title: A multicenter randomized comparative trial of implants with different abutment interfaces to replace anterior maxillary single teeth.
abstract: OBJECTIVE
  The implant-abutment interface may affect peri-implant mucosal architecture, and influence health and esthetics. The goal of this 1-year follow-up report of a 5-year clinical investigation was to examine the peri-implant mucosal tissue responses to different implant-abutment interface designs.
  
  
  METHODS
  Subjects requiring an anterior maxillary implant were recruited. Tooth extractions, with or without preservation or ridge augmentation procedures, were performed as required. After 5 months of healing, one of three different implant-abutment combinations (conical interface [CI] n = 48); flat-to-flat interface [FI] n = 49); or platform switch interface [PS] n = 44) was placed and provisionalized. Twelve weeks later, permanent crowns were placed and data gathered throughout the first year. Peri-implant mucosal architecture and bone levels were evaluated clinically, photographically, and radiographically.
  
  
  RESULTS
  At 1 year, seven FI and six PS implants failed and two FI and two PS implant participants were lost to follow-up, resulting in survival rates of 100% (CI), 85.7% (FI), and 86.4% (PS) (90.8% overall). Marginal bone level changes were -0.22 mm (CI, P < .05), -1.2 mm (FI, P < .05), and -1.32 mm (PS, P < .05) after 1 year. Marginal bone level stability (≤ 0.5-mm bone loss or gain) was recorded for 87% (CI), 8% (FI), and 27% (PS) of implants. Measurement of midbuccal mucosal zenith and papilla positions revealed no change in the mucosal positions and 0.2 to 0.3 mm of gain in papilla dimensions in all groups.
  
  
  CONCLUSIONS
  Significant differences in marginal bone loss were observed among the three implant-abutment interfaces. At 1 year follow-up, changes in the buccal mucosal zenith position or papilla dimensions were not discernable. A continued longitudinal evaluation of peri-implant bone and mucosal changes around these different interfaces is ongoing.
authors.forename: Lyndon F
authors.initials: LF
authors.lastname: Cooper
authors.forename: Glenn
authors.initials: G
authors.lastname: Reside
authors.forename: Clark
authors.initials: C
authors.lastname: Stanford
authors.forename: Chris
authors.initials: C
authors.lastname: Barwacz
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Feine
authors.forename: Samer
authors.initials: S
authors.lastname: Abi Nader
authors.forename: E Todd
authors.initials: ET
authors.lastname: Scheyer
authors.forename: Michael
authors.initials: M
authors.lastname: McGuire
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000601:surgery*; D003442:Crowns; D003757:Dental Implantation / Q000379:methods*; D019250:Dental Implants, Single-Tooth; D003771:Dental Papilla / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000601:surgery*; D008875:Middle Aged; D014070:Tooth / Q000601:surgery*; D014081:Tooth Extraction; D055815:Young Adult