MICROMOVEMENTS AT THE IMPLANT-ABUTMENT INTERFACE:
MEASUREMENT, CAUSES, & CONSEQUENCES
Zipprich, Holger/ Weigl, Paul / Lange, Bodo / Lauer, Hans-Christoph
Most of two-component or multi-component implant systems use an implant-abutment connection with a clearance fit. The clinical impact is assumed as high according to the following factors:
- Implant systems consisting of two or several components are much more widespread than single component systems because they offer a number of well-known clinical and technical advantages.
- Unconnected crowns in the posterior region are more susceptible to technical failure of the implant-abutment interface.
- Crestally or subcrestally placed implant-abutment interfaces are frequently subjected to crestal bone resorption following abutment connection.
This in-vitro study examined the dynamic behaviour of different designs of implant-abutment connections. Abutments were loaded at an angle of 30° with a force of up to 200 N. The distance of the point of force application from the implant platform was 8 mm; the gradation of the force was 0.3 N/ms. The interface of the implant-abutment connection was examined and measured radiologically using a professional high speed digital camera (1,000 images per second).
The results showed that, under simulated clinical conditions, complex mechanisms are responsible for the presence or absence of a micro-motion. All implant-abutment connections with a clearance fit exhibit a micro-motion (implant systems: SIC®; Replace Select®; Camlog®; XIVE®; Straumann synOkta®; Bego-Semados®; Straumann massive conical abutment®). Precision conical connections (implant systems: Ankylos®; Astra Tech®) show no micro-motion.
The potential clinical relevance of these results can at this point only be derived from theoretical considerations. Presumably, the pumping effect caused by the micro-motion plays an important role for crestal bone resorption. It is assumed that the bone is contaminated with liquid contained in the implant.