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A comparison of different kinds of European on human plaque pH E. VERAKAKI, M.S. DUGGAL

ABSTRACT. Aim To investigate the acidogenic response of plaque with various European chocolates of varying cocoa contents. Methods 14 subjects participated in the study. On each test day plaque pH measurements were taken at baseline and at 2, 5, 10, 15, 20 and 30 minutes after challenge with the test chocolates or control foods. A plaque sample was removed from the buccal surfaces of posterior teeth representing all quadrants, within 30 seconds. The plaque pH was measured on an ISFET electrode connected to a Sentron 2001 pH system. The test chocolates were: Diet (DC), Plain European chocolate (PEC 70% cocoa), Plain English chocolate (PenC 34% cocoa), English chocolate (MenC 20% cocoa), Milk European chocolate (MEC 30% cocoa), (WC no cocoa), with hazelnuts (MHC 20% cocoa). 15 g of each chocolate was consumed by the volunteers and 10 ml of 10% sucrose and sorbitol solutions were included as controls. Results The data were analysed for: minimum pH, area below baseline, area below “critical pH”, time spent below “critical pH” and Acidogenic Potential Index (API). DC was found to be significantly different to sucrose and all the other test chocolates, and similar to sorbitol for all the parameters studied. The area below baseline plaque pH was also significantly smaller for PEC (p<0.006) and MHC (p<0.028) as compared with sucrose. The mean area below the “critical pH” (5.7) for PEC and MHC was lower at 0.20±0.34 and 0.60±1.40 respectively, compared with sucrose at 1.38±1.03, but not statistically significant. The API of DC, PEC, PEnC, MEnC, MEC, WC and MHC was 0.03, 0.41, 0.66, 0.93, 0.94, 0.88 and 0.45 respectively compared with an API of 1.00 of sucrose. Conclusion Diet chocolate was found to have no acidogenic effect on dental plaque. Also, the PEC and MHC had a lower acidogenic potential compared with sucrose.

KEYWORDS: Chocolate, Plaque, pH.

Introduction design, found milk chocolate to have low cariogenic The interaction between chocolate and dental caries potential. Reynolds and Black [1987] reported chocolate has been evaluated by using several methodologies to be cariogenic in animals and Grenby and Mistry available to assess the relationship between diet and [1995] identified as more cariogenic than dental caries development. The classic Vipeholm study milk chocolate when an electronic system to feed [Gustafsson et al., 1954], the only human intervention animals was used. study, revealed that the people who were included in the Previously Bibby et al. [1951] had carried out an in chocolate group developed the lowest number of caries vitro study and found chocolates, such as milk lesions. Stephan [1966] found that milk chocolate was chocolate and milk chocolate with almonds, to produce among those foods that induced or increased the number significant amounts of acids. In addition, Linke et al. of caries in animals. Bowen et al [1980] used the Konig- [1995] noted that milk chocolate produced a Hofer automatic feeding system to find that chocolate considerable amount of acids. Pearce and Hampton had a moderate cariogenic potential in rats. However, [1987], being among the few to describe the tests Morrisey et al. [1984], with a similar experimental products with their commercial names, found milk chocolate (Cadbury’s Milk) to be of intermediate cariogenicity in vitro. Mörch [1961] assessed the effects of , or foods containing carbohydrates, on Department of Paediatric Dentistry, Leeds Dental Institute, Leeds, England plaque pH. Milk chocolate was included to the study and gave a considerable effect in pH values within a

