You may have seen many successful dental implant cases online, but very few people want to talk about failure of dental implants. Like any other dental work, dental implant can fail even though it has a very high success rate.
Dental implant failure is classified as early and late implant failure. Early implant failure happens before the placement of a final prosthesis, like crowns, bridges or dentures. Late implant failure occurs within 1-3 years after the placement of the implant.
Causes of earl implant failure can be patient-related factors (e.g., general patient health status, smoking habits, quantity and quality of bone, medications such as corticosteroids and bisphosphonates, etc), infection, lack of primary stability, surgical trauma and other clinician skill-related factors.
Causes of late failure may include excessive loading, peri-implantitis, bruxism, teeth grinding at night time, inadequate prosthetic construction and traumatic occlusion.
In this case, the implant was placed more than 6 years ago. It might not be a failure from definition, however, most dental implants we placed can survive 15+ years if maintained well. Unfortunately, this patient had never come back for regular examination since the crown was inserted, until it became loose. The damage of the implant crown looked more severe than a 20 year old crown.
The casue of this failure is very obvious - traumatic occlusion (biting):
It's the only molar in that area.
The patient mainly chews on that side.
Exposed metal because of worn off porcelain.
Porcelain fracture of the implant supported crown.
Possible night grinding.
However, the implant wouldn't be doomed to failure if regular maintainence had been carried out, which includes regular oral hygiene maintainence, biting adjustment and possible occlusal splint (night guard).
Dental implants like natural teeth, need regular maintainence to last long.