| TissueCare Concept |
TissueCare News 02/2008
EDITORIAL
Dear readers,
Public awareness of implants is more pronounced today than ever before and our patients' information requirements have risen significantly. At the same time, the means of achieving completely natural esthetics is a topic of intense discussion among colleagues.
In the last issue of TissueCare News we presented the TissueCare Concept. Its components not only define today's scientific discussion but are also of major importance in daily practice, because only with a suitable design for the implant-abutment connection does the bone, the basis of the overlying soft tissue, remain durably stable. Micromovements between the implant and abutment can lead to microgaps in conventional systems. Bacterial colonization of the microgap frequently causes inflammatory reactions and bone decay. However, a highly precise, microsealed design is predestined for long-term esthetic success – as is the case with the TissueCare Connection. Micromovement is avoided and the two-part implant behaves like a one-part implant.
In this newletter issue, you will find out why a stable and microsealed connection stabilizes the peri-implant tissue and therefore also the long-term esthetics.
Enjoy reading.
Your DENTSPLY Friadent
Stable connection for stable tissue
Why the implant-abutment connection is an important success factor
The failure of an implant-borne restoration can many causes. The prerequisites for success are high mechanical stability of all components and a tissue-friendly design. The boundary between the bone, the overlying soft tissue and the implant-abutment connection is of special importance. Why this connection should be as free of movement as possible and microsealed - you can find out here.
Today the most common problem facing implant-borne restorations is failure of the prosthetic suprastructure in an average of 14 percent of cases. Loosening or breakage of the fixation screw that connects the abutment with the implant is also a not uncommon cause at 7.3 percent. The most frequent problems are those with the fixture screw in single-tooth restorations, but they also occur with multi-unit restorations.
Avoiding screw loosening
A defined torque applied to the screw in the abutment and implant leads to a strong connection. Anti-vibration threads, direct mechanical locks, variations in the screw design and torque control mechanisms have been developed in order to avoid the risk of loosening. But loosening can still occur under loads in excess of the effective force between the implant and abutment. It is ideal if the horizontal forces are converted to vertical forces in two-part implant systems. This eliminates uneven loading of the central fixture screw and loosening is improbable. This is possible tanks to conical connections with precise solid and interlocking surfaces of sufficient length. This can be described as a virtually one-part implant system.
The significance of the microgap
A microgap in the region of the implant-abutment connection is unavoidable with most implant systems. This is the case irrespective of whether an internal or external connection mechanism is used. Micromovement increases these intrinsic inaccuracies with each physiological chewing cycle – even without loosening of the fixture screw. This undesired effect makes itself clearly apparent with external hex connections. But a microgap can also occur with conical connections depending on the length and precision of the joining surface. In an in-vitro study of an implant system with conical connection and beveled implant shoulder, it was found that after 1,000,000 cycles under a loading of 200 newtons almost all connection screws had loosened. Microloosening leads to bacterial colonization which can cause local infections and decay of the surrounding hard and soft tissue. The extent of these developments clearly depends on the position of the unsealed abutment connection in relation to the bone.
The ANKYLOS TissueCare Connection
In order to control the microgap at the connection point between the implant and abutment, a special conical design has been developed for the ANKYLOS system which overcomes the problems described above: the TissueCare Connection. In contrast to other conical connections, the design of the taper, the length of the joining surfaces and the manufacturing precision guarantee a completely solid and interlocking connection. Perfect vertical force distribution parallel to the axis of the virtually one-part implant-abutment unit prevents loosening and breakage of the screw given correct joining – even after 1,000,000 load cycles (Fig. 4). The TissueCare Connection is rotationally stable and requires a comparatively low torque of just 15 Ncm for the greatest possible stability. A precisely manufactured conical connection can be gapless and thereby ensure a bacteriologically sealed connection.
Significance for clinical use
Importance for the clinic
The essential advantage of the microsealed TissueCare Connection is the achievable level of bone stability. In contrast to other systems, bacterial contamination from inside the implant is nearly eliminated or reduced to a minimum. This results in:
- Stable crestal bone
- Stable soft tissue conditions
- Esthetically favorable clinical results, both in the short and long term
The horizontal displacement of the boundary surface implant shoulder and abutment ensures that no soft tissue can be trapped on insertion of the abutment. This makes an important contribution to prosthetic precision and to microsealing. The high mechanical stability of the TissueCare Connection means that crowns which are very long compared with the implant have good prospects of success. The special design of the enossal implant thread also contributes to high primary stability. A particularly high load bearing capacity (“bone clamp”) develops following osseointegration through the microrough plus surface up to above the implant shoulder and a slightly subcrestal position. Even composite bridges with free-end saddles are successful.
For literature see page 4 of TissueCare News 02.
© 2009 by Friadent GmbH
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