title: Correlation between bone density and angular deviation of implants placed using CT-generated surgical guides.
abstract: BACKGROUND
  The aim of this study was to evaluate the correlation between the density of bone where implants were placed and the angular deviations that occurred between the virtually planned and actually placed implants using 2 different stereolithographic surgical guides.
  
  
  METHODS
  The study population consisted of 54 patients who received 216 implants. Computed tomography machine was used for preoperative evaluation of the jawbone for implant therapy as well as determination of the bone density values (Hounsfield units [HU]) of the implantation site. All implant sockets were prepared using 2 different types of stereolithographic surgical guide. Ninety-four implants were installed using the surgical guides (Stentcad Beyond, Ay-Design; Kos-gep, ODTU, Ankara, Turkey) in the mouth, whereas 122 implants were placed after the surgical guides (Stentcad Classic; Kos-gep, ODTU) were removed.
  
  
  RESULTS
  The mean bone densities of maxilla and mandible were 561.36 (SD, 229.46) HU and 890.63 (SD, 361.85) HU, respectively. The mean angular deviations between planned and placed implants using Stentcad Classic and Stentcad Beyond surgical guides were 5.32 (SD, 1.96) degrees and 3.73 (SD, 1.14) degrees, respectively. Highly negative correlation was found between the bone density of the placed implant sites and angular deviations in the group in whom implants were installed with freehand.
  
  
  CONCLUSIONS
  The lower bone density values have resulted in the greater angular deviations in the group, in whom the implants were placed after the surgical guides were removed. This deviation might have been derived from the freehand placement of the implants and the poor quality of the bone.
authors.affiliation: Department of Prosthodontics, Near East University, Faculty of Dentistry, Mersin, Turkey. oguzozan@gmail.com
authors.forename: Oguz
authors.initials: O
authors.lastname: Ozan
authors.forename: Kaan
authors.initials: K
authors.lastname: Orhan
authors.forename: Ilser
authors.initials: I
authors.lastname: Turkyilmaz
mesh_terms: D015519:Bone Density; D016009:Chi-Square Distribution; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D005260:Female; D006801:Humans; D007575:Jaw, Edentulous / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery; D008875:Middle Aged; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants