Riggs' disease

Riggs' disease is a historical eponym for periodontitis, the chronic inflammatory disease of the gums and tooth-supporting tissues that was once called pyorrhea alveolaris and is now classified by the pattern and severity of attachment loss

The name honours John M. Riggs, a nineteenth-century American dentist who argued that the condition was a local disease of the periodontal tissues and promoted subgingival scaling rather than extraction

Because Riggs' disease is no longer a formal diagnostic term, modern entries use it as a historical entry point into periodontitis, its classification, microbiology, risk factors and evidence-based treatment

Terminology and classification

• Riggs' disease, Riggs disease and pyorrhea alveolaris all refer to the same historical concept, and the modern equivalent is periodontitis rather than a separate entity
• Periodontitis is defined by inflammation of the periodontal tissues with loss of clinical attachment and alveolar bone, which distinguishes it from gingivitis, where inflammation is confined to the gingiva and attachment is preserved
• The 2017 World Workshop classification replaced the chronic and aggressive periodontitis categories with a staging system based on severity and complexity and a grading system based on progression rate and risk
• Stage I to IV describes increasing attachment loss, bone loss, probing depth and complexity, while grade A to C describes slow, moderate or rapid progression and incorporates smoking and glycaemic control
• ICD-10 codes periodontitis under K05.3 for chronic periodontitis and K05.4 for periodontosis, ICD-11 places chronic periodontitis under DA0C.Y as other specified periodontal disease, MeSH uses D010518 and Wikidata uses Q7333419
• The main named differentials are gingivitis, necrotising periodontal disease, periodontitis as a manifestation of systemic disease, endodontic-periodontal lesions, drug-induced gingival enlargement and oral squamous cell carcinoma

History

• John M. Riggs, who lived from 1810 to 1885, practised in Hartford, Connecticut, between the 1830s and 1880s and became known for treating loose and suppurating teeth by removing calculus from the roots rather than extracting them
• Riggs presented his views on the local nature of periodontal disease in the 1870s, and his name became attached to the condition in the English-language dental literature of the late nineteenth century
• The term pyorrhea alveolaris was widely used in the nineteenth and early twentieth centuries, and Riggs' disease was used as a synonym that emphasised his contribution to treatment rather than a distinct pathology
• The focal infection theory of the 1920s to 1950s led to widespread extraction of teeth in patients with systemic complaints, a practice later abandoned when controlled studies failed to support it
• The plaque hypothesis and later the specific plaque and ecological plaque hypotheses, developed from the 1960s onward, reframed periodontal disease as a biofilm-induced inflammatory condition rather than a simple infection
• The 1989 and 1999 classifications organized periodontal diseases into chronic, aggressive, necrotising and systemic categories, and the 2017 World Workshop replaced them with the current staging and grading framework

Epidemiology

• Global Burden of Disease estimates attributed about 743 million cases of severe periodontitis to 2010, corresponding to roughly 10.8% of the world population, and a 2018 Global Burden of Disease analysis reported more than one billion total cases
• Periodontitis is the leading cause of tooth loss in adults worldwide, and its prevalence rises with age because attachment loss accumulates over decades
• Mild to moderate periodontitis affects a large proportion of adults, while severe disease with attachment loss of 5 mm or more affects about one in ten adults globally
• Prevalence is highest in low-income and middle-income countries and in populations with limited access to oral health care, and it is strongly associated with socioeconomic disadvantage
• Men generally have higher prevalence and severity than women in large surveys, although the difference is partly explained by smoking and oral hygiene behaviours
• Smoking increases the risk of periodontitis several-fold and worsens response to treatment, and diabetes is associated with both higher prevalence and more rapid progression
• In people with diabetes, periodontitis is more severe and more likely to recur, and treatment of periodontal inflammation has been associated with modest improvements in glycaemic control
• The global burden includes tooth loss, impaired chewing, reduced quality of life and systemic inflammation, and the economic cost of periodontal care is substantial in both high-income and emerging economies

Pathophysiology

• Periodontitis begins with a dysbiotic plaque biofilm in which anaerobic gram-negative bacteria such as Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola proliferate in subgingival pockets
• The host inflammatory response, rather than bacterial virulence alone, drives tissue destruction through cytokines, matrix metalloproteinases and the RANK-RANKL system that activates osteoclasts
• Neutrophils and macrophages recruited to the gingival crevice release reactive oxygen species and proteases, and a susceptible host mounts an exaggerated response that destroys collagen and alveolar bone
• Periodontal pockets provide an anaerobic niche that protects biofilm from mechanical removal, and deepening pockets create a self-perpetuating cycle of inflammation and attachment loss
• Smoking impairs neutrophil function and gingival blood flow, diabetes promotes advanced glycation end products and inflammatory signalling, and both modify the host response rather than the bacterial challenge alone
• Periodontal inflammation is associated with systemic endothelial dysfunction and low-grade inflammation, which may explain epidemiological links with cardiovascular disease, adverse pregnancy outcomes and aspiration pneumonia

