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New peri-implantitis classification

“Bone loss thresholds are not relevant for daily practice”

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What is peri-implantitis? How frequent is it? The 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions aimed at establishing a new internationally accepted classification. Jan Derks, Gothenburg, gave us an update on the results.

Verena Vermeulen | Switzerland

Jan, according to current evidence, how many implant patients and how many implants develop peri-implantitis?
Dr. Jan Derks:
The numbers depend on the definition of peri-implantitis: With very tough case definitions, we see peri-implantitis in about 40-50 percent of implant patients...

Oh, wow…
Dr. Jan Derks:
Yes, but this high prevalence results from a very low bone loss threshold of 0.5 mm which may be difficult to detect on a radiograph. Moderate to severe peri-implantitis with bone loss of more than 2 mm occurs in roughly 15 percent of patients and 8 percent of implants.1 These values have been confirmed in several cohorts from different countries.

The problem in peri-implantitis epidemiology is that there is no common classification – which is why different studies come to different numbers. The World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions, organized by the European Federation of Periodontology (EFP) and the American Academy of Periodontology (AAP), was a first step to solve this problem. How difficult is it to reach a commonly accepted consensus for this topic?
Dr. Jan Derks: The future will tell. Although all authors base their examinations on the same parameters – for example bone loss, probing pocket depths and bleeding on probing – the published data are currently not as complete as we would want. Preferably, everybody should use the same case definitions for peri-implantitis and maybe even apply different thresholds to the same data set. This would allow the reader to really understand the severity of the condition. 

Which thresholds and which classification system does the consensus group promote now?
Dr. Jan Derks: The suggested classification involves the two major parameters “soft tissue inflammation” and “radiographic bone loss”.2,3 The suggested definition of peri-implantitis is based on the presence of bleeding and/or suppuration on gentle probing, increased probing depth compared to previous examinations and the presence of bone loss beyond crestal bone level changes resulting from initial bone remodeling.
The important message regarding thresholds for bone loss is: Thresholds are relevant for research, but not for peri-implantitis diagnosis in daily clinical practice. Here, it is not a question of bone loss above a certain threshold, but more of a “yes or no” situation. If radiographic bone loss is detectable and signs of soft-tissue inflammation are present, the site should be diagnosed as peri-implantitis and treated accordingly.


The classification is based on parameters assessed in relation to baseline documentation, such as “increased probing depth” or “increased bone loss compared to baseline”. But what if there is no such baseline documentation? 
Dr. Jan Derks: For such situations, the Workshop suggested some guidelines for clinicians: probing depths of at least 6 mm and radiographic bone levels at least 3 mm apical of the most coronal portion of the intraosseous part of the implant are consistent with peri-implantitis. But the Workshop really emphasized the value of reliable baseline documentation for the subsequent follow-up of implants. This is something that we should try to implement in daily practice.

Was there already a more or less common understanding? Or where the positions of the invited experts far from each other?
Dr. Jan Derks: Of course there were some different views and some controversial issues, but in principal there was a high level of agreement from the start, also between the US and Europe. The position papers prepared prior to the Workshop were of great help and the chairmen of Working Group 4, Tord Berglundh and Gary Armitage, guided the discussions and put together a well-balanced consensus report.4

With a worldwide agreed peri-implantitis classification system one could measure incidence and prevalence of peri-implantitis over time and see whether the number of affected patients is increasing or not. What would you expect?
Dr. Jan Derks:
The data on peri-implantitis we have today are solid and similar numbers are reported for different countries and continents. I do not expect any increase or decrease of the incidence of peri-implantitis over the next years. Due to an increasing number of implant patients in general, there will be a growing number of peri-implantitis patients, but I expect the proportion of affected implants to remain stable. This is speculation of course.

There is a growing knowledge regarding peri-implantitis and risk factors. This could help to decrease the incidence…
Dr. Jan Derks:
Yes, true. Prevention already starts with treatment planning. In this context, are implants always the number one choice or should we consider other treatment options in risk patients? When is the prognosis of a tooth truly “hopeless”? I believe that dental professionals are today more aware of potential complications affecting implants. There will be more focus on prevention and supportive therapy.


How about mucositis? Is there any news from the workshop on this topic?
Dr. Jan Derks:
Mucositis has been elevated in its importance as it is considered the precursor of peri-implantitis. Dealing with peri-implantitis is difficult and demanding. Therefore, we should identify mucositis cases. Treat mucositis, prevent peri-implantitis - that’s the concept. Therefore, mucositis deserves the same attention as peri-implantitis, although the latter one is the more frequent topic at congresses.

Verena Vermeulen

Verena Vermeulen | Switzerland

Manager Medical Communications
Geistlich Pharma

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