title: In vitro assessment of artifacts induced by titanium, titanium-zirconium and zirconium dioxide implants in cone-beam computed tomography.
abstract: OBJECTIVE
  The aim of this study was to test whether or not the intensity of artifacts around implants in cone-beam computed tomography (CBCT) differs between titanium, titanium-zirconium and zirconium dioxide implants.
  
  
  METHODS
  Twenty models of a human mandible, each containing one implant in the single-tooth gap position 45, were cast in dental stone. Five test models were produced for each of the following implant types: titanium 4.1 mm diameter (Ti4.1 ), titanium 3.3 mm diameter (Ti3.3 ), titanium-zirconium 3.3 mm diameter (TiZr3.3 ) and zirconium dioxide 3.5-4.5 mm diameter (ZrO3.5-4.5 ) implants. For control purposes, three models without implants were produced. Each model was scanned using a CBCT device. Gray values (GV) were recorded at eight circumferential positions around the implants at 0.5 mm, 1 mm and 2 mm from the implant surface (GVT est ). GV were assessed in the corresponding volumes of interest (VOI) in the control models without implants (GVC ontrol ). Differences of gray values (ΔGV) between GVT est and GVC ontrol were calculated as percentages. One-way ANOVA and post hoc tests were applied to detect differences between implant types.
  
  
  RESULTS
  Mean ΔGV for ZrO3.5-4.5 presented the highest absolute values, generally followed by TiZr3.3 , Ti4.1 and Ti3.3 implants. The differences of ΔGV between ZrO3.5-4.5 and the remaining groups were statistically significant in the majority of the VOI (P ≤ 0.0167). ΔGV for TiZr3.3 , Ti4.1 and Ti3.3 implants did not differ significantly in the most VOI. For all implant types, ΔGV showed positive values buccally, mesio-buccally, lingually and disto-lingually, whereas negative values were detected mesially and distally.
  
  
  CONCLUSIONS
  Zirconium dioxide implants generate significantly more artifacts as compared to titanium and titanium-zirconium implants. The intensity of artifacts around zirconium dioxide implants exhibited in average the threefold in comparison with titanium implants.
authors.affiliation: Clinic for Fixed and Removable Prosthodontics and Material Science, Center for Dental and Oral Medicine and Cranio-Maxillofacial Surgery, University of Zürich, Zürich, Switzerland.
authors.forename: Manuel
authors.initials: M
authors.lastname: Sancho-Puchades
authors.affiliation: Clinic for Fixed and Removable Prosthodontics and Material Science, Center for Dental and Oral Medicine and Cranio-Maxillofacial Surgery, University of Zürich, Zürich, Switzerland.
authors.forename: Christoph H F
authors.initials: CH
authors.lastname: Hämmerle
authors.affiliation: Clinic for Fixed and Removable Prosthodontics and Material Science, Center for Dental and Oral Medicine and Cranio-Maxillofacial Surgery, University of Zürich, Zürich, Switzerland.
authors.forename: Goran I
authors.initials: GI
authors.lastname: Benic
mesh_terms: D016477:Artifacts; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D015921:Dental Implants; D003764:Dental Materials; D006801:Humans; D008334:Mandible / Q000000981:diagnostic imaging; D008954:Models, Biological; D011861:Radiography, Dental / Q000379:methods*; D014025:Titanium; D015040:Zirconium
chemical_list: D015921:Dental Implants; D003764:Dental Materials; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide
keywords: artifact; cone-beam computed tomography; dental implant; in vitro; radiology; titanium; titanium-zirconium; zirconia; zirconium dioxide