|Year : 2016 | Volume
| Issue : 1 | Page : 10-16
pH modulation and salivary sugar clearance of different chocolates in children: A randomized clinical trial
SVSG Nirmala, Mohammed Akhil Quadar, Sindhuri Veluru
Department of Paedodontics and Preventive Dentistry, Narayana Dental College and Hospital, Nellore, Andhra Pradesh, India
|Date of Web Publication||2-Feb-2016|
Department of Paedodontics and Preventive Dentistry, Narayana Dental College and Hospital, Nellore - 524 003, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Sugars that occur naturally in foods and those added in processed foods may act as the source for fermentable carbohydrates and may initiate caries process. Among all the foods consumed by children, chocolates form an important constituent. A wide variety of chocolates are available in the Indian market and very few studies have compared their acidogenicity and salivary sugar clearance. Objectives: To compare the acidogenicity and salivary sugar clearance of 6 different commercially available chocolates in the Indian market. Materials and Methods: Thirty subjects aged 10-15 years were selected randomly from one of the available public schools in Nellore city. Six commercially available chocolates in the Indian market were divided into three groups, unfilled (dark and milk chocolate), filled (wafer and fruit and nuts chocolate), and candy (hard milk and mango-flavored candy) groups. Plaque pH values and salivary sugar clearance rates are assessed at baseline, 5, 10, 15, 20, and 30 min after consumption. All the data obtained were statistically evaluated using independent sample t-test and one-way ANOVA for multiple group comparisons. Results: Mango-flavored candy had maximum fall in plaque pH and least fall in plaque pH was recorded with milk chocolate. Fruit and nuts chocolate had a maximum clearance of salivary sugar and least fall in the salivary sugar clearance was recorded with dark chocolate. When the plaque pH and salivary sugar clearance of all the chocolates were assessed, it was seen that the values were statistically significant at all the time intervals (P < 0.05). Conclusion: Dark chocolate had a high fall in pH and milk chocolate had low salivary sugar clearance which signifies that unfilled chocolates are more cariogenic than other chocolates. Even though mango-flavored candy had maximum fall in plaque pH, its salivary sugar clearance was high.
Keywords: Candies, chocolates, plaque pH, salivary sugar clearance
|How to cite this article:|
Nirmala S, Quadar MA, Veluru S. pH modulation and salivary sugar clearance of different chocolates in children: A randomized clinical trial. J Indian Soc Pedod Prev Dent 2016;34:10-6
|How to cite this URL:|
Nirmala S, Quadar MA, Veluru S. pH modulation and salivary sugar clearance of different chocolates in children: A randomized clinical trial. J Indian Soc Pedod Prev Dent [serial online] 2016 [cited 2019 Sep 22];34:10-6. Available from: http://www.jisppd.com/text.asp?2016/34/1/10/175502
| Introduction|| |
The knowledge of dentistry was protracted, ever since there has been conjecturing about the source of dental caries. In the present day, all connoisseurs generally agree that dental caries is an infectious and communicable disease and that manifold factors influence the instigation and evolution of the disease.  It is broadly accepted that all foods containing "fermentable carbohydrates" have the prospective to subsidize to caries formation. 
Dental caries is instigated by the ingestion of fermentable carbohydrates, which are converted into organic acids by bacteria in dental plaque. The rise in acidity can cause demineralization.  The interface between chocolate and dental caries has been assessed by using several approaches, which are available to assess the relationship between diet and dental caries. Most of the plaque pH studies have compared one type of chocolate with the other frequently disbursed products, and suppositions were made about their virtual cariogenicity. 
Though chocolates are considered cariogenic food, their cariogenic nature may vary from low to moderate. Moreover, there is limited availability of literature on the composition of different chocolates such as milk and plain chocolates that have been compared with snacks and other foods with known cariogenicity. ,
Some other elements that should be considered regarding the cariogenic potential of chocolates are multifarious conformities regarding its manufacturing, its ingredients, and its disparities that exist between different countries. ,
Since cariogenic properties are, comparatively, related to the retention time of carbohydrates in the mouth as a result of their acidogenicity, the role of saliva in oral carbohydrate clearance is also of primary interest. The salivary clearance of sugars is prejudiced by the properties of the foodstuff,  the sum of ingested carbohydrate,  the sampling site in the mouth, , and physiological factors such as salivary flow rate and the volume of saliva in the mouth before and after swallowing. , Estimation of carbohydrates in foods was done by analytical methods, enzymatic methods, ,, and chromatographic techniques including paper chromatography and thin-layer chromatography. ,
The purpose of this study was to assess the acidogenic response of plaque to various chocolates available in the Indian market and to assess the clearance rate of various chocolates from the saliva in vivo.
| Materials and Methods|| |
After obtaining Institutional Ethical Committee approval, a total of 30 subjects (15 boys and 15 girls) aged 10-15 years were selected through lot randomization from a public school in Nellore city, which gave consent to the study from 17 th to 21 st February 2015. Six commercially available chocolates in the Indian market were divided into three groups, as unfilled, filled, and candy groups. Each one of the groups consists of 10 subjects correspondingly (5 boys and 5 girls). Unfilled chocolate group includes plain milk and dark chocolates, whereas filled chocolate group contains fruits and nuts and wafers and candy group includes hard milk candy and mango-flavored candy. The quantity of each chocolate tested was 15 g.
Subjects with decayed-missing-filled teeth value ranging from 0 to 3 and those who are co-operative and willing to participate in the study.
Subjects who were having active carious lesions, any oral soft tissue pathology, with any systemic illness, and those who are on any antimicrobial therapy were excluded from the study.
Plaque sampling technique and pH measurement
Frostell  and Rugg-Gunn et al.  technique was used to measure plaque pH prior to the sample collection and participants were instructed neither to brush at least for 48 h nor to eat or drink at least 2 h apart from water. Sterile blunt explorer was used to collect plaque, approximately 1 mg from buccal surface of 4 posterior and 2 anterior teeth, which represents all the quadrants of mouth. Later, 20 ml of distilled water was added to each plaque sample and then thoroughly mixed followed by pH recording. The apparatus was precalibrated using two buffering solutions of pH 4.0 and 7.0 and electrode tip was cleaned with distilled water prior to and in-between each sample. 
A plaque sample was taken before the test products were consumed, which represents baseline plaque pH. The subjects were then instructed to eat the chocolates. Plaque samples were taken at 5, 10, 15, 20, and 30 min after the consumption of chocolates. Thereafter, the measurement of plaque pH was done with the help of portable standard digital pH meter with glass microelectrode (model Eq-612 with stand for the pH electrode, Elico Electronics, Mumbai).
Salivary sugar clearance rate of various chocolates
The subjects are instructed not to eat or drink anything (except water) for 2 h before the collection of saliva sample. Before intake (baseline) and 5, 10, 15, 20, and 30 min after the intake of chocolates, approximately 20 μl of saliva was collected in plastic test tubes which are commonly used for saliva sample collection (CB PLUS, Quantum Biomedicals, India). After thawing and centrifugation, the concentration of glucose was analyzed enzymatically.
All the data obtained were statistically evaluated using independent sample t-test and one-way ANOVA for multiple group comparisons.
| Results|| |
Determination of plaque pH values was done for all the groups before the consumption of chocolates. Plaque pH values declined after the consumption of chocolates in all the three groups and remained the same until 30 min [Graph 1].[Additional file 1]
The drop in pH for unfilled group was statistically significant between 5-10 and 20-30 min, but the pH changes seen from 15 to 20 min after consumption were not statistically significant. It was found that the maximum drop of pH was seen with respect to dark chocolate (5.41) and milk chocolate (5.82) at 30 min, suggesting milk chocolate was less cariogenic in the unfilled group [Graph 1].
Likewise, in the filled group, a maximum drop of pH was seen with wafer chocolate (5.58) and fruit and nuts chocolate (5.74), at 30 min, suggesting fruit and nuts chocolate was less cariogenic [Graph 1].
Similarly, in the candy group, it was more significant with mango-flavored candy (4.68) when compared with hard milk candy (5.65), at 30 min, suggesting hard milk candy to be less cariogenic [Graph 1].
When the chocolates of all the three groups were assessed, it was found that the plaque pH was statistically significant at all the time intervals (P < 0.05). Mango-flavored candy had the maximum fall in plaque pH making it most cariogenic followed by dark chocolate, and least fall in plaque pH was recorded with milk chocolate making it least cariogenic [Table 1] and [Graph 1].
|Table 1: Descriptive statistics of plaque pH of three groups at different time intervals|
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When the intergroup comparison of plaque pH values of three groups was done at different time intervals, it was observed that the comparison between Group I and II, Group II and III, and Group III in relation to Groups I and II was statistically significant at baseline, 5, 10, 15, 20, and 30 min, respectively [Table 2].
|Table 2: Intergroup comparison of plaque pH of three groups at different time intervals|
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Regarding salivary sugar clearance rate, among all the three groups, it declined immediately after the consumption of the chocolates and remained to continue until 30 min except for the dark chocolate where the clearance in the salivary sugar started after 5 min of consumption.
Clearance of the salivary sugar for unfilled group was statistically significant after 5 min, 15 min, and 30 min, but the salivary sugar clearance after 10 and 20 min of consumption was not statistically significant. It was found that the maximum clearance of salivary sugar was seen with respect to the milk chocolate (mean difference-4.2) and for dark chocolate (mean difference-3.8) at 30 min, suggesting milk chocolate to be less cariogenic.
Salivary sugar clearance for filled group was statistically significant after 30 min, whereas the clearance of the salivary sugar after 5, 10, 15, and 20 min of consumption was not statistically significant. It was found that the maximum clearance of salivary sugar was seen with respect to the fruit and nuts chocolate (mean difference-7.4) and for wafer chocolate (mean difference-5.4) at 30 min, suggesting fruit and nuts chocolate being less cariogenