An Overview of Patterns and Trends in Oral and Dental Diseases

An Overview of Patterns and Trends in Oral and Dental Diseases

Jenny Gallagher


What do people from different parts of the world have in common (Figure 2.1)? They will almost all suffer from one or more oral diseases at some stage in their lives, diseases that are largely preventable. As a result they will require oral and dental care. Some will be fortunate and receive high‐quality dental care in a timely manner; others will not, continuing to suffer either from the symptoms of disease or at the hands of non‐qualified personnel in its treatment. As dental professionals, we should do everything possible to improve oral health and to ensure equitable access to oral healthcare for everyone in the world. Getting to grips with patterns and trends in oral health can assist us with this challenge and help us think through our roles and responsibilities. Even in high‐income countries with well‐developed dental services many adults suffer from urgent conditions and the impact of disease.

Illustration of a globe with different flags illustrating global connections.

Figure 2.1 Global connections.

Source:‐World‐Flags‐Globe.svg. Public Domain.

Why Is It Important to Examine Population Oral Health?

Why should clinicians who are largely concerned about the health of individuals be concerned with the health of populations? And the global population at that? Why not skip this chapter to discover more about the business of dentistry given that as dental professionals we are largely trained to identify and treat disease? Can I suggest a few reasons to explore these issues in more detail?

First, we are health professionals and therefore have a professional responsibility to be advocates for oral health and the patients whom we serve. Many think of dentistry as a business and, taking that approach, any business needs to understand the market, which for dentistry includes the population whom we serve, their health trends and the determinants of health. This will equip us better in our overarching goal to improve oral health – the ultimate business of dentistry.

Second, they can act as a mirror to our professional action. As dentists we become absorbed in minutiae; trained to consider details, we often fail to stand back and look at the big picture. Once in a while it is helpful to do so. One example which had a particular impact on me was the story of an epidemiologist who visited the same schools in England at regular intervals to undertake surveys of dental caries in 12‐year‐old schoolchildren during the period when oral health was improving. The team identified that caries prevalence (numbers of Decayed, Missing and Filled Teeth = DMFT) was not reducing in one school and they explored why this was the case. It came down to the fact that the local dentist was using an outmoded treatment approach and the profile of fillings in primary molars, the ‘F’ component, was excessive. Once one first permanent molar became —carious, there was the assumption that all would do so. After discussions with that dental practice, the pattern of treatment changed and, interestingly, so did the epidemiology statistics for that school. So this reminds us that monitoring trends in oral health has wide implications including informing the practice of appropriate dental care in support of oral health.

Third, global mobility means that clinicians are increasingly faced with new patient groups from different parts of the world. Furthermore, clinicians themselves may take the opportunity to work in different countries during their professional careers. Data on oral health are available from many countries across the globe and within countries. Even within the UK there is significant variation between different geographic areas. An understanding of population health information helps us to better understand the risk factors amongst different communities and their impact on oral health. For example Chinese populations have a higher prevalence of nasopharyngeal cancer (Yu and Yuan, 2002; Donaldson et al., 2012) and Bangladeshis have a higher rate of oral cancer (Efroymson et al., 2001; Donaldson et al., 2012), associated with viruses and cultural health behaviours respectively.

Fourth, and finally, consideration of trends in oral health and the determinants of health should therefore empower us to challenge environmental factors in culture, society and politics in support of health and inform our provision and planning of oral and dental care to individuals. This is the best way to promote health and address inequalities. Given the importance of promoting health and preventing disease, this chapter therefore links closely with Chapter 7 on prevention of oral diseases.

This chapter will provide you with an overview of global oral health patterns and trends and consider the public health implications for us as health professionals wherever we practise. As an introduction to considering trends and patterns in oral health, it is important to start first with the demography or composition of the global population.

The Global Population

It is staggering to consider how the world is changing in our lifetime. The global population has doubled in the past 50 years and will continue to expand exponentially. Between 2011 and 2050, the world population is expected to increase by 2.3 billion, from 7.0 to 9.3 billion (United Nations, 2011). Websites such as‐population‐pyramid show how the age‐based population pyramid changes over time from a traditional pyramid with a large base towards a more rectolinear shape.

We each view the world map from our physical perspective – usually our country is centre stage– but also in relation to land mass (Figure 2.2); however, the global population is not evenly distributed, as demonstrated by Figure 2.3 which cleverly adapts the land mass to represent population size, providing us with a startling view of the world.

Image described by caption and surrounding text.

Figure 2.2 Global perspective: land area.

Source: © Copyright / Sasi Group (University of Sheffield) and Mark Newman (University of Michigan).

Image described by caption and surrounding text.

Figure 2.3 Global perspective: total population (population cartogram).

Source: © Copyright / Sasi Group (University of Sheffield) and Mark Newman (University of Michigan).

In more developed regions of the world, the majority of the population live in cities whilst in less developed regions the majority live in rural populations; however, this is predicted to change as outlined below.

The population living in urban areas is projected to increase by 2.6 billion, rising from 3.6 billion in 2011 to 6.3 billion by 2050 (United Nations, 2011). The United Nations (UN) also suggest that the rural population is projected to decrease from 3.1 to 2.9 billion over the same time period. Therefore, the urban areas of the world are expected to absorb all the anticipated population growth over the next four decades while at the same time drawing in some of the rural population. There are currently 23 megacities (>10 million) and by 2025 this is expected to increase to 37. By 2025, the population living in megacities is expected to reach almost 8% of the overall world population; one in 13 people globally will then reside in a megacity (United Nations, 2011).

According to UN reports, most of the predicted growth will be absorbed by developing countries (United Nations, 2011). Whereas between 2011 and 2050 the population of the more developed regions will remain largely unchanged at 1.3 billion inhabitants, the population of the less developed regions is projected to rise from 5.7 billion in 2011 to 8 billion in 2050. At the same time, the population of the least developed countries is projected to more than double from 851 million inhabitants in 2011 to over 1.7 billion in 2050. Consequently, by 2050, 90% of the world’s population is expected to live in the less developed regions, including 18.6% in the least developed countries, whereas only 14% will live in the more developed regions (Figure 2.4).

World map displaying the global population prediction: 2050.

Figure 2.4 Global population prediction: 2050.

Source: © Copyright Sasi Group (University of Sheffield) and Mark Newman (University of Michigan).

To properly interpret the significance of health trends it is really important to consider the size and distribution of the population within our geographical sphere of work. Relatively low levels of disease in a large population may represent a much bigger challenge than high levels of disease in a small population, particularly because many larger countries tend to be less affluent at present and have less well developed health promotion and treatment services.

Oral Health

A recent definition from the World Dental Federation (FDI) highlights that ‘oral health is multifaceted and includes the ability to speak, smile, smell, taste, touch, chew, swallow, and convey a range of emotions through facial expressions with confidence and without pain, discomfort, and disease of the craniofacial complex’ (Glick et al., 2016).

Poor oral health can limit the ability to eat, speak and socialise. Oral diseases are largely preventable and yet remain common in most societies across the lifespan (WHO, 2012a). Within any community, there is great diversity of oral health by age, gender, geography and socio‐economic status, as well as changes over time. Diseases and conditions that threaten oral health may be considered a ‘silent epidemic’ affecting our most vulnerable citizens in society (Benzian, Monse and Helderman, 2011).

Oral Health Needs

This chapter focuses on oral health needs globally as well as some local examples, particularly from the UK. ‘Need’ is a concept that requires some ‘unpacking’. Bradshaw’s taxonomy provides a simple overview of the concept of ‘need’ (Bradshaw, 1972) and has remained an important concept in health and social care over recent decades (Cookson, Sainsbury and Glendinning, 2013). Bradshaw described different types of need as normative, expressed and perceived, as outlined in Table 2.1.

Table 2.1 Bradshaw’s taxonomy of need.

Type of need Definition Example of how this need is measured
Normative need Need that is defined by experts. Normative needs are not absolute and there may be different standards laid down by different experts. Epidemiological surveys
Felt need Need perceived by an individual. Felt needs may be limited by individual perceptions and knowledge of services. Quality of life indicators
Expressed need or Demanded need Felt needs turned into action.
Help seeking.
Uptake of dental care (emergency and routine)
Comparative need Individuals (or populations) with similar characteristics to those receiving help. Comparison between areas and populations

Adapted from Bradshaw, 1972.

Oral health needs, as considered from the clinician’s perspective, or that of an epidemiologist, are termed ‘normative’ need. In public health circles, when we describe oral health and oral health trends we generally use epidemiological data that report the clinical epidemiologist’s perspective on need. Examples include the wealth of data collected in national decennial surveys (The Information Centre for Health and Social Care, 2011a), or by the public health service in England (Public Health England, 2014). In more recent years we have begun to place more emphasis on perceived oral health with the development of special questionnaire instruments to measure the impact on health and wellbeing for which there is a raft of measures such as the Oral Health Impact Profile (Slade and Spencer, 1994). Expressed oral health needs tend to be measured as the level of uptake of dental care, i.e. the use of dental services. None of these measures alone provides a perfect overview of oral health, but together they contribute a population profile that can assist in setting targets for improvement. Comparative need is the difference between two populations. In addition to the above, ‘unmet need’ is the difference between perceived and expressed need.

