title: Comparison of peri-implant bone level assessment in digitized conventional radiographs and digital subtraction images.
abstract: OBJECTIVE
  Radiographic assessment of marginal bone height is included in longitudinal control of osseointegrated implants. However, accurate and reproducible results are difficult to obtain. The aim of the present study was to examine the differences between linear measurements in digitized radiographs (DR) and digital subtraction images (DSI) around endosseous implants and the interobserver variability.
  
  
  METHODS
  The bone height around 30 implants in 22 patients was assessed by 5 observers. Standardized periapical radiographs were obtained just after the surgery and 4 months later. The radiographs were digitized and manipulated by means of EMAGO software, and linear and logarithmic DSIs were produced. Furthermore, the logarithmic subtraction was enhanced with the use of a filter. The observers had the DRs and three methods of subtraction to assess bone height. ANOVA statistical procedures were applied to analyse differences between the observers in the four assessed images and the Tukey test was used to evaluate the differences between the images.
  
  
  RESULTS
  Comparison of the bone height assessments indicated significantly (P<0.05) higher values in the DR than the three methods of DSI. The observers also had a statistically significant variability in this assessment (P=0.00003).
  
  
  CONCLUSIONS
  DSI demonstrated lower values of linear measurements of the bone height around endosseous implants, compared with DR. Interobserver variability should be considered when comparing values from follow-up studies.
authors.affiliation: Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, State University of Campinas, Brazil.
authors.forename: J A
authors.initials: JA
authors.lastname: Bittar-Cortez
authors.forename: L A
authors.initials: LA
authors.lastname: Passeri
authors.forename: S M
authors.initials: SM
authors.lastname: de Almeida
authors.forename: F
authors.initials: F
authors.lastname: Haiter-Neto
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging*; D000704:Analysis of Variance; D015921:Dental Implants; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015588:Observer Variation; D011856:Radiographic Image Enhancement; D019252:Radiography, Dental, Digital; D012984:Software; D018709:Statistics, Nonparametric; D013382:Subtraction Technique; D014962:X-Ray Film
chemical_list: D015921:Dental Implants