title: Comparison of hard tissue density changes around implants assessed in digitized conventional radiographs and subtraction images.
abstract: OBJECTIVE
  The aim of this in vivo study was to compare peri-implant bone density assessed by the mean gray value of the histogram in digitized conventional radiographs and two digital subtraction images (DSI) methods: linear and logarithmic.
  
  
  METHODS
  Thirty-four patients were monitored by standardized periapical radiographs 1 week after surgery and 4 months later. The radiographs were digitized and manipulated by means of EMAGO software. Linear and logarithmic DSI were obtained, and a filter was added to the logarithmic image. Control and test regions were selected and the mean value of the gray level of the histogram of these selected areas was obtained. This process was carried out in the digitized conventional radiographs (DCR) and the two methods of DSI. After that, the images were divided into two groups, with and without bone loss, and statistical analysis was performed.
  
  
  RESULTS
  The results indicate that differences between the jaws did not reach significance, in all the images and in the two groups with and without bone loss. Furthermore, there was no statistically significant difference between the radiographic density assessed in the DCR and the two methods of subtraction images.
  
  
  CONCLUSIONS
  Monitoring of peri-implant bone density by the mean gray value of the histogram in a selected area can be assessed either by linear and logarithmic DSI or by DCR.
authors.affiliation: Division of Oral Radiology, Piracicaba Dental School, State University of Campinas, Limeira Avenue 901, Bairro Areião, Piracicaba 13.414-903, São Paulo, Brazil.
authors.forename: Juliana Araujo
authors.initials: JA
authors.lastname: Bittar-Cortez
authors.forename: Luis Augusto
authors.initials: LA
authors.lastname: Passeri
authors.forename: Frab Norberto
authors.initials: FN
authors.lastname: Bóscolo
authors.forename: Francisco
authors.initials: F
authors.lastname: Haiter-Neto
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging; D015519:Bone Density / Q000502:physiology*; D015921:Dental Implants; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008334:Mandible / Q000000981:diagnostic imaging* / Q000601:surgery; D008437:Maxilla / Q000000981:diagnostic imaging* / Q000601:surgery; D010486:Periapical Tissue / Q000000981:diagnostic imaging; D011856:Radiographic Image Enhancement; D013382:Subtraction Technique
chemical_list: D015921:Dental Implants