title: Evidence for survival of implants placed into infected sites is limited.
abstract: METHODS
  This study comprises a systematic review of the literature reporting implant placement into immediate extraction sites compromised by pathological lesions of endodontic or periodontal origin. The study proposes 3 focused questions looking at potential compromise of osseointegration, immediate implant success, and types of protocols adopted. The authors performed a MEDLINE/PUBMED search for articles published between 1982 and November 2009 using a combination of key words, including dental implant, immediate, extraction, and infections. They included both animal and human studies published in the English language. The search found 417 references. Following screening and exclusion, the authors presented results from 4 animal studies and 8 human studies.
  
  
  METHODS
  The impact of preexisting infection on the osseointegration of immediately placed implants and subsequent implant success.
  
  
  METHODS
  Implant survival.
  
  
  RESULTS
  Animal Studies. All animal studies were performed with 4 to 5 dogs per study with insertion of 24 to 40 implants. Two articles examined the effects of induced peri-radicular lesions and 2 articles (on the same experimental group of 5 dogs) described effects of ligature-induced periodontitis. Treatment included local and systemic antibiotics and debridement/curettage. No implant failures and no significant differences in bone to implant contact in test and control groups were observed. Human Clinical Studies. These included 6 noncontrolled case reports or case series of between 1 and 33 patients (3 to 97 implants) with a wide variety of infections of endodontic and periodontal origin. The lesions were in various stages of the inflammatory process from chronic or cystic lesions to painful and suppurative lesions. They all included a protocol of debridement and varying courses of antibiotics (5 to 31 days), and guided bone regeneration (GBR) of some description in 5 of the reports and use of platelet-rich growth factor in the other study. Implant survival ranged between 97% and 100%. Only 2 studies were found that reported a controlled clinical trial (both including treatment involving debridement, antibiotics, and GBR). One study described 50 patients with chronic apical infections. They were randomized to immediate or delayed (control) implant placement. Two implants were lost in the immediate group (92% survival) and none in the control group. The second study described a prospective trial of 16 consecutive patients receiving immediate implant placement into infected sites compared with another group of 17 patients without periapical lesions. Four test subjects and one control subject had to be withdrawn because of lack of implant stability at implant placement. Thereafter, there were no implant failures in either group.
  
  
  CONCLUSIONS
  The authors concluded that implants can be placed into sites compromised by periapical and periodontal infections following debridement of the site. Antibiotics should be used until further controlled trials prove otherwise.
authors.affiliation: King's College London Dental Institute, Floor 25 Tower Wing, Guy's Hospital Campus, London SE1 9RT, UK. richard.m.palmer@kcl.ac.uk
authors.forename: Richard
authors.initials: R
authors.lastname: Palmer