The consumption of beverages by children has changed in the types and quantities (Marshall et.al, 2003), in such a way that milk and water intakes have decreased and fruit juices and carbonated soft drinks have increased (Heller et.al, 1999, cited by Sohn et.al 2006). This change is of the interest of the public health concern because it is may be associated to both general health diseases e.g. obesity and diabetes (Marshall, 2003), and oral health diseases e.g. dental caries and dental erosion (Tahmassebi e.t.al, 2006).
Sugar consumption has also increased in developing countries (Ismail et al., 1997); this is also applied to carbonated soft drinks consumption in the Sultanate as recently reported (WHO, 2005).
However, the consequences of these patterns of consumption of soft drinks on dental caries have not well studied (Sohn et al, 2006). Furthermore, it is described that the implications of soft drinks on dental caries is weak or not existent (Froshee and Storey, 2004). Main explanation for this is that fluoride exposure has weakened this relationship (Karjalainen, 2007). Consequently, some authors concluded that soft drinks are not serious threat to dental caries, and the strategies to reduce dental caries should be based on good oral hygiene and the use of fluoridated toothpastes (Froshee and Storey, 2004).
Although dental caries is declining in developed countries, the situation is not the same in developing countries (Moynihan and Petersen, 2004). Sultanate of Oman is a developing country, and the three national surveys of the prevalence of dental caries in schoolchildren in Oman are in consistent with this concept (Alismaily et al. 1996; Alisamaily e.t.al, 1997, Alismaily et al, 2004). And the prevalence is expected to increase in this country (MOH, 2010).
The school preventive oral health programme didnâ€™t discuss the issue of high consumption of carbonated soft drinks to increase the awareness among the health care workers in the school especially the dental team and the students. This is also applied to the dietary guidelines in Oman, although they recognised the issue of carbonated soft drinks but there are no guidelines to minimise the effects of these drinks other than recommending reducing the consumption of sugary drinks.
Against this background to develop oral health promotion programmes to reduce dental caries prevalence in this group of the population and related to soft drinks consumption should be based on evidence based relationship between dental caries and the consumption of soft drinks.
soft drinks and public health
The increase in the consumption of soft drinks raises the concern of public health as it may be related to both general health e.g. obesity, and oral health e.g. dental caries and dental erosion.
1.1.1soft drinks and obesity
The rate of obesity is associated with overconsumption of soft drinks (Marshall et al, 2003). This is because of the increase in energy intake which is related to soft drink consumption (Guthrie and Morton, 2001cited by Shenkin et al., 2002). Obesity is a main public health interest as it is linked to chronic disease e.g. cardiovascular diseases and diabetes type2, which are historically associated to old age but now are being seen frequently in children and adolescent ( Shenkin et al., 2002).
1.1.2. Soft drinks and dental erosion
Dental erosion is the loss of the hard tissue of the tooth without involvement of bacteria (Barbour et al., 2008). The demineralisation of enamel occurs when the PH falls below the critical value 5.5, thereby a drink or a food of PH lower than 5.5 may cause erosion (Moynihan and Petersen, 2004). There is evidence of prevalence increasing of dental erosion in industerlised countries, and this is related to increase in trend of acidic beverages consumption (Moynihan and Petersen, 2004).
1.1.3 Soft drinks and dental caries
Dental caries is the loss of tooth tissue mediated by bacteria. It is a multifatorial disease, where the bacteria in oral cavity (streptococcus Mutans) ferments the carbohydrates (sucrose and fructose) this produces acid which lowers oral PH below 5.5 and demineralises the tooth structure (Marshall et al., 2002).
Soft drinks are rendered cariogenic because they contain high amount of sucrose and fructose, there are 10 spoons of these sugars in one 12 ounce can of sugary soda (Shenkin et al., 2002). Another factor is its acidogenicity, most of these products have PH below the threshold level of 5.5, their PH in the range of 2.5-3.5 (Milosevic, 1997 cited by Shenkin et al., 2002), and this may cause dental caries and dental erosion (Shenkin et al., 2002).
Although sugar is an etiological factor of dental caries but the extent of its effect is also determined by other factors these are; frequency and amount of ingestion, exposure to fluoride either topically e.g. toothpaste, or systematically by water fluoridation, and also the level of bacteria (Shenkin et al., 2002).
In a systematic review by Burt and Pai to evaluate the association between sugar consumption and caries risk they found that two studies out of 36 have strong relation between these two factors whereas the rest either moderate or no association (Burt and Pai, 2001). And regarding the association between soft drinks consumption and dental caries there is inconsistency in the results and the relation is less recognised (Marshall, 2003). This led some authors to recommend that the strategy of dental caries prevention should be based on improving oral hygiene than sugar restriction (Gibson and Williams, 1999; Froshee and Storey, 2004).
The trend of Soft drink consumption in developed countries and in Oman
In USA there is an increase in the consumption of soft drinks in schools in the last 30 years and there is a decline in dairy consumption (Shenkin et al., 2002). A range of 56%-85% of schoolchildren consume 1 soft drink daily at least (committee on School Health, 2004).
