Clinical Feature Soft Drinks: Hard on Teeth With soda pop decay contributing to an alarming increase in caries among young people, dentistry finds itself fighting another kind of access problem: sweetened beverages within reach 24 hours a day. Pamela R. Erickson, D.D.S., Ph.D.*, more than 27% of Americans’ beverage Deanna L.Alevizos, D.D.S., M.S.**, consumption.1 In 1997, Americans *Dr. Erickson is a pediatric dentist in and Darcy J. Rindelaub, D.D.S.*** spent more than $54 billion to buy 14 private practice in Minnetonka, billion gallons of soft drinks. Today Minnesota. She is the immediate past- oft drinks are popular Americans consume more than 56 president of the Minnesota Association beverages. These cool, bubbly gallons per year,or more than one-and- of Pediatric Dentistry. drinks are being consumed a-half 12 ounce cans per day for every ** Dr.Alevizos is a pediatric dentist in everywhere. In fact, you may man, woman, and child. private practice. She is a 2000 gradu- very well have a can sitting Dentists are becoming increasingly ate of the University of Minnesota Snext to you as you read this article. In concerned that over-consumption of School of Dentistry. the United States, it is culturally accept- soft drinks may result in greater able to consume soft drinks any time amounts of dental disease. In a letter ***Dr. Rindelaub is a second year pedi- of the day. copied in the December 1997 Journal of atric dentistry resident at the University Carbonated soft drinks account for the American Dental Association,Dr. Paul of Minnesota School of Dentistry. March-April 2001 15 Clinical Feature Readhead from Ames,Iowa was curious dentin, leaving the outer 20- to 50- easily penetrated and dissolved by to know if any other dentist had micrometer-thick surface preserved acids.4 Even in the absence of carbohy- noticed significant increase in decay more or less intact.3 drates, soft drinks can be destructive to among teenagers and adults due to With the consump- teeth.These acidic, or low patients drinking either regular or diet tion of acidic, carbohy- pH, beverages can con- Coke® or Pepsi®.Dr. Readhead noticed, drate-rich soft drinks, Children tribute to the demineral- looking at the ingredients of the soft teenagers are at high start con- ization of dental hard drinks, that most of them, especially the risk for caries develop- tissues. colas, contain phosphoric acid, and ment, which can be suming soft Dental erosion is the loss some, citric acid. The patients he had quite aggressive (Figure drinks at a of tooth structure by a identified who were experiencing this 1). Eight- to 17-year-old chemical process not decay were noted to have had above children are at greatest remarkably involving bacteria.5 Initially, average oral hygiene and very little risk. Normally, as the young enamel will demineralize previous decay. young, immature enamel and dissolve, with the sur- is bathed by salivary ions age... face appearing dull. Acids Acid Versus Enamel and the intercrystalline can also enter the pits and It is well known by the medical profes- spaces fill, it becomes progressively pores of enamel and cause subsurface sion that disease loves acid,2 and this is harder and more mature. Mature structure loss.6 The solubility of particularly true of dental caries. enamel appears as a very dense, less hydroxyapatite increases logarithmi- Dental caries, by definition, is tooth penetrable, glassy hard structure that is cally with decreasing pH. demineralization caused by acidic fairly resistant to acid attack. Erosion may be caused by either byproducts of the bacterial fermenta- However, enamel maturation takes intrinsic or extrinsic sources. The tion of dietary sugars. The resulting time. The newly erupted enamel in intrinsic causes have been documented caries lesion involves gradual deminer- teenagers is immature, and the crys- to include cases of anorexia nervosa alization of subsurface enamel and talline structure is porous, chalky, and and bulimia, as well as any gastrointesti- nal disorder that involves increased outputs of gastric acids. Extrinsic Figure 1. sources include acidic medicines such as vitamin C and aspirin, aerosol acid chemicals in the work environment, or the frequent consumption of acid food- stuffs or drinks. Simple pH monitors have shown that all types of soft drinks are very acidic, especially the colas, which can have a pH of 2.4 or less (Table I). In order to neutralize a glass of cola, it takes 32 glasses of high pH alkaline water.2 Exposure of enamel to Coca-Cola® for one hour leads to significant reduction in microhardness, and scanning electron microscopic evaluation has revealed surface irregularities.7 Soft Drink