|Year : 2010 | Volume
| Issue : 3 | Page : 189-192
Evaluation of acidity and total sugar content of children's popular beverages and their effect on plaque pH
S Saeed1, M Al-Tinawi2
1 DDS, Specialist in pediatric dentistry, Department of Pediatric Dentistry, Faculty of Dentistry, Damascus University, Syrian Arab Republic
2 Professor, Department of Pediatric Dentistry, Faculty of Dentistry, Damascus University, Syrian Arab Republic
|Date of Web Publication||11-Dec-2010|
Department of Paediatric Dentistry, Damascus University, Syrian Arab Republic Mazzeh Highway, Damascus, Syria
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: In the developing countries, dental caries has increased with the increased exposure to dietary sugars. There is no data on the cariogenicity and acidogenicity of popular beverages in the Syrian market. Aims: To investigate the endogenous pH, titratable acidity, and total sugar content of popular beverages (cola, orange juice, and full-fat milk), and assess plaque pH drop after consumption. Settings and Design: Twenty-five healthy children with a mean age of 11.8 ± 0.6 years were recruited for this single blinded study. Materials and Methods: The pH of beverages was measured by a digital pH meter and the titratable acidity was expressed as the volume of 0.1 N sodium hydroxide required to neutralize the beverage. The total sugar content was estimated using High Performance Liquid Chromatography. Children rinsed with 15 mL of each of the beverages for 1 min. The controls used were 10% sucrose and 10% sorbitol solutions. The plaque pH was assessed before and after rinsing. Statistical Analysis: Statistical analysis was performed using analysis of variance followed by Bonferroni test to assess minimum pH, maximum pH drop, and the area under curve. P value was set as 0.05. Results: Both cola and orange juice had a low pH and similar total sugar content in contrast to the high pH and low sugar content of milk. Cola and orange juice were not statistically different from 10% sucrose (P > 0.05), but different from 10% sorbitol (P < 0.05), in contrast to milk, for all the parameters studied. Conclusion: Cola and orange juice are cariogenic/acidogenic and frequent intake should be discouraged. A reasonable intake of unsweetened milk may be advised safely.
Keywords: Beverages, dental caries, dental erosion, plaque pH
|How to cite this article:|
Saeed S, Al-Tinawi M. Evaluation of acidity and total sugar content of children's popular beverages and their effect on plaque pH. J Indian Soc Pedod Prev Dent 2010;28:189-92
|How to cite this URL:|
Saeed S, Al-Tinawi M. Evaluation of acidity and total sugar content of children's popular beverages and their effect on plaque pH. J Indian Soc Pedod Prev Dent [serial online] 2010 [cited 2019 Feb 16];28:189-92. Available from: http://www.jisppd.com/text.asp?2010/28/3/189/73783
| Introduction|| |
Contemporary fluid consumption patterns of children are more diverse than in the past years, since carbonated soft drinks and fruit juices have replaced much of the previous consumption of water and milk among children. 
Soft drinks, in contrast to milk and water, have been suggested as causing damage to the teeth for two reasons. Firstly, the low pH and high titratable acidity of some drinks may lead to erosion of the enamel surface. Secondly, the sugars in these drinks are metabolized by plaque microorganisms to generate organic acids that bring about demineralization leading to dental caries. 
Tahmassebi  concluded that plaque pH responses were significantly less acidic in children as compared with adults. Therefore, acidogenicity studies of children's foods and drinks should be carried out in children rather than in adults.
Aims and objectives
To investigate the total sugar content, endogenous pH, and titratable acidity of commercial beverages (cola, orange juice, and full-fat dried milk), and assess dental plaque pH drop after consumption in a group of healthy children.
| Materials and Methods|| |
Three beverages were selected for the study, a cola-type drink (pepsi cola), orange juice (fruity), and full-fat dried milk (Nido).The initial pH of each drink was measured using a digital portable pH meter (Orion model 230A, Thermo Scientific Inc., Beverly, MA, USA) on opening or preparing the product. The electrode was calibrated before measurement using standard buffers of pH 4.0 and 7.0. Measurements were repeated in triplicates for each drink. Titratable acidity was estimated by calculating the volume of 0.1 N sodium hydroxide required to neutralize 50 mL of the beverage. Titrations were repeated in triplicate. The cola-type drink was degassed before titration by vigorous stirring. The total sugar content was estimated using High Performance Liquid Chromatography (HPLC). Regarding the in vivo study, ethical approval was obtained from the Ethical Committee of the Damascus Dental School as well as the informed consent from the children's parents, and the child's verbal consent was gained after the verbal and written explanation of the tests were discussed with the child and the parent. Twenty-five healthy subjects (11 males, 14 females) whose mean age was 11.8 ± 0.6 years and mean number of decayed, missing, and filled teeth (DMFT) was 2.32 ± 2.88 were selected for the study. Exclusion criteria included subjects on antibiotic therapy 2 weeks before the test session, with xerostomia, with lactose intolerance, allergy to any of the test products, or wearing orthodontic appliances. All subjects were required to refrain from brushing their teeth or using any oral hygiene aid for 48 h and to abstain from any food or drink (except water) for at least 2 h 30 min before each test session. Each volunteer was seen at the same time of the day to avoid changes in the circadian rhythm. These criteria conformed to the guidelines of the Plaque Acidity Working Group of the Food, Nutrition, and Dental Health Committee of the American Dental Association.  On each test day, a sample of plaque was taken from the buccal surfaces of six sites of the subject's teeth representing all quadrants using a sterile excavator. The subjects were asked to swallow immediately before plaque collection to minimize salivary contamination, and during sample collection, care was taken to avoid contamination with blood or saliva or plaque deposited on restorations. This formed the baseline plaque sample. The collection time for each sample was standardized (within 30 s). The plaque sample was mixed with 20 ΅L of distilled water and the pH was measured with a micro-combination electrode (Orion model 9802BN, Thermo Scientific Inc.) in conjunction with a portable pH meter (Orion model 230A, Thermo Scientific Inc.). The pH was read after allowing the reading to stabilize for 30 s. The volunteers then rinsed their mouths thoroughly with 15 mL of one of the test drinks for 1 min. The plaque samples were harvested from the same areas of teeth at 2, 5, 10, 15, 20, and 30 min after rinsing, and the pH of each sample was measured as before. Calibration of the system was carried out using standard solutions of pH 7.0 and 4.0 before each test. In between each reading, the electrode was cleaned with a stream of distilled water and placed in a standard solution of pH 7.0.
