**3. Trends in dental caries**

Caries epidemiology continues to be an important issue in both oral health surveillance and research into refined methods for caries diagnosis (Marthaler, 2004). The changing on caries disease patterns throughout the world are closely linked to number of public health measures, including effective use of fluorides, together with changing living conditions, lifestyles and improved self- care practices (Petersen, et al., 2005).

In Europe and specifically in Western Europe the decline in caries prevalence has been very substantial. It has not received much attention until recently but is now often taken for granted. However, caries prevalence is still very different when looking at various parts of Europe, and may undergo unexpected changes due to various factors. Increasing immigration has been identified as a new factor, leading to increases of the overall dental caries prevalence in Switzerland (20% non-Swiss residents), the Netherlands and Germany (Marthaler, 2004). Furthermore, there has been a decline in caries prevalence between 1993 and 2003 in all age groups apart from 3-year-old Sweden children (Jacobsson, et al., 2011).

As levels of oral disease decreased in the 1980s and 1990s, the oral health of children and adults in the UK has been improving steadily since the 1970s. The average number of decayed missing and filled permanent teeth (DMFT; a measure of the severity of caries attack in the permanent dentition) at 12 years fell rapidly in the 1980s and has since shown a further steady decline. This has been matched by an increase in the proportion of children who have no evidence of decay. Thus by 2009, only 33% of 12-year-old children had a mean DMFT>0 (a measure of caries prevalence) and the average decay experience was 0.74 DMFT. Nonetheless, those children with treated or untreated dental caries had, on average, 2.21 DMFT and the care index, which is the proportion of that decay which is filled, was only 47%. In addition there was a marked geographic gradient with the north of England showing higher levels of decay than the south of England. For 5-year-olds there has been an overall decline in the average level of dental disease and an increase in the proportion of children who are decay-free, but the change is less pronounced. Over 20 years, the average number of decayed, missing and filled primary teeth has fallen from 1.80 in 1983 to 1.55 in 2004 (Drugan & Downer, 2011).

On the other hand in the United States of America the caries continues to decline in the permanent dentition for many children but is increasing among poor non-Hispanic whites

fermenting carbohydrates causes the decrease in pH, with the subsequent loss of tooth minerals. The preventive measures include: diet and plaque control (mechanical and chemical methods), use of fluorides (systemic and topical), pit and fissure sealants (Harris & García-Godoy, 1999; Featherstone, 2000; Axelsson, 2000, 2004; Gussy, et al., 2006). Furthermore, strategies to control the disease through risk assessment have been developed, which have also been extensively investigated (Vanobbergen, et al., 2001; Pearce, et al., 2002; Bratthall & Hänsel Petersson, 2005; Featherstone, et al., 2007; Ramos-Gomez, et al., 2010; Gao, et al., 2010). On the other hand, the advance of technology has also developed tools for the proper diagnosis of the lesion incipient such as DIAGNOdent and QLF (Stookey, 2004; Berg, 2007; Tranæus, et al., 2007) as well as the need to detect in epidemiological studies noncavitated lesions (Ismail, et al., 2007). In the treatment of lesion there is a large amount of literature, resources and works focused on prevention of the formation of cavities. Despite all the existing

measures for caries control there are no populations free of dental caries in the world.

lifestyles and improved self- care practices (Petersen, et al., 2005).

Caries epidemiology continues to be an important issue in both oral health surveillance and research into refined methods for caries diagnosis (Marthaler, 2004). The changing on caries disease patterns throughout the world are closely linked to number of public health measures, including effective use of fluorides, together with changing living conditions,

In Europe and specifically in Western Europe the decline in caries prevalence has been very substantial. It has not received much attention until recently but is now often taken for granted. However, caries prevalence is still very different when looking at various parts of Europe, and may undergo unexpected changes due to various factors. Increasing immigration has been identified as a new factor, leading to increases of the overall dental caries prevalence in Switzerland (20% non-Swiss residents), the Netherlands and Germany (Marthaler, 2004). Furthermore, there has been a decline in caries prevalence between 1993 and 2003 in all age groups apart from 3-year-old Sweden children (Jacobsson, et al., 2011).

As levels of oral disease decreased in the 1980s and 1990s, the oral health of children and adults in the UK has been improving steadily since the 1970s. The average number of decayed missing and filled permanent teeth (DMFT; a measure of the severity of caries attack in the permanent dentition) at 12 years fell rapidly in the 1980s and has since shown a further steady decline. This has been matched by an increase in the proportion of children who have no evidence of decay. Thus by 2009, only 33% of 12-year-old children had a mean DMFT>0 (a measure of caries prevalence) and the average decay experience was 0.74 DMFT. Nonetheless, those children with treated or untreated dental caries had, on average, 2.21 DMFT and the care index, which is the proportion of that decay which is filled, was only 47%. In addition there was a marked geographic gradient with the north of England showing higher levels of decay than the south of England. For 5-year-olds there has been an overall decline in the average level of dental disease and an increase in the proportion of children who are decay-free, but the change is less pronounced. Over 20 years, the average number of decayed, missing and filled primary teeth has fallen from 1.80 in 1983 to 1.55 in 2004 (Drugan & Downer, 2011).

On the other hand in the United States of America the caries continues to decline in the permanent dentition for many children but is increasing among poor non-Hispanic whites

**3. Trends in dental caries** 

aged 6–8 years (8–22%) and poor Mexican-Americans aged 9–11 years (38–55%). Although dental caries in older children continues to decline or remain unchanged, increasing tooth decay among some young children is a concern. Moreover, it is also troublesome that paediatric caries appears to be disproportionately affecting young boys compared with girls considering that here has not been a difference in prevalence of caries between boys and girls observed in national surveys prior to NHANES 1999–2004. Although the increasing prevalence of dental caries appears to be occurring in some of our traditionally 'low-risk' groups such as the nonpoor, primary caries is also increasing in a small number of 'highrisk' groups as well. Our findings suggest that future caries research should be expanded towards better understanding of not only the factors that promote paediatric dental caries among traditionally high-risk children, but also among those once considered low-risk for tooth decay (Dye, et al., 2010).

The prevalence of dental caries in primary teeth of children aged 2–4 years increased from 18% in 1988–1994 to 24% in 1999–2004. Racial disparities persisted in that age group, with caries significantly more prevalent among non-Hispanic black and Mexican American children than among non-Hispanic white children. Caries prevalence in primary teeth of non-Hispanic white children aged 6–8 years remained unchanged, but increased among non-Hispanic black and Mexican American children. State-specific prevalence of caries among third-graders ranged from 40.6% to 72.2%. Caries in permanent teeth declined among children and adolescents, while the prevalence of dental sealants increased significantly. State oral health programs' funding and staffing remained modest, although the proportion of states with sealant programs increased 75% in 2000 to 85% in 2007 and the proportion with fluoride varnish programs increased from 13% to 53% (Tomar & Reeves, 2009).

For most Americans, oral health status has improved since 1988–1994. Dental caries continues to decrease in the permanent dentition for youths, adolescents, and most adults. Among seniors, the prevalence of root caries decreased, but there was no change in the prevalence of coronal caries. However, the prevalence of dental caries in the primary dentition for youths aged 2–5 years increased from 1988–1994 to 1999–2004. The prevalence of dental sealants among youths and adolescents increased. Tooth retention and periodontal health improved for both adults and seniors, and edentulism among seniors continued to decline. Dental utilization (experiencing a dental visit within the past 12 months) remained unchanged between 1988–1994 and 1999–2004 for youths, adolescents, and seniors; however, dental utilization declined for most adults (Dye, et al., 2007).

According to the World Health Organization the dental caries is still a major public health problem in most industrialized countries, affecting 60–90% of schoolchildren and the vast majority of adults. It is also a most prevalent oral disease in several Asian and Latin American countries while it appears to be less common and less severe in most African countries. Currently, the disease level is high in the Americas but relatively low in Africa. In light of changing living conditions; however, it is expected that the incidence of dental caries will increase in the near future in many developing countries in Africa, particularly as a result of growing consumption of sugars and inadequate exposure to fluorides (Petersen, 2003).

