title: Early loading of splinted implants supporting a two-unit fixed partial denture in the posterior maxilla: 13-month results from a randomized controlled clinical trial of two different implant systems.
abstract: OBJECTIVE
  The aim of this study was to evaluate early-loaded implants supporting a two-unit fixed dental prosthesis in the posterior maxilla and to compare the clinical and radiological outcomes of two different implant systems in terms of success rates, implant stability quotient (ISQ) values, and peri-implant parameters.
  
  
  METHODS
  Thirty patients with the unilateral loss of two consecutive maxillary posterior teeth were randomly assigned to two different implant systems: SLActive Bone level implant (Institut Straumann AG, Basel, Switzerland) in the control group and CMI IS-II active implant (Neobiotech Co., Seoul, Korea) in the experimental group. The patients received provisional and definitive two-unit fixed prostheses at 4 weeks and 6 months after implant surgery, respectively. The peak insertion torque was recorded at surgery. The stability of each implant was evaluated during surgery and at 2, 3, and 4 weeks and 6 and 13 months after implant placement by means of ISQ values. In addition, periapical radiographs and peri-implant parameters were taken throughout the trial.
  
  
  RESULTS
  Overall, comparable results were obtained between the control and experimental groups in terms of insertion torque, ISQ values, marginal bone loss, and peri-implant soft tissue parameters. All 60 implants had 100% of success rate. The average insertion torque was 36.83 ± 6.09 (control) and 35.33 ± 3.20 (test) Ncm. The ISQ values remained steady until 4 weeks and then increased with statistical significance during 4 weeks to 13 months after surgery. Both groups exhibited no stability dip during the early phase of healing. The average marginal bone loss from the baseline of implant placement for the control and experimental groups was 0.38 and 0.45 mm after 4 weeks and 0.98 and 0.61 mm after 13 months. All of the soft tissue parameters were within normal limits.
  
  
  CONCLUSIONS
  The results of this study indicate that the concept of early loading at 4 weeks after placement in the posterior maxilla can be an effective treatment option, even in the areas of low bone density, when implants satisfy the inclusion criteria of minimum insertion torque and ISQ of 30 Ncm and 65, respectively.
authors.affiliation: Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
authors.forename: Hyo-Sook
authors.initials: HS
authors.lastname: Ryu
authors.affiliation: Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
authors.forename: Cheol
authors.initials: C
authors.lastname: Namgung
authors.affiliation: Director, Global Academy of Osseointegration, Seoul, Korea.
authors.forename: Young-Ku
authors.initials: YK
authors.lastname: Heo
authors.affiliation: Department of Oral Maxillofacial Surgery and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
authors.forename: Jong-Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Lim
mesh_terms: D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D003825:Denture, Complete, Immediate; D003830:Denture, Partial, Fixed; D005260:Female; D006801:Humans; D057893:Immediate Dental Implant Loading / Q000379:methods*; D007576:Jaw, Edentulous, Partially / Q000534:rehabilitation; D008297:Male; D008437:Maxilla / Q000601:surgery*; D008875:Middle Aged; D019415:Torque
keywords: dental implants; early loading; implant stability dip; insertion torque; posterior maxilla; resonance; resonance frequency analysis