At an individual patient level, the same applies. Patients may perceive a need and complain of pain and express their need by attending for dental care, whilst others may suffer pain or discomfort without expressing their need (unmet need). When we as clinicians identify the presence of dental caries following clinical and/or radiological examination, this is evidence of ‘normative need’, which may or may not relate to perceived need.

As with individual patient care, it is important to understand the needs of the population, their help‐seeking behaviour and how they are changing over time.

Chapter Aims

Having set the scene by examining the importance of understanding our population and their health needs, the aims of this chapter are as follows: first, to outline very briefly how oral health is measured, and provide examples of oral health surveys; second, to describe key trends and patterns in oral diseases and conditions; third, to highlight inequalities in health and wellbeing; and fourth, to explore the implications of these oral health trends for policy makers and clinicians.

Surveys of Oral Health – Epidemiology

Epidemiology can help to answer some important questions. What are the trends and patterns of oral health? What sections of society are most affected? What are the risk factors for the disease or condition? This includes social, physical, behavioural and genetic factors. Epidemiology is the study of disease or condition (logos) upon (epi) a population (demos) and has been defined by Mausner, Kramer and Bahn (1985) as ‘the orderly study of diseases and other conditions in human populations where the group rather than the individual is the unit of interest’.

Unlike many aspects of general health, oral disease and morbidity can be measured directly. However, this is an expensive process as it generally involves using dentists, and support staff who have been trained and calibrated, to undertake epidemiological surveys. Epidemiologists first need to be trained to measure dental disease according to set criteria so that when we consider trends over time or compare one survey finding with another we can be reasonably confident that we are comparing like with like. Epidemiological surveys of oral health generally involve dental examinations of a representative or random sample of the population. Most of our data come from cross‐sectional surveys and thus reflect the prevalence of a disease or condition. Cross‐sectional studies give us a snapshot in time, and trends over time may be inferred from regular cross‐sectional studies in the population. Longitudinal studies are particularly important to look at changes over time but are much more difficult and expensive to conduct given population mobility. They can, however, provide rich data on the incidence rate of a disease, i.e. the number of new cases per population at risk in a given time period. A good example of a current longitudinal study which is providing the global dental community with important and interesting findings is the Dunedin study in New Zealand, where the birth cohort of 1972–73 has been followed up regularly over the decades (Dunedin Health and Multidisciplinary Research and Development Unit, 2014). Great effort is made to follow up as many people as possible, even those who have left the country. The findings are reviewed at key points in this chapter.

Some studies will combine an epidemiological survey or normative needs assessment with a questionnaire survey to explore perceived needs, thereby providing a better overview of the population’s oral health. Where resources permit, this may be undertaken in conjunction with questionnaire surveys which examine perceived oral health and wellbeing, the impact of oral disease and health behaviours. The latter include diet, oral hygiene, tobacco, alcohol, fluoride use and dental attendance.

A wide range of oral diseases is measured by means of epidemiological surveys including those listed in Table 2.2. From the data collected, other dimensions of oral health may be reported such as edentulousness, having ‘excellent’ oral health or a ‘functional dentition’, as explored in later sections of this chapter. Other conditions such as cancers tend to be measured through health services data, both from registries (all cancer data have to be shared with the national cancer registry) and routine activity data where diagnoses are part of the data set.

Table 2.2 Data sources on the prevalence of oral diseases and conditions.

Epidemiological surveys Health services registry and activity data
Dental caries Cancers (oral, oropharyngeal, etc.)
Periodontal diseases Cleft lip and/or palate
Tooth wear Noma
Fluorosis HIV/AIDS
Trauma to teeth
Orthodontic need
Other, e.g. soft tissue abnormalities

As one would expect, the most commonly measured diseases are the most prevalent: dental caries and periodontal diseases. The World Health Organization (WHO) global oral health database is currently held by Malmo University,, and the periodontal database in Japan, on behalf of WHO/FDI, www.dent.niigata‐ They provide a very useful, but sadly sometimes outdated, source of information, either because national surveys have not been undertaken, or not reported to the WHO. Additionally the FDI is launching a new oral health observatory app on which it is possible to look at available data by country:

National statistics on oral health need to be treated with caution because they are not all collected at the same time and may not be fully representative of their country, depending on whether they come from a national survey involving a random sample of the population or a local survey of a particular area. They may include data on age ranges rather than one specific age. Whatever data are presented, we recognise that even within one country patterns of oral health will vary greatly, so even where data are representative of the national picture, they are average values and will not reflect the variation within society. Therefore clinicians may find themselves practising in areas where disease levels are higher or lower than the national average.

