Periodontics
Dental Specialty · Periodontium, Disease & Treatment
TL;DR
Periodontics is the dental specialty concerned with the health and disease of the periodontium — the tooth-supporting apparatus comprising the gingiva, periodontal ligament (PDL), cementum, and alveolar bone. Periodontal disease is initiated by the accumulation of a dysbiotic subgingival biofilm but sustained by the host’s immune-inflammatory response, which ultimately destroys the supporting structures and results in clinical attachment loss (CAL), radiographic bone loss, and — untreated — tooth loss. The current disease classification framework is the landmark 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions, which replaced the outdated chronic/aggressive distinction with a multidimensional Staging and Grading system that characterises severity, complexity, and rate of progression.
- Periodontitis Staging (I–IV) reflects disease severity and complexity: Stage I (mild CAL 1–2 mm) → Stage II (moderate CAL 3–4 mm) → Stage III (severe CAL ≥5 mm with potential tooth loss risk) → Stage IV (very severe, with masticatory dysfunction, bite collapse, or ≤20 remaining teeth). Staging is assigned at the worst tooth in the mouth and can only move upward.
- Periodontitis Grading (A–C) reflects the rate of progression and biofilm-to-destruction ratio: Grade A (slow) is characterised by no radiographic bone loss over 5 years and heavy biofilm with minimal destruction; Grade B (moderate) shows proportionate destruction; Grade C (rapid) shows significant bone loss beyond what biofilm would predict — or is modified to C by diabetes (HbA1c ≥7%) or smoking (>10 cigarettes/day).
- Non-surgical treatment (cause-related therapy) — oral hygiene instruction and full-mouth supra/subgingival debridement (scaling and root planing, SRP) — is the cornerstone of periodontal treatment and is effective for most Stage I–II and many Stage III cases. Re-evaluation at 6–8 weeks after SRP determines whether residual disease warrants surgical intervention.
- Periodontal surgery is indicated for persistent pockets ≥5–6 mm after SRP, furcation involvement Class II–III, or anatomical conditions that prevent adequate non-surgical access. Surgery is categorised as resective (removes bone to achieve positive architecture), regenerative (GTR, bone grafts, biologics), or mucogingival/plastic (root coverage grafts, keratinised tissue augmentation).
- Periodontal disease has a bidirectional relationship with systemic health, particularly diabetes (periodontal treatment reduces HbA1c by ~0.3–0.4%), and is associated with cardiovascular disease, adverse pregnancy outcomes, and respiratory disease. Smoking is the most significant environmental risk factor — it masks bleeding on probing (BOP) and impairs healing after all forms of treatment.
Key Facts
What Is Periodontics?
Periodontics is the dental specialty focused on the periodontium — the four tissues that support and attach the teeth within the alveolar bone: the gingiva, periodontal ligament (PDL), cementum, and alveolar bone proper. The specialty encompasses the diagnosis and management of all conditions affecting these structures, including inflammatory diseases (gingivitis, periodontitis), necrotising conditions, developmental deformities, mucogingival conditions (recession, inadequate keratinised tissue), and the management of peri-implant conditions. It also includes dental implantology — the surgical placement of implants and management of peri-implant health and disease.
The healthy periodontium is characterised by a shallow sulcus (≤3 mm), absence of bleeding on probing, firm pink gingiva with knife-edge margins and stippling, a positive gingival architecture (papillae filling the embrasures), no clinical attachment loss, and radiographically intact alveolar crestal bone at 1–2 mm below the cementoenamel junction (CEJ). The junctional epithelium (JE) — the epithelial lining of the base of the sulcus that attaches to the tooth surface via hemidesmosomes and the internal basal lamina — is the critical biological seal between the oral environment and the supporting apparatus. It has a high turnover rate (approximately 4–6 days) and is highly permeable to leukocytes (primarily neutrophils), which provide the first line of defence against the subgingival biofilm. When this equilibrium is disturbed — by an increasingly dysbiotic biofilm that shifts from Gram-positive aerobic commensal bacteria to Gram-negative anaerobic pathogenic species — the host’s immune-inflammatory response produces the collateral tissue destruction that defines periodontal disease.
Periodontal disease is the world’s most prevalent chronic inflammatory condition. Severe periodontitis affects approximately 11% of the global population — approximately 800 million people — and is the sixth most prevalent disease worldwide. Gingivitis, which is reversible with appropriate plaque control, affects the vast majority of adults at some point in their lives. Understanding periodontics is therefore not a specialty concern alone — every general dental practitioner is responsible for the routine diagnosis, risk stratification, and initial management of periodontal disease, referring to a periodontist when disease is beyond their competence or when specialist surgical expertise is required.
Why It Matters (Clinical + Exam Context)
Periodontics is one of the most heavily tested topics in dental board examinations because it integrates microbiology, immunology, histology, pharmacology, and multi-step clinical management. The 2017 World Workshop classification is a universal board target, as is the Staging and Grading system, furcation classification, biological width, and the evidence base for surgical and non-surgical treatment decisions.
Clinical Relevance
- Staging and Grading changed the language of periodontitis forever: The pre-2017 terms “chronic periodontitis” and “aggressive periodontitis” have been formally retired. The 2017 classification recognises that the distinction between aggressive and chronic periodontitis was not scientifically defensible — what was called “aggressive” often reflects a rapidly progressing Grade C case in a patient with a systemic risk modifier (diabetes, smoking, genetic susceptibility). Board exams actively test this transition: the correct answer to “what type of periodontitis does this young patient with rapid bone loss have?” is not “aggressive periodontitis” but rather “Stage III or IV, Grade C periodontitis.”
