title: Effect of combined digital imaging parameters on endodontic file measurements.
abstract: BACKGROUND
  This study assessed the effect of the combination of a dedicated endodontic filter, spatial resolution, and contrast resolution on the determination of endodontic file lengths.
  
  
  METHODS
  Forty extracted single-rooted teeth were x-rayed with K-files (ISO size 10 and 15) in the root canals. Images were acquired using the VistaScan system (Dürr Dental, Beitigheim-Bissingen, Germany) under different combining parameters of spatial resolution (10 and 25 line pairs per millimeter [lp/mm]) and contrast resolution (8- and 16-bit depths). Subsequently, a dedicated endodontic filter was applied on the 16-bit images, creating 2 additional parameters. Six observers measured the length of the endodontic files in the root canals using the software that accompanies the system. The mean values of the actual file lengths and the measurements of the radiographic images were submitted to 1-way analysis of variance and the Tukey test at a level of significance of 5%. The intraobserver reproducibility was assessed by the intraclass correlation coefficient.
  
  
  RESULTS
  All combined image parameters showed excellent intraobserver agreement with intraclass correlation coefficient means higher than 0.98. The imaging parameter of 25 lp/mm and 16 bit associated with the use of the endodontic filter did not differ significantly from the actual file lengths when both file sizes were analyzed together or separately (P > .05). When the size 15 file was evaluated separately, only 8-bit images differed significantly from the actual file lengths (P ≤ .05).
  
  
  CONCLUSIONS
  The combination of an endodontic filter with high spatial resolution and high contrast resolution is recommended for the determination of file lengths when using storage phosphor plates.
authors.affiliation: Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Campinas, São Paulo, Brazil. matheusoliveira@hotmail.com
authors.forename: Matheus Lima
authors.initials: ML
authors.lastname: de Oliveira
authors.forename: Geraldo Camilo de Souza
authors.initials: GC
authors.lastname: Pinto
authors.forename: Glaucia Maria Bovi
authors.initials: GM
authors.lastname: Ambrosano
authors.forename: Guilherme Monteiro
authors.initials: GM
authors.lastname: Tosoni
mesh_terms: D000704:Analysis of Variance; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D004867:Equipment Design; D005374:Filtration / Q000295:instrumentation; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015588:Observer Variation; D009811:Odontometry / Q000379:methods*; D019252:Radiography, Dental, Digital / Q000379:methods*; D018915:Root Canal Preparation / Q000295:instrumentation*; D018709:Statistics, Nonparametric