Reclassifying periodontal disease

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Learning outcomes

Aims and objectives

The aim of this article is to share the outcome of the British Society of Periodontology's (BSP) new periodontal disease classification guidelines, as well as looking at the Basic Periodontal Examination (BPE) and the practical implications for dental professionals and patients.

On completing this CPD session, the reader will:

• Understand the aims and outcomes of the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions
• Understand the BSP’s diagnostic pathway for plaque-induced periodontal diseases in line with accepted guidelines and the new classification system

• Understand what constitutes periodontal health, which has been defined for the first time

• Understand how the BPE fits in with the new classification system

• Understand how to use the BPE effectively.

Reclassifying periodontal disease

This article shares the BSP’s new periodontal disease classification guidelines, as well as looking at the BPE and the practical implications for dental professionals and patients.

In 2017, at the World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions, expert participants from across the globe met to align the classification of these oral conditions with emerging scientific evidence.1

The aim was, ‘…to create a system that could be implemented in general dental practice, the environment where over 95% of periodontal disease is diagnosed and managed.’2

Significant changes

This new system involves a staging and grading system similar to that used to diagnose cancer, with staging describing the seriousness of the disease and grading reflecting the patient’s susceptibility (see Table 1 for further details).2,3

Thus, as stated by Ower (2019): ‘Staging of periodontitis, as described by the World Workshop, involves an assessment of the greatest site of clinical attachment loss, an assessment of bone loss and tooth loss (due to periodontitis) and other factors, such as maximum pocket depth, pattern of bone loss, furcation involvement, ridge defects, occlusal trauma and restorative needs.’3

In relation to grading, he continued: ‘Grading involves assessment of bone and attachment loss
over a 5-year period, the ratio of % bone loss to age, the relationship between biofilm volume and level of destruction, levels of smoking and blood glucose status.’3

In addition, reporting back from working group 1, Chapple and colleagues (2018) stated that the classification system defines periodontal health for the first time.2,4 They described it as:4
A. Clinical health on an intact periodontium
B. Clinical gingival health on a reduced periodontium
(i) Stable periodontitis patient
(ii) Non-periodontitis patient.

Placing this in context, they wrote: ‘Clinical gingival health may be found in a periodontium that is intact, i.e. without clinical attachment loss or bone loss, and on a reduced periodontium in either a non-periodontitis patient (e.g. in patients with some form of gingival recession or following crown lengthening surgery) or in a patient with a history of periodontitis who is currently periodontally stable. Clinical gingival health can be restored following treatment of gingivitis and periodontitis. However, the treated and stable periodontitis patient with current gingival health remains at increased risk of recurrent periodontitis, and accordingly, must be closely monitored.’4

A further significant consensus reached by the Workshop participants was that there should be no distinction between aggressive and chronic periodontitis. They found that there is little evidence upon which to base such a distinction and that, rather, they are ‘variations along a spectrum of the same disease process’.2

Other issues of significance covered by the World Workshop participants include the support given to personalised medicine and the inclusion of peri-implantitis diseases and conditions.3

To learn more about the proceedings, the full workshop document can be accessed free of charge at

Periodontal disease in practice

Following the 2017 World Workshop, the BSP began work on creating a ‘diagnostic pathway for plaque-induced periodontal diseases’ in line with accepted guidelines and the new classification system.2

Acording to Dietrich and colleagues (2019), ‘It is important to understand that the new classification system of periodontal diseases and conditions is not a diagnostic system or diagnostic algorithm, the diagnosis must accommodate both the classification (type of periodontal disease and, if applicable, staging and grading based on bone loss or clinical attachment loss [CAL]), and also current disease status (based on PPD [probing pocket depth] and BoP [bleeding on probing]). Secondary to the diagnosis, but equally important, is the third stage of determining a patient’s risk factor profile.’2

They continued: ‘As periodontitis is a complex multifactorial disease, a plethora of causal factors determine the host response to the microbial challenge, including genetic, epigenetic, environmental and behavioural factors. The percentage of bone loss/age ratio captures the historical disease susceptibility due to the life-long exposure to all causal factors of a specific patient at that moment in time, including established, modifiable risk factors such as smoking and sub-optimally controlled/undi-agnosed diabetes.’2

As for the diagnostic work-up, this should include:2
• A detailed medical and dental history
• An oral examination
• Further investigation, when appropriate (for example, radiographs and a radiological report).

This will enable dif¬ferentiation between the different types of periodontal disease, as well as identification of alveolar bone or attachment loss due to causes other than periodontitis.2

The BPE and the new classification system

The BPE remains important, as stated by Dietrich and colleagues (2019): ‘…the BPE is a screening tool employed to rapidly guide clinicians to arrive at a pro¬visional diagnosis of periodontal health, gingivitis or periodontitis, irrespective of his¬torical attachment loss and bone loss (that is, irrespective of staging and grading). As such, the BPE guides the need for further diagnostic measures before establishing a definitive peri¬odontal diagnosis and appropriate treatment planning.’2

It is however important to note that the BPE is of limited value in patients who have already been diagnosed with periodontitis, as it is not able to identify historical problems that are resolved at the time of the patient presenting.2

Thus, as stated by Holland (2019), ‘A periodontal assessment should begin with a comprehensive history. If the patient has no evidence of a history of periodontitis, then a BPE screening should be performed.’5

A WHO periodontal probe, which has a ball-shaped tip 0.5mm in diameter, a black band between 3.5 and 5.5 mm and rings at 8.5 and 11.5 mm, is used to record a patient’s BPE. 