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short period of time, but the values tended to return to chocolate confectionery might be a factor influencing the normal more quickly than other tested products. cariogenic response of different type and their Macpherson and Geddes [1990] supported these results. acidogenic potential was considered worthy of study. Edgar et al. [1975] used the plaque sampling The purpose of this study was to assess the acidogenic technique to measure the effects of 54 different snack response of plaque to chocolates with varying cocoa foods on plaque pH. In their research milk and the dark contents, those containing hazelnuts and diet chocolate. chocolate were ranked among the least acidogenic foods. These latter results have been confirmed by Rugg-Gunn et al. [1975]. Materials and methods The majority of plaque pH studies have compared one Subject selection. Fourteen volunteers were selected type of chocolate with other commonly consumed according to the criteria laid down by the plaque pH products and assumptions made about their relative committee of Food, Nutrition and Dental Health of the cariogenicity. Frostell [1970] carried out experiments in American Dental Association [Harper et al., 1986]. order to evaluate the effects of different types of Consenting subjects were included in the study if they chocolates on the pH of dental plaque. This study is were fit and healthy, aged between 16-50 years, with a among the few where the effects of different chocolates DMFS≥ 12 and with at least 20 teeth. Moreover, a drop were compared. The criteria to select the tested products in plaque pH below 5.5 on challenge for 1 minute with were the concentration of sucrose and cocoa substances. 10 ml of 10% sucrose solution had to be achieved. Stephan curves were created by using the plaque Test products. Seven commercially available sampling technique and it was found that the chocolate chocolates were selected for the study. Plain European with a high concentration of cocoa and low and English chocolates were chosen to assess the effect concentration gave an increased plaque pH. The cocoa of different cocoa levels. European chocolate has a high and sucrose poor chocolate gave less pronounced pH cocoa content (70%) as compared with English decrease than the sucrose rich chocolate. chocolate (34%). For the same reason a Milk European Although chocolate is among the foods that are (30% cocoa) and Milk English (20% cocoa) chocolates considered as cariogenic, this review of the literature has were tested. In addition a Milk chocolate containing revealed that chocolate’s cariogenicity might be low to hazelnuts (20% cocoa) was included to examine any moderate. Also, there are only few studies where the effect of addition of nuts on the plaque pH. A white different have been studied whereby chocolate, which did not contain any , was mainly milk and plain (dark) chocolates have been selected. Finally, in order to study the effect of chocolate compared with a number of other foods, mainly snacks, with very low levels of fermentable carbohydrates on or were used as products with known cariogenic plaque pH, a diet chocolate was included in the study. potential in order to compare other foods or to assess The compositional details of the test products were as methodologies. follows (see also Table 1 with some nutritional, cocoa There are some other factors that should be considered and milk content information): regarding the cariogenic potential of chocolates. 1 - Swiss reduced fat, plain chocolate, no added sugar, Different regulations regarding chocolate manufacturing, Boots (Diet chocolate); constituents, and definitions exist between various 2 - Lindt, Excellence Dark, 70% cocoa Extra Fine Dark European countries [Beckett, 1999; Bixler and Morgan, Chocolate, Chocolate Negro (Plain European 1999]. For instance, UK chocolate follows different chocolate); regulations than the other countries of the European 3 - Cadbury’s, Bournville‚ The original plain chocolate Union and chocolate constituents are in different (Plain English chocolate); proportions. Cocoa and its extracts, which have been 4 -Cadbury’s, Dairy milk, Milk Chocolate (Milk reported to exhibit an anticariogenic action [Strålfors, English chocolate); 1967; Oosima et al., 1999], is one such constituent used 5 - Lindt‚ Excellence Milk, Extra Creamy, Extra Fine in different proportions and only in some cases have Milk Chocolate, Chocolate Con Leche (Milk these proportions been studied for any relationship to European chocolate); plaque acidogenicity. Additionally, cocoa levels in 6 - Nestle‚ Milkybar‚ Smooth Creamy-White Chocolate chocolate seem to be related to the percentages of the (White chocolate); other constituents, such as carbohydrates that might also 7 - Cadbury’s‚ Milk chocolate with Hazelnuts, whole influence the cariogenic potential. Furthermore, nut (Milk chocolate with hazelnuts); chocolates containing polyols had never been studied. 8 - 10% sucrose solution as a positive control; It was concluded that different cocoa proportions in 9 - 10% sorbitol solution as a negative control.

