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Int Poster J Dent Oral Med 6 (2004), No. 3     15. Sep. 2004

Int Poster J Dent Oral Med 2004, Vol 6 No 03, Poster 238

Failure mode of implant-abutment connections after horizontal cyclic loading

Language: English

Authors:
Dipl.-Ing. Holger Zipprich,
OA Dr. Paul Weigl,
ZÄ Silke Fischbach-Sedlatschek,
Prof. Dr. Hans-Christoph Lauer,
Department of Prosthetic Dentistry,
Johann-Wolfgang-Goethe-University Frankfurt am Main

Date/Event/Venue:
October, 16-18th, 2003
DGZMK
Aachen/Germany

Poster Award
3. Platz des 17. DGZMK / BZÄK / DENTSPLY Förderpreises

Introduction

The use of single tooth implant restorations in the lateral region is increasing. The clinical long term success of those restorations seems to be less dependant of a failure of the osseointegration, but rather more on the material fatigue of the implant's components.

Single tooth implant

In-vivo implant fracture with cycle loading caused fatigue striations

Objectives

The purpose of this study was to evaluate the mode of failure, as well as the reasons of failure resulting from constructional and manufacture weaknessed, after cyclic loading in a chewing simulator.

Material und Methods

For this experiment a chewing simulator (Fa. Willytec) was modified as follows in order to:

  • a.) lead the horizontal cyclic load, which was exercised bilaterally (±100N, at a 8mm distance), on the implant-abutment connection.
  • b.) measure the maximum of dynamical chewing force in each chewing cycle
  • c.) to detect and register during the cyclic loading the interfering signal (coming out from a piezoelectric sound-sensor), which precedes any micro-movement/loosening, and to stop the chewing simulator at the time of detection.

The implant abutment connection was:

  • a.) mounted with the suggested screw torque and
  • b.) standardized V2A caps (Ø 5mm) were cemented on the abutments
  • c.) embeded with "Knethartz, Metaflux" in accordance with DIN 148
Force
[N]
Frequency
[Hz]
cycle loadings
n
loading weight
[kg]
distance
[mm]
speed
[m/s]
± 100 2 1.000.00000 5 ± 1.5 40
Experimental Parameters of the chewing simulator

Results

Implantat diameter average life failure rate failure mode
[Implant/Abutment] [cycles] [number]
ITI-Synoktamilling cylinder 4,8 / 3,45 149.758 8 Suprastructure 8 micromovements / 8 lossenings
ITI-WN-massive abutment 4,8 / 3,45 395.699 8 6 screw- / 2 abutment fractures
Impla 4,2 / 4,2 524.714 6 6 screw fractures
Brånemark 4,0 / 4,0 599.495 8 8 screw- / 5 impant fractures
Camlog 4,3 / 4,3 822.656 3 1 loosening / 2 screw fractures
Frialit 2 4,5 / 4,5 968.813 1 1 screw- / 1 abutment fracture
Bio-Horizon 5,0 / 5,0 1.000.000 0 no failure to detected
Ankylos 4,5 / 2,5 1.000.000 0 no failure to detected

Failure modes

Brånemark


Embrittlement at fracture surface of the goldscrew Cycle loading caused fatigue striations at fractrue surface of the Implant

ITI-SynOkta
milling cylinder

Signal in course of time of a loosened ITI suprastructure  Frequency spektrum of a loosening ITI Supra structure

Virgin connection

ITI-WN-massive Abutment
Screw fracture

Caused by incongruent conical surface = Flaw. ⇒ Abutmentfracture

Impla
Screw fracture

Caused by undersized Screw 5 of 6 fracured screws are easy to remove

At 1 of 6 fractures second fracture at the beginning of thread

Camlog
Fracture of both Screws

Connection after 1.000.000 cycles


Frialit 2
Fracture of connection:

Failed abutment is difficult to remove

Cycle loading caused fatigue striations Undersized screw

Ankylos
Before cyclic loadings

Congruent conical surface After 1.000.000 cyclic loadings

Bio-Horizons

Caused of Implant diameter (5mm) no failure detacted

Discussion and Conclusions

The material fatigue after horizontal cyclic loading depends on the intrinsic tolerance of the materials and the type of the connection between implant body and abutment. Force fit and form fit conical connections or none conical connections with a diameter up to 5mm, proved to have the minimal failure rate.

Abbreviations

  • Implant-abutment connections (IAV)
  • Loosening (L)
  • Fractures (F)
  • Micro movements (MM)

This poster was submitted by Dipl.-Ing. Holger Zipprich.

Correspondence address:
Dipl.-Ing. Holger Zipprich
Poliklinik Prothetik
Theodor-Stern-Kai 7 / Haus 29
60596 Frankfurt
Germany