Clinical features

• Gingival bleeding on brushing or probing, redness, swelling and tenderness are early signs, and they may be painless and therefore ignored until attachment loss is advanced
• Periodontal pocket formation, gingival recession, clinical attachment loss and alveolar bone loss on radiographs are the defining features of periodontitis rather than gingivitis
• Tooth mobility, drifting, spacing and changes in occlusion occur as supporting bone is lost, and anterior teeth may migrate labially in advanced disease
• Halitosis, food impaction, dentine hypersensitivity and episodic pain are common, and acute periodontal abscess produces throbbing pain, swelling and sometimes fever
• In necrotising periodontal disease, punched-out papillary necrosis, pseudomembrane, bleeding and severe pain appear, and this pattern is more common in immunosuppression, malnutrition and smoking
• Advanced disease can lead to tooth loss, impaired mastication and speech, social embarrassment and reduced oral health-related quality of life, and these outcomes are the main patient-reported burden

Diagnosis

• Diagnosis requires a full periodontal examination with probing depth, clinical attachment level, bleeding on probing, plaque scores and assessment of furcation and mobility
• Radiographs, especially bitewing and panoramic images, document alveolar bone loss and help distinguish horizontal from vertical defects and identify endodontic involvement
• The 2017 classification assigns a stage based on severity and complexity and a grade based on progression, and the grade incorporates smoking status, diabetes and the ratio of bone loss to age
• Microbiological testing is not routine in clinical practice, because the subgingival flora is complex and treatment is guided by clinical findings rather than by a single pathogen
• The differential includes gingivitis, necrotising periodontitis, periodontitis as a manifestation of systemic disease, endodontic-periodontal lesions, drug-induced gingival overgrowth and malignancy
• Systemic assessment should document smoking, diabetes, pregnancy, immunosuppression and medications associated with gingival enlargement, because these modify both risk and treatment planning

Management

• Treatment begins with oral hygiene instruction, including effective tooth brushing, interdental cleaning and control of risk factors such as smoking and poor glycaemic control, and it follows the 2020 EFP S3 clinical practice guideline
• Scaling and root planing, performed quadrant by quadrant or under local anaesthesia, removes subgingival biofilm and calculus and is the cornerstone of nonsurgical periodontal therapy
• Systemic antibiotics such as amoxicillin combined with metronidazole are reserved for severe, necrotising or rapidly progressive disease and are used as an adjunct to mechanical debridement rather than as monotherapy
• Local delivery of antimicrobials, such as chlorhexidine chips or doxycycline gel, can reduce pocket depth at individual sites but has modest and temporary effects compared with mechanical therapy
• Surgical therapy, including flap surgery, osseous resective surgery and regenerative procedures, is considered for residual deep pockets or intrabony defects after nonsurgical treatment
• Hopeless teeth with extensive bone loss, mobility or repeated abscesses are extracted, and prosthetic replacement or implant planning should account for the patient's periodontal risk profile
• Supportive periodontal care every three to six months, with re-evaluation of probing depths and bleeding, is essential because untreated maintenance failure is a major cause of recurrence
• Risk-factor modification, including smoking cessation, diabetes management, nutrition and stress reduction, improves treatment response and should be integrated into periodontal care rather than left to other clinicians

Research and controversies

• Whether Porphyromonas gingivalis acts as a keystone pathogen that reprograms the whole biofilm or whether dysbiosis arises from a broader ecological shift is still debated and affects the design of microbiome therapies
• Host-modulation therapy, including anti-cytokine and RANKL-targeted approaches, is promising in principle but has not replaced mechanical debridement because of infection risk and cost
• The causal direction of associations between periodontitis and cardiovascular disease, diabetes and adverse pregnancy outcomes remains uncertain, and trials of periodontal treatment have not consistently shown improvement in hard systemic outcomes
• Regenerative approaches using growth factors, scaffolds and stem cells can restore some intrabony defects, but predictability varies and evidence for long-term tooth survival is limited
• Precision periodontology aims to use microbial, genetic and inflammatory biomarkers to predict progression and personalize treatment intervals, but no validated biomarker panel is yet in routine use