- Smoking masks disease severity: Nicotine causes vasoconstriction of the gingival microvasculature, which suppresses the vascular component of the inflammatory response — including bleeding on probing. This means that in a heavy smoker, BOP is significantly reduced even in the presence of active periodontitis. A clinician interpreting low BOP in a smoker as “healthy gingiva” may profoundly underestimate disease severity. The absence of BOP in a smoker is not reassuring — it is an artefact of the pharmacological effect of nicotine on the vasculature.
- Furcation involvement is a complexity factor that changes the entire treatment plan: Once a multi-rooted tooth has furcation involvement beyond Class I, it becomes significantly more difficult to debride, maintain, and predict long-term. Class II and III furcations are surgical indications and also affect staging: furcation involvement ≥Class II is a complexity factor that automatically assigns the tooth to at least Stage III. In the maxilla, furcation involvement in the first molar is particularly challenging because of the proximity of the sinus floor and the trifurcation anatomy. Clinicians must probe furcations at every recall appointment — not just at baseline — because furcation involvement can develop or worsen during maintenance.
- The periodontium is the restorative foundation: No restorative, prosthetic, or orthodontic treatment can succeed long-term on a compromised periodontal foundation. Crown margins that violate the biologic width provoke chronic inflammation, bone loss, and eventual tooth loss. Orthodontic tooth movement into areas of inadequate bone or keratinised tissue can cause dehiscences and recession. Full arch fixed prostheses in patients with untreated periodontitis rapidly become catastrophic failures. The periodontal treatment sequence — cause-related therapy first, reassessment second, definitive restorative work only after periodontal stability is confirmed — is not optional; it is the biological prerequisite for all dental care.
- Periodontal maintenance (supportive periodontal therapy) is lifelong: Periodontitis is a chronic inflammatory disease that is managed, not cured. Once a patient has been diagnosed with periodontitis and treated, they require lifelong periodontal maintenance at intervals determined by their disease risk (typically every 3 months for active disease or high-risk patients; 4–6 months for well-controlled patients with no remaining pockets). The evidence clearly shows that patients who adhere to periodontal maintenance lose significantly fewer teeth over time than those who do not. Treatment without maintenance planning is incomplete treatment.
2017 Classification and the Staging/Grading System
The 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases (Tonetti et al., Caton et al.) produced the most significant revision to periodontal classification in over two decades. The overarching framework distinguishes between periodontal health, gingival diseases and conditions, periodontitis, other conditions affecting the periodontium, and peri-implant diseases and conditions.
The most clinically important change was the replacement of the 1999 classification’s “chronic periodontitis” and “aggressive periodontitis” categories with a single Periodontitis category characterised by a two-dimensional Staging and Grading system. Staging describes the severity and complexity of the disease; Grading describes the rate of progression and risk of further progression. Together, they allow clinicians to communicate disease status and treatment complexity in a standardised, reproducible framework.
Periodontitis Staging (I–IV)
Staging is assigned at the worst tooth in the dentition — the tooth with the greatest CAL, deepest pocket, most bone loss, or greatest complexity factor. It can only increase over time, never decrease. The staging criteria:
| Criterion | Stage I — Mild | Stage II — Moderate | Stage III — Severe | Stage IV — Very Severe |
|---|---|---|---|---|
| Interdental CAL (worst tooth) | 1–2 mm | 3–4 mm | ≥5 mm | ≥5 mm |
| Radiographic bone loss (RBL) | Coronal third (<15%) | Coronal third (15–33%) | Extending to middle or apical third | Extending to middle or apical third |
| Tooth loss due to periodontitis | No tooth loss | No tooth loss | ≤4 teeth | ≥5 teeth |
| Max probing depth | ≤4 mm | ≤5 mm | ≥6 mm | ≥6 mm |
| Bone loss pattern | Horizontal | Horizontal | Vertical ≥3 mm; furcation Class II or III | Vertical ≥3 mm; furcation Class II or III |
| Complexity factors (Stage IV only) | — | — | — | Masticatory dysfunction; secondary occlusal trauma; severe ridge defect; bite collapse; flaring/drifting; <20 remaining teeth (10 opposing pairs) |
Periodontitis Grading (A–C)
Grading assesses the rate of progression and the influence of risk factors on that rate. The primary criterion is the ratio of radiographic bone loss to patient age — expressed as the % bone loss divided by age. Additional criteria include the case phenotype (amount of destruction relative to the amount of biofilm) and secondary modifiers (smoking, diabetes).
