In a new report, the World Health Organization (WHO) has provided the first-ever comprehensive picture of oral disease burden with data profiles for 194 countries, giving unique insights into key areas and markers of oral health that are relevant for decision-makers.
Oral diseases: Apart from the five main diseases (caries of deciduous and permanent teeth, severe periodontal disease, edentulism and lip and oral cavity cancer), many other diseases and conditions are relevant for oral health. These include oral manifestations of systemic diseases (metabolic, allergic and immunologic diseases, including HIV infection); oral mucosa diseases; erosion and tooth wear; oral impacts of substance abuse; noma; congenital malformations of teeth and the enamel; viral, fungal
and bacterial infections; trauma (including physical and chemical injuries) of the teeth, jawbones and adjacent maxillofacial structures; cysts and tumours of odontogenic origin; salivary gland diseases; and disturbances in the development and growth of oral
Dental Caries: Dental caries is defined as a gradual loss and breakdown (decay) of tooth hard tissues (enamel and dentine) that results when free sugars contained in food or drink are converted by bacteria into acids that destroy the tooth over time.
Periodontal disease: Periodontal disease is a chronic inflammation of the soft and hard tissues that support and anchor the teeth. Periodontal diseases include gingivitis (gum
disease), a superficial and reversible inflammation of the gum resulting in swelling and bleeding. In the presence of other accelerating factors, such as tobacco use, systemic diseases or a compromised immune response, gingivitis may develop into periodontitis, thereby affecting the deeper gum tissues and bone. The loss of attachment (“pocket”)
eventually leads to increased mobility and tooth loss. Only severe periodontal disease, defined as the presence of a pocket of more than 6 mm depth, is a condition of public health concern.
Severe tooth loss and edentulism: A person is said to suffer from severe tooth loss when fewer than nine teeth are remaining in the mouth, which includes complete toothlessness, or edentulism.
Oral Cancer: The umbrella term oral cancer includes malignant neoplasms, predominantly squamous cell carcinomas occurring in the mucosa of the lips and oral cavity (tongue, upper and lower gums, floor of the mouth, palate and other parts of the mouth), corresponding to the International Classification of Diseases (ICD-10) codes C00–C06. The IARC groups lip and oral cancers together under the generally used term oral cancer, yet they are cancers with distinct epidemiological and clinical profiles.
About 3.5 billion people worldwide were affected by oral diseases in 2019, making them the most widespread conditions among the more than 300 diseases and conditions that affect humanity.
Among the major oral diseases, untreated caries of permanent teeth is the
most prevalent with around 2 billion cases, severe periodontal disease follows with around 1 billion cases, then untreated caries of deciduous teeth with about 510
million cases and edentulism with 350 million cases (all in 2019).
The combined estimated number of cases of oral diseases globally is about 1 billion higher than cases of all five main NCDs (mental disorders, cardiovascular disease, diabetes mellitus, chronic respiratory diseases and cancers) combined.
Three quarters of people affected by oral diseases live in lower- and upper-middle income countries, followed by 16% in high-income countries and 9% in low-income countries.
Between 1990 and 2019, estimated case numbers of oral diseases grew by more than 1 billion – a 50% increase, higher than the population increase of about 45% during the same period.
Common Determinants and risk factors of oral diseases
Social and political determinants of oral health:
The underlying causes of oral health inequalities are often complex and related to country-specific historical, economic, cultural, social or political factors. The conditions in which people are born, grow, live, work and age and the structural drivers of those conditions – the inequitable distribution of power, money and resources in society – are the underlying social determinants of oral health inequalities.
Commercial determinants of oral health:
Commercial determinants of health are the corporate-sector activities that affect people’s health positively or negatively. Corporations, often with transnational or global reach, are promoting products that are detrimental to population health, particularly in the areas of NCDs and oral health. The global tobacco and alcohol industries are prime examples that increasingly target emerging economies in low- and middle-income countries or particularly vulnerable population groups.
Common risk factors for NCDs and oral diseases
The common risk factor approach recognizes that noncommunicable diseases and conditions, including oral diseases, share a set of key modifiable risk factors. For example, tobacco use is a major risk factor for a range of conditions, such as cardiovascular diseases, respiratory diseases and many cancers, but also for severe periodontal disease and lip and oral cavity cancer. The common risk factor approach is
the basis for linking action on oral disease prevention with the wider NCD agenda. This can be seen most notably in relation to the integrated action on improving poor diets, tackling tobacco use and reducing harmful alcohol consumption.
High sugar intake, all forms of tobacco and harmful alcohol use are major public health challenges for a wide range of NCDs. They are also the key modifiable risk factors for oral diseases.
Sugar consumption is the main cause of dental caries, showing a clear dose–effect relationship.
Despite overall reductions, 22.3% of the global population were estimated to use some forms of tobacco (2020).
An estimated 1.3 billion people aged over 15 years consume alcohol at harmful levels (above non-drinker equivalence, 2020), with the highest rates found across Europe, the Americas and the Western Pacific region.
Prevalence rates of four major oral diseases over the life course
Oral diseases affect individuals and populations across the entire life course (see Fig. below). The main oral diseases impair different age groups in specific ways. Deciduous teeth are prone to caries as soon as they erupt, with a peak of prevalence around the age of 6. Similarly, prevalence of caries in permanent teeth typically shows steep increases after eruption and reaches the highest levels in late adolescence and early adulthood before remaining stable for the rest of the lifetime. Severe periodontal
disease is a disease of middle age, reaching highest prevalence rates around 60 years. Edentulism (total tooth loss) steadily increases with a peak in older age groups.
Selected impacts of oral diseases
The cost of oral health care:
The total direct expenditure for oral diseases among 194 countries amounted to US$ 387 billion or a global average of about US$ 50 per capita in 2019. This represents about 4.8% of global direct health expenditures. At the same time, productivity losses from oral diseases were estimated at about US$ 42 per capita, totalling to around US$ 323 billion globally.
Link to the WHO news release:
Link to the new WHO report: