title: Marginal bone levels measured in film and digital radiographs corrected for attenuation and visual response: an in vivo study.
abstract: OBJECTIVE
  To compare the accuracy and precision of measurements on marginal bone levels in differently processed digital radiographs and in film-based radiographs.
  
  
  METHODS
  Twenty-one patients with a diagnosis of chronic periodontitis were included in this study. Periapical radiographs were exposed with the Dixi digital intraoral radiographic system (Planmeca Oy, Helsinki, Finland) and the F-speed Film (Insight, Eastman-Kodak Co., Rochester, NY), respectively. Digital radiographs were subsequently processed into two sets: (a) correction for attenuation and visual response and (b) the same correction but with an additional shift in grey levels. Patients had periodontal surgery immediately after the radiographs were exposed. The vertical distance from cementoenamel junction to the most apical part of the marginal bone was assessed. The measurements were then employed as reference standard and subtracted by the vertical distance from radiographs accordingly. Altogether, 47 sites were evaluated. Seven observers were employed for evaluation under the same viewing conditions. ANOVA was employed for statistical analysis.
  
  
  RESULTS
  No significant differences were found between the absolute differences of the vertical distance obtained from radiographs to their corresponding reference standards when comparing differently processed digital radiographs, but the absolute differences were significantly smaller in digital radiographs than in films. Interobserver variances were not significant.
  
  
  CONCLUSIONS
  Digital radiographs have a favourable measurement accuracy compared with film radiographs when assessing marginal bone levels.
authors.affiliation: Department of Oral and Maxillofacial Radiology, ACTA, Louwesweg 1, 1066 EA Amsterdam, The Netherlands. g.li@acta.nl
authors.forename: G
authors.initials: G
authors.lastname: Li
authors.forename: P E
authors.initials: PE
authors.lastname: Engström
authors.forename: K
authors.initials: K
authors.lastname: Nasström
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Lü
authors.forename: G
authors.initials: G
authors.lastname: Sanderink
authors.forename: U
authors.initials: U
authors.lastname: Welander
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000473:pathology; D000539:Alveolar Process / Q000000981:diagnostic imaging* / Q000473:pathology; D002508:Cephalometry / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D015588:Observer Variation; D010518:Periodontitis / Q000000981:diagnostic imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D019252:Radiography, Dental, Digital / Q000706:statistics & numerical data; D012015:Reference Standards; D019237:Tooth Cervix / Q000000981:diagnostic imaging / Q000473:pathology; D014962:X-Ray Film / Q000706:statistics & numerical data