Consumption Photograph of a 16-year, two-month-old male with rampant caries secondary to Children start consuming soft drinks at soft drink consumption.This teenager presented for consultation after referral from a remarkably young age, and consump- a general dentist.The previous dental examination at 14 years, five months of age tion increases through young adult- showed no dental caries. Contributing etiology was the consumption of three to four cans of Mountain Dew per day while at school. Patient reported starting to hood. Twenty percent of one- consume these large quantities upon entering high school, where vending machines and two-year-old children consume were readily available. soft drinks.8 Those toddlers drink an 16 Northwest Dentistry average of seven ounces — nearly one from 72% in 1977-79 to 57% in 1994.10 teenagers. Furthermore, children who cup — per day. Data from national surveys indicate consume more than 26 ounces of soft The consumption of soft drinks has that calcium intakes of a drinks per day were four increased in the United States over considerable propor- times more likely to con- the past decades. United States tion of U.S. children, Milk con- sume less than eight Department of Agriculture Food teenagers in particular, ounces of milk per day.14 Consumption Surveys (1977-1978, are well below the sumption Nearly a tenth of the 1987-88, 1994-96) have found that Recommended Daily has dropped calories consumed by almost half of all children between six Allowance (RDA).11 For American teenagers and eleven years of age consume soft instance, data from a in children come from nutrition- drinks, with the average child consum- 1989 survey indicated over this ally empty sodas, ing 15 ounces per day, up slightly from that just 39.5% of girls which they drink at the 12 ounces in 1977-78. The most avid aged 12-18 were con- same expense of calcium rich consumers are 12- to 29-year-old suming 75% or more of period. milk. As a result, many males. Boys between 12 and 19 years of the RDA for calcium.12 young Americans today age who consume soft drinks take in an Guenther13 found that are reaching the age of average of almost two 12 ounce sodas soft drink intake was negatively associ- maximum bone growth with bones (28.5 ounces) per day. Teenage girls ated with milk, calcium, magnesium, vit- highly prone to osteoporosis. also drink large amounts (20 amin A, and vitamin C intake in U.S. Soft drinks and fruit juices have ounces/day), although slightly less than their male counterparts. Table I. Another analysis9 found that one fourth of males 13 to 18 years old pH and Sugar Content of a Variety of Soft Drinks and Other drank two or more cans of soft drinks Popular Beverages. a day, while one out of 20 drank five or Sugar Sugar more cans per day. One-fourth of Beverage pH (gm/serving) Beverage pH (gm/serving) 13- to 18-year-old females drank two Coca-Cola Orange Slice 3.12 50 Classic 2.53 39 cans per day, and one out of 20 drank Squirt 2.85 40 three or more cans per day. Diet 3.39 0 Cherry 2.53 42 Minute Maid Orange Soda 2.80 47 Nutritional Impact Sprite 3.42 26 Lipton’s Soft drink vending machines have Surge 3.02 46 added to this substantial increase in Iced Tea 3.86 22 soft drink consumption. Comparison 7-Up Lemon Iced Tea 2.90 33 Regular 3.19 26 of the results of the 1965-66 USDA Nestea Iced Tea 3.04 22 Diet 3.67 0 Food Consumption Survey with those Gatorade Pepsi one decade later showed that the Citrus Cooler 2.97 14 Regular 2.49 42 percentage of toddlers who consumed Lemon Lime 2.97 14 soft drinks increased from 30% to Diet 3.05 0 Snapple 40%. Furthermore, in the 1977-78 Mountain Dew Plain Tea 3.93 25 survey, the typical (50th percentile) Regular 3.22 31 Lemon Iced Tea 2.98 25 teenager drank about one half of Diet 3.34 0 Pink Lemonade 2.54 26 the current consumption. Data from Dr. Pepper the USDA surveys indicate that the Diet Pink Regular 2.92 27 Lemonade 3.10 0 proportion of adolescent boys and Diet 3.41 0 girls consuming soft drinks on any Lemonade 2.56 30 given day increased by 74% and 65%, Barq’s Root Beer Diet Lemon respectively.10 Regular 4.61 45 Iced Tea 2.55 0 Concomitantly, milk consumption Diet 4.55 0 Raspberry has dropped in children over this same A&W Root Beer 4.41 31 Iced Tea 2.95 29 period. For example, the proportion of Diet Rite 3.46 0 adolescent girls drinking milk dropped March-April 2001 17 Clinical Feature minimal nutritional content. All contain sustains a neonate’s preference for million on advertising, while the four negligible amounts of the RDA for sweets.18 Studies have shown that major soft drink companies spent vitamins, minerals, and protein.14 sweet preference changes with expo- $631 million.