Implant survival versus implant success: what the criteria actually say

Two words that get used as if they were one

Read enough clinic websites and you will see "success rate" used for almost any percentage. In the research literature the words are kept apart. Survival is a simple yes or no: is the implant still there? Success asks more. Is the implant firm, free of pain and infection, surrounded by stable bone, and holding teeth that work?

The gap between the two can be large. In a systematic review of implant-supported bridges, about 95% of the implants and bridges were still in place after five years, yet only 66.4% of patients had been completely free of complications over that time (Pjetursson et al., 2012). Most of those complications were fixable, such as chipped porcelain or a loose screw, but they show why "still there" and "no problems" are different claims.

Where the idea of success criteria came from

Early implant designs in the 1970s and before often failed in ways that were hard to measure. Some stayed in the mouth surrounded by soft tissue instead of bone and gradually loosened. The Swedish group led by Per-Ingvar Brånemark showed a different result: titanium screws in direct contact with bone, with bridges that stayed stable for years. Their 15-year report described the first year's bone loss averaging 1.5 mm, followed by about 0.1 mm a year (Adell et al., 1981).

In 1986 Tomas Albrektsson, George Zarb and colleagues used this kind of data to propose criteria that a successful implant should meet (Albrektsson et al., 1986). As they are usually summarised:

• the individual implant does not move when tested clinically;
• an X-ray shows no dark zone (radiolucency) around it;
• bone loss is less than 0.2 mm a year after the first year in function;
• there are no persistent signs or symptoms such as pain, infection, numbness or damage to the nerve canal.

They also proposed that a method should reach at least 85% success at five years and 80% at ten years to be considered acceptable. Those thresholds now look modest, because implant surfaces and techniques have improved.

The 2008 Pisa health scale

Albrektsson's criteria sort implants into success or not. In practice dentists see a range: some implants are perfect, some have lost a little bone and are stable, some are inflamed and need treatment. In 2007 an international consensus conference in Pisa, organised by the International Congress of Oral Implantologists, proposed a health scale with four groups (Misch and colleagues, 2008, linked in the sources). The summary below follows that paper's categories.

The value of the scale is that it treats "survival" as a range of states, not a single box. An implant in the "compromised" group still counts as surviving in most statistics, which is one more reason survival figures alone can mislead.

What researchers measure today

A 2012 systematic review looked at which success criteria long-term studies actually used, limited to rough-surface implants with at least five years of follow-up (Papaspyridakos et al., 2012). It found success being judged at four levels:

Implant

Mobility, pain, radiolucency, bone loss over 1.5 mm

Soft tissue

Suppuration (pus) and bleeding

Prosthesis

Technical problems, function, appearance

Patient

Discomfort, numbness, appearance, chewing and taste

The authors argued that success should ideally be judged on the implant and the teeth on top as one unit, over the long term. For full-mouth treatment that makes sense. A set of four perfect implants holding a bridge that keeps chipping is not what most patients would call a success.

Gum health has its own definitions now

Since 2017 there has been an agreed international classification of the gum and bone conditions around implants. The 2017 World Workshop described peri-implant health as the absence of redness, bleeding on gentle probing, swelling and pus. It defined peri-implant mucositis mainly by bleeding on gentle probing, and peri-implantitis as inflammation with progressive loss of supporting bone (Berglundh and colleagues, 2018, in the sources). It also noted that health can exist around implants that have less bone than at the start.

These definitions matter because many older papers used their own thresholds. A study reporting "5% peri-implantitis" and another reporting "45%" may be using very different cut-offs for bone loss. Our complication rates page notes the definition beside each figure for this reason.

Success for a full-arch bridge, not just the implants

Most success criteria were written with the single implant in mind. For someone having a whole jaw restored, the bridge on top matters at least as much. A fixed full-arch bridge can chip, wear, crack, loosen at its screws or stop looking right as the gum shrinks underneath it. None of those problems remove an implant, so none of them show up in implant survival figures.

Researchers who study bridges therefore report technical complications separately. In the systematic review of implant-supported bridges mentioned above, the most frequent problem over five years was fracture of the veneering material, in 13.5% of bridges (Pjetursson et al., 2012). The bridges in that review were mostly partial rather than full arches, but the lesson carries over: a realistic definition of success includes the number of repair visits, not only the number of implants lost.

For a patient this suggests two practical questions. What is the bridge made of, and how is it repaired if it chips? And is it fixed with screws that a dentist can undo, so that the bridge can be taken off for cleaning, repair or an implant problem without being cut away? Our materials pages cover the first question and our article on screws and torque the second.

How to use this when you read a number

When you see a percentage in a brochure or a forum post, try to place it:

1. Is it survival or success? If it does not say, assume survival.
2. If success, which criteria? Albrektsson, Pisa, a study's own definition?
3. Per implant or per patient? Patient figures are lower.
4. At what time point? One year, five, ten?
5. Does it include the bridge, or only the implants?

A number that answers all five is worth taking seriously. A number that answers none of them is marketing.

What we do with this at our clinic

Precious Dental publishes this library and we are not neutral. What we can say is factual: each implant patient receives an implant passport and copies of their X-rays and scans, so a dentist anywhere can compare future X-rays with the starting point. That baseline is what success criteria are measured against. If you have treatment elsewhere, ask for the same, wherever you go.

For the numbers themselves, see our survival data, the evidence library, and the guide to survival curves.

Common questions

Is a surviving implant with some bone loss a failure?

Not necessarily. Under the 2008 Pisa scale, an implant with moderate bone loss but no pain or mobility can be classed as satisfactory or compromised survival rather than failure. It may need closer monitoring or treatment.

How much bone loss around an implant is normal?

Some remodelling in the first year is expected. The 1986 criteria allowed less than 0.2 mm a year after the first year in function. Our article on marginal bone loss looks at this in more detail.

Who checks whether my implants are successful?

Your dentist, at check-ups, by looking at the gum, probing gently around the implant and taking X-rays to compare bone levels over time. Keep copies of your first X-rays as a baseline.

Do success criteria include how I feel?

Some do. A 2012 systematic review found that studies increasingly add patient measures such as comfort, numbness, satisfaction with appearance and ability to chew and taste.

Why does it matter which definition a clinic uses?

Because success rates are always lower than survival rates when the same patients are measured. A clinic quoting survival as success makes its results look better than they are.

Sources

1. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term efficacy of currently used dental implants: a review and proposed criteria of success. Int J Oral Maxillofac Implants 1986. PMID 3527955
2. Misch CE, Perel ML, Wang HL, et al. Implant success, survival, and failure: the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference. Implant Dent 2008. PMID 18332753
3. Papaspyridakos P, Chen CJ, Singh M, Weber HP, Gallucci GO. Success criteria in implant dentistry: a systematic review. J Dent Res 2012. PMID 22157097
4. Pjetursson BE, Thoma D, Jung R, Zwahlen M, Zembic A. A systematic review of the survival and complication rates of implant-supported fixed dental prostheses (FDPs) after a mean observation period of at least 5 years. Clin Oral Implants Res 2012. PMID 23062125
5. Berglundh T, Armitage G, Araujo MG, et al. Peri-implant diseases and conditions: consensus report of workgroup 4 of the 2017 World Workshop. J Clin Periodontol 2018. PMID 29926491
6. Adell R, Lekholm U, Rockler B, Brånemark PI. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981. PMID 6809663

Checked October 2026. Where we give our own view as a clinic, we say so.