title: The 'Sharpen' filter improves the radiographic detection of vertical root fractures.
abstract: OBJECTIVE
  To compare the diagnostic accuracy of digital enhancement filters in the diagnosis of vertical root fractures.
  
  
  METHODS
  The sample consisted of 40 single-rooted teeth randomly divided into two groups: experimental and control. Vertical root fractures were induced in the experimental group using a universal testing machine. All teeth were individually radiographed with three different horizontal angles using the Digora Optime(®) digital system. Three observers separately examined the original and filtered images (3D Emboss, Negative, Sharpen and Shadow). The area under Receiver Operating Characteristic curve values (Az) for each protocol were compared by one-way anova with post hoc Bonferroni test. The significance level was set at 5%.
  
  
  RESULTS
  The highest Az value was obtained using the Sharpen filter, with significant differences from the original and other filtered images (P < 0.05). The 3D Emboss filter had the lowest Az value, which was significantly different from the other filtered images (P < 0.05).
  
  
  CONCLUSIONS
  When using the Digora Optime(®) system, the 'Sharpen' filter is recommended to improve the radiographic detection of vertical root fractures.
authors.affiliation: Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil.
authors.forename: H A R
authors.initials: HA
authors.lastname: Nascimento
authors.forename: A C A
authors.initials: AC
authors.lastname: Ramos
authors.forename: F S
authors.initials: FS
authors.lastname: Neves
authors.forename: S L
authors.initials: SL
authors.lastname: de-Azevedo-Vaz
authors.forename: D Q
authors.initials: DQ
authors.lastname: Freitas
mesh_terms: D006801:Humans; D066298:In Vitro Techniques; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D011857:Radiographic Image Interpretation, Computer-Assisted; D019252:Radiography, Dental, Digital / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014082:Tooth Fractures / Q000000981:diagnostic imaging*; D014092:Tooth Root / Q000000981:diagnostic imaging* / Q000293:injuries
keywords: dental radiography; digital radiography; radiographic image enhancement; root fracture