The incidence and prevalence of other serious conditions such as oral cancer are measured in high‐income countries, such as the UK, by means of data from cancer registries, and supplemented by information from health services. Similarly, there is also registration of cleft lip and palate and HIV/AIDS which require formal reporting, thus providing robust information at local and national levels. In low‐income countries the incidence may be estimated based on hospital activity and registries in the urban areas only. Hence, many of these diseases and conditions are likely to be under‐reported and the incidence and prevalence likely to be much greater than the statistics suggest. For example, information on oral cancer in India only exists for patients who attend urban hospitals, whilst many attend only rural hospitals, or none. Global data must therefore be interpreted in light of data quality as outlined in subsequent sections.

Challenges of Measuring Oral Diseases and Conditions


Epidemiology is generally undertaken for population rather than direct individual benefit. People are encouraged to take part for the good of society. Thus, it is important that the data from epidemiological surveys or questionnaire surveys are used to inform the planning of oral health services including health promotion. A further ethical consideration is that individuals taking part in epidemiological examinations should have the opportunity to have any serious oral health needs addressed appropriately; thus, all survey protocols should outline how someone with an acute or serious lesion will be facilitated to access care in a timely manner.


Population studies are rarely conducted as they are expensive and generally not necessary; instead a representative sample is selected. Sampling of populations is informed by science but requires practical consideration of which sections of the population may be measured and where. There is always consideration of keeping costs to a minimum whilst ensuring that the sample is large enough to be representative but selected in a random manner. Hence, the majority of what is known about common oral diseases and conditions comes from cross‐sectional studies involving a random sample of the population. It is always worth checking if nationally available data come from a national or a local sample randomly selected or merely a convenience sample; and also whether there have been power calculations to check if the sample size is sufficient. This will provide an indication of its representativeness. Birth cohort studies involve following up a specific section of the population, e.g. the birth cohort of 1972–73 in Dunedin, New Zealand (Dunedin Health and Multidisciplinary Research and Development Unit, 2014), or the Avon Longitudinal Study of Parents and Children (ALSPAC, 2014), both of which are population‐based, prospective cohort studies, with an important oral health component.


Table 2.3 shows the most common indices of oral health used in surveys, of which dmft/DMFT is the most frequently used. Dental caries has been measured by epidemiologists and clinicians counting the number of decayed [dt or DT], missing [mt or MT] and filled [ft or FT] teeth. This provides a composite score or number of affected teeth. This index was first described by Klein and colleagues in 1938 and adapted by the World Health Organization in 1986. It has been universally used in dentistry and advocated by the WHO in their ‘Survey Methods’ (WHO, 2013a).

Table 2.3 Epidemiological indices by disease and condition.

Diseases and conditions Index name (abbreviation) Reference
Authors Year
Dental caries deft/defs: primary dentition (usually younger children)
d – decayed
e – tooth indicated for extraction
f – filled
t – teeth
s – surfaces of the teeth
Gruebbel 1944
dmft/dmfs: primary dentition
d – decayed
m– missing
f – filled
t – teeth
s – surfaces of the teeth
H. Klein,
C.E. Palmer, and
J.W. Knutson
Modified by WHO
DMFT/DMFS: permanent dentition
D – decayed
M– missing
F – filled
T – teeth
S – surfaces of the teeth
H. Klein,
C.E. Palmer, and
J.W. Knutson
Modified by WHO
Root caries index R.V. Ratz 1979
Significant caries index D. Bratthall 2000
Care index = FT/DMFT% n/a n/a
The International Caries Detection and Assessment System, or ICDAS, is a simple, logical, evidence‐based system for detection and classification of caries in dental education, clinical practice, dental research, and dental public health Ismail et al. 2007
Periodontal diseases Periodontal index A.L. Russell 1956
Gingival index (GI) J. Silness and
H. Loe
Plaque index (PI) H. Loe and
J. Silness
Community Periodontal Index of Treatment Needs (CPITN) World Health Organization (WHO)
Dentaire Internationale (FDI)
IOTN – Index of Orthodontic Treatment Need P.H. Brook
W.C. Shaw
PAR Index – Peer Assessment Rating S. Richmond et al. 1992
ICON – Index of Complexity, Outcome and Need C. Daniels and
S. Richmond
Tooth wear Eccles index for dental erosion of non‐industrial origin J.D. Eccles 1979
TWI – tooth wear index B.G. Smith
J.K Knight
Lussi’s index for erosion A. Lussi 1996
O’Sullivan index E.A. O’Sullivan 2000
Simplified TWI (tooth wear index) P.F. Bardsley,
S. Taylor and
A. Milosevic
Basic erosive wear examination (BEWE).‐background/erosion‐diagnosis/basic‐erosive.html Bartlett et al. 2008
Fluorosis Dean’s index H.T. Dean 1934
TF Index – Thylstrup and Fejerskov’s index for fluorosis A. Thylstrup
O. Fejerskov
Horowitz et al. index of fluorosis H.S.Horowitz, W.S. Driscoll,
R.J. Meyers,
S.B. Heifetz,
A. Kingman
Dental trauma Trauma index: developed during Child Dental Health Survey in the UK M. O’Brien 1993

