title: The Influence of Crown-to-Implant Ratio on Short Implant Marginal Bone Loss.
abstract: OBJECTIVE
  There is a need for more studies evaluating the marginal bone loss (MBL) of rehabilitations in the posterior regions of extremely resorbed maxillae and mandibles supported by short-length dental implants with a high crown/implant ratio (C/I-R). The aim of this study was to evaluate the influence of the C/I-R in implants on MBL considering dental implants with 4 mm of width and 7 mm of length.
  
  
  METHODS
  This retrospective cohort study included 59 patients (mean age of 52.8 years) rehabilitated with at least one implant 4 mm in width and 7 mm in length, with an anodically oxidized surface and external connection on the premolar or molar positions, supporting a fixed prosthesis, and in function for a period of 36 months. Periapical radiographs at 36 months were used to calculate the C/I-R and MBL. The Spearman correlation coefficient was used to test the correlation between C/I-R and MBL. The level of significance was set at 5%.
  
  
  RESULTS
  One hundred eighteen implants from 59 patients were evaluated. The mean ± SD MBL was 0.67 ± 0.63 mm. The C/I-R mean ± SD was 2.53 ± 0.79 mm. Thirty implants presented a C/I-R ≤ 2, while 88 implants had a C/I-R > 2. A weak nonsignificant inverse correlation (r = -0.081; P = .383, Spearman) was registered between C/I-R and MBL.
  
  
  CONCLUSIONS
  Within the limitations of this study, it is possible to conclude that implant-supported fixed prostheses with C/I-R > 2 do not correlate positively with MBL.
authors.forename: Mariana
authors.initials: M
authors.lastname: Nunes
authors.forename: Ricardo Faria
authors.initials: RF
authors.lastname: Almeida
authors.forename: Antonio Campos
authors.initials: AC
authors.lastname: Felino
authors.forename: Paulo
authors.initials: P
authors.lastname: Malo
authors.forename: Miguel
authors.initials: M
authors.lastname: de Araújo Nobre
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000473:pathology*; D003442:Crowns; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported / Q000379:methods*; D019232:Dental Restoration Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000534:rehabilitation*; D008297:Male; D008334:Mandible / Q000601:surgery; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants