Implant Survival

The success of implants has been tremendous. Never before have we had a treatment option to replace missing teeth or stabilize dentures that performs so well. But just how successful are dental implants?

In the May 2018 edition of Oral Health, Dr. Gary Glassman wrote an editorial discussing the hierarchy of implants compared to endodontic therapy when treatment planning. The decision to remove a tooth and replace it with an implant is a challenging one that we often face in clinical practice and it’s not just in contrast to endodontics. How large does a carious lesion need to be, how deep must a fracture sit, or how much bone loss must be present?

To make these decisions, it is important to know the relative prognoses of the options available. The merits of different tooth restorations is a large topic. In this editorial, I’d like to discuss implant survival.

Some of the best data on implant survival comes from studies with follow-up times of 10 to 20 years. These studies may only be measuring a fraction of an implant’s lifespan. Ideally we would like to know what happens beyond 30 years but such data is not available. As such, we look to the evidence we have.

Most data on implant survival begins when implants became a more common treatment modality – the early 1990’s. My partner in practice, Dr. Murray Arlin, has tracked nearly 15,000 implants since 1989 and his database reports a 28-year cumulative survival rate of 91%. Buser’s group out of Sweden published controlled data in 2013 showing a 20-year survival rate of 90%. Many other studies with shorter follow-up times have reported survival rates from 90 to 98%. Two points emerged from this data: (1) most implants last over 20 years and (2) the rate of implant failures did not increase as time passed. In other words, implants had continued excellent survival regardless of how long they had been placed. This trend is different than the survival rates of other dental prostheses which often show an accelerating failure rate as they age.

There are two caveats to this. These survival rates don’t apply to all implant placements; they are reported by trained clinicians in controlled settings treating appropriate cases. Secondly, implants have significant complication rates despite high survival. A reasonable estimation is that half of all implants will require additional treatment throughout their function. This is true even when implants are well placed.

We don’t have a definitive survival rate for implants because every case is different. Additionally, our studies are too short-term to define survival rates after 20 years. Still, the data suggests implants continue to survive well beyond 20 years and a conservative extrapolation is an 80% survival rate at 40 years.

When you consider that the average implant patient is over 50 years old, surviving 40 years means the implant will usually outlast the patient. So when my patients ask me how long implants last, I tell them, “They don’t always last forever, but I expect most to last a lifetime.” OH

About the Editor
Dr. Mark Nicolucci is Oral Health’s editorial board member for implantology. He is a graduate of the University of Western Ontario and received his specialty certificate from Temple University in periodontology and oral implantology. He has a masters in oral biology and lectures regularly in the Toronto area. He maintains a full-time specialty practice in West Toronto.