Diet and dental cariesAhmed Abdulelah Al-jawadyUniversity of Mosul
Introduction A dynamic relation exists between sugars and oral health. Dietaffects the integrity of the teeth; quantity, pH, and composition ofthe saliva; and plaque pH. Sugars and other fermentablecarbohydrates, after being hydrolyzed by salivary amylase,provide substrate for the actions of oral bacteria, which in turnlower plaque and salivary pH. The resultant action is thebeginning of tooth demineralization.
Many factors in addition to sugars affect thecaries process, including the form of food or fluid the duration of exposure nutrient composition sequence of eating salivary flow presence of buffers and oral hygiene.
According to the American Dietetic Association(2): 1- “nutrition is an integral component of oral health. 2- diet and nutrition are major multifactorialenvironmental factors in the etiology andpathogenesis of craniofacial diseases.
Relation between diet and caries(Miller’s chemoparasitictheory)(3) Dental caries was first described in Miller’schemoparasitic theory in 1890 (3). Caries is caused bythe dissolution of the teeth by acid produced by themetabolism of dietary carbohydrates by oral bacteria.The 2 primary bacteria involved in caries formation aremutans streptococci and lactobacilli. In the 1960s thecaries theory was depicted as 3 circles representing the3 prerequisites for dental caries: the tooth, the diet,and dental plaque (Figure 1) (4)
Since then, many modifying factors have been recognized,resulting in a more complex model that includes saliva, theimmune system, time, socioeconomic status, level ofeducation, lifestyle behaviors, and the use of fluorides.Sugars and dental caries The caries process can bedescribed as loss of mineral (demineralization) when thepH of plaque drops below the critical pH value of 5.5; thecritical value for enamel dissolution is 5–6, and an averagepH of 5.5( 4) is the generally accepted value. Redispositionof mineral (remineralization) occurs when the pH ofplaque rises. The presence of fluoride reduces the criticalpH by 0.5 pH units, thus exerting its protective effect.
Diet and nutrition may interfere with the balance oftooth demineralization and remineralization in severalways. The diet provides sugars and other fermentablecarbohydrates, which are metabolized to acids byplaque bacteria (Figure 2). The resultant low pH favorsthe growth of the acidogenic and aciduric bacteria(mutans streptococci). In contrast, a diet lower inadded sugars and fermentable carbohydrates and highin calcium-rich cheese may favor remineralization.
The anticariogenic effect of cheese:Mechanisms proposed to explain the anticariogeniceffects of cheeses are as follows:1-increased salivary flow and the subsequent buffering effect,which can neutralize plaque acids;2-inhibition of plaque bacteria and the effect of that inhibition onreducing the amount of bacteria, thereby reducing acidproduction; and3-intake of increased alkaline substances, calcium, inorganicphosphate, and casein, which decrease demineralization andenhance remineralization (6)
What do we mean by sugar? When we say “sugar”, we usually mean granulated Table sugar. However thereare so many kinds of sugars these days, we need to be very clear the word“sugar” includes these things ending in “ose”: 1. Sucrose (Table sugar) a simple sugar made from cane sugar or beets. 2. Fructose, a simple sugar in fruits, plants and honey. 3. Maltose, a complex sugar in barley and malt syrups. 4. Lactose, a complex sugar in milk. 5. Dextrose, a refined simple sugar from corn, sugar cane or beets. 6. Glucose, a simple sugar in fruits, vegetables and grains.
Recommended and current levels of sugar intake The recommended intake of non-milk extrinsic sugarsis a maximum of 60g/day, which is about 10% of dailyenergy intake.
The influence of fluoride on the sugars–caries relationship(7) 1-reduces and inhibits demineralization. 2- remineralisation of enamel . 3-affects plaque :by inhibiting bacterial metabolism ofsugar thus reducing acid production.
Factors that affecting the foodcariogenicity (8) 1-types of carbohydrate 2-physical form of food retention and oral clearancetime 3-factor in the diet that protect against dental caries 4-intake frequency 5-nature of diet
1-types of carbohydrateCLASSIFICATION OF SUGARS FOR DENTAL HEALTHPURPOSESsugarsMonosaccharide: naturally found infruit ,vegetable andhoneyGlucose FructoseDisaccharide:Sucrose foundin sugarcane andsugarbeetsLactose foundin milkMaltosedeliveredfromhydrolysis ofstarchPolysaccharidestarchPotatoespeas andricedextrin glycogen
2-physical form of food retention and oral clearancetime Forms of sugars and starch in the diet Sugars are a form of fermentable carbohydrate.Fermentable carbohydrates are carbohydrates (sugarsand starch) that begin digestion in the oral cavity viasalivary amylase. Sugars enter the diet in 2 forms: those found naturally in foods (e.g.,fruit, honey, and dairy products) and those that areadded to foods during processing to alter the flavor,taste, or texture of the food (9)
food retention Prolonged oral retention of cariogenic components offood may lead to extended periods of acid productionand demineralization and to shortened periods ofremineralization. Retentiveness of foods is not thesame as stickiness. A caramel or jellybean may besticky, but its retentive properties are fairly low andthey are cleared from the oral cavity faster than areretentive foods such as cookies or chips .
