title: Survival rate of Astra Tech implants with maxillary sinus lift.
abstract: OBJECTIVE
  The aim of this study was to retrospectively evaluate the clinical survival rate of Astra Tech implants in the maxillary molar region performed with sinus lift and bone graft.
  
  
  METHODS
  Ninety-nine Astra Tech implants (Osseospeed) placed in the maxillary molar region using sinus lift from September 2009 to February 2012 were selected with a minimum follow-up period of 1 year. The height of alveolar bone, sinus approach technique, bone material and implant survival rate were evaluated.
  
  
  RESULTS
  Of the 99 implants, the survival rate was 90.9%; 8 implants failed within 1 year after implant placement, and 1 implant failed 1 year after implant loading. All failed implants were placed with sinus lift simultaneously. The average height of alveolar bone before implant placement was 6.9 mm, while the height of alveolar bone of failed implants was 2.1 mm, on average.
  
  
  CONCLUSIONS
  Astra Tech implants placed in the maxillary molar region had generally good survival rates, but the relationship between reduced pre-implant alveolar bone height and implant failure requires further attention.
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea.
authors.forename: Wook-Jae
authors.initials: WJ
authors.lastname: Yoon
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea.
authors.forename: Kyung-In
authors.initials: KI
authors.lastname: Jeong
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea.
authors.forename: Jae-Seek
authors.initials: JS
authors.lastname: You
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea.
authors.forename: Ji-Su
authors.initials: JS
authors.lastname: Oh
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea.
authors.forename: Su-Gwan
authors.initials: SG
authors.lastname: Kim
keywords: Dental implants; Sinus floor augmentation