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Test chocolates Cocoa solids Milk solids Protein Fat CHO (% min) (% min) (g) (g) (g)

Diet chocolate NK - 5.5 25 61 Plain European chocolate 70% - NK NK NK Plain English chocolate 34% - 4.6 26.7 59.6 Milk English chocolate 20% 20% 7.8 29.4 56.8 Milk European chocolate 30% 20% NK NK NK White chocolate - NK 7.6 31.3 57.5 Milk chocolate/hazelnuts 20% 20% 9.2 34.4 48.4

CHO = carbohydrates NK = not known

TABLE 1 - Nutritional information per 100 g of chocolate for all the test chocolates with their cocoa (solids in %) and milk (solids in %) content.

The quantity of each chocolate tested was 15 g. A and control products and to swish them around all the person not related with the study in any way used a teeth for 1 minute before swallowing. Plaque samplings portable top-loading digital battery powered electronic were taken 2, 5, 10, 15, 20 and 30 minutes thereafter for balance and weighed the chocolate samples. These were the measurement of the plaque pH. The time was kept wrapped with aluminum foil in order to cover the with a timer (Tudor). chocolate samples and so that all looked identical. This Statistical evaluations. The data were analysed for the ensured that neither the examiner measuring plaque pH minimum pH, area under the curve, area under the curve nor any subjects knew which chocolate was being tested. below the “critical pH” equal to 5.7 and spent below the The samples were also coded, therefore, double blind, “critical pH” 5.7. The Acidogenic Potential Index (API) randomized, Latin Square, crossÐover in design was used. was also calculated for each chocolate. The area under Plaque Sampling (Harvesting) Technique and pH the curve for the sucrose was assigned as being equal to measurements. Plaque pH was measured using the 1 and the relative API of the other foods was calculated technique of Fosdick et al. [1957], as modified by as a ratio of this score. Finally, Stephan’s curves were Frostell [1970] and Rugg-Gunn et al. [1975]. Subjects plotted by using the mean pH values achieved by all 14 participating in the study were asked to refrain from subjects at predetermined time intervals. The aim of the tooth brushing at least for 48 hours and from eating or statistical analysis was to investigate how the above drinking anything apart from water at least 2.5 hours under investigation measurements for each chocolate prior to each visit. On each test day pooled plaque compared with sucrose and sorbitol and between the samples of approximately 1 mg were removed from six chocolates themselves. Therefore, for each chocolate the buccal surfaces, of posterior teeth representing all the following relationships were examined: quadrants of the mouth, using a sterile blunt explorer. - difference between the test chocolates, The collection time for each sample was standardized to - difference between test chocolates and the sucrose and be within 30 seconds. Each plaque sample was sorbitol controls. thoroughly mixed with 20 ml of distilled water, For data analysis, multiple comparisons were carried measured by a pipette into a disposable tray and carried out and because these were between many different with another clean pipette on an Ion Sensitive Field substances, Tukey’s HSD test was used in order to Transistor with a diameter of 10 mm connected to a correct for the increased chance of a false positive result. Sentron 2001 pH system. The reading was recorded after The SPSS 9.0 statistical program and Microsoft Excel 97 30 seconds and thereafter the electrode was cleaned with were used for the analysis of the data. a steam of distilled water and dried gently with soft tissue. The electrode was calibrated before starting the tests and in between measurements by using two Results buffering solutions of pH of 4.0 and 7.0. Following the screening procedure, 14 subjects A plaque sample was taken before the test products participated in the study with a mean age of 29.9 years, were consumed and a baseline plaque pH was recorded. a DMFS ranging between 13 to 39. The gender ratio, The subjects were then instructed to eat or drink the test female to male was 9:5.

