum Compounds; D002327:Cariostatic Agents; D005460:Fluorides, Topical; D009566:Nitrates; D000149:Acidulated Phosphate Fluoride; C050609:aluminum nitrate