title: Marginal bone response of implants with platform switching and non-platform switching abutments in posterior healed sites: a 1-year prospective study.
abstract: OBJECTIVE
  This 1-year prospective study evaluated the implant success rate and marginal bone response of non-submerged implants with platform and non-platform switching abutments in posterior healed sites.
  
  
  METHODS
  Nineteen patients (9 male, 10 female) with posterior partially edentulous spaces, between the ages of 23 and 76 (mean = 55.4 years), were included in this study. A total of 30 implants (15 implants restored with platform switching [PS] abutments [control] and 15 implants restored with non-platform switching [NPS] abutments [test]) were assigned between two groups using a randomization procedure. The definitive abutments with conical connections were placed at the time of surgery, and the definitive restorations were placed at 3 months. All patients were evaluated clinically and radiographically using standardized radiographs at time of implant placement (0), 3, 6 and 12 months after implant placement. Data were analyzed using Friedman test with post hoc pairwise comparisons, Mann-Whitney U-test, and Pearson's chi-square test at the significance level of α = 0.05.
  
  
  RESULTS
  At 12 months, all 30 implants remained osseointegrated corresponding to a 100% success rate. The overall mean marginal bone level change at 12 months was -0.04 ± 0.08 mm for PS group and -0.19 ± 0.16 mm for NPS group. Statistically significant difference in the marginal bone level change was observed between groups at 0 to 12 months and 3 to 12 months (P < 0.05).
  
  
  CONCLUSIONS
  This 1-year randomized control study suggests that when a conical implant-abutment connection is present, similar peri-implant tissue responses can be achieved with platform switching and non-platform switching abutments.
authors.affiliation: Advanced Education in Implant Dentistry, Loma Linda University, School of Dentistry, Loma Linda, CA, USA.
authors.forename: Yun-Chi
authors.initials: YC
authors.lastname: Wang
authors.forename: Joseph Y K
authors.initials: JY
authors.lastname: Kan
authors.forename: Kitichai
authors.initials: K
authors.lastname: Rungcharassaeng
authors.forename: Phillip
authors.initials: P
authors.lastname: Roe
authors.forename: Jaime L
authors.initials: JL
authors.lastname: Lozada
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology*; D016723:Bone Remodeling; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants / Q000009:adverse effects*; D019232:Dental Restoration Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000601:surgery; D008297:Male; D008875:Middle Aged; D016348:Osseointegration; D011446:Prospective Studies; D011897:Random Allocation; D055815:Young Adult
chemical_list: D015921:Dental Implants
keywords: bone change; conical connection; implant; partial edentulism; platform switching; posterior healed site; subcrestal placement