Whelton estimated that changes in the progression of caries have been problematic due to the shortage of longitudinal data in the literature for children, adolescents, and young and older adults. The cohort effect, combined with sampling effects and diagnostic differences,

Caries Incidence in School Children Included in

40%) (Axelsson, 2004).

health effects.

fluoridated areas.

reduction (Newbrum, 2001).

and rinses.

systematic reviews concluded that:

15% and in absolute terms by 2.2 dmft/DMFT.

not cause dental caries (Petersen, et al., 2004).

a Caries Preventive Program: A Longitudinal Study 367

low. Few schoolchildren cleaned their teeth every day. Therefore, caries prevalence among children was very high, and most children developed several new caries lesions every year. Under these conditions, the introduction of a simple preventive measure, supervised rinsing with 0.2% NaF solutions once a week, resulted in very significant caries reductions (25% to

Several efforts have been made to summarize these extensive data sets through systematic reviews, such as those conducted on water fluoridation by the UK University of York Centre for Reviews and Dissemination; on fluoride ingestion and bone fractures; and on fluoride toothpastes and rinses through the Cochrane Collaboration Oral Health Group. These

1. Water fluoridation reduces the prevalence of dental caries (% with dmft /DMFT > 0) by

2. Fluoride toothpastes and mouth rinses reduce the DMFS 3-year increment by 24–26%. 3. There is no credible evidence that water fluoridation is associated with any adverse

4. At certain concentrations of fluoride, water fluoridation is associated with an increased risk of unaesthetic dental fluorosis although further analysis suggested that the risk might be substantially greater in naturally fluoridated areas and less in artificially

5. There was a paucity of research into any possible adverse effects of fluoride toothpastes

Although these findings are important, it must be acknowledged that a lack of fluoride does

Not all fluoride agents and treatments are equal. Different fluoride compounds, different vehicles, and vastly different concentrations have been used with different frequencies and durations of application. These variables can influence the clinical outcome with respect to caries prevention and management. The efficacy of topical fluoride in caries prevention depends on a) the concentration of fluoride used, b) the frequency and duration of application, and, to a certain extent, c) the specific fluoride compound used. The more concentrated the fluoride and the greater the frequency of application, the greater the caries

In recent years, an increasing number of reports have been published in which the observed caries- preventive effect of fluoride has been lower than could have been expected on the basis of the earlier literature. This is true for both systemic and topical methods such as water fluoridation, fluoridated school milk, fluoride mouthrinses and professional applications of topical fluoride including fluoride varnish applications. The current low levels of caries occurrence and the wide spread use of fluoridated toothpastes as well as other fluoride products and methods have been suggested as reasons for the reduced relative effect of water fluoridation. In the same way, the fact that people are today commonly exposed to fluoride from multiple sources is likely to dilute the effect of fluoride from any single source. The moderate usefulness of added fluoride exposure at the population level today may also be due to the fact that individually applicable fluoride regimes are most likely to reach people who least need them. The individuals whose dental health-related lifestyles are most unfavorable and who are not visiting a dentist regularly

confounds the investigation of the true changes in caries progression with time. The elucidation of the age-related pattern and rate of caries development in successive age cohorts will be important in informing future clinical trial design. In summary, the changes in caries patterns which have an impact on the design of caries clinical trials are:


These changes indicate that caries continues to be a challenge throughout life. The conduct of clinical trials of caries-preventive agents must now incorporate more sensitive diagnostic methods capable of valid and reliable measurement of caries initiation and progression in its early stages. The application of sophisticated statistical analysis which takes account of the pattern of caries attack will also help to overcome the difficulties posed by these changes in caries patterns. The application of such techniques to dental datasets which have large numbers of tooth-surface variables and multiple observations has been made possible by the increasing capacity of and accessibility to high-speed computers (Whelton, 2004).
