title: Randomized controlled trial comparing a variable-thread novel tapered and a standard tapered implant: interim one-year results.
abstract: BACKGROUND
  A tapered implant with continuously changing threads purported to provide stable tissue support and allow immediate function has been developed. Treatment success and stabilization of supporting tissues over time require documentation.
  
  
  OBJECTIVE
  The purpose of this prospective, randomized, controlled, multicenter study was to evaluate changes in bone level and soft tissue behavior between the novel implant (NobelActive/NA) and a standard tapered implant (NobelReplace Tapered Groovy/NR) with regard to immediate function.
  
  
  METHODS
  A total of 177 patients randomly allocated to 3 treatment groups (2 different test implant groups: NA Internal (n=117; internal connection) and External (n=82), and 1 standard treatment group, NR (n=126)) received 325 implants. Implants were placed into healed sites, and all but 6 implants were immediately nonocclusally loaded. Clinical and radiographic evaluations of treatment success, crestal bone levels, and soft tissue changes were performed at the time of placement and after 3, 6, and 12 months. Log-Rank test was used to analyze the differences in survival rate. Marginal bone level was compared using the Kruskal-Wallis test and Mann-Whitney U-test (alpha=.05).
  
  
  RESULTS
  One-year cumulative survival rates were comparable (96.6% for NA Internal; 96.3% for NA External; 97.6% for NR; P=.852; Log-Rank). Mean (SD) change in bone level was -0.95 mm (1.37) for NA Internal, -0.64 mm (0.97) for NA External, and -0.63 mm (1.18) for NR (P=.589; Kruskal-Wallis). Stable soft tissues and significantly increased papilla scores (P<.001; Wilcoxon signed-rank) were observed for all implant types.
  
  
  CONCLUSIONS
  The novel implants showed high survival rates as well as stable bone and soft tissue levels after 1 year, and may be recommended for clinical use, even under immediate function.
authors.affiliation: Department of Operative Dentistry and Periodontology, CharitéCentrum 3, University School of Dental Medicine, Charité - Universitätsmedizin Berlin, Berlin D-14197, Germany. andrej.kielbassa@charite.de
authors.forename: Andrej M
authors.initials: AM
authors.lastname: Kielbassa
authors.forename: Rafael
authors.initials: R
authors.lastname: Martinez-de Fuentes
authors.forename: Moshe
authors.initials: M
authors.lastname: Goldstein
authors.forename: Christoph
authors.initials: C
authors.lastname: Arnhart
authors.forename: Alberto
authors.initials: A
authors.lastname: Barlattani
authors.forename: Jochen
authors.initials: J
authors.lastname: Jackowski
authors.forename: Marko
authors.initials: M
authors.lastname: Knauf
authors.forename: Martin
authors.initials: M
authors.lastname: Lorenzoni
authors.forename: Carlo
authors.initials: C
authors.lastname: Maiorana
authors.forename: Regina
authors.initials: R
authors.lastname: Mericske-Stern
authors.forename: Eric
authors.initials: E
authors.lastname: Rompen
authors.forename: Mariano
authors.initials: M
authors.lastname: Sanz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000539:Alveolar Process / Q000000981:diagnostic imaging; D015519:Bone Density; D016723:Bone Remodeling; D003442:Crowns; D003758:Dental Implantation, Endosseous; D019250:Dental Implants, Single-Tooth; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003825:Denture, Complete, Immediate; D003831:Denture, Partial, Immediate; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000033:anatomy & histology*; D011446:Prospective Studies; D011859:Radiography; D016896:Treatment Outcome; D055815:Young Adult