| Criterion | Grade A — Slow Rate | Grade B — Moderate Rate | Grade C — Rapid Rate |
|---|---|---|---|
| Primary: % bone loss / age | <0.25 | 0.25–1.0 | >1.0 |
| Primary: Bone loss over 5 years | No evidence of bone loss | <2 mm over 5 years | ≥2 mm over 5 years |
| Case phenotype | Heavy biofilm deposits; destruction inconsistent with biofilm (very little destruction despite heavy plaque — host response suppressing disease) | Destruction proportionate to biofilm deposits | Destruction exceeds what biofilm would predict; vertical bone loss; rapid progression; early-onset in young patient |
| Risk modifiers — Smoking | Non-smoker | <10 cigarettes/day | ≥10 cigarettes/day → upgrade to Grade C |
| Risk modifiers — Diabetes | Normoglycaemic | Controlled (HbA1c <7%) | Poorly controlled (HbA1c ≥7%) → upgrade to Grade C |
Clinical application: A 50-year-old patient with 30% bone loss has a % bone loss/age ratio of 30/50 = 0.6 — Grade B. A 30-year-old patient with the same 30% bone loss has a ratio of 30/30 = 1.0 — borderline Grade B/C. The same amount of bone loss in a younger patient carries a worse grade because it has accumulated faster. If that 30-year-old is also a heavy smoker (>10 cigarettes/day), the grade is immediately upgraded to Grade C regardless of the ratio. This grading system codifies what experienced clinicians knew intuitively — that young patients with significant bone loss, and patients with diabetes or heavy smoking histories, have more aggressive disease that requires more intensive management and vigilant maintenance.
Necrotizing Periodontal Diseases
Necrotizing periodontal diseases are a distinct category characterised by necrosis of the gingival tissues (and potentially deeper structures) in the context of a compromised immune response. They are not simply “severe gingivitis” — they involve actual tissue death, are associated with systemic predisposing factors, and require specific management. The spectrum includes:
- Necrotizing gingivitis (NG): Necrosis limited to the gingival tissues. Classic signs: punched-out, crater-like ulceration of the interdental papillae; grey-white pseudomembrane overlying necrotic tissue; intense pain; characteristic fetor ex ore (malodour); lymphadenopathy; and malaise. The microbiology is a specific fusospirochetal complex — primarily Fusobacterium nucleatum, Treponema species, and Prevotella intermedia. Predisposing factors include psychological stress, sleep deprivation, poor nutrition, smoking, and HIV infection. Treatment: gentle subgingival debridement (cannot perform aggressive instrumentation acutely); metronidazole 200–400 mg TID × 5–7 days; chlorhexidine 0.12–0.2% rinse; supportive care (fluids, analgesia, vitamin C if deficient); definitive debridement once acute phase resolves.
- Necrotizing periodontitis (NP): Necrosis extends into the PDL and alveolar bone. Clinical appearance as above but with radiographic and probing evidence of bone loss. In immunocompetent patients, bone loss may be rapid but limited. In severely immunocompromised patients (advanced HIV, neutropenia, malnutrition), bone destruction can be catastrophic and rapid. Management as for NG with additional attention to systemic health and immediate specialist referral.
- Necrotizing stomatitis: The most severe form — large areas of bone exposure extending beyond the alveolar process; pathognomonic of severe immune compromise (HIV with CD4 count <200 cells/mm³, chemotherapy-induced neutropenia). Requires urgent medical co-management and specialist periodontal care; may require surgical debridement of necrotic bone.
Peri-Implant Diseases and Conditions
Peri-implant diseases are inflammatory conditions affecting the tissues around osseointegrated dental implants, analogous to gingivitis and periodontitis around natural teeth. They are classified as:
- Peri-implant health: No bleeding on probing, no bone loss beyond initial remodelling (0.5–1.0 mm in the first year post-placement). Can occur with or without a reduced (surgically modified) bone support.
- Peri-implant mucositis: Reversible inflammatory lesion in the soft tissue around an implant — BOP ± suppuration, increased probing depths; no progressive bone loss. Analogous to gingivitis. Caused by biofilm accumulation. Managed by thorough debridement (non-metallic instruments on implant surfaces); improved home care; possible local antiseptic adjuncts. Fully reversible if treated.
- Peri-implantitis: Progressive, inflammatory bone loss around an implant in addition to soft tissue changes. BOP, suppuration, probing depths ≥6 mm, progressive bone loss on serial radiographs. Analogous to periodontitis but responds less predictably to treatment and has no equivalent of regeneration to healthy “cementum/PDL/bone.” Management: non-surgical debridement as first step; if insufficient, surgical access for mechanical decontamination of the implant surface (titanium brushes, air-abrasive, Er:YAG laser) ± bone grafting and membrane for regeneration. Success rates for peri-implantitis treatment are significantly lower than for natural tooth periodontitis.
Periodontal Diagnosis and Treatment
The Periodontal Examination
A complete periodontal examination forms the foundation of every periodontal diagnosis and treatment plan. It must include the following components:
- Six-point periodontal probing: Probing depths recorded at six sites per tooth — mesiobuccal (MB), buccal (B), distobuccal (DB), mesiolingual (ML), lingual (L), distolingual (DL) — using a calibrated periodontal probe (Williams, UNC-15, or Nabers probe for furcations) with standardised force (~25 g). Probing depth alone is not sufficient; clinical attachment level (CAL) must be calculated: CAL = recession + probing depth (when the GM is at or coronal to the CEJ) or probing depth minus the distance from the GM to the CEJ (when the GM is coronal to the CEJ, indicating a pseudo-pocket or gingival enlargement).
- Bleeding on probing (BOP): Presence or absence of bleeding within 30 seconds of probing. A BOP percentage >10% indicates active gingival inflammation. BOP is one of the most sensitive (though not specific) indicators of periodontal disease activity — a site that does not bleed has a very high negative predictive value for attachment loss over the next 12 months (healthy site). Note: BOP is suppressed by smoking (vasoconstriction) and should not be interpreted normally in smokers.
