What Causes Osseointegration Failure?
Osseointegration is a highly reliable biological process. As bone heals, it connects well with titanium oxide on the surface of dental implants. This bone/implant interface is remarkably strong and holds the tooth restoration firmly in place – often for decades. Dentists and their patients have come to count on the predictable nature of osseointegration to provide a very high success rate for dental implant treatment. However, that rate is still only about 90-95 percent. What happens in the other 5-10 percent of cases? What underlying factors cause osseointegration failure?
Periapical Lesion
A periapical lesion is an inflamed and infected area around the root of a tooth. It may feature scar tissue or a cyst. This kind of lesion is common in patients who have an abscessed tooth pulp and need a root canal. An untreated periapical lesion in a tooth next to a dental implant can contribute to osseointegration failure. Ideally, the bone, gums and teeth on either side of the implant should be in good health to help ensure bone healing progresses as planned.
Smoking
This is a significant risk factor for all types of oral surgery – and dental implants are no exception. Smoking interferes with healing by restricting blood flow, reducing oxygen content and increasing the risk of abnormal clotting. It also decreases saliva production. Dry mouth makes it easier for bacteria to thrive in the mouth and may increase the risk of wound infection after surgery. Patients who smoke have a higher chance of developing complications during recovery. In addition, full osseointegration may take longer.
Gum Disease
Periodontitis is caused by tartar buildup under the gum line. The irritation from this dental calculus leads to gum inflammation. Eventually, the gum tissue begins to recede and the underlying jawbone starts to be reabsorbed into the body. This leaves the tooth root without sufficient support, leading to tooth loss. The same process can occur around an artificial tooth root (a titanium post). This is called peri-implantitis. This deterioration of the gums and underlying bone is a leading cause of dental implant failure over the long term. Patients should work with a periodontist to get gum disease under control before having an implant installed. Otherwise, osseointegration may well be followed by bone resorption and loss of the implant.
Bone Density and Volume
Osseointegration is often inadequate in areas with low bone density and areas where the jawbone has receded or thinned out. These problems are most common in the upper jaw and in patients who have lost bone tissue to gum disease. Your dentist will use a CT scan to evaluate your bone density and use this information to select the proper implant type. There are some implants (such as blade implants) that can be used in areas with low bone density or volume. However, you may need a bone graft prior to implant surgery to build up enough bone to support an implant. If the graft fails, the subsequent implant will probably fail as well.
Dental Errors
Successful dental implantation requires a high degree of experience and skill. Specialists such as prosthodontists, periodontists and oral & maxillofacial surgeons receive advanced training in osseointegration and dental implants as part of their postgraduate education. Many other dentists also pursue continuing education and learn to install dental implants as a supplement to their general or cosmetic dentistry practice. With a less qualified dentist, there may be a higher likelihood of dental implant and osseointegration failure due to mistakes in the procedure. These may include:
Using the wrong drilling technique (this can actually fracture the bone in some cases)
Picking the incorrect implant (size, shape, surface texture, etc)
Misjudging bone density or volume
Using a restoration (crown, bridge, etc) that is poorly designed
Failing to ensure the implant is free of contaminants introduced during manufacturing (such as carbon-based lubricants used in machining)
It is important for you to find a dentist who has substantial experience placing dental implants. Ask questions about:
The total number of implants they have placed
How many years they have been doing implants
The percentage of patients whose implants fail
The underlying problems leading to these failures
Osseointegration Complications
Even if a dental implant does not fail outright, some patients experience unwanted side effects during healing. This can lead to less than satisfactory outcomes for both comfort and aesthetics. It can also mean more treatment (including surgery) to correct the problem. Here are some of the additional issues patients sometimes encounter during the osseointegration and dental restoration process:
Implant exposure (the gum tissue recedes leaving the titanium post visible)
Implant fracture (some materials are more brittle than others)
Failure of the crown or other restoration components (screws, the abutment, etc)
Excess bone resorption (a small amount of bone loss near the implant is expected, but too much is a problem)
Since patients who have lost teeth usually have gum disease, cavities or both, it’s not surprising they sometimes have ongoing oral health issues that impact healing gum and bone healing. However, the individual components of an implant and restoration should rarely fail. If they do, there may be a mechanical flaw in their design or other factors that require a closer look. You may want to get a second opinion to find out if a different implant or restoration would be a better choice.
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