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The Stephan’s curves created by using the mean pH Milk chocolate with hazelnuts (p<0.028). However, no readings achieved in relation to the time are shown in differences were observed between sucrose and the rest Figure 1. The mean minimum pH achieved from all the of the chocolates. Moreover, Diet chocolate did not tested products and the two controls are summarised in differ significantly from sorbitol. Table 2. It can be seen that use of the Plain European, The mean areas below the “critical pH” (5.7) for each Diet, and Milk chocolate with hazelnuts did not lead to of the test products including the two controls are a drop in the plaque pH below the “critical pH” that was presented in Table 3. It can be seen that the area below defined as 5.7. Sorbitol and Diet chocolate were 5.7 was the largest for sucrose with all the test chocolates statistically significantly different from sucrose showing a smaller area under pH 5.7 compared with (p<0.001). Plain European chocolate and Milk sucrose. Statistical analysis, however, revealed that chocolate with hazelnuts were also significantly sorbitol and Diet chocolate differed significantly from different as compared with sucrose (p<0.003 and sucrose (p<0.031), while none of the other test p<0.002 respectively) whereas the rest of the chocolates chocolates differed statistically from sucrose. were not significantly different. The mean time spent below the critical pH is shown in The results for the area below baseline plaque pH are Table 3. It can be seen that the plaque pH stayed below also shown in Table 2. The mean area below baseline 5.7 the longest with sucrose followed in order by Milk pH value was greatest for sucrose and smallest for European chocolate, Milk English chocolate, Plain sorbitol. The mean areas were also small for the Diet English chocolate, Milk chocolate with hazelnuts, White chocolate, Plain European chocolate, and Milk chocolate and Plain European chocolate. Diet chocolate chocolate with hazelnuts. Multiple comparisons did not depress plaque pH below 5.7 and therefore was revealed that there were significant differences between found to be similar to sorbitol. However, results for none the sucrose and the negative control, Diet chocolate of the test chocolates, except Diet chocolate, was (p<0.001), Plain European chocolate (p<0.006) and the significantly different as compared with sucrose. The Acidogenic Potential Index results are shown in Table 3. The APIs for Milk European chocolate and Milk English chocolate were very close to that of sucrose. The White chocolate and Plain English chocolate had moderate APIs and the rest of the chocolates below 0.5. Diet chocolate had an API very close to that of sorbitol.

Discussion Chocolate has been associated with dental caries by various researchers both positively and negatively, FIG. 1 - Stephan’s curves for all the test chocolates, sucrose although its role is uncertain. Rugg-Gunn et al. [1984] and sorbitol. found in their study that each child consumed a mean of

Tested products Mean minimum Mean area below pH (±SD) baseline plaque pH (±SD)

Sucrose 5.37±0.12 24.72±7.74 Sorbitol 6.67±0.33* 3.07±2.62* Diet chocolate 6.52±0.33* 4.02±3.84* Plain European chocolate 5.86±0.38* 11.59±11.33* Plain English chocolate 5.65±0.41 14.91±11.36 Milk English chocolate 5.56±0.28 19.40±8.68 Milk European chocolate 5.57±0.30 21.35±6.97 White chocolate 5.68±0.24 19.98±6.52 Milk chocolate with hazelnuts 5.87±0.39* 13.29±13.06*

TABLE 2 - Mean minimum pH and mean area below baseline plaque pH for all the test chocolates and controls (±SD).

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Tested products Mean area below Mean time below API “critical pH” (±SD) pH 5.7 (min, ±SD) Sucrose 1.38 6.91 1.00 (1.03) (3.29) Sorbitol 0.00* 0.00* 0.00 Diet chocolate 0.00* 0.00* 0.036 Plain European chocolate 0.20 2.15 0.41 (0.34) (2.79) Plain English chocolate 0.88 3.98 0.66 (1.23) (4.13) Milk English chocolate 0.90 4.41 0.93 (1.32) (5.15) Milk European chocolate 1.12 4.83 0.94 (1.78) (5.29) White chocolate 0.46 2.86 0.88 (1.12) (3.55) Milk chocolate with hazelnuts 0.60 3.23 0.45 (1.40) (6.71) *significantly different to sucrose

TABLE 3 - Mean area below “critical pH” (5.7), mean time spent below “critical pH” (minutes), and API for all the test chocolates and controls (±SD).