- Furcation assessment: All multi-rooted teeth are probed at the furcation entry with a Nabers probe. The Glickman classification (Class I–IV) or the Hamp classification (F0–F3) is used: Class I — incipient furcation involvement; pocket suprabony, probe just enters furcation <3 mm. Class II — partial furcation involvement; probe enters furcation but does not pass through to the other side; horizontal probing >3 mm but furcation not through-and-through. Class III — through-and-through furcation involvement; probe passes from one aspect of the furcation to the other; furcation covered by soft tissue (not visible clinically). Class IV — as Class III but gingival recession has exposed the furcation clinically.
- Tooth mobility: Graded I (horizontal displacement <1 mm), II (horizontal displacement 1–2 mm), III (vertical mobility in addition to horizontal). Mobility can result from periodontal bone loss, occlusal trauma, or both — these must be distinguished because the management differs (treat the occlusal trauma if that is the primary cause; if periodontitis is the primary cause, treat the periodontitis first).
- Radiographic assessment: Vertical bitewing radiographs provide the best assessment of interproximal bone levels because the X-ray beam is perpendicular to the alveolar crest. Full-mouth periapical series provides views of all root surfaces and periapical regions. The alveolar crest in a healthy periodontium should be 1–2 mm below the CEJ. CBCT is indicated for complex surgical planning (implants, regeneration, furcation anatomy).
Non-Surgical Periodontal Treatment
Non-surgical treatment — also called cause-related therapy or Phase I therapy — is the first and most fundamental phase of periodontal treatment. It is effective for the majority of periodontitis cases and must be completed and re-evaluated before any surgical decision is made.
Oral hygiene instruction (OHI) addresses the primary cause of the disease — the subgingival biofilm. Patients must be instructed in effective interproximal cleaning (interdental brushes — the most effective method for interproximal plaque removal in adults with periodontal disease; floss is second-line; single-tufted brushes for furcations and complex anatomy), appropriate toothbrushing technique (modified Bass for pockets; rolling technique for younger patients), and the correct use of adjunctive chemotherapeutic agents (chlorhexidine 0.12–0.2% rinse for acute phases and post-surgery; sodium fluoride rinse for root surface caries risk).
Scaling and root planing (SRP) — also called subgingival debridement — is the gold standard non-surgical periodontal treatment. Hand instruments (Gracey curettes are site-specific and preferred for root planing; universal curettes; sickle scalers for supragingival calculus) and ultrasonic/piezoelectric scalers (highly effective for subgingival biofilm disruption and calculus removal) are used to remove subgingival calculus and disrupted cementum, eliminate the subgingival biofilm, and reduce the microbial load in the pocket. SRP reduces probing depths by an average of 1–2 mm and gains approximately 0.5–1.0 mm of CAL in pockets 4–6 mm. Deeper pockets (≥7 mm) respond less predictably to non-surgical treatment alone — residual pocket depth after SRP predicts the need for surgery.
Adjunctive Pharmacological Therapy
| Agent | Type | Dose / Application | Evidence / Indication |
|---|---|---|---|
| Amoxicillin + Metronidazole | Systemic antibiotic combination | Amoxicillin 500 mg TID + metronidazole 250–400 mg TID × 7–14 days; taken simultaneously with or immediately after full-mouth SRP | Strongest evidence for Grade C periodontitis; adjunct to SRP — not as monotherapy; targets red/orange complex; Socransky/Haffajee protocol |
| Doxycycline (systemic) | Systemic antibiotic; also host modulator at sub-antimicrobial dose | Sub-antimicrobial dose: doxycycline 20 mg BID (Periostat); antimicrobial: 100 mg daily × 14 days | Sub-antimicrobial dose inhibits matrix metalloproteinases (MMPs) — reduces connective tissue breakdown; useful as adjunct in moderate–severe disease |
| Chlorhexidine chip (PerioChip) | Local delivery — controlled release | Biodegradable gelatin chip inserted into pocket ≥5 mm after SRP; releases CHX over 7–10 days | Adjunct to SRP for pockets ≥5 mm; modest additional probing depth reduction (~0.4 mm); limited evidence for clinical attachment gain |
| Minocycline microspheres (Arestin) | Local delivery — sustained release | Minocycline HCl 1 mg microspheres injected into pocket after SRP; sustained release for 21 days | Adjunct to SRP; additional ~0.5 mm probing depth reduction vs SRP alone; particularly used for maintenance pockets |
| Doxycycline hyclate gel (Atridox) | Local delivery — biodegradable | 10% doxycycline hyclate in a flowable biodegradable polymer; injected into pocket, hardens on contact with GCF | Controlled release over 7 days; comparable evidence to other local delivery agents as adjunct to SRP |
Re-evaluation (periodontal reassessment) is performed 6–8 weeks after completion of SRP to allow tissue healing. At re-evaluation, a full six-point probing is repeated and compared with baseline. Teeth with residual pockets ≥5–6 mm after SRP, persistent BOP, furcation Class II–III, or inadequate access for instrumentation are identified as candidates for surgical intervention. Many Stage I and II cases respond fully to non-surgical treatment without requiring surgery — the re-evaluation determines the treatment pathway, not the baseline findings alone.