Lower case ‘dmft’ denotes the primary dentition and upper case the permanent dentition; dmft/DMFT numerically expresses caries prevalence and is obtained by calculating the number of affected teeth at ‘tooth’ or ‘surface’ level. If the data relate to tooth surfaces, then they are reported as dmfs or DMFS and teeth dmft or DMFT. In countries where caries prevalence is high, the simple measure of dmft/DMFT is sufficient. The index does have a number of limitations in that caries is cumulative and therefore it is less helpful in adults than in children, particularly when teeth have been extracted.

Indices for measuring dental caries are undergoing further development: where caries levels are lower, there is increasing emphasis on developing more sophisticated dental indices to measure the depth and extent of dental caries, and to link the index to clinical care. Where disease levels are low and careful planning of both preventative and treatment services is required, it is important to begin to explore the use of more sophisticated clinical indices. An increasingly used index in clinical care is ICDAS, which may also be used as an epidemiological tool. ICDAS is the International Caries Detection and Assessment System (ICDAS Foundation, 2014), which is a ‘system for detection and classification of caries in dental education, clinical practice, dental research, and dental public health’.

Historically, the majority of surveys of oral health worldwide have been conducted in schoolchildren for the following reasons. First, because most children attend school, they are the easiest section of the population to identify and access. Second, given that oral disease is one of the most prevalent conditions in children, it is important to measure in childhood, before (5 or 6 years) and after (12 or 14/15 years) they develop their permanent dentition. Third, it is important to inform action such as oral health promotion and plan healthcare so that children are given the best start in life with healthy lifestyle and free from disease. This is particularly important because much oral disease is cumulative and patterns of oral health are established at an early age. However, as all countries have an ageing population it becomes increasingly important to understand and reflect on how best to address the various sub‐groups, giving increasing importance to the oral health needs of the older population (Petersen and Yamamoto, 2005). Cohort studies in high‐income countries are now suggesting that older people are a caries‐active group, experiencing new disease at a rate which is at least as great as that of adolescents (Thomson, 2004).

Training and Calibration

Much effort goes into planning an oral health survey. It is important to develop a clear written protocol for the study and ensure that all those administering a survey are trained in the criteria for diagnosing and recording diseases and conditions. Once staff have been trained then they need to be calibrated against a ‘gold standard’, to assess how accurately they use the survey criteria. Epidemiologists need to be reliable both internally and externally. Their findings should correlate with the ‘gold standard’, thus confirming that they are externally reliable. Internal consistency is demonstrated by re‐examining a sub‐sample of subjects (usually 10%), and comparing the scores to determine their level of consistency.

Surveys of Health and Wellbeing

Increasingly, information on the perceived needs of populations’ oral health and wellbeing is being collected. This involves using quality of life surveys, often as part of a general or oral health survey. One of the most popular indices is the Oral Health Impact Profile; the main measure has 49 items (Slade and Spencer, 1994), and the short‐form OHIP‐14 has 14 (Slade, 1997). It is one of the most common measures used in national surveys (Nuttall et al., 2006; The Information Centre for Health and Social Care, 2011b).

How Are Data Used?

Epidemiological and quality of life data may be used in the planning of oral health services and preventive programmes. One of the most dramatic uses of epidemiology in the last century was the study of fluoride in water by Trendley Dean, who in his ‘21 cities study’ identified the optimal level of fluoride in water to reduce dental caries whilst minimising the level of fluorosis and therefore bring great benefit to oral health; a good example of public health initiatives (Murray et al., 2003).

Evidence of poor oral health, obtained through population surveys, can stimulate action on tooth brushing and application of fluoride varnish in schools, together with action to improve the uptake of dental care, as with the Childsmile programme in Scotland (NHS Scotland, 2014). However, in many countries without state funded dental services there is not always such obvious use of information for planning dental care because of the way dentistry is organised and delivered – largely as a business. However, as outlined in the introduction, the use of epidemiology and health service data to demonstrate unmet need can be extremely helpful when considering where to invest existing time and resources and perhaps gain additional resources to address problems.

How Does Epidemiology Differ from Screening?

Sometimes there is confusion between screening for oral disease and epidemiology – often because the two have historically been combined for schoolchildren. Screening has been defined as ‘A public health service in which members of a defined population, who do not necessarily perceive they are at risk of, or are already affected by a disease or its complications, are asked a question or offered a test, to identify those individuals who are more likely to be helped than harmed by further tests or treatment to reduce the risk of a disease or its complications’ (UK National Screening Committee, 2014). Essentially epidemiology is primarily conducted for the benefit of the population, and screening for the benefit of the individual. People testing positive at screening are sent for an examination and further investigations.

