08 - New Periodontal Classification System

purpose of classification

translate a lifelong, complex disease process into a short diagnostic statement

• periodontitis is not identical between patients, between teeth, between sites, and at different times

• disease can progress at different rates

• host response and risk factors differ

• treatment complexity varies

evolution of classification

the 1999 system included terms like chronic periodontitis and aggressive periodontitis

• newer system does not classify aggressive periodontitis as a separate disease category

• classic localized phenotype can be described using a molar/incisor pattern

• older termed phenotypes can still exist clinically, but newer classification describes disease through stage, grade, and distribution/pattern

therapeutic goals around natural teeth

ultimate purpose of diagnosis is not the diagnosis itself, but rather the treatment to create a periodontal environment

• minimal probing depths

• no adequate furcation problems

• adequate fiber barrier

• harmonious occlusion

• biological stability

• effective plaque control

• endpoint — treatment must be maintainable by the patient

  • patient must be able to clean the area themselves

  • if a deep inaccessible pocket remains, plaque returns and the patient cannot clean effectively; disease risk remains

staging vs grading

• staging — evaluates severity and extent based on measurable extent of destroyed and damaged tissues attributable to periodontitis

  • assesses complexity through specific factors that may determine complexity of controlling current disease

  • assesses management of long-term function and esthetics

• grading — estimates future risk of periodontitis progression and responsiveness to standard therapeutic principles

  • guides intensity of therapy and monitoring

  • estimates potential health impact of periodontitis on systemic disease to guide monitoring and co-therapy with medical colleagues

clinical attachment level

measured from CEJ to base of pocket

• different than probing depth, which measures from gingival margin to base of pocket

  • CEJ is fixed, whereas gingival margin can move due to enlargement or recession

• CAL tells you attachment loss more accurately than probing depth

• if gingival margin is at CEJ → CAL = PD

• if there is recession → CAL = PD + recession

• if gingiva is coronal to CEJ → CAL = PD - coronal gingival excess

CAL vs radiographic bone loss

ideally, CAL = radiographic bone loss; but they may not match perfectly

• bone architecture is three-dimensional, but radiographs compress anatomy into a 2D image

• facial/lingual bone can obscure defects

  • vertical defects may be underestimated radiographically

• recent changes may not yet be obvious radiographically

  • CAL can appear worse than radiographic bone loss

• use clinical findings + CAL + radiographs to determine periodontal diagnosis

• newer classification system describes radiographic bone loss by how far it extends along the root

  • divide the root into coronal, middle, and apical thirds

  • a 2mm of bone loss means something different on a short root vs a long root

    • proportional loss is more useful than millimeters alone

• normal alveolar bone height on a radiograph is 0.5-2.0 mm

periodontitis staging

staging considers severity, complexity, and extent/distribution

1. stage I — initial periodontitis

   • severity → interdental CAL = 1-2 mm; RBL = coronal third (<15%); no tooth loss due to periodontitis

   • complexity → maximum PD ≤ 4mm; mostly horizontal bone loss

   • good prognosis with maintenance

2. stage II — moderate periodontitis

   • severity → interdental CAL = 3-4 mm; RBL = coronal third (15-33%); no tooth loss due to periodontitis

   • complexity → maximum PD ≤ 5mm; mostly horizontal bone loss

   • good prognosis with maintenance

3. stage III — severe periodontitis with potential for tooth loss

   • severity → CAL ≥ 5mm; RBL = middle third and beyond; ≤4 tooth loss due to periodontitis

   • complexity → PD ≥ 6mm; vertical bone loss ≥ 3mm; class II or III furcation involvement; moderate ridge defect

   • disease is severe and more difficult to maintain, at meaningful risk for additional tooth loss

   • fair prognosis with maintenance

4. stage IV — severe periodontitis with potential for loss of dentition

   • severity → CAL ≥ 5mm; RBL = middle third and beyond; ≥5 teeth lost due to periodontitis

   • complexity → masticatory dysfunction, secondary occlusal trauma (tooth mobility degree ≥2), severe ridge defects, bite collapse, drifting, flaring, <20 teeth remaining (10 opposing pairs)

   • represents severe periodontal destruction + functional restorative collapse

   • questionable prognosis with maintenance

• extent and distribution for each stage adds to stage as a descriptor

  • localized (<30% teeth involved), generalized, or molar/incisor pattern

• tooth loss due to periodontitis is important

  • do not count a tooth lost due to caries, trauma, endodontic failure, or other untreated reasons

  • past periodontal tooth loss tells you disease has demonstrated severity, future management is more complex, and restoring the patient may be difficult

• complexity can increase the stage

  • an apparent moderate case can become a higher stage due to deep pockets, furcations, vertical defects, tooth loss, mobility, functional problems, and complex rehabilitation needs

  • not classified only from CAL

• goals of staging:

  1. identify periodontitis as early as possible

  2. separate stage I/II from stage III/IV

process to classify periodontitis

1. initial case overview

   • assess full-mouth probing depths, full-mouth radiographs, missing teeth, overall disease severity

   • initial staging determined by CAL and RBL, where tooth loss due to periodontitis modifies stage definition

2. establish stage

   • determine CAL, RBL, tooth loss due to periodontitis, complexity

3. establish grade

   • determine rate of previous progression, bone loss relative to age, phenotype, smoking, diabetes, other medical/systemic conditions