Each volunteer received one of the test drinks in a randomized order, with at least a 7-day interval between each test day to avoid any carryover effect. Solutions of 10% sucrose and 10% sorbitol were used as controls.
Three parameters were extracted: minimum pH, maximum pH drop from baseline, ∆pH, and area under curve (AUC), that is, the area enclosed by the plaque pH curve and the baseline.
Statistical evaluation was performed using analysis of variance (ANOVA) followed by the Bonferroni test. Statistical significance was assessed at the conventional level of 5%.
| Results|| |
The physicochemical properties of the beverages are presented in [Table 1].
The mean values of minimum pH (±SD), maximum pH drop (±SD), and the area under the baseline pH (±SD) are presented in [Table 2].
|Table 2: The mean values of minimum pH (±SD), maximum pH drop (±SD), and the area under the baseline pH (±SD) |
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Stephan curves of the beverages using the mean readings at each time interval are illustrated in [Figure 1].
|Figure 1: Stephan curves of the beverages using the mean readings at each time interval|
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ANOVA test showed a significant difference among the beverages for all the parameters.
Bonferroni test showed that there were no significant differences between cola and orange juice and also between both products and 10% sucrose (P ≥ 0.05) for minimum pH, maximum pH drop, and AUC. On the other hand, milk was statistically different from 10% sucrose, cola, and orange juice (P ≤ 0.05), but not from 10% sorbitol for all the parameters studied.
| Discussion|| |
This study showed that the inherent pH of a beverage gave no indication of the underlying titratable acidity and, therefore, the erosive potential of the drink. Pure fruit juices had a higher initial pH than the carbonated drinks but required much more sodium hydroxide to raise the pH. This study is in agreement with those of Edwards et al.  and Grenby et al.  However, milk had a remarkably higher pH and the lowest titratable acidity. The ranking of both pH and buffering capacities of the beverages studied is similar to that of Lehl et al. 
The plaque pH measurement method has been used in many studies and widely accepted as it provides a valuable guide to the cariogenicity of food.  Plaque pH methods would satisfactorily identify nonacidogenic foods when compared with appropriate positive (sucrose) and negative (sorbitol) controls.  The fall in plaque pH itself has been correlated with the caries increment.  This study used the harvesting method, an appropriate method for ranking the cariogenicity of food by their acidogenicity. 
The volunteer children who participated in this study were not selected according to their ability to produce a large drop in the plaque pH with a 10% sucrose rinse due to the difficulty of getting cooperative children.
The plaque pH in this study was apparently higher than those of the previous reports due to the difference in the method of plaque pH measurement and/or the subject age and selection criteria.
In the present study, the mean minimum plaque pH, ∆pH, and AUC values for cola were not significantly different from 10% sucrose, which is in accordance with the findings of Bowen  on desalivated rat model and Koparal et al.  Orange juice was not significantly different from 10% sucrose for all the parameters studied and the shape of the plaque pH curve for orange juice in comparison with sucrose is explained by the inherent acidity rather than acid production in plaque. This result is in agreement with the findings of Hussein et al.  This is explained by the comparable values of total sugar content of both cola and orange juice with sucrose in this study. Frostell  showed that all sugars have virtually the same potential for acid production in plaque as sucrose. However, Johansson et al.  stated that Coca-Cola caused a slightly more pronounced drop in pH during the first few minutes than it did with orange juice using the microtouch method.
On the other hand, milk was significantly different from 10% sucrose for minimum pH, ∆pH, and AUC, which is in accordance with the findings of Koparal et al.  and Bowen et al.  It was interesting to note, in this study, that dental plaque pH did not reach minimum pH after rinsing with milk until after 10-20 min. This is explained by the presence of casein in milk that may act as a buffer against plaque pH depression in the initial period. 
The area under baseline pH is considered to be a more important parameter in plaque acidity studies than minimum plaque pH, as it takes into account both pH values and the time that plaque pH is actually depressed. The same trend was found for both the maximum pH drop and the AUC supporting the findings of the minimum plaque pH results.
Reports have been published on excessive or unusual consumption of acidic fruits, fruit juices, and acidic beverages and its relationship to dental erosion. 
One hundred percent fruit juice, which contains about the same amount of sugar as soft drinks, can be cariogenic if consumed frequently. The cariogenicity of sugared drinks is determined not only by their potential to induce demineralization of the enamel, but also by the frequency of consumption. 
Therefore, parents should be informed about the detrimental effects of excessive consumption of these beverages.
Further research is needed on the effect of consumption of these beverages in combination with protective foodstuffs or after dilution to minimize its harmful effects.
| Conclusion|| |
Cola and orange juice are cariogenic/acidogenic, and therefore their frequent intake should be discouraged, especially among children by whom such beverages may be overconsumed. Unsweetened milk may be a safe alternative if consumed sensibly. The role of the dental profession in promoting the awareness on the detrimental effect of carbonated and noncarbonated beverages on dental health is essential, and the emphasis should be on safer patterns of consumption.
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[Table 1], [Table 2]
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