In dentistry, oral screening for dental caries or cancer generally involves a visual examination to determine if there is possible disease, which means it is easy to get epidemiology and screening confused.

Global Oral Health

The World Health Organization (WHO), working closely with the World Dental Federation (Fédération Dentaire Internationale, or FDI), plays an important role in monitoring oral health. This involves producing a manual, Oral Health Surveys – Basic Methods, which is now in its fifth edition (WHO, 2013a). This guidance, which includes advice on pathfinder surveys, is available online via WHO publications. The WHO manual has encouraged countries to conduct standardised oral health surveys that are comparable internationally. It facilitates development of procedures for management and analysis of data based on the use of information technology. The findings of national surveys are lodged in the Global Oral Health Data Bank, which is an important component of the Country/Area Profile Programme information system.

Because there may be so much difference in oral health within a population, it is important to ensure that there are robust data on key age groups to enable comparison over time and across countries. The key age groups as advised by the WHO (2013a) are:

  • 5 years: dental caries in primary teeth (or later if children start school at 6 or 7 years).
  • 12 years: dental caries in secondary teeth.
  • 15 years: dental caries in secondary teeth.
  • 35–44 and 65–74 years for dental caries in permanent teeth and periodontal disease.
  • 65 years and over: edentulousness.

Pathfinder survey methods outlined by the WHO (2013b) are designed to assist those beginning epidemiological work in a given country and to assist in planning the provision of oral healthcare or further survey work and thus provide a practical, economic survey sampling method. A pathfinder survey is a stratified cluster sampling technique of key age groups. The sites are usually based on administrative districts and include the most important population sub‐groups likely to have different disease levels. For example, a sample design for a national pathfinder survey for each ‘index age’ as shown in Box 2.1 may include 300 per group.

At the time of writing there are 196 countries in the world. Countries are encouraged to report their epidemiological findings centrally. The WHO oral health databank contains information on the oral health of many countries for certain diseases and the key age groups. The most common data held relate to dental caries in 12‐year‐olds. Data on 12‐year‐olds are available for over 90% of countries worldwide, There are some data on periodontal diseases in adults, www.dent.niigata‐, and oral cancer data are available through Cancer Today at

What Do We Learn from Countries with Surveys of Oral Health?

The following sections will examine oral health using a series of markers relating to the common oral conditions as well as perceived oral health. Each section will examine global information on the size of the problem, as well as reviewing risk factors and interesting facts. Each section will conclude with consideration of the relevant global targets for oral health which should be formulated at country level (Hobdell et al., 2003a) to reflect the local disease levels rather than having the same targets for all. Finally, each section explores the challenges for those of us who seek to promote oral health.

The most basic of marker of oral health, and the easiest to measure, is whether people have retained any natural teeth; this will be considered first.


Becoming edentate is the ultimate marker of dental morbidity and has significant implications for general health and wellbeing. Interestingly, as surveys of adults are less common than those of children, there are limited data on edentulousness worldwide.

Size of the Problem

The CAPP (WHO/FDI) database has information on adults of 65 years and over (CAPP, 2014a). Looking across global oral health data, it is clear that relatively few countries (n = 56) have conducted surveys of adults in older age groups and that data that are available cover several decades, thus the findings are not directly comparable. Furthermore, there is little indication of the extent to which the data are representative of the population as a whole. Nonetheless, there are some interesting findings and the variation in reported levels of edentulousness is marked across continents and countries. Looking at the countries listed – and absent – Europe has more data (57% of the listed countries are European) (CAPP, 2014b) and higher levels of edentulousness, whereas Africa (CAPP, 2014c) has much less data coverage.

Although the global picture on edentulousness must be viewed with caution, total tooth loss appears to be common in high‐income countries with a western diet and many dentists (Figure 2.5). The USA is a notable exception where edentulousness is low; this may be related to widespread water fluoridation which has benefits for all age groups in the population.

Graph illustrating edentulousness in adults aged 65 years and over, displaying bars (percent of the affected) representing Iceland, Turkey, Netherlands, Saudi Arabia, Sri Lanka, Lebanon, South Africa, etc.

Figure 2.5 Edentulousness in adults aged 65 years and over.

Adapted from CAPP. Oral Health Country Area Profile Project, 2014a.

Trends in Edentulousness

Countries which have a wealth of epidemiological data on edentulousness over time present an interesting story. They suggest that levels of edentulousness, which were highest in the latter part of the twentieth century, are falling. For example in the UK, edentulousness has fallen from 29% to 6% in just three decades (1978–2009); however, many people who lost all their teeth are still alive and so we see high levels of edentulousness in older people (Kelly et al., 2000). Who removed all their teeth? For the majority this involved professional intervention by dentists. Within the UK, the odds of being edentate have been shown to be almost nine times higher for those adults with no qualification and four times higher for those with qualifications below degree level. Being from the north of Great Britain was also a factor that had an effect, with the odds of having no teeth rising as distance from the south of England increased (Treasure et al., 2001).

