Common Causes of Late Implant Failure

Common Causes of Late Implant Failure George A. Nail, MD, DDS Dental implant replacement of teeth has become one of the most predictable and successful of all procedures in dentistry. Indeed, implant treatment has changed the way we think about dental treatment options and redefined treatment plans. Previous “heroic” efforts to save marginal teeth such as root amputation, hemi–sectioning of teeth, tooth transplantation, long-span dental bridges, and even apicoectomy and endodontic re–treatments have been abandoned in favor of the more cost effective and

predictable dental implant options.

But dental implants, while remarkable, are not without the potential to fail. Teeth are lost for two basic reasons (other than trauma): decay and periodontal disease. Obviously, dental implants are not subject to decay, but they can fail due to loss of bone support. How might this happen?

Peri-implantitis can occur with dental implants in much the same way that periodontitis can occur with natural teeth. Patients have the same responsibility to care for their dental implants that they have for caring for their natural teeth. In fact, when patients ask me how long an implant will last, I tell them that in general, a dental implant can last as long as their healthy, well-cared for natural teeth. In other words, they need to brush 2–3 times per day, floss daily, and see their dentist at least twice a year (or more, if appropriate) as well as not perform any para–functional oral activities that are hazardous to teeth, such as chewing on ice.

All of that aside, the two most common causes of late implant failure are retained subgingival dental cement and traumatic occlusion.

I am fortunate to have only seen a handful of late implant failures (but a slightly greater number of ailing implants with crestal saucerization of bone) in the past 15 years, and of these the overwhelming majority have involved retained deep chunks of dental cement. The bone loss usually becomes apparent crestally within 1–3 years after implant restoration when he chronic irritation from the cement finally overwhelms the local reparative capacity of the site. This can be quite simply avoided by keeping the implant replica, generally sent back on the stone model with each case, and placing the crown filled with cement on the replica. One simply then wipes away the excess cement that extrudes from the margin of the crown and then removes the crown from the replica and seats it fully on the abutment in the mouth. Using this method, almost no excess cement ever has to be removed.

The other common reason for late implant failure is related to traumatic occlusion or occlusal overload. This can be particularly true in patients with bruxism or in patients where implant bridgework replaces quadrants or full arches of missing teeth. Obviously, occlusion needs to be checked at the time of implant restoration delivery, but it should also be checked at every dental visit and adjustments made as needed. Additionally, in patients with known bruxism or in any patient with implants replacing a quadrant or more of occlusion, a night guard should be included as part of their treatment plan. A few minutes spent addressing these details can avoid significant problems for patients down the line as well as increase patient satisfaction and keep dental chair time free from having to deal with complications and retreatments.