title: Comparison of implant survival with implants placed in acceptable and compromised bone: a literature review.
abstract: BACKGROUND
  Survival rates for conventional dental implant systems are relatively high in normal healthy bone. However, there are subgroups of patients that are at an increased risk of implant failure. In particular, patients with compromised quantity or quality of bone present a significant challenge to the dental implantologist.
  
  
  OBJECTIVE
  To perform a review of the literature in an attempt to quantify the relative risk of implant failure in compromised bone compared to good or acceptable bone and to identify whether certain anatomical regions are at greater risk.
  
  
  METHODS
  We conducted a systematic electronic database search of Medline, Cinhahl and the Cochrane Library through March 2006 identifying articles meeting the eligibility criteria.
  
  
  RESULTS
  We calculated an increased risk of implant failure in compromised bone compared to healthy bone in both the maxilla and the mandible using conventional dental implant systems. Relative risks ranged from 2 to 12 with the highest risk of failure in the maxilla. Conventional systems are often used in combination or after bone augmentation procedures or more innovative methods for stimulating bone growth in patients with compromised bone. These approaches do have their limitations including high costs, the accumulation of the surgical risks, and delayed time to loading.
  
  
  CONCLUSIONS
  Quantifying the risk of implant failure in patients with compromised bone should assist the implantologist in treatment decision making and patient counseling. Alternative methods for treating patients with compromised bone include zygomatic and lateral implants, neither of which typically require bone augmentation procedures. More studies are needed to evaluate their safety and efficacy.
authors.affiliation: Lindenstr.68, CH-8738 Uetliburg, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Ihde
authors.forename: Sigmar
authors.initials: S
authors.lastname: Kopp
authors.forename: Thomas
authors.initials: T
authors.lastname: Maier
keywords: Bone quality; Bone quantity; Compromised bone; Dental implants