• staging/grading applies only to periodontitis

  • other categories include health, biofilm-induced gingivitis, non-biofilm-induced gingival disease, peri-implant conditions and are not staged/graded the same as natural-tooth periodontiis

periodontitis grading

start every patient at grade B, then use evidence to determine whether the patient should move grades

• grade A — slow progression

  • no bone loss/CAL over 5 years

  • <0.25% bone loss / age

  • heavy biofilm with little destruction

    • despite significant plaque challenge, tissues have broken down relatively slowly

  • nonsmoker, normoglycemic with no diagnosis of diabetes

• grade B — moderate progression

  • < 2mm bone loss/CAL over 5 years

  • 0.25-1.0% bone loss / age

  • destruction is commensurate with biofilm

    • amount of disease approximately makes sense for amount of local challenge

  • <10 cigarettes/day, diabetes with HbA1c <7.0%

• grade C — rapid progression

  • ≥ 2mm bone loss/CAL over 5 years

  • >1.0% bone loss / age

  • destruction exceeds what is expected from biofilm

    • little plaque/calculus, young patient, major attachment loss

  • ≥10 cigarettes/day, diabetes with HbA1c ≥7.0%

• grading aims to indicate rate of periodontitis progression, responsiveness to therapy, and potential impact on systemic health

  • primary criteria → direct evidence (CAL or RBL) and indirect evidence (phenotype, % bone loss/age)

    • case phenotype compares amount of biofilm with amount of periodontal destruction

  • grade modifiers → risk factors (smoking, diabetes)

    • push toward a worse grade

health on a reduced periodontium

a patient can have significant previous attachment loss but currently have healthy gingiva with stable attachment and no active periodontitis

• health a reduced periodontium in a non-periodontitis patient vs health on a reduced periodontium in a stable patient

• no need to restore lost bone to normal to maintain periodontal health

• reduced periodontium can remain stable for many years with good plaque control and appropriate peridontal maintenance

  • often approximately 3-4 month recall intervals

periodontitis case definition

2mm attachment loss on at least 2 non-adjacent teeth

• periodontitis requires a pattern of attachment loss rather than one isolated abnormal measurement

• clinical gingival health — <10% bleeding sites with no pockets >3mm

  • bleeding on probing is central when distinguishing health from gingival inflammation

gingival recession classification

newer classification system also describes recession based on interproximal attachment loss

1. recession type 1 — gingival recession without interproximal attachment loss

2. recession type 2 — recession + interproximal attachment loss

   • interproximal attachment loss ≤ buccal attachment loss

3. recession type 3 — recession + interproximal attachment loss

   1. interproximal attachment loss > buccal attachment loss

• more inteproximal loss results in worse predictability for root-coverage grafting

mucogingival conditions

newer classification system expands how mucogingival deformities are described based on whole soft-tissue phenotype and associated clinical problems

• periodontal phenotype → thin/scalloped, thick/scalloped, thick/flat

• gingival recession

• gingival thickness

• gingival width

• cervical caries

• esthetic concerns

• hypersensitivity

• lack of keratinized gingiva

• decreased vestibular depth

• abnormal frenum / muscle position

• gingival excess

endo-perio lesions

classification distinguishes lesions with root damage vs lesions without root damage

• with root damage:

  • root fracture or crackling

  • root canal or pulp chamber perforation

  • external root resorption

• without root damage:

  • endo-periodontal lesions in periodontitis patients

  • endo-periodontal lesions in non-periodontitis patients

  • narrow vs wide vs deep pockets

  • one vs multiple tooth surfaces

• isolated periodontal defect may not be purely periodontal

• always consider endodontic origin + root damage + combined lesions

peri-implant disease categories

peri-implant disease is not given the same stage I-IV / grade A-C system

1. peri-implant health

2. peri-implant mucositis

   • bleeding, erythema, swelling, and/or supporation with or without increased probing depth compared to previous examinations

   • no bone loss

   • reversible

3. peri-implantitis

   • bleeding and/or suppuration on gentle probing

   • increased probing depth compared to previous examinations

   • bone loss beyond changes from initial remodeling

   • irreversible

   • in absence of previous data:

     • bleeding and/or suppuration on gentle probing

     • probing depth ≥ 6mm

     • ≥ 3mm of bone loss

4. hard and soft-tissue deficiencies

• probing around implant is different

  • natural teeth have PDL and fiber insertion into cementum/tooth

  • implants do not have same fiber attachment to implant surface

• probe penetration can naturally be deeper around an implant

  • increased probing depth around an implant does not mean the same thing as the identical probing depth around a natural tooth

  • use clinical findings + radiographs when diagnosing peri-implant disease

initial implant bone remodeling vs peri-implantitis

bone loss around an implant does not automatically equal peri-implantitis, and radiographic bone loss should be used in conjunction with CAL

• some bone changes may have existed at implant placement, from initial remodeling, or because of initial hard-tissue deficiencies

  • compare with baseline / previous records whenever possible

  • disease means progressive bone loss beyond expected initial change

• peri-implant health — absence of bone loss beyond crestal bone level changes resulting from initial bone remodeling

  • no inflammation and no bleeding

• peri-implant mucositis — absence of bone loss beyond crestal bone level changes resulting from initial bone remodeling

  • signs of inflammation and bleeding and/or suppuration on gentle probing

• peri-implantitis — presence of bone loss beyond crestal bone level changes resulting from initial bone remodeling

  • probing depths ≥ 6mm

  • bleeding and/or suppuration on gentle probing

  • bone levels ≥ 3mm apical of most coronal portion of intraosseous part of implant