Oral clearance properties vary by individual person anddepend On: 1- metabolism by microorganisms, 2- adsorption onto oral surfaces, 3-degradation by plaque and salivary enzymes, 4-saliva flow, and 5-swallowing. Most carbohydrates will be cleared bythese simultaneous mechanisms.
Frequency The frequency of consumption seems to be asignificant contributor to the cariogenicity of the diet,although Bowen et al (10) concluded that it is not thefrequency of ingestion per sec that is related to thedevelopment of caries but the time that sugars areavailable to microorganisms in the mouth caries isregarded as the outcome of the alternation ofdemineralization and remineralization. Higherfrequency means more demineralization and lessremineralization. The duration of the decrease in pHafter intake of a cariogenic food is an importantconfounder in this relation
anticariogenic sugars 1-Polyphenols Polyphenols such as tannins in cocoa, coffee, tea, and many fruit juices mayreduce the cariogenic potential of foods. In vitro experiments have shown thatthese polyphenolic compounds may interfere with glucosyltransferase activityof mutans streptococci, which may reduce plaque formation (11). In ratexperiments, tea polyphenols reduced caries (11). 2-Sugar alcohol–based products Sugar-free gums can stimulate saliva, increasing the clearance of sugars andother fermentable carbohydrates from the teeth and the oral cavity andincreasing buffer capacity. Tooth-friendly polyols include sorbitol, xylitol,mannitol, erythritol, and isomalt. However, xylitol—a 5-carbon sugar that oralmicroflora cannot metabolize—has additional anticariogenic effectsattributable to antimicrobial action, stimulation of saliva resulting in increasedbuffer activity and an increase in pH, and enhanced remineralization (12).Sorbitol-sweetened gums simulate saliva without causing a drop to the criticalpH and have been shown to be equal to xylitol gum in terms of caries control(13).
TOOTH EROSION Tooth erosion is the progressive loss of dental hard tissue by acids in aprocess that does not involve bacteria or sugars. The intrinsic acids arefrom vomiting, gastroesophageal reflux, and regurgitation. Theextrinsic acids are from the diet [e.g. sports beverages and citrusproducts, including citrus fruit, juices, soft drinks, and citrus-flavoredcandies and lozenges]or from the occupational environment (e.g.,battery and galvanizing factories). Tooth erosion as a result of eatingdisorders (bulimia nervosa) and dietary practices involving frequentintake of acidic foods and beverages can weaken tooth integrity.( 14,15)
Groups at particular risk of caries in relation todiet 1-Infants and toddlers with prolonged breast-feedingon demand Infants and toddlers provided with a feeding bottle atbedtime, or bottle suspended in the cot for use duringthe night, with sugar containing liquid
2-People with increased frequency of eating because ofa medical problem, e.g., gastrointestinal disease,eating disorders, uncontrolled diabetes. 3-Those with an increased carbohydrate intake due toa medical problem e.g., Crohn’s disease, chronic renalfailure, or other chronic illness, malnutrition or failureto thrive. 4-Those with reduced salivary secretion. Sjogren’ssyndrome, irradiation in the region of the salivaryglands.
5-Athletes taking sugar-containing sport supplementdrinks. 6-Workers subject to occupational hazards such as foodsampling and those on a monotonous job such as a nightshift. 7-Drug abusers who have a craving for sugar and aprolonged clearance rate as a result of reduced salivarysecretion 8-People of any age, on long term and/or multiplemedications. Are these sugar-based and/or do they cause adry mouth? 9-Any sugary bedtime snacks or drinks.
DIETARY RECOMMENDATIONS FOR REDUCING THERISK OF ORAL INFECTIOUS DISEASE (16,17,18) 1) eat a balanced diet rich in whole grains, fruit, and vegetables and practice good oralhygiene—particularly the use of fluoridated toothpastes—to maximize oral and systemichealth and reduce caries risk. 2) eat a combination of foods to reduce the risk of caries and erosion; include dairyproducts with fermentable carbohydrates and other sugars and consume these foodswith, instead of, between meals; add raw fruit or vegetables to meals to increase salivaryflow; drink sweetened and acidic beverages with meals, including foods that can bufferthe acidogenic effects. 3) rinse mouth with water, chew sugarless gum (particularly those containing sugaralcohols, which stimulates remineralization), and eat dairy product such as cheese afterthe consumption of fermentable carbohydrates. 4) chew sugarless gum between meals and snacks to increase salivary flow. 5) drink, rather than sip, sweetened and acidic beverages. 6) moderate eating frequency to reduce repeated exposure to sugars, other fermentablecarbohydrates, and acids. 7) avoid putting an infant or child to bed with a bottle of milk, juice, or other sugar-containing beverage.
FOODS AND DRINKS WITH LOW POTENTIAL FORDENTAL CARIES Bread (sandwiches, toast, crumpets, pitta bread). Pasta, rice, starchy staple foods Cheese Fibrous foods (e.g. raw vegetables) Low sugar breakfast cereals (e.g. shredded wheat) Fresh fruit (whole and not juices) Peanuts (not for children under 5 years) Sugar-free chewing gum Sugar-free confectionery Water Milk Sugar-free drinks Tea and coffee (unsweetened)
Ahmed Abdulelah Al-jawady University of Mosul