The NobleDentist Blog

This is an article by a staff writer that was published recently in www.ArabianBusiness.com.

Diet plays a crucial role in optimising oral health. A dynamic relationship exists between nutrition and overall oral health, and it is recognised that one of the primary measures for reducing caries risk is adherence to healthy dietary practices. While the frequent intake of acidic foods and beverages is well established as having a detrimental effect on teeth, many dentists are unsure of how to advise parents on dietary guidelines for their children. This article aims to give an overview of current dietary advice, from a dental perspective.

Fermentable CARBS

The cariogenic potential of sugar and other fermentable carbohydrates is evident. That the incidence of caries still ranks worldwide as one of the most common diseases in society demonstrates that established oral hygiene practices, and fluoride use, do not completely protect teeth from dietary risk factors.

Sugar consumption is reported to be higher in Middle Eastern countries than in many other developing areas. A study conducted by Sayegh et al. (2002) in Jordan shows that sugary snacks are consumed by a majority of children. Confectionary was reported to be regularly consumed by 76% of the 4 to 5 year-old children surveyed, and biscuits and cakes by 71%. More than 50% were reported to drink canned fruit juice and carbonated drinks regularly between meals. Consequently, the prevalence and severity of caries in 4 to 5 year-old children was high; 67% of the children had some caries experience and 33% had DMFT greater than 4.

Dental caries is caused by the dissolution of the teeth by acid, produced by the metabolism of dietary carbohydrates by oral bacteria. The process can be explained as a loss of mineral, as the neutral pH value of saliva is affected. From an average value of 7, once the pH of saliva drops below 5.7, the dental enamel begins to lose calcium and other minerals, leading to dissolution. Many common food products containing fermentable carbohydrates can, after consumption, drop a plaque pH below 4.

The development of caries requires the presence of sugars and other fermentable carbohydrates, which are metabolised to acids by plaque bacteria. Sucrose is one of the most, but not the only, cariogenic substance in the diet. Glucose, fructose, lactose and starch are examples of other fermentable carbohydrates.

The relation between frequent sugar consumption and caries is notable in early childhood caries (ECC). This condition is characterised by significant decay of a child’s teeth, particularly the upper and lower incisors. Poor feeding practices without appropriate preventive measures can lead to a distinctive pattern of caries in infants and toddlers, known as baby bottle tooth decay (BBTD). Frequent bottle feeding at night, nocturnal breast-feeding on demand, and extended and repetitive use of a no-spill training cup are associated with ECC. Caries is often triggered by prolonged exposure to liquids or snacks containing sugar, or by the tradition of dipping pacifiers in honey, sugar or syrup.

The correlation between sugar consumption and caries is also a sociocultural phenomenon. In newly industrialised countries, such as certain Middle Eastern countries, the incidence of caries has increased as residents switch from a dependence on traditional, staple foods, to a dependence on refined carbohydrates, without an accompanying change to regular oral hygiene habits.

Food acids and erosion

Tooth erosion is the progressive loss of dental hard tissue by acids, in a process that does not include plaque bacteria. Tooth erosion is not an infectious disease, but the resulting defects can impair the integrity of the tooth. Dental erosion is less common than caries primarily because saliva flow protects the teeth by neutralising acids. When dental erosion does occur, it is usually the result of either a diminished saliva flow rate or frequent consumption of soft drinks, fruit juices, sports drinks and flavoured waters.

The majority of soft drinks contain one or more acids, most commonly phosphoric and citric acids. Consumers often mistakenly believe that sugar-free soft drinks are safe for teeth. Although diet sodas may not have sugar, their pH value may be lower than 3.5, and therefore can also break down enamel. Besides water and unsweetened tea, only milk is recommended due to its relatively low cariogenicity and high calcium content.

Limiting sugar intake

The frequency of sugar consumption is a significant contributor to the cariogenicity of the diet. Each time fermentable carbohydrates are nibbled or sipped, demineralisation commences. This continues for about 30 minutes, or longer if teeth are coated in existing plaque. Repeated acid attacks do not give teeth the time to recover, thus small amounts of snacks with fermentable carbohydrates eaten frequently during the day increase caries risk.

