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Study revisits early & late dental implant failures & compares various implant removal techniques

By Dental Tribune International
September 04, 2019

ZURICH, Switzerland: Clinical evidence has established dental implants as a great treatment option to replace missing teeth. However, even with the high success rates reported, like in every medical technique, there are possibilities of biological complications that may lead to implant failure, necessitating the removal of the implant. A recent study by the University of Zurich has revisited the reasons for implant failure and compared different techniques used for implant removal.

A literature search identified 28 studies, conducted up to 2018, that had assessed implant failures, removal techniques and the reinsertion of implants in a previously failed site.

The researchers classified the factors for implant failures into different categories. Peri-implantitis and inability to attain or maintain osseointegration were included under biological factors. Mechanical factors included implant fractures. Bone overheating, site contamination and malpositioning etc. were grouped under iatrogenic errors. Prosthesis design and functional overload were categorised as functional reasons.

The study showed that an early implant failure is typically caused by deficient osseointegration - either the lack of attaining it or maintaining it, or by bone overheating or site contamination. Late implant failures are caused by implant fractures, malpositioned implants and progressive peri-implantitis. To date, peri‐implantitis remains the main reason for late implant failures (81.9%). Early implant failure results in implants that are generally mobile and easy to remove. Late implant failure means the implants can be at least partially osseointegrated in the apical region. Most late failing implants are not mobile and, therefore, are more difficult to remove.

For implant removal techniques, the study compared tooth extraction set, trephine burs, piezo-surgery, laser surgery, the counter-torque ratchet technique (CTRT) and electrosurgery. The study found trephine burs to be the best-known method for implant removal. However, the study recommended that the CTRT method, alone or combined, should be the first choice for the removal of implants because of its low invasiveness.

Furthermore, the researchers studied the survival rates of implants placed in the previously failed sites, which was, irrespective of early or late failure, in the range of 71–100% over five years.

Little data is available regarding zirconia implant removal. The unique physical properties of Zirconia make it necessary to use a different approach for the removal of zirconia implants as compared to titanium implants.

“If removal is required, interventions should be based on considerations regarding minimally invasive access and management as well as predictable healing. (Post)Operative considerations should primarily depend on the defect type and the consecutive implantation plans,” concluded the authors in their paper.

The study, titled “Removal of failed dental implants revisited: Questions and answers”, was published online in Clinical and Experimental Dental Research on 21 August 2019, ahead of inclusion in an issue.

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