The dental implant fixture is connected to the implant-retained crown or implant abutment with a retaining screw, know as the implant abutment screw. This is usually a titanium or stainless steel screw that is tightened to a particular torque value. This is known as the Preload or clamping force on the implant abutment screw.

After the dental implant and crown has been in function for a period of time, this retaining screw is subjected to vertical and lateral forces, that may result in the implant abutment screw loosening, or being damaged and breaking. If the implant abutment screw fractures, the implant crown will drop out.

When this happens, part of the implant abutment screw may be still embedded within the dental implant fixture. Sometimes this can be removed easily by turning the broken fragment with an explorer or ultrasonic scaler. If this does not work, most implant systems will have a screw removal kit that can be used to retrieve the fractured implant abutment screw that is custom designed for this purpose.

Fig. 1 Fractured Abutment screw in Implant Fixture.

Fig. 2 Implant Crown with Broken Abutment Screw

Fig. 3 Intact Abutment Screw

Fig. 4 Fractured Abutment Screw removed from Fixture

If the implant abutment screw can be removed without damaging the internal screw threads of the implant fixture, the dental implant crown can be reconnected to the implant fixture and a new implant abutment screw inserted and tightended to the appropriate preload.

However, if the screw threads are damaged, a replacement screw cannot be used. Some implant systems allow for the implant fixtured to be retapped, and a rescue implant abutment screw, which has a slightly larger diameter, can be used to secure the implant crown.

If such an option is not available, then a custom post can be fabricated, as is done with root canal treated teeth. This post is then cemented into the implant fixture, and a crown is cememnted onto it.

If this is not possible, the implant will need to be surgically removed. After a period of healing, a new dental implant fixture is inserted in the same position. Once fusion of the dental implant fixture to the jaw bone has occured, a new implant crown can be fabricated. This process usually takes 6-8 months to be completed.

If you are facing a similar issue with one of your dental implants, Contact Us for a comprehensive examination. We will assess your specific issue and inform you of the treatment options that are available to you.

Fig. 5 Cast Post Core in Implant Fixture