The erosive potential of some flavoured waters ters lie close to neutrality10,11 but the much more ied quite widely from 1.18 μm for the elderflower acidic values found in this study of less than 3.5 product to 6.28 μm for the lemonade based prod - suggest that flavoured waters are potentially uct and 6.86 μm for the cranberry based product. more erosive than their non-flavoured counter- These values probably reflect the amount of natu- parts. Furthermore, the critical pH below which rally occurring fruit acids in the parent product. enamel begins to erode significantly is 4.5.13 This Elderflowers do not have a high concentration of is presumably due to the addition of fruit extracts fruit acids (Table 4), whereas lemons and cranber- as flavouring agents. These are high in naturally ries both have large amounts of citric acid and it is occurring fruit acids, such as citric acid, used as this that probably accounts for the large amounts flavouring agents. Some manufacturers also add of erosion recorded. citrate based compounds to enhance the shelf life The positive control, orange juice, removed and this adds to the acidic burden of these drinks. 3.24 μm of enamel and this is typical of most or - However, pH measurement of a drink does not ange juices that tend to remove 3-4 μm of enamel give the whole picture14 and one must also consid- in one hour in a laboratory test. er the neutralisable acidity which gives a measure Apart from the elderflower product and Volvic of all the free hydrogen ions available to cause orange and peach, all the other flavoured waters erosion. The neutralisable acidity values of the fla- were capable of producing large amounts of enam- voured waters varied more widely from 4.16 mls el erosion. However, the erosion results of this of 0.1M NaOH for Volvic still orange and peach to study must be interpreted with a certain degree 16.3 mls for Boots cloudy lemonade spring water of caution as clinically the enamel surface will be drink. The reasons for this wide variation in these covered by a protective pellicle and/or plaque lay- values are not immediately obvious and it is dif- er and the tooth surface will also be subject to the ficult to form an informed opinion as the product flushing, buffering and remineralising effects of labelling does not give any percentages or con- saliva.15,16 A further factor to consider is the clear- centrations for the components of the drinks. In ance rates of these drinks from the mouth.17 Oral comparison, the neutralisable acidity of the con- clearance of drinks may well be related to their trol orange juice was slightly higher than any of viscosity17 and although this was not measured in the flavoured waters tested at 19.68 mls. this study, being water based, these drinks had a The range of values for the neutralisable acid- low viscosity. ity of the flavoured waters is broadly comparable Finally, this study was deliberately carried out to other drinks that have been evaluated including at 37°C to allow comparison with previous work white wine, alcopops and fruit teas (Table 3). (Table 3). However, these sports drinks are usu- The values for the enamel erosion also var- ally consumed cold at around 5°C and the drinks erfncs ocnlusInos will therefore have fewer dissociated H+ ions and therefore produce less erosion.18 In spite of the limitations of this simple in vitro study, many of these flavoured waters may con- tribute to erosion in patients who are either sus- ceptible to erosion or use these drinks on a daily or more regular basis. 1. Eccles JD. Tooth surface loss from abrasion, attrition and erosion. Dent Update 1982;35:373-381. 2. Eccles JD, Jenkins WG. Dental erosion and diet. J Dent 1974;2:153-159. 3. Asher C, Read MJF. Early enamel erosion in children as- sociated with the excessive consumption of citric acid. Br Dent J 1987;162:384-387. 4. Järvinen VK, Rytömaa I, Heinonen OP. Risk factors in den- tal erosion. J Dent Res 1991;70:942-947. 5. Millward A, Shaw L, Smith AJ, Rippin JW, Harrington E. The distribution and severity of tooth wear and the relationship between erosion and dietary constituents in a group of children. Int J Paediatr Dent 1994;4:151-156. 6. Shaw L , Smith AJ. Erosion in children: an increasing clini- cal problem? Dent Update 1994;21:103-106. 7. Rees JS. The role of drinks in tooth surface loss. Dent Up- date 2004; 31:318-326. drinks. Drink Alcopops19 White wine20 Ciders21 Fruit teas22 Sports drinks23 Fruit juice Cranberry Grapefruit Lemon Orange Elderflower European Journal of Dentistry 100 0 290 Trace 66 1560 1460 6080 980 0 Total acid content 15 1460 6370 980 66 Table . Neutralisable acidity values of other types of Table . Concentration of malic and citric acids found in various fruit juices (mg per 100 gms of fruit) .24 Malic acid Citric acid Neutralisable acidity (mls 0.1M NaOH) 15.4 - 23.1 mls 9.4 - 27.1 mls 14.5 - 21.5 mls 3.5 - 60.3 mls 9.7 – 13.4 mls