To record the BPE for adults:7
1. The teeth are divided into six sextants – upper right, upper anterior, upper left, lower right, lower anterior and lower left
2. All teeth in each sextant are examined, except for 3rd molars (unless the 1st and / or 2nd molar(s) is / are missing). For a sextant to qualify for examination, at least two natural teeth must be present.
3. The probe is ‘walked’ around the pockets / sulcus in all qualifying sextants, with the clinician recording the highest score in each. A light probing force of 20-25g should be used.

It is important to note that where a BPE score of 4 is recorded, all areas in the sextant should be examined, to ensure furcation involvements are not overlooked and to gain a better understanding of the patient’s periodontal health.7

The BSP’s guidance indicates that BPE codes should be scored as follows:7
• 0 – pockets <3.5mm, first black band completely visible, healthy periodontal tissues, no calculus/overhangs, no bleeding on probing
• 1 – pockets <3.5mm, first black band completely visible, no calculus/overhangs, presence of bleeding on probing
• 2 – pockets <3.5mm, first black band completely visible, supra or subgingival calculus or plaque retention factor (overhang)
• 3 – probing depth 3.5mm to 5.5mm, first black band partially visible, indicating pocket of 4mm to 5mm
• 4 – probing depth >5.5mm, first black band entirely within the pocket, indicating pocket of 6mm or more
• * – furcation involvement.

In terms of interpreting scores for practical purposes, BSP guidance further suggests:7
• Code 0 – no need for periodontal treatment
• Code 1 – provide oral hygiene instruction
• Code 2 – provide oral hygiene instruction and remove plaque retentive factors, including both supra- and sub-gingival calculus
• Code 3 – provide oral hygiene instruction, remove plaque retentive factors (including both supra- and sub-gingival calculus), and perform root surface debridement if appropriate
• Code 4 – provide oral hygiene instruction and perform root surface debridement where required. In addition, assess the need for more involved treatment, for which a referral may be appropriate
• * – treat in line with BPE code 0 to 4, as well as assessing the need to perform more complex dentistry, perhaps via a referral.

A detailed infographic showing how to use the BPE in relation to the new classification system is available at

A diagnostic statement

The BSP’s views and recommendations, made in line with the 2017 World Workshop guidance, ‘...aims to provide a simpli¬fied staging and grading system as well as a diagnostic decision-making algorithm … with BPE screening as a starting point in most patients, to guide the clinical management process. The diagnostic pathway includes the following stages:
    • ‘Determination of the type and extent of periodontal disease and, in the case of peri¬odontitis, its staging and grading
    • Identification of current health/disease status (via PPD and BoP).

‘The final diagnosis would embed all of these components in a ‘diagnostic statement’, for example:
 Diagnosis = generalised periodontitis; stage IV, grade B; currently unstable.

‘Finally, relevant risk factors should be documented immediately below the diagnostic statement, eg:
Diagnosis = generalised periodontitis; stage IV, grade B; currently unstable.

‘Risk factors:
1. Current smoker >10 cigarettes per day
2. Sub-optimally controlled diabetes.’2

This article can only provide a snapshot of the new guidelines in relation to periodontal care in the UK, so it is recommended all dental professionals visit for full details.

Table 1: Staging and grading of periodontitis2

Staging of periodontitis


Stage I


Stage II


Stage III


Stage IV

(very severe)

Interproximal bone loss*

<15% or <2 mm**

Coronal third of root

Mid third of root

Apical third of root


Describe as:

Localised (up to 30% of teeth)

Generalised (more than 30% of teeth)

Molar/incisor pattern

Grading of periodontitis


Grade A


Grade B


Grade C


% bone loss / age




*Maximum bone loss in percentage of root length.

**Measurement in mm from CEJ if only bitewing radiograph available (bone loss) or no radiographs clinically justified (CAL).



  1. Caton JG et al. A new classification scheme for periodontal and peri‐implant diseases and conditions – introduction and key changes from the 1999 classification. Clin Periodontol 2018; 45(Suppl 20): S1-S8

  2. Dietrich T et al. Periodontal diagnosis in the context of the 2017 classification system of periodontal diseases and conditions – implementation in clinical practice. BDJ 2019; 226(1): 16-22

  3. Ower P. New classification system for periodontal and peri-implant diseases. Dental Update 2019; 46: 8-11

  4. Chapple ILC et al. Periodontal health and gingival diseases and conditions on an intact and a reduced periodontium: Consensus report of workgroup 1 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018; 89(Suppl 1): S74-S84

  5. Holland C. Rethinking perio classification for the 21st century. BDJ Team 2019; Accessed 23 May 2019

  6. Preshaw PM. Detection and diagnosis of periodontal conditions amenable to prevention. BMC Oral Health 2015; 15(Suppl 1): S5-S15

  7. The Good Practitioner’s Guide to Periodontology. BSP 2016. Accessed 23 May 2019