35 g of chocolate/day with mean frequency of intake begins to dissolve (“critical pH”) is not known, although 0.9/day. They found that those children who ate more widely assumed. According to Edgar and Geddes [1986], sweets and chocolates had more caries, but this this probably varies among individuals and among oral difference was not statistically significant, and concluded sites in any one individual and Harper et al. [1986] that sweet (candy) consumption was not as strong a mentioned that the dissolution of enamel is a result of factor for the occurrence of caries as others, e.g. oral what happens in the plaque, pellicle and enamel. hygiene and fluoride [Sundin et al., 1983]. In this study Edmondson [1990] suggested that the varying and adults were used as subjects while the results are critical level of saturation with and phosphate in reported for their applicability to children. Previously plaque and saliva was important, while Larsen and Tahmassebi and Duggal [1996] have compared plaque Pearce [1997] added that due to these variations the pH findings made on both adults and children when “critical pH” of the plaque varies correspondingly. using the same test materials. They found that the Different estimates of “critical pH” have ranged from response in children was less than in adults. Thus any 5.7 to 5.5 or lower [Margolis and Moreno, 1992]. results of plaque pH response in adults will be greater Prolonged pH drop is considered to be more harmful than in children. Suitable adult subjects are considerably than that of short duration. In addition, the depth of the easier to find than children. In this study the findings on pH drop within a certain period of time is proportional adults are, therefore, directly applicable to children. to the potential dissolution of enamel. This Data from plaque pH studies have been presented in proportionality, however, does not accord with the many forms, such as using minimum pH, time and areas concept, as enamel apatite solubility is not proportional under given pH values. Clearly, a substrate that does not to pH. Moreover, the function of concentration of H+ is cause any drop in plaque pH will probably have no related closely to solubility of apatite in a sense that both detrimental effects on teeth. The amount of time that pH solubility and concentration of H+ increase remains depressed is important and time spent under logarithmically with decreasing pH. different pH values is probably indicative of a food’s In this study it was found that Plain English, Milk retentiveness and may have an effect on its cariogenicity. English, Milk European, and White chocolates depressed However, the chemistry of the tooth surface should be the pH below pH 5.7 (not significantly different to taken into account, as there are variations among the sucrose). The rest of the chocolates (Diet, Plain European, tooth surfaces and food retention or salivary access Milk with hazelnuts) were found to give results [Harper et al., 1986]. The pH value at which enamel statistically different to sucrose. There are only very few