Surgical Periodontal Treatment
Periodontal surgery is indicated when non-surgical treatment has been completed and re-evaluated, and residual disease persists that cannot be managed by further non-surgical means. The primary indications are: persistent pockets ≥5–6 mm with BOP; furcation involvement Class II–III; inadequate surgical access for subgingival instrumentation (thick bony ledges, complex root morphology); requirement for regenerative treatment; and mucogingival problems (recession, inadequate keratinised tissue).
Resective surgical approaches aim to eliminate pockets by removing bone to create a more physiological osseous architecture (positive architecture: interproximal bone coronal to radicular bone) that is easier to maintain. The procedures include:
- Osseous resective surgery (ORS): Comprises osteoplasty (reshaping non-supporting bone — the bony ledges and craters — without removing supporting bone) and ostectomy (removing supporting alveolar bone to eliminate reverse architecture). ORS is effective for eliminating pockets and creating maintainable tissue contours but sacrifices bone height. It is most appropriate for Stage II–III cases with horizontal bone loss and irregular bony architecture where regeneration is not indicated. The apically positioned flap (APF) is typically used in conjunction with ORS to maximise keratinised tissue preservation.
Regenerative surgical approaches aim to reconstruct the periodontium that has been lost — restoring bone, PDL, and cementum to root surfaces that have been exposed by disease. True regeneration requires formation of new cementum, new PDL fibre insertion, and new alveolar bone — not just bone fill (which can occur by long junctional epithelium or fibrous repair without functional PDL). Key regenerative modalities include:
- Guided tissue regeneration (GTR): A membrane barrier is placed between the bone defect and the flap to exclude fast-proliferating epithelial and gingival connective tissue cells while allowing the slower-growing PDL and bone cells to repopulate the defect. Membranes are classified as: non-resorbable (expanded PTFE — e-PTFE; requires a second surgery for removal) and resorbable (collagen — most commonly used; polylactic acid/polyglycolic acid — PLA/PGA). GTR is most effective for deep, narrow, multi-wall (three-wall) vertical intrabony defects — these have a good blood supply and bony walls to support the membrane.
- Bone grafts: Fill the intrabony defect to support membrane placement and provide a scaffold for new bone formation. Classified by source: autograft (patient’s own bone — the gold standard biologically; from the retromolar area, chin, or extraorally from the iliac crest); allograft (from a human donor — freeze-dried bone allograft FDBA; demineralised freeze-dried bone DFDBA — which has osteoinductive properties due to BMPs); xenograft (bovine-derived — Bio-Oss; most widely used in periodontal regeneration; osteoconductive scaffold that is slowly resorbed); alloplast (synthetic — tricalcium phosphate, hydroxyapatite — osteoconductive only).
- Biologics: Growth factors and proteins that enhance cellular proliferation, differentiation, and matrix production. Enamel matrix derivative (EMD — Emdogain): Contains amelogenins (the proteins of the enamel matrix); mimics the developmental induction of cementum by HERS; promotes formation of acellular cementum and PDL. Applied as a gel to the root surface after root conditioning with EDTA. Level I evidence for intrabony defect regeneration. Platelet-derived growth factor (PDGF — GEM 21S): Recombinant human PDGF-BB combined with beta-tricalcium phosphate; FDA-approved for periodontal defects; promotes PDL cell proliferation and angiogenesis. rhBMP-2 (Infuse): FDA-approved for ridge augmentation and sinus grafting; not typically used for intrabony periodontal defects due to risk of ankylosis.
Root Coverage and Mucogingival Surgery
Gingival recession — the apical migration of the gingival margin below the CEJ, exposing root surface — is managed by mucogingival surgical procedures when there is dentinal sensitivity, patient aesthetic concern, progressive recession threatening bone support, or root surface caries risk. The Cairo classification (RT1–RT3), adopted by the 2017 World Workshop, is the current system for categorising recession and predicting root coverage outcomes:
| Cairo Class | Definition | Expected Coverage | Procedure of Choice |
|---|---|---|---|
| RT1 | Recession with no interproximal CAL loss (interproximal CEJ not detectable) | Complete (100%) root coverage predictably achievable | CTG + CAF (gold standard); tunnel technique; VISTA |
| RT2 | Recession with interproximal CAL loss ≤ the coronal boundary of the buccal recession | Partial coverage expected; 100% achievable in some cases | CTG + CAF; outcomes variable depending on papilla height |
| RT3 | Recession with interproximal CAL loss > coronal boundary of buccal recession | Partial coverage only; complete coverage not achievable | CTG + CAF for maximum coverage and root protection; manage expectations |
The connective tissue graft (CTG) is the gold standard for root coverage. A subepithelial connective tissue graft is harvested from the palate (trap-door technique or parallel incision technique) and placed under a coronally advanced flap (CAF) at the recipient site. The CTG provides a superior blood supply via the overlying flap and the recipient bed, produces a keratinised tissue phenotype at the recipient site, and achieves the most predictable and aesthetically pleasing results of any root coverage procedure. The tunnel technique — threading the CTG beneath a continuous tunnel without a vertical releasing incision — is an increasingly popular modification that avoids the vertical incision scarring and produces excellent aesthetic outcomes. The free gingival graft (FGG) is preferred when the primary goal is increasing the width of keratinised tissue rather than root coverage — it produces a wider keratinised band but with less aesthetic result than the CTG+CAF.
