Dental Implant Fractures
Dental implants have been a preferred treatment option for rehabilitation of completely and partially edentulous patients. One of the most important complications is the fracture of a dental implant that has undergone osseointegration by which the prosthesis is adversely affected by the loss of the supporting tissue. Although the success rate of this procedure is >95%, at times it was also reported with fractures at rare incidence.
Implant design and manufacturing defects
Nonpassive fit of the prosthetic framework
Physiologic or biomechanical overload.
Other possible causes of fracture can also include failure in the production and design of dental implants, bruxism or large occlusal forces, superstructure design, implant localization, implant diameter, fatigue, and bone resorption around the implant. The risk of fracture also increases with time.
Implants made of one-piece design are stronger than two-piece conventional titanium implants. Here is one example of a CeraRoot fracture and how it was solved without removing the implant completely:
Ceramic dental implant fractures
CeraRoot without crown
CeraRoot with crown
CeraRoot with a broken abutment
Crown lengthening on the implant and new abutment preparation.
CeraRoot without a new crown cemented on the remaining structure
The implant was able to be saved by performing a treatment called crown lengthening and using remaining structure to create a new abutment. This type of approach is not possible to do with titanium implants because, they are hollow inside and they can't be prepared with a diamond bur, because they are not solid inside out.
This patient had a CeraRoot 34 of 12mm placed. After 3 years in function, she had an accident and she broke the implant. The patient wanted to have another implant, so Dr. Robin Gallardi from Chicago, who placed all the implants, used a trephine to removed the broken implant. The area was grafted and a new implant was placed after 4 months. The new implant is a CeraRoot 34 of 10mm. The patient is happy again after the new crown is cemented.
Implant placed 4 months after removal of the broken one.
Crown cemented 3 months after the second implant was placed.
Titanium dental implant fractures
Implant removal is also indicated when the implant fractures. Titanium Dental implants are made of commercially pure titanium, which ranges from Grade 1 to 4, in increasing degree of strength. All are capable of withstanding biting forces over the long term once they are integrated with bone. However, if oral hygiene is poor, implants are susceptible to peri-implantitis, ie inflammation of the bone around the implant, just as natural teeth are susceptible to periodontitis. This results in bone loss originating from the part of the implant which connects to the crown. This is the part of the implant that is weakest mechanically because it is hollowed out to accommodate the abutment screw. Without external support from the bone coupled with lateral forces transmitted by the abutment screw may cause the implant to fracture.
Implant removal is also indicated when the implant fractures. Dental implants are made of commercially pure titanium, which ranges from Grade 1 to 4, in increasing degree of strength. All are capable of withstanding biting forces over the long term once they are integrated with bone. However, if oral hygiene is poor, implants are susceptible to peri-implantitis, ie inflammation of the bone around the implant, just as natural teeth are susceptible to periodontitis. This results in bone loss originating from the part of the implant which connects to the crown. This is the part of the implant that is weakest mechanically because it is hollowed out to accommodate the abutment screw. Without external support from the bone coupled with lateral forces transmitted by the abutment screw may cause the implant to fracture.
A fractured implant is even more difficult to remove because unlike the earlier example, there is no exposed implant sticking out for the trephine to go over. Bone has to be trimmed to expose the retained part of the broken implant before the trephine can be applied. Furthermore, the broken end does not have an engaging part for a driver to be connected for reversion and can only be drilled and elevated like a broken tooth.
As the implant removal entails removing a lot of bone, due consideration must be given to whether there is sufficient bone remaining for a replacement implant. When the bone is insufficient, multiple stages of bone and soft tissue grafting may be needed over a period of several months or even more than a year. Reconstructive surgery is not always an exact science and revisions to initial surgeries may be needed to create an aesthetic result. The alternative is to accept the compromised position of the implants and improve on the aesthetics and function by minor gingival plastic surgical procedures