title: Interventions for replacing missing teeth: 1- versus 2-stage implant placement.
abstract: BACKGROUND
  Implants may be placed penetrating the oral mucosa (1-stage procedure) or can be completely buried under the oral mucosa (2-stage procedure) during the healing phase of the bone at the implant surface. With a 2-stage procedure the risk of having unwanted loading onto the implants is minimized, but a second minor surgical intervention is needed to connect the healing abutments and more time is needed prior to start the prosthetic phase because of the wound-healing period required in relation to the second surgical intervention.
  
  
  OBJECTIVE
  To evaluate whether a 1-stage implant placement procedure is as effective as a 2-stage procedure.
  
  
  METHODS
  The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched. Handsearching included several dental journals. Authors of all identified trials, an Internet discussion group and 55 dental implant manufacturers were contacted to find unpublished randomised controlled trials (RCTs). The last electronic search was conducted on 21 January 2009.
  
  
  METHODS
  All RCTs of osseointegrated dental implants comparing the same dental implants placed according to 1- versus 2-stage procedures with a minimum follow up of 6 months after loading. Outcome measures were: prosthesis failures, implant failures, marginal bone level changes on intraoral radiographs, patient preference including aesthetics, aesthetics evaluated by dentists, and complications.
  
  
  METHODS
  Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two review authors. Authors were contacted for missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals.
  
  
  RESULTS
  Five RCTs were identified and included reporting data on 239 patients in total. On a patient, rather than per implant basis, the meta-analyses showed no statistically significant differences for prosthesis and implant failures, though trends, especially in fully edentulous patients, favoured 2-stage (submerged) implants.
  
  
  CONCLUSIONS
  The number of patients included in the trials was too small to draw definitive conclusions. The 1-stage approach might be preferable in partially edentulous patients since it avoids one surgical intervention and shortens treatment times, while a 2-stage submerged approach could be indicated when an implant has not obtained an optimal primary stability or when barriers are used for guided tissue regeneration, or when it is expected that removable temporary prostheses could transmit excessive forces on the penetrating abutments especially in fully edentulous patients.
authors: Department of Oral and Maxillofacial Surgery, School of Dentistry, University of Manchester, Higher Cambridge Street, Manchester, UK, M15 6FH.
authors: Marco
authors: M
authors: Esposito
authors: Maria Gabriella
authors: MG
authors: Grusovin
authors: Yun Shane
authors: YS
authors: Chew
authors: Paul
authors: P
authors: Coulthard
authors: Helen V
authors: HV
authors: Worthington
mesh_terms: D003757:Dental Implantation / Q000379:methods*; D015921:Dental Implants; D005881:Gingiva / Q000601:surgery*; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation*; D008334:Mandible; D009061:Mouth Mucosa / Q000601:surgery*; D016032:Randomized Controlled Trials as Topic
chemical_list: D015921:Dental Implants