Biologic Width and the Supracrestal Tissue Attachment
The biologic width — now termed the supracrestal tissue attachment (STA) in the 2017 classification — refers to the combined dimension of the junctional epithelium and the supracrestal connective tissue attachment above the alveolar crest. The classic Gargiulo, Wentz, and Orban (1961) histometric study established the average dimensions:
- Sulcular epithelium: 0.69 mm
- Junctional epithelium: 1.07 mm
- Supracrestal connective tissue attachment: 0.97 mm
- Total average biologic width (JE + CT attachment): 2.04 mm
When a restorative margin (crown margin, preparation margin, or bracket/band) is placed within or apical to the supracrestal tissue attachment — i.e., invading the biologic width — the periodontium responds with chronic inflammation, bone loss, and eventual pocket formation to re-establish the physiological minimum dimension between the alveolar crest and the restorative margin. This violation of biological width is a common cause of otherwise unexplained gingival inflammation around crowns and restorations. The clinical response to suspected biological width violation is: (1) confirm that the margin is subcrestal on a periapical X-ray; (2) manage by crown lengthening (surgical exposure of tooth structure by resecting the gingival margin and underlying bone to re-establish the 3 mm minimum of supracrestal tissue attachment plus restorative space) before remounting the restoration.
Periodontal–Systemic Connections
Periodontal disease exists within — and influences — the broader systemic health of the patient. The 2017 classification formally recognises a category of “Periodontitis as a Manifestation of Systemic Disease” (e.g., rare systemic conditions such as Papillon-Lefèvre syndrome, Chediak-Higashi, leukocyte adhesion deficiency, cyclic neutropenia) and a separate category of systemic conditions modifying the course of periodontitis (the Grade modifiers). The key systemic relationships include:
| Systemic Condition | Effect on Periodontium | Effect of Periodontal Treatment | Clinical Management Note |
|---|---|---|---|
| Diabetes mellitus (Type 1 & 2) | Bidirectional relationship: hyperglycaemia impairs neutrophil function, promotes AGE (advanced glycation end-product) formation → increased tissue breakdown; increases severity and progression of periodontitis (Grade C modifier when HbA1c ≥7%) | Treating periodontitis reduces HbA1c by ~0.3–0.4% — clinically meaningful improvement in glycaemic control | Record HbA1c; refer to physician if poorly controlled; co-manage; advise patient of bidirectional relationship |
| Cardiovascular disease (CVD) | Strong association (shared risk factors: smoking, age, male sex); periodontal bacteria (P. gingivalis, S. sanguinis) found in atherosclerotic plaques; systemic inflammation from periodontitis elevates CRP and fibrinogen | Observational data suggest periodontal treatment may reduce systemic inflammatory markers; causal relationship not proven | Assess CVD risk; note that the association exists but causation is debated; advise patient |
| Pregnancy | Elevated progesterone → exaggerated gingival inflammatory response to plaque; pregnancy gingivitis (reversible); pregnancy epulis (pyogenic granuloma); association between severe periodontitis and preterm birth / low birth weight | Periodontal treatment during pregnancy is safe and effective; reduces pregnancy gingivitis; evidence for preterm birth prevention is inconclusive but risk reduction is plausible | Routine SRP is safe in all trimesters; avoid elective surgery in 1st and 3rd trimesters; epulis managed conservatively — regresses postpartum in most cases |
| Smoking | Vasoconstriction suppresses BOP (masks disease); impairs neutrophil and macrophage function; reduces healing after SRP and surgery; 3–7× increased risk of periodontitis; associated with more aggressive disease course | SRP produces less probing depth reduction in smokers vs non-smokers (~50% of expected response); surgical wound healing impaired; smoking cessation dramatically improves treatment response | Strongly advise cessation at every appointment; refer to cessation programme; document smoking status and quantity; incorporate cessation support into treatment plan |
| Medications affecting gingiva | Drug-influenced gingival overgrowth: calcium channel blockers (nifedipine — most common; amlodipine less severe); phenytoin (antiepileptic); ciclosporin (immunosuppressant). Frequency and severity exacerbated by presence of plaque | Optimal plaque control reduces severity but does not eliminate overgrowth; if functionally or aesthetically unacceptable, gingivectomy/osseous surgery may be required; liaise with prescribing physician about alternative medications | Prescribing physician consultation for medication substitution (e.g., amlodipine instead of nifedipine; azathioprine instead of ciclosporin) can reduce severity |
Clinical Considerations
- The treatment sequence is non-negotiable: Phase I (cause-related therapy: OHI + SRP) must always precede Phase II (surgical treatment), which must precede Phase III (definitive restorative/prosthetic treatment). Performing restorative work in active periodontal disease produces restoration failure and perpetuates disease. Performing surgery without completing SRP leaves the biofilm undisturbed and undermines healing. The periodontal sequence exists for biological reasons — it is not a protocol preference but a requirement of tissue physiology.
- Antibiotics in periodontitis are adjuncts — not monotherapy: Systemic antibiotics are not a substitute for mechanical debridement. The subgingival biofilm is a structured community (a biofilm) with an extracellular matrix that protects bacteria from antibiotic penetration at achievable serum concentrations. Antibiotics only reach effective concentrations against biofilm bacteria after mechanical disruption of the biofilm by SRP. Prescribing antibiotics without SRP produces transient reduction in bacterial load that rebounds within weeks. The evidence supports systemic antibiotics (amoxicillin + metronidazole) as an adjunct to full-mouth SRP in Grade C periodontitis — not as a standalone treatment for “gum disease.”
