title: Relationship between the bone density estimated by cone-beam computed tomography and the primary stability of dental implants.
abstract: OBJECTIVE
  The aims of this study were to objectively assess bone quality with density values obtained by cone-beam computed tomography (CBCT) and to determine the correlations between bone density and primary stability of dental implants.
  
  
  METHODS
  Eighteen Straumann implants were inserted into 18 fresh femoral heads of swine. The bone densities of implant recipient sites were preoperatively determined by the density value using CBCT. The maximum insertion torque value of each implant was recorded using a digital torque meter. Resonance frequency, which represented a quantitative unit called the implant stability quotient (ISQ), was measured using an Osstell Mentor immediately after the implant placement. Spearman's correlation coefficient was calculated to evaluate the correlations among density values, insertion torques, and ISQs at implant placement.
  
  
  RESULTS
  The density values ranged from 98 to 902. The mean density value, insertion torque, and ISQ were 591 ± 226, 13.4 ± 5.2 Ncm, and 67.1 ± 8.1, respectively. Statistically significant correlations were found between the density values and insertion torque (r(s) =0.796, P<0.001), density values and ISQ (r(s) =0.529, P=0.024), and insertion torque and ISQ (r(s) =0.758, P<0.001).
  
  
  CONCLUSIONS
  The bone quality evaluated by specific CBCT showed a high correlation with the primary stability of the implants. Hence, preoperative density value estimations by CBCT may allow clinicians to predict implant stability. Whether the density values obtained by the CBCT device used in the present study could be applied to other devices requires further elucidation.
authors.affiliation: Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan. k-isoda @dent.kyushu-u.ac.jp
authors.forename: Kei
authors.initials: K
authors.lastname: Isoda
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Ayukawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tsukiyama
authors.forename: Motofumi
authors.initials: M
authors.lastname: Sogo
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Matsushita
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Koyano
mesh_terms: D000818:Animals; D015519:Bone Density; D054893:Cone-Beam Computed Tomography; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis; D005270:Femur Head / Q000000981:diagnostic imaging* / Q000601:surgery; D013552:Swine; D019415:Torque
chemical_list: D015921:Dental Implants