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studies where comparisons between different types of only Diet chocolate was significantly different from chocolate have been carried out selected according to the sucrose. Mörch [1961] reported that the time at cocoa level [Strålfors, 1966a; 1966b], therefore our minimum pH spent with milk chocolate was short as the results cannot be compared to that obtained from other plaque pH values returned to normal very quickly. studies. Edgar et al. [1975] reported only the presence of Because the time spent below pH values, and especially milk and semi-sweet flavours as chocolate constituents of the “critical pH”, could characterise food retention, it interest. The cocoa and levels were not should be more widely tested or used as an index of given. They found that milk chocolate and dark chocolate cariogenicity. Linke et al. [1991] found that the amount gave a minimum pH of 6.06 and 6.10 respectively, values of acids produced from milk chocolate could hardly be that are higher than that obtained from our study. Bibby detected two hours after consumption, while Kashket et and Mundorff [1975] reported minimum pH values of al. [1991] reported that milk chocolate was not 5.85 and 5.65 respectively for dark and milk chocolate detectable at 2 minutes after consumption. (no constituent proportions reported) that are similar to Bibby and Mundorff [1975] found milk chocolate to those for Plain European chocolate and both Milk have a moderate retentiveness, and food retention is also chocolates reported here. On the other hand, Jensen and dependant on the amount that is consumed. However, Schachtele [1983a], using in-dwelling electrode milk chocolate has shown high retention, independent of telemetry, reported a minimum plaque pH of 4.54 with the amount, followed by rapid rates of clearance milk chocolate. Similar results were presented for milk [Kashket et al., 1991] as a high sugar content results in chocolate of a minimum pH 4.6, recorded with touch rapid clearance due to stimulation of salivary [Bibby and electrode, from Harper et al. [1985a], while in another Mundorff, 1975]. study done by the same authors [1985b] minimum plaque It was found that, with sucrose having an API of 1.00, pH given from milk chocolate was 5.2 when measured the Milk English chocolate and Milk European chocolate with indwelling electrode and 6.0 with the touch had high scores, White chocolate and Plain English electrode. Koparal et al. [1998] reported a minimum pH chocolate moderate scores. The rest of the chocolates value of 5.50 when milk chocolate was tested in children had APIs equal or lower than 0.4. Although API has been with a touch electrode. However, there are differences in previously calculated for a number of foods [Gardiner et the research designs for these studies and the ways in al., 1997; Tahmassebi, 1993] it has not been estimated which the pH measurements were carried out. for chocolates. Nevertheless, in animal studies a CPI Futhermore, not all the studies reported the chocolate (Cariogenic Potential Index) was reported to be 0.72. constituent proportions. For instance, differences in the Mundorff et al., [1990] ranked USA milk chocolate to values obtained by different plaque pH monitoring have CPI equal to 0.8. In our study, the API of Plain methods [Jensen and Schachtele, 1983b] or differences in English chocolate was 40% less than that of sucrose, plaque reactions following cariogenic challenge in while Plain European and Milk chocolate with hazelnuts children and adults [Tahmassebi, 1993; Koparal et al., had an API of less than half that of sucrose. 1998] might influence the results. It was clear from our Diet chocolate was found to be significantly different study that the minimum pH value obtained with all the to sucrose in all the parameters tested. The levels of chocolates was higher than that with 10% sucrose cocoa were not available, however Diet chocolate solution. As far as the mean area below baseline is contained aspartame and acesulfame K instead of concerned, only Diet, Plain European and Milk chocolate sucrose, generally found to be anticariogenic [Das et al., with hazelnuts were significantly different from sucrose. 1997], to prevent the fall in plaque pH [Mishiro and For the mean area below pH 5.7, only Diet chocolate Kaneko, 1977] and the adherence of plaque formed by was found to be statistically significant different to Mutans Streptococcus [Olson, 1977]. Acesulfame K has sucrose. It is not surprising that Diet chocolate and Milk also been found to have anticariogenic action [Ziesenitz chocolate with hazelnuts gave higher pH readings and and Siebert, 1986]. Moreover, Edgar and Dodds [1985] therefore a smaller area under the curve. It is interesting to stated that the most probably beneficial action of these note that the Plain European chocolate also produced a sweeteners is the stimulation of salivary flow and thus smaller area under the curve as compared with sucrose. raising the plaque pH. Krasse [1985] reported from the This might be attributed to a higher cocoa content in this literature that chocolate with sweeteners belonged to the chocolate. European chocolates have a higher cocoa group with low cariogenic potential. content than the English chocolates and therefore this Studies had shown the low cariogenicity of nuts might have influenced the plaque pH. Previous studies had [Mundorff et al., 1990] while others reported that if nuts shown an anticariogenic action of cocoa [Strålfors, 1967]. were given after sugar, it could raise the plaque pH For the time spent below critical pH it was found that effectively [Geddes et al., 1977]. One of the chocolates