In Oman the trend of Soft drink consumption is also increasing. International Marketing Economic Service (IMES) reported that the consumption of soft drinks in Oman has increased between 2001 and 2005, in 2005 the market was around US$ 87 million, and the most popular carbonated soft drink was Mountain Dew (IMES Consulting, 2006). Among school age children, it was identified by Global School Survey (GSHS) in 2004 that 33.4% of the Omani students drink carbonated soft drinks which are specifically Coke, Pepsi, and Mountain Dew two or more times per a day in the last 30 days. Actually this was one of the most alarming behaviors found in this questionnaire, and it recommended the implementation of national strategy to improve the school communityâ€™s health (WHO, 2005).
Table1. Trend of soft drink consumption in Oman. Source (IMES, 2006).
The properties of carbonated soft drinks in Oman
In a study done by me in 2000 as an undergraduate student in the form of Summer Project the properties of common beverages in two cities from two countries; Cork city in Republic of Ireland and Jalaan city in Sultanate of Oman related to dental health are analysed, and these are the PH and fluoride content (DOHC, not mentioned). The PH and the fluoride content of the common carbonated soft drinks in jalaan city from Oman are summarised in table2.
Carbonated soft drinks
Everves Club Soda
Table.2. PH and fluoride level of carbonated soft drinks in Jalaan city (source DOHC)
We can consider these samples are representative of the hall country as there are only three local producers and one importer of carbonates in Oman and each producer is for different brands e.g. Cola and Pepsi brands (IMES consulting, 2006). The average PH for the carbonated soft drinks was 3.23 which is below the critical value 5.5 as we mentioned earlier which render these drinks as potentially cariogenic and erosive. The average fluoride level was 0.25 ppm; this is below the public fluoridated water in Oman which is 0.5ppm (Alismaily et al, 2004). Unfortunately there is no data regarding the consumption of bottled water in schoolchildren, and if the pattern that carbonated soft drinks is replacing the use of bottled water then the exposure to fluoride is less than the optimal preventive level and this will increase the prevalence of dental caries.
The trend of dental caries
Although there is an increase in the consumption of soft drinks in developed countries the prevalence of dental caries is declining in the last 30 years in these countries, and it is increasing in developing countries (Moynihan and Petersen, 2004). This is attributed to the exposure of fluoride (Karjalainen, 2007).
The trend of dental caries in Oman
There were three national surveys conducted in Oman to determine the prevalence of dental caries in three group school children. The prevalence was 84.5% in 6 years old children (Alisamaily e.t.al, 1997), and it was 58% in 12 years children (Alismaily e.t.al, 1996). When the same cohort was examined three years later the prevalence increased to 69% (Alismaily et al, 2004). The Mean DMFT has risen from 1.5 to 3.2, and those who were caries free fallen from 42% to 27% (Alismaily et al, 2004).Actually these figures are alerting if we put in our mind that nearly 35.3% of the Omani population are under 15 years of age (MOH, 2008) so the prevalence of dental caries is high in the third of the population. These surveys also expect the prevalence is on the rise (MOH, 2010). And since the second survey there was a call for the development of preventive oral health program (Alisamaily e.t.al, 1997).
Although the trend of the prevalence of dental caries can be recognized in these three surveys, the determinants of dental caries in these age groups e.g. the dietary habits of sugar intake are not determined yet there is an increase of consumption of carbonated soft drinks. These factors are important to develop a preventive strategy for dental caries.
The effect of dental caries on quality of life
One of the most common chronic diseases in children is dental caries and it can affect school attendance (Marshall et al, 2003). In all over the world, children with dental caries might get apprehension from others because of their appearance, anxiety and pain, malnutrition because eating diet with low fruit, and early loss of the tooth (Moynihan and Petersen, 2004). For these reasons it is important to reduce the prevalence of dental diseases in Oman as it is also a preventable disease.
The current dietary guidelines in Oman regarding dental caries and soft drinks
The risk factors presented in the dietary guidelines which are associated with dental caries are the amount and frequency of free sugar intake and undernutrition, and those which are associated with reducing dental caries are fluoride exposure, hard cheese and chewing gum (MOH, not mentioned). Actually these factors are taken from WHO report of Diet, Nutrition and Prevention of Chronic diseases on 2003 (WHO,2003), however carbonated soft drinks are not specifically associated with dental caries in the guideline nor even the best ways to reduce its effects have been discussed (MOH, not mentioned).
Furthermore the Manual Guidelines for Preventive School Oral Health Programme which was developed in 2005 in Oman didnâ€™t discuss the issue of soft drinks and its impact on dental health, and this including also the oral health education programme in schools (MOH, 2005).
Review the association between the consumption of carbonated soft drinks and dental caries experience among schoolchildren.
Develop oral health recommendations related to soft drinks consumption for children (in schools) in Sultanate of Oman.
Conduct a literature review to assess the relationship between consumption of carbonated soft drinks and dental caries experience among schoolchildren. And determining the factors that minimise or reduce the cariogenic effect of carbonated soft drinks.
Review the evidence base on the existing health promotion recommendations for carbonated soft drink consumption among schoolchildren.
Make recommendations for the consumption of soft drinks by schoolchildren in Oman.