Randomized controlled trial comparing a variable-thread novel tapered and a standard tapered implant: interim one-year results

Kielbassa, Andrej M; Martinez-de Fuentes, Rafael; Goldstein, Moshe; Arnhart, Christoph; Barlattani, Alberto; Jackowski, Jochen; Knauf, Marko; Lorenzoni, Martin; Maiorana, Carlo; Mericske-Stern, Regina; Rompen, Eric; Sanz, Mariano (2009). Randomized controlled trial comparing a variable-thread novel tapered and a standard tapered implant: interim one-year results. The journal of prosthetic dentistry, 101(5), pp. 293-305. New York, N.Y.: Elsevier 10.1016/S0022-3913(09)60060-3

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STATEMENT OF PROBLEM: 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. PURPOSE: 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. MATERIAL AND 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.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > School of Dental Medicine > Department of Prosthodontics [discontinued]

UniBE Contributor:

Mericske, Regina








Eveline Carmen Schuler

Date Deposited:

04 Oct 2013 15:11

Last Modified:

25 Jan 2017 12:16

Publisher DOI:


PubMed ID:


Web of Science ID:



https://boris.unibe.ch/id/eprint/31131 (FactScience: 195536)

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