Why Dental Implants Fail: A Clinician's Perspective

A patient seeks dental implants to improve their appearance and ability to eat, hoping for a lifetime of comfort. When these expectations aren't met, the treatment is a failure. From the moment an implant is placed, it begins a battle against failure. The long-term success of dental implant treatment hinges on proper patient assessment and knowledgeable treatment planning by the dental provider.

Implants can fail when the dentist lacks the sufficient knowledge and experience to properly evaluate several critical areas. Here are the key factors from a provider's standpoint that can lead to implant failure:

Inadequate Patient Evaluation:

Medical and Dental Health: Certain medications, like bisphosphonates and some antidepressants, can interfere with bone healing. Uncontrolled medical conditions such as diabetes and autoimmune diseases impair healing and increase infection risk. A history of radiation therapy to the head and neck can also compromise bone quality. 

Lifestyle Factors: Smoking and excessive alcohol use are significant risk factors, as they impair blood flow, slow healing, and increase the risk of infection and peri-implantitis.

Insufficient Bone and Tissue:

After a tooth is lost, the surrounding bone naturally shrinks. If there isn't enough quality or quantity of bone to secure the implant, it is likely to fail, even if placed correctly. In these cases, bone grafting may be a necessary prerequisite.

Flawed Treatment Planning and Execution:

Mechanical Overload: The forces of biting and chewing are immense, ranging from 200 psi for a typical person to 1,200 psi in some healthy males. If the biting force (load) exceeds the implant's support from the integrated bone, the connection will fail. Conditions like teeth grinding (bruxism) place excessive stress on implants and can lead to bone loss. 

Surgical and Prosthetic Principles: Implant placement is a complex surgical procedure that requires knowledge beyond the scope of many general dentists. Improper placement can damage nerves, while poor positioning can make cleaning difficult and increase stress on the implant. Furthermore, the fabrication of the final crown or denture requires specialized experience to avoid complications like loosened screws, fractured porcelain, or trapped dental cement that can cause inflammation. 
 
Ultimately, the failure rate in the first year can be as high as 5% to 15%, and this is often attributed to a lack of knowledge or experience on the part of the treatment provider.