- Three-wall intrabony defects have the best regenerative prognosis: The number of bony walls surrounding an intrabony defect determines the regenerative potential. A three-wall defect — with mesial, distal, and lingual/palatal bony walls — provides maximum blood supply, containment for the graft or membrane, and osteogenic cell populations on three sides. Two-wall defects have intermediate prognosis; one-wall and combined defects have the least favourable prognosis for regeneration. Before recommending regenerative surgery, the defect morphology must be assessed from periapical radiographs and — ideally — pre-surgical sounding (bone mapping under local anaesthesia).
- Furcation Class II in maxillary molars is the most surgically challenging: The maxillary first molar trifurcation presents three furcation entries (mesial, buccal, distal) at varying heights, often with close proximity to the sinus floor. Class II and III furcation involvement in maxillary molars is associated with higher tooth loss rates than mandibular molars over 10-year maintenance. Regenerative treatment of furcation defects produces less predictable results than intrabony defect regeneration — particularly Class III (through-and-through) furcations have very poor regenerative prognosis and often represent an indication for extraction and implant replacement as part of long-term treatment planning.
- Adequate keratinised tissue width matters at implants more than at natural teeth: The evidence for a minimum keratinised tissue (KT) width around natural teeth is debated — good plaque control may compensate for narrow or absent KT bands in some patients. Around implants, however, the absence of keratinised peri-implant mucosa is associated with greater plaque accumulation, more inflammation, greater peri-implant probing depth, and higher rates of peri-implantitis. A minimum of 2 mm of keratinised peri-implant mucosa (1 mm attached) is widely recommended. If inadequate KT exists before implant placement or after the healing abutment is placed, a free gingival graft can augment the keratinised tissue zone before or during implant treatment.
- Periodontal maintenance intervals are risk-based, not calendar-based: The standard “every six months recall” is not appropriate for periodontal patients. After active treatment, patients are enrolled in supportive periodontal therapy (SPT) at intervals based on their risk level: every 3 months for high-risk patients (heavy smokers, poorly controlled diabetics, Stage III/IV, compliance issues, multiple remaining pockets); every 4 months for moderate risk; every 6 months for well-controlled Stage I/II with good plaque control. At every SPT visit, the clinician should perform six-point probing, BOP assessment, furcation probing, and subgingival instrumentation of sites with ≥4 mm pockets and BOP.
Common Mistakes & Misconceptions
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Misconception: “The terms ‘chronic periodontitis’ and ‘aggressive periodontitis’ are still the correct diagnostic terms.”
Correction: These terms were formally retired by the 2017 World Workshop. The correct current terminology is Periodontitis Stage I–IV, Grade A–C. What was formerly labelled “aggressive periodontitis” — typically a young patient with rapid bone loss disproportionate to biofilm — is now classified as Stage III or IV, Grade C periodontitis. The Grade C designation captures the rapid progression; the Stage captures the severity. Board examinations from 2018 onward use the 2017 classification. Using the old terminology in a clinical context signals unfamiliarity with current evidence-based practice. -
Misconception: “Low bleeding on probing means the patient’s gums are healthy.”
Correction: BOP absence is highly reliable in non-smokers — it has a high negative predictive value for disease activity. However, in a smoking patient, vasoconstriction caused by nicotine suppresses the vascular component of the inflammatory response, dramatically reducing BOP even in the presence of active periodontitis with bone loss. Never interpret low BOP in a smoker as a reassuring sign. Probing depth, CAL, and radiographic assessment must be used to accurately assess disease severity in smokers regardless of BOP. -
Misconception: “Periodontal surgery is the definitive treatment — once the surgery is done, the patient is cured.”
Correction: Periodontitis is a chronic, biofilm-driven inflammatory disease that is managed, not cured. Surgery improves access for debridement and may regenerate lost tissue, but it does not eliminate the patient’s susceptibility to periodontitis, modify the composition of their biofilm permanently, or remove the need for meticulous home care and professional maintenance. Without lifelong supportive periodontal therapy (SPT) at risk-appropriate intervals, disease recurs. Studies show that patients who undergo surgical treatment but then fail to maintain regular SPT lose significantly more teeth than those who comply with maintenance — sometimes more than patients who received non-surgical treatment with excellent maintenance. -
Misconception: “Probing depth and clinical attachment level (CAL) are the same measurement.”
Correction: Probing depth (PD) measures from the gingival margin to the base of the pocket and tells you how deep the instrument goes. CAL measures from the CEJ to the base of the pocket and tells you how much attachment has actually been lost. When the gingival margin is at the CEJ (no recession, no pseudo-pocket), PD = CAL. When there is recession (GM apical to CEJ), CAL = PD + recession — the attachment loss is greater than the probing depth suggests. When there is gingival enlargement (GM coronal to CEJ — as in drug-influenced overgrowth or pregnancy gingivitis), CAL = PD − the distance from the GM to the CEJ — a deep-looking PD may have no attachment loss. The 2017 staging criteria use CAL, not PD. Confusing the two measurements leads to incorrect staging and misguided treatment planning. -
Misconception: “A connective tissue graft always achieves 100% root coverage.”
