Dental implants are artificial teeth surgically put in place of the missing teeth. It is a metal fixture fixed in the jawbone for a period of time for it to become fused with the jawbone and tissues, which is then used as a tooth root for an artificial tooth or a bridge between missing teeth. This method relies on the ability of the bone to grow around some metals.
Different materials used in dental implants
Titanium is used most commonly in dental implants. Zirconium also is used widely. With technological advances, more options are available now with their ability for micro structures affecting their feasibility for clinical applications, and biocompatibility.
Although a lot of researches have led to better materials and improved techniques of dental implants surgery, there are cases where these surgeries have failed and the implants had to be removed or further treatment required even after initial successful implants.
What are the reasons for dental implants failure?
Though the success rate of dental implants is high, they may sometimes fail due to a few reasons.
Faulty selection of implants
The crown should fit snugly on to the root for successful implant. When the crown root ratio is not favourable (like if a short implant is used for a longer crown or an implant with lesser diameter is used for a bigger crown), the implant will not be able to take the pressure of chewing and will collapse eventually.
Lack of osseointegration
Osseointegration is the growth of bone tissue around the metal screw implanted in the jawbone. When enough tissues have not grown before the crown has been placed on the implant, the implant gets loosened. When fibrous tissue grows instead of proper osseointegration, the implant moves away and causes failure.
Occlusal overload means the amount of force applied on biting by the teeth is more than the teeth can withstand. Bruxism is one condition where the patient applies force of upper teeth on the lower set of teeth, unconsciously, during sleep at night. Occlusal force in implants has to be balanced. When the force of teeth is more than the implant can withstand, it leads to implant failure.
When implants are installed, it is vital that the surgeon keeps in mind the prosthetic crown in proper judgment of the inclination. The prosthetic has to be placed in such a way that the force lies properly on the implant. It is also seen that sometimes the proportion of crowns are misjudged in relation to number of implants. More crowns on implants increases the pressure of chewing on implants and even after initial success the osseointegration fails.
Faulty selection of patient
The implant professional has to consult with the dentist and the patient’s physician before taking up the implant procedure. The surgeon should know the patient’s medical history. For example, a patient with diabetes will take very long to get the wound healed completely. This condition inhibits the process of osseointegration. Similarly, arthritis may affect density of bones which hinders the osseointegration. These and many other such medical conditions hamper the success of implants. It is very important that the surgeon verifies the medical condition of the patient before taking up the project.
Poor oral hygiene
There are many reasons for poor osseointegration. Lack of oral hygiene is one of them. Infections due to bacterial growth on the site of implants are caused by poor oral hygiene. Infection does not allow bone to grow around the implanted screw. Infections before the osseointegration and also after the osseointegration the implant can fail. Peri-implantitis is inflammation due to biological reasons around implants. This condition is found to be one of the reasons for implant failure.
Conditions and environment during surgery
While performing the surgery, it is very important to keep in mind the sterility of the environment, the surgical equipment and also the cleanliness of the patient and conditions around him.
Apart from other conditions, it is also important to assess the bone which is going to receive the implant. Bone should be mature to hold the implant structure in place. If the patient is suffering from any bone diseases, the proper osseointegration fails even after initial growth of bone tissue around the implant.
There are lifestyle habits which are detrimental to implants. Tobacco has found to be a major reason of bone loss among failure cases in implant surgery. Reduced bone density in smokers is the cause for lack of osseointegration required for implants to remain in place. After successful implants the responsibility to take care of implants falls on the patient. If he does not follow strict oral hygiene routine, things can go bad leading to implant failure.
Psychological factors responsible for implant failure include immaturity in patients. People suffering from emotional imbalance also suffer late implant failures as they cannot follow the instructions due to emotional reasons. Depression in patients also lead to implant failure as not taking care of dental implants becomes the reason for bacterial growth leading to loosening the implant from the bone growth around it. There are other diseases which develop after the successful implant installation which may lead to implant failure including cancer.
Multifactorial – a combination of causes
Usually factors responsible for failure of implants are manifold. The decision to use implant surgery for replacement of lost teeth are taken by many professionals and is done in multiple stages. First of all, it is your dentist who starts the process towards deciding whether or not implants can be used to replace your lost teeth. He refers you to the implant surgeon, who in turn consults with your physical practitioner. A wrong assessment in any of these steps can cause the implants to fail.
It is important that you approach the best qualified dental professionals who have experience in dental implants. This is an important and expensive procedure, so take your time and get it right.