Trend analysis in the USA highlights that is also now a rare condition in high‐income households, and it has contracted geographically to states with disproportionately high poverty. Thus, with the passing of generations born in the mid‐twentieth century, ‘the rate of decline in edentulism is projected to slow, reaching 2.6% (95% prediction limits: 2.1%, 3.1%) by 2050’ (Slade et al., 2014). Slade et al. suggest that the continuing decline will be offset only partially by population growth and population ageing such that the predicted number of edentulous people in 2050 (8.6 million; 95% prediction limits: 6.8 million, 10.3 million) will be 30% lower than the 12.2 million edentulous people in 2010 (Slade et al., 2014).

Looking back, it is clear that some of the dental profession were practising within the focal infection paradigm and were of the view that all pain and sepsis could be avoided by the removal of all teeth. This occurred without thought of the pain and discomfort and social embarrassment associated with long‐term denture wearing. This view was also accepted by the local population. For example within certain regions of the UK, most notably the north of England (Treasure et al., 2001; Steele et al., 2000), where edentulousness is highest, women were provided with a dental clearance and complete dentures for their twenty‐first birthday present or as a wedding present from parents – just in case the husband‐to‐be could not afford to provide for his wife!

Risk Factors for Edentulousness

The main risk factors for edentulousness appear to be extensive disease, particularly dental caries, and demography (age, educational and social status), together with professional practice and population norms regarding appropriate dental care. Surveys around the world suggest that periodontal diseases are less often a cause of total tooth loss than one might expect.

The philosophy or paradigm in which dentists are practising and available facilities will contribute to the care available, together with patient behaviour in seeking regular care or preferring to attending later in the disease process when they are ‘in trouble’.

Interesting Facts Regarding Edentulousness

  • There is national level evidence in Great Britain from older people’s national diet and nutrition survey that maintaining a natural and functional dentition (defined as having more than 20 teeth into old age) plays an important role in having a healthy diet rich in fruits and vegetables, a satisfactory nutritional status, and an acceptable body mass index (BMI) (Marcenes et al., 2003).
  • Edentulous adults are less likely to attend dental services as they do not perceive a need for dental care (Kelly et al., 2000).

Global Targets

Suggested goals for oral health relating to edentulousness are outlined in Box 2.2.

Meeting the Challenge – So What Do We Do?

As oral health improves (The Information Centre for Health and Social Care, 2011c), edentulousness is increasingly not a useful marker of oral health, thus other markers of health are being tested such as having positive attributes, e.g. ‘functional dentition’ or ‘excellent oral health’ (The Information Centre for Health and Social Care, 2011c), or negative markers, e.g. ‘PUFA’, or ‘high complexity’. All of these markers recognise improvements in oral health and that adults will retain some or all of their natural teeth into older age and probably for life.

Where information on edentulousness is collected, given the ageing global population, it is important to ensure that data are collected and reported by age band including older people aged 65 years and over so that there is greater understanding of those in need. The data from high‐income countries such as the UK (The Information Centre for Health and Social Care, 2011c) suggest that edentulous adults are increasingly old, therefore special domiciliary denture services may be required for older and more vulnerable house‐bound people.

Reflecting on history, it is really important that we as a profession think about the paradigm underpinning our patient care, moving away from a merely restorative and surgical approach to ensure that dental caries is managed preventatively and conservatively (Baelum et al., 2007; Fejerskov et al., 2013).

Functional Dentition

It is important that adults retain the ability to eat, speak and socialise throughout life. There is evidence that having 20 or more natural teeth enables dentate individuals to eat what they want in comfort, without the need for partial dentures; this is known as having a ‘functional dentition’(Gotfredson and Walls, 2007). Within the UK, 21 or more teeth, or two thirds of the permanent dentition, is used as the marker for having a ‘functional dentition’, with patients having a ‘shortened dental arch’. In 2009, 86% of dentate adults across England, Wales and Northern Ireland were reported as having a functional dentition (21 or more natural teeth). Furthermore, whilst almost all young adults had a functional dentition, this reduced with age.

Interesting Facts about Functional Dentition

There is national level evidence from a national diet and nutrition survey that maintaining a natural and functional dentition, which is defined as having 20 or more teeth into old age, plays an important role in having a healthy diet rich in fruits and vegetables, a satisfactory nutritional status, and an acceptable body mass index (BMI) (Marcenes et al., 2003).