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used in this study was Milk chocolate with hazelnuts should not be considered as entirely “safe for teeth” and (Milk English chocolate with added nuts). According to frequent consumption by children of any food containing this study, Milk English chocolate was not significantly fermentable carbohydrates should be avoided. Diet different to sucrose, however when nuts were added the chocolate was found to have a low API and was effects on plaque pH could be attributed to the presence significantly different to sucrose, similar to sorbitol in its of the nuts in the chocolate. effect on plaque pH. Milk European chocolate, Milk White chocolate is made using all the conventional English chocolate and White chocolate were found to be ingredients of chocolate except for cocoa solids. It similar to sucrose and with high API. Moderate to low contains whole milk powder that has a number of APIs were found for Plain English chocolate and Plain constituents that exhibit anticariogenic action such as European chocolate. The area below and the time spent casein [Reynolds and Black, 1987], protein in below ‘critical pH’ of 5.7 were not significantly different bovine milk [Reynolds and Del Rio, 1984], calcium and to sucrose. Milk chocolate with hazelnuts gave phosphorus [Rugg-Gunn, 1993]. The chocolate that we significantly lower area under the ‘critical pH’ and spent tested contained cocoa and vegetable fats (31.3 significantly less time below ‘critical pH’ as compared g/100 g) and carbohydrates (57.5 g/100 g). The presence with sucrose with moderate API of less than half of that of fat in a diet seems to accelerate clearance [Brudevold of sucrose. et al., 1990] and therefore reduces the acidogenic potential of foods. Nevertheless, Brudevold et al. [1990] emphasised that the relationship between fat content and References oral clearance rate (and plaque pH values consequently) Beckett ST. Industrial chocolate, manufacture, and use. 3rd edition. depended on the type of fat and other procedures, for Oxford: Blackwell Science; 1999. example cooking procedures. Bibby BG, Goldberg HJ, Chen E. Evaluation of caries-producing As this study failed to show any differences between potentialities of various foodstuffs. J Am Dent Assoc Milk English and Milk European chocolate it can be 1951;42(5):491-509. concluded that the difference in cocoa solids between Bibby BG, Mundorff SA. Enamel demineralization by snack foods. J the two chocolates was not of a significant level to Dent Res 1975 May-Jun;54(3):461-70. influence their acidogenic potential. Moreover, it can be Bixler RG, Morgan NM. Cacao bean and chocolate processing. assumed that the concentration of sugar into Milk Chapter 3. In: Knight I. 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Caries Res 1997;31(1):78-83. a high carbohydrate concentration (59.6 g/100 g of Edgar WM, Bibby BG, Mundorff S, Rowley J. Acid production in chocolate) and no milk solids; therefore it was found to plaques after eating snacks: modifying factors in foods. J Am Dent have a moderate acidogenic potential (API: 0.66) when Assoc 1975 Feb;90(2):418-25. compared with the other test chocolates. Plain European Edgar WM, Dodds MW. The effect of sweeteners on acid production chocolate was found to be moderately acidogenic (API: in plaque. Int Dent J 1985 Mar;35(1):18-22. 0.41), probably due to high concentration of cocoa Edgar WM, Geddes DAM. Plaque acidity models for cariogenicity solid, although the area below pH 5.7 and the time spent testing - some theoretical and practical observations. J Dent Res below this level was less than sucrose. However, the API 1986;65(Special Issue):1498-502. was less than half that of sucrose. Edmondson EM. Food composition and food cariogenicity factors affecting the cariogenic potential of foods. Caries Res 1990;24 Suppl 1:60-71; discussion 72-9. Conclusion Fosdick LS, Englander HR, Hoerman KC, Great Lakes MS, Kesel RG. Some chocolates, particularly the Plain European A comparison of pH values of in vivo dental plaque after sucrose chocolate (high cocoa content) and the Milk chocolate and sorbitol mouth rinses. J Amer Dent Assoc 1957;55:191-5. with hazelnuts had a lower acidogenic potential than Frostell G. A method for evaluation of acid potentialities of foods. sucrose. However, it should be remembered that they Acta Odontol Scand 1970 Nov;28(5):599-622.

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