The amount of sugar consumed is less important than how quickly it is cleared from the oral cavity. The longer carbohydrate-containing foods are retained, the greater the potential the starch has to break down into sugars and contribute to the caries process. For example, liquids consumed with a straw do not expose teeth to the degree that a sipped beverage does. Retentive foods – as opposed to sticky foods, such as jellybeans or caramels – are slower to clear from the mouth. Cookies or potato chips, for example, have high retentive properties, while the soluble sugars found in ‘sticky’ confectionary are washed away more quickly by saliva flow. Besides sweets, certain medicinal products such as cough drops, vitamin chews, cough syrups and lozenges may be detrimental to teeth when consumed frequently or during the night.

Diets that favour remineralisation are typically high in calcium, phosphate and protein, to take advantage of the anticariogenic properties of cheese and milk. Lactose is the least cariogenic sugar and, although milk supports bacterial growth, it has a high buffering capacity and requires substantially more time than sucrose to produce caries. Milk may be encouraged as a snack drink in preference to more acidic drinks such as orange juice, soft drink, or flavoured mineral waters.

Cheese, specifically mature cheddar-type cheese, has been shown to protect against coronal and root caries. In vivo studies have found that when eaten immediately after sugar, cheese naturalises saliva pH levels. Its high calcium and phosphorus content appears to be a factor in its cariostatic mechanisms; decreasing demineralisation and enhancing remineralisation.

To motivate patients to reduce the number of snacks, it is vital to stress the importance of main meals to their child’s oral and physical health. Once main meals are properly made up, the desire of eating between meals is reduced. The goal is not to exclude sugar from the diet but rather to consume sugar in a more sensible way, meaning in reasonable amounts and predominately at meal-times.

Sugar substitutes

In certain product groups, sugar can be fully substituted by non-cariogenic sweeteners. Sugar-free confectionery, soft drinks, medicine, mouth wash and toothpaste are examples of products where sweetness is provided without fermentable carbohydrates. Toothfriendly sugar substitutes can be divided into two distinct groups: polyols and intense sweeteners. Polyols are sugar alcohols which can be found naturally in various fruits and vegetables. Sorbitol, mannitol, maltitol, isomalt, lactitol, xylitol and erythritol are members of the polyol family. Polyols deliver the taste and texture of sugar with approximately half the calories of sucrose. Intense sweeteners include sucralose, acesulfame K, aspartame, cyclamates, saccharin, thaumatin and neohesperidine DC. These products have played an important role in weight control, diabetes and dental health for over four decades. The intense sweeteners used in food production today have been deemed safe for daily consumption by national food safety authorities.

While the Middle East food industry has been slow to target healthier options, when compared to other industrialised countries, there has been some progress with tooth-friendly confectionery. Tooth-friendly chewing gum and sugar-free sweets are an alternative to high-sugar snacks between meals. Products that carry the ‘Happy Tooth’ symbol, attesting to their approval by Toothfriendly International, do not contain fermentable ingredients or high amounts of harmful erosive substances.

The role of fluoride

It has been demonstrated that water fluoridation and topical fluoride supplements decrease the incidence of dental caries. Fluoride helps prevent decay of a tooth by binding to the hydroxyapatite crystals in enamel. According to caries data, children living in the poorest, non-fluoridated communities suffer highest levels of tooth decay.

WHO recommends community water fluoridation as a safe and cost-effective means in preventing dental caries in every age group, benefiting all residents served by the community water regardless of their social or economic status. Domestic salt fluoridation is another method of automatic fluoridation. Switzerland was the first country to introduce fluoridated salt in 1983. Since then, positive experience has been made in other European and Latin American countries. In 2006, fluoridated salt was consumed by 180 million people.

Conclusion

Sugars and oral health are integrally related. Dental professionals must recognise the relationship between diet and caries risk, and manage patients accordingly. Routine appointments should include a degree of dietary advice to provide a framework for parents and their children for the prevention and management of dental caries, and the management of sugar intake.