Global Targets

Suggested targets in relation to achieving a functional dentition are outlined in Box 2.3.

Meeting the Challenge

Retaining a functional dentition, ideally with opposing pairs of teeth, must as far as possible become a long‐term goal of patients and clinicians, at least where there are resources to do so.

Excellent Oral Health

The UK Adult Dental Health Survey 2009 instituted a category of ‘excellent’ oral health for the first time, defined by five features (The Information Centre for Health and Social Care, 2011c):

  • Number of teeth – 21 or more natural teeth.
  • Number of sound and untreated natural teeth – 18 or more.
  • Decay – no decay at any site.
  • No periodontal loss of attachment (LOA) >4 mm.
  • No bleeding or calculus.

Overall, 10% of the adult population were reported as having excellent oral health, ranging from 23% of 16 to 24‐year‐olds through to only 5% of adults in the 45 to 54‐year‐old age group (The Information Centre for Health and Social Care, 2011c); only 1% of those aged over 55 years were recorded as having excellent oral health. As with improvements in functional dentitions, this marked transition could be associated with access to fluoride whereby older adults, who did not have access to fluoride when their adult dentition was emerging, did not have as much protection against dental caries. Adults aged 45 years and below will have benefitted from fluoride in products such as toothpaste and/or water in retaining their natural dentition, together with changes in caries management (Baelum et al., 2007; Fejerskov et al., 2013). Despite decades of improvements in oral health, it is still salutary to realise just how few adults have good oral health.

Global Targets for Oral Health

There are no global targets relating to excellent oral health. However, this is something that should actively be considered by clinicians and patients, from childhood onwards, as oral diseases, particularly dental caries, are cumulative.

Meeting the Challenge

Patients’ expectations are rising, particularly in high‐income countries and amongst socially affluent individuals (Clow, Fischer and O’Bryan, 1995). Retaining excellent oral health into adult life is clearly possible as highlighted above, but maintaining this state through adult life and into older age increasingly becomes a challenge for individuals in relation to their self‐care and wider psychosocial and environmental conditions.

Clinicians should be encouraging those with good oral health to maintain excellent oral health. It is notable amongst children and young people that more lesions will arise in the section of the population who appear to be disease free, i.e. ‘low risk’, than in those who are ‘high risk’ (Batchelor and Sheiham, 2002, 2006). However, wider environmental influences can support or detract from oral health so not everything is as much under the control of individuals as we would like to think. Our behaviours are heavily influenced by environmental, cultural and social norms.

Urgent Conditions

The last UK Adult Dental Health survey reported on ‘urgent’ conditions using an index called PUFA (Box 2.4). This index was first used in the Philippines amongst schoolchildren to report the clinical consequences of untreated dental caries (Benzian et al., 2011a; Monse et al., 2011). It was designed to provide additional information to inform healthcare planning. PUFA (pulp, ulceration, fistula, abscess) provides a measure of badly diseased and broken down teeth which have been attacked by dental decay and are causing significant problems in need of early attention. It is now advocated for use by the FDI as a tool that can help to stress the importance of tackling dental caries to planners (Benzian et al., 2011b). It is interesting to note that in the UK, where there have been massive improvements in oral health, some 7% of dentate adults (adults with teeth) had one or more conditions. A PUFA score of one or more was more common in men than women, adults from lower social groups than more affluent, amongst adults who reported brushing less than once a day than amongst those who brushed once or twice, and amongst smokers rather than non‐smokers. These findings contrast with the Philippines where over half (56%) of 12‐year‐olds had PUFA lesions (Monse et al., 2011). The evidence from UK adults is that having a PUFA score was very strongly associated with perceived poor oral health (The Information Centre for Health and Social Care, 2011b; Monse et al., 2011).

Suggested targets proposed in relation to acute conditions can best be related to pain as presented in Box 2.5, since many oral and dental conditions involve pain.

Meeting the Challenge

Even in countries where there are established dental services and state subsidies to support care for low‐income families, there is still a section of the population that attends only when in trouble and even then delays dental attendance for as long as possible (The Information Centre for Health and Social Care, 2011d). This impacts on disease levels and the restorability of lesions. It is important to address this because retaining a functional dentition must as far as possible become a long‐term target of patients and clinicians, at least where there are resources to do so.


In order to make sense of the data on adult oral health and the implications of the burden of disease for maintenance and care, the researchers involved in the latest UK adult dental health survey have helpfully created a complexity score (The Information Centre for Health and Social Care, 2011e). There are eight possible indicators of how adults with a combination of issues may lead to a degree of complexity in management. The index includes the factors listed in Box 2.6.

Jan 22, 2018 | Posted by in General Dentistry | Comments Off on An Overview of Patterns and Trends in Oral and Dental Diseases
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