Early dental implant failure: 4 tips on lowering risks to osseointegration

Assess bone quality before implant site preparation

Implant site preparation should aim to keep bone trauma to a minimum and assist primary stability. As such, site preparation requires knowledge of the bone quality.

A big challenge at this stage is a degree of guesswork that this entails. While the experienced implantologist might “feel” the bone quality with the first drill, if you are not an implant specialist or have less experience in implant treatment, you should regularly attend hands-on training to improve this ability, and I particularly recommend attending cadaver training courses.

This knowledge is important because the drilling protocol is adapted depending on bone quality, to not over- or under-size the implant site. Conventional site preparation requires the use of multiple drills with different diameters which, together with irrigation, cause trauma to the surrounding alveolar bone⁵: a so-called “zone of death”. If the trauma is too great – which can occur especially in a lower jaw with predominantly cortical bone (bone quality I) – osseointegration might be impeded. If the trauma is mainly around the platform, vertical resorption can occur. Excessive preparation of predominantly cancellous bone (bone quality IV) also leads to a lack of primary stability of the implant, and potentially early implant loss.⁶

Implant torque and primary stability

The next step is the selection of the implant itself, which is again influenced by bone quality and the preparation of the implant site. The choice of implant (geometry, diameter, platform) and implant site preparation (underpreparation of the osteotomy) influences primary stability and is therefore an important factor for osseointegration.⁷ A much-discussed figure is the torque value. High torque values are often viewed as positive for immediate loading. However, overtightening may damage or fracture the implant and could cause necrosis of the bone site and early dental implant failure.⁶

A 35 Ncm value is often recommended as standard, however I personally do not see the torque values of the individual implant systems as being comparable with one another, as the individual geometry of an implant causes different reactions in the bone. The implant manufacturer provides guidance on maximum torque values, and you should follow this.

Passive fit

A gap-free and tension-free connection between the implant and the superstructure, and regular follow-ups soon after treatment, alongside stable oral hygiene are important for success.

You should aim for a gap-free and tension-free prosthetic reconstruction, both with immediate loading and with delayed restorations. If this is not the case, vertical bone loss or screw loosening occurs and, as a result, peri-implant complications. Particularly with connections featuring a deep cone, taking an impression of multiple implants carries the risks of inaccuracies and tension, which should be taken into account when planning a screw-retained restoration. If screw loosening occurs, the restoration must be removed, the cause determined, and a new original screw of the implant system inserted again.

Nobel Biocare N1™ dental implant system