Correction: Complete root coverage is only predictably achievable in Cairo RT1 recession — where there is no interproximal attachment loss. The presence of interproximal CAL loss (RT2 and RT3) limits coverage because the height of the interdental papilla — which determines how coronally the flap can be advanced — is determined by the interproximal bone level. In RT2 and RT3 cases, the interdental papilla has been lost or reduced; advancing the flap coronally is limited, and complete coverage is not achievable regardless of technique. Managing patient expectations before surgery is essential — promising 100% root coverage in an RT2 or RT3 case is a clinical communication error.
Related Topics
Periodontics intersects with virtually every other dental specialty — restorative, implant, orthodontic, oral medicine, and systemic medicine all depend on a healthy periodontal foundation.
References & Sources
This article is based on the 2017 World Workshop Classification, IADT guidelines, and landmark periodontics research texts.
- Tonetti MS, Greenwell H, Kornman KS (2018). Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. Journal of Periodontology, 89(S1):S149–S161.
- Caton JG, Armitage G, Berglundh T, et al. (2018). A new classification scheme for periodontal and peri-implant diseases and conditions — introduction and key changes from the 1999 classification. Journal of Periodontology, 89(S1):S1–S8.
- Berglundh T, Armitage G, Araujo MG, et al. (2018). Peri-implant diseases and conditions: Consensus report of workgroup 4 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. Journal of Periodontology, 89(S1):S313–S318.
- Socransky SS, Haffajee AD, Cugini MA, Smith C, Kent RL Jr (1998). Microbial complexes in subgingival plaque. Journal of Clinical Periodontology, 25(2):134–144. [Original description of the microbial complexes — red, orange, yellow, green, purple]
- Gargiulo AW, Wentz FM, Orban B (1961). Dimensions and relations of the dentogingival junction in humans. Journal of Periodontology, 32:261–267. [Original biologic width measurements]
- Cairo F, Nieri M, Cincinelli S, Mervelt J, Pagliaro U (2011). The interproximal clinical attachment level to classify gingival recessions and predict root coverage outcomes: An explorative and reliability study. Journal of Clinical Periodontology, 38(7):661–666. [Cairo RT1/RT2/RT3 classification]
- Lindhe J, Lang NP, Berglundh T (Eds) (2015). Clinical Periodontology and Implant Dentistry, 6th ed. Wiley Blackwell. [Comprehensive periodontics reference]
- Herrera D, Sanz M, Jepsen S, Needleman I, Roldán S (2002). A systematic review on the effect of systemic antimicrobials as an adjunct to scaling and root planing in periodontitis patients. Journal of Clinical Periodontology, 29(S3):136–159.
Summary
Periodontics encompasses the diagnosis, classification, and treatment of all conditions affecting the tooth-supporting periodontium. The 2017 World Workshop Classification represents the current international standard — formally retiring the terms “chronic” and “aggressive” periodontitis in favour of a multidimensional Staging (I–IV, reflecting severity and complexity) and Grading (A–C, reflecting rate of progression and risk modifiers including smoking and diabetes) system. Treatment follows a strict sequential approach: cause-related therapy (OHI and SRP) must precede surgical intervention, which must precede definitive restorative work — with re-evaluation at each phase determining the need for progression. Non-surgical treatment is effective for the majority of cases; persistent pockets ≥5–6 mm, furcation Class II–III involvement, and anatomical complexity are the primary surgical indications. Surgical options include resective approaches (ORS + APF), regenerative procedures (GTR, bone grafts, EMD), and mucogingival/plastic surgery (CTG + CAF for root coverage). The biologic width — comprising the junctional epithelium and supracrestal connective tissue attachment (~2 mm total) — must be respected by all restorative margins to prevent chronic inflammatory bone loss. Periodontal disease is a chronic condition requiring lifelong supportive periodontal therapy at risk-stratified intervals; treatment without maintenance is incomplete treatment.
Key Takeaways
- “Chronic” and “aggressive” are retired: The 2017 World Workshop replaced these terms with Periodontitis Stage I–IV (severity/complexity) and Grade A–C (rate of progression). Grade C is assigned when % bone loss/age >1.0, or when smoking ≥10 cigarettes/day or HbA1c ≥7% are present as modifiers.
- CAL ≠ probing depth: CAL = probing depth + recession (when the GM is at or apical to the CEJ). Staging uses CAL, not PD. Stage I: CAL 1–2 mm; Stage II: 3–4 mm; Stage III/IV: ≥5 mm. Stage IV adds masticatory dysfunction or ≤20 remaining teeth.
- SRP first — always: Non-surgical cause-related therapy precedes any surgical decision. Re-evaluate at 6–8 weeks. Residual pockets ≥5–6 mm with BOP after SRP = surgical indication. Antibiotics are adjuncts to SRP, never substitutes.
- Biologic width ~2 mm: JE (~1 mm) + supracrestal CT attachment (~1 mm). Crown margins that violate this dimension cause chronic inflammation and bone loss. Crown lengthening surgery must establish ≥3 mm from crown margin to alveolar crest (2 mm STA + 1 mm restorative space).
- Red complex = P. gingivalis + T. forsythia + T. denticola: Most virulent periodontal pathogens. Furcation Class II–III = Stage III complexity factor. Cairo RT1 recession = predictable 100% root coverage with CTG+CAF. Smoking suppresses BOP — never interpret low BOP in a smoker as reassuring.
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