Demystifying the S3 guidelines: what do they actually mean?

The treatment of periodontitis encompasses management of the disease itself as well as appropriate management of the consequences of the disease, for example mobility, recession and tooth loss. Periodontology is fortunate in its abundance of robust evidence, which continues to expand. However, as research increases at a rapid rate, this provides a challenge for clinicians delivering evidence-based dentistry to their patients. Clinical guidelines can therefore help consolidate complex research into statements supporting clinical decision making. The European Federation of Periodontology (EFP) Workshop Committee have therefore developed comprehensive evidence-based S3-level treatment guidelines for both the treatment of periodontitis and the rehabilitation/maintenance of treated periodontitis patients. This brief article explores what S3 guidance is, and how guidelines are structured, while the subsequent articles in this issue of Dental Update explore the content of these guidelines across a range of periodontally relevant topics for clinicians in general practice.

What is S3-level guidance?

When guidelines are proposed for clinical care, there are various ways in which they can be developed, namely, an informal recommendation by a group of experts, a structured consensus, systematic evaluation of the evidence or, ideally, a combination of both these, that is, a synthesis of available evidence and structured consensus by a representative committee. Table 1 summarizes the different levels of guideline development and as can clearly be seen, S3 guideline development represents the highest level.

As part of the evidence-based approach to the guideline development, invited systematic reviewers submitted specific PICO(S) questions for decisions by the organizing committee on which subsequent systematic reviews were considered and decided upon. In total, 15 systematic reviews were proposed to working group chairs and methodological consultants for approval. The PICO(S) format for systematic reviews provides focused questions to guide objective outcomes and consists of:

• P: Population
• I: Intervention/s
• C: Comparison/s
• O: Outcome/s
• S: Study design

Once completed, the systematic reviews were submitted for peer review and an initial guideline draft with various statements/recommendations was produced by the workshop committee. A few of the recommendations were based upon expert consensus, but supported by existing systematic reviews. By November 2019, the official EFP Workshop commenced in La Granja, using the systematic reviews and combining this with a moderated and formalized consensus process facilitated by an independent guideline methodologist.

As mentioned, however, recommendations are not purely based on the evidence from the systematic reviews. Within expert working groups the following factors are also considered to allow formulation of a recommendation:

• Relevance of outcomes and quality of the available evidence;
• Consistency of the study results;
• Direct applicability of the evidence to the target population (external validity);
• Precision of the effect;
• Magnitude of effect
• Balance of benefit and harm
• Ethical, legal and economic considerations
• Patient preferences

How is a recommendation structured?

As part of the guideline, each statement/recommendation is accompanied by the following information:

• The supporting literature used to arrive at the statement (in most cases these were the systematic reviews produced specifically for the workshop);
• The quality of the evidence from the systematic review;
• The grade of recommendation that was categorized into either strong recommendations, recommendations or open recommendations (Table 2);
• The strength of consensus (Table 3). Participants who voted were required to declare any potential conflicts, and would abstain from voting where there was such a declaration of interest.

Following the workshop additional stakeholders were formally consulted, and by April 2020, the first guideline document was published, alongside the relevant systematic reviews in the Journal of Clinical Periodontology for the treatment of stages I–III periodontitis (WWP classification).²

The final guidance divides the treatment of periodontitis into four steps, which are considered in further detail within this issue of Dental Update:²

• Step 1: educating patients, guiding behaviour change, risk-factor control and supragingival professional mechanical plaque removal (PMPR).
• Step 2: cause-related therapy and subgingival PMPR with consideration of the use of adjunctive therapies.
• Step 3: the management of non-responding sites, which may include repeated subgingival PMPR or various approaches to periodontal surgery.
• Step 4: supportive periodontal care, which involves maintaining stability in the treated periodontitis patient.

The same process was completed for the treatment of stage IV periodontitis (WWP classification) from systematic review through to EFP Workshop, with the second guideline document published in June 2022.³ Rather than treatment of the inflammatory lesion, this document focuses more on the rehabilitation of periodontitis patients/treatment of complicating factors, which are also covered within this issue of Dental Update. These factors include:

• Management of teeth with hypermobility;
• Management of teeth with pathological migration;
• Restoration of partially edentulous patients;
• Restoration of fully edentulous patients.

British Society of Periodontology adolopment process

While the original guidelines were produced at a European level, it has been left to each national periodontal society to implement the clinical guidelines at a national level to ensure they are workable for clinicians within their country and healthcare systems (‘adolopment’).

The British Society of Periodontology and Implant Dentistry has therefore carried out two adolopment processes to date, shortly after the publication of the original guideline documents to ensure recommendations are appropriate for UK clinical practice.⁴

To maintain the robust nature of guideline development, a ‘GRADE adolopment’ approach was employed.⁵ This involved a review of all systematic reviews to ensure potentially new and relevant research that had been published since the original guideline was not missed. Various working groups included representation from stakeholders across the UK dental industry including the GDC, OCDO, BDA, non-periodontal specialist societies and the BSP Patient Forum. They worked through each recommendation and ensured their suitability within UK practice. A major benefit to the BSP adolopment is the engagement of patient representatives, who provide critical insights as stakeholders of the care received, and improve the robustness of the guidelines. A moderated plenary meeting with participants of all working groups concluded the process with each recommendation receiving an outcome by consensus vote of either:

• Adoption (unmodified acceptance of the recommendation);
• Adaptation (modification from the original recommendation);
• De novo recommendation (new recommendation).

Conclusion

S3-level guidance combines the evidence base with expert consensus in a moderated forum, allowing consolidation of significant amounts of research into clinically friendly guidelines. The process has been implemented successfully for the treatment of periodontitis and, at the time of writing, the EFP has released guidelines for the prevention and treatment of peri-implant diseases.⁶ Their use is also expanding beyond periodontology in dentistry, with S3-level guidance on the treatment of pulpal and peri-apical disease developed by the European Society of Endodontology.^7,8