title: Evaluation of peri-implant bone metabolism under immediate loading using high-resolution Na18F-PET.
abstract: OBJECTIVE
  This study aimed to examine the influence of immediate loading on the dynamic changes of bone metabolism around dental implants using a high-resolution semiconductor sodium18F-fluoride (Na18F)-PET.
  
  
  METHODS
  Tibiae of 12 adult male rats were divided into 4 groups: immediate loading (IL), no loading (NL), bone defect (BD), and control (CTR). For the IL group, a 4.0-N load was applied continuously by two closed-coil springs attached between two implants in tibia. Each rat received an intravenous injection of Na18F and was scanned by high-resolution Na18F-PET at day 1 and then at weeks 1, 2, 3, 4, 5, 6, and 8 after surgery. Bone metabolism around the implant was evaluated by standardized uptake value (SUV), which indicates the outcome of Na18F accumulation. CT scanning was also performed, and PET and CT images were superposed to determine the anatomical orientation in PET images.
  
  
  RESULTS
  Bone metabolism peaked at 7 days after surgery and then gradually decreased in all three test groups (IL, NL, and BD). SUVs of all three test groups were significantly higher than the baseline at 1, 2, 3, and 4 weeks after surgery, with SUVs in the IL group returning to baseline levels earlier than those in the NL and BD groups.
  
  
  CONCLUSIONS
  Fluorine integrates preferentially with the initial low-calcified bone; thus, our results suggest that immediate loading promotes the calcification of the bone tissue in the early stage on peri-implant bone formation.
  
  
  CONCLUSIONS
  Na18F-PET allows for an estimate of bone metabolism change around the implant.
authors.affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Matsuo
authors.affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan. ogat-thk@umin.ac.jp.
authors.forename: Toru
authors.initials: T
authors.lastname: Ogawa
authors.affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Miou
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Shibamoto
authors.affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Juan Ramón Vanegas
authors.initials: JRV
authors.lastname: Sáenz
authors.affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Yokoyama
authors.affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kanda
authors.affiliation: Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Toyohara
authors.affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Sasaki
mesh_terms: D000818:Animals; D015921:Dental Implants; D005462:Fluorine Radioisotopes; D057893:Immediate Dental Implant Loading; D020007:Implants, Experimental; D008297:Male; D023421:Models, Animal; D049268:Positron-Emission Tomography; D051381:Rats; D017208:Rats, Wistar; D013977:Tibia / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000601:surgery*
chemical_list: D015921:Dental Implants; D005462:Fluorine Radioisotopes
keywords: Bone metabolism; Immediate loading; Na18F-PET; Peri-implant bone