title: Evaluation of intensity of artefacts in CBCT by radio-opacity of composite simulation models of implants in vitro.
abstract: OBJECTIVE
  The aim was to compare the intensity of artefacts in CBCT images caused by different percentages of radio-opacifying material in composite simulation models of implants. Titanium and zirconia models of implants were used as a reference for the evaluation of the intensity of artefacts.
  
  
  METHODS
  Seven different percentages of radio-opacifying BaAlSiO2 fillers were added to composite resin to fabricate seven step wedges and simulation models of implants. Titanium and zirconia simulation models of implants were also fabricated. Aluminium step wedge was used as a reference for the measurement of grey values in intraoral radiographs. Step wedges were exposed with a Planmeca Intra X-ray machine (Planmeca Oy, Helsinki, Finland). All composite, titanium and zirconia simulation models of implants were exposed with a SCANORA(®) 3D dental X-ray machine (Soredex, Tuusula, Finland). Images and grey values were analysed with ImageJ software (National Institutes of Health, Bethesda, MD). To demonstrate possible artefacts between all the simulation models of implants, the images were also visually compared with each other using ImageJ software.
  
  
  RESULTS
  Artefacts were clearly present in CBCT images caused by titanium and zirconia and when the composite material consisted at least 20% BaAlSiO2. The intensity of artefacts increased when the radio-opacity of the composite material increased.
  
  
  CONCLUSIONS
  Materials containing less radio-opacity produce less pronounced artefacts. The cut-off point for artefacts is at 20% radio-opaque filling material in composite material.
authors.affiliation: 1 Department of Oral Pathology and Radiology, Institute of Dentistry, University of Turku, Turku, Finland.
authors.forename: N
authors.initials: N
authors.lastname: Kuusisto
authors.forename: P K
authors.initials: PK
authors.lastname: Vallittu
authors.forename: L V J
authors.initials: LV
authors.lastname: Lassila
authors.forename: S
authors.initials: S
authors.lastname: Huumonen
mesh_terms: D000180:Acrylic Resins; D016477:Artifacts; D054893:Cone-Beam Computed Tomography; D015921:Dental Implants; D066298:In Vitro Techniques; D011857:Radiographic Image Interpretation, Computer-Assisted; D019252:Radiography, Dental, Digital; D014025:Titanium; D015040:Zirconium
chemical_list: D000180:Acrylic Resins; D015921:Dental Implants; C041289:Radio-Opaque acrylic resin; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide
keywords: artifact; composite-based implant model; cone beam CT; radio-opacity