title: To what extent does the crown-implant ratio affect the survival and complications of implant-supported reconstructions? A systematic review.
abstract: OBJECTIVE
  To evaluate the occurrence of biological and technical complications with respect to the crown-implant (C/I) ratio of implant-supported reconstructions.
  
  
  METHODS
  Electronic (MEDLINE) and hand searches were conducted for longitudinal prospective studies with a follow-up period of at least 4 years. One reviewer performed screening and data abstraction. The following complications were evaluated: implant survival, peri-implant crestal bone loss, implant fracture, and technical complications related to implant components and suprastructure.
  
  
  RESULTS
  The search provided 41 articles and abstracts, seven of which were selected for full-text analysis. Only two articles were finally included. A qualitative data analysis revealed that the survival rate of implant-supported reconstructions with a C/I ratio of more than 2 was 94.1%. In addition, peri-implant crestal bone loss seemed not to be influenced by the C/I ratio of the implant rehabilitation, except in one study, which noted greater crestal bone loss with lower (<1) compared with higher (>2) C/I ratios. Technical complications related to implant components and suprastructure according to different C/I ratios were not found in any of the studies.
  
  
  CONCLUSIONS
  Despite the diversity among studies with respect to data collection and study design, the current literature shows that the C/I ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss.
authors: Private Practice, Clinica Pronova, Palma de Mallorca, Spain. rafael.blanes@clinicapronova.com
authors: Rafael Juan
authors: RJ
authors: Blanes
mesh_terms: D016301:Alveolar Bone Loss / Q000209:etiology; D003442:Crowns; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D017267:Dental Prosthesis Design / Q000009:adverse effects; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006801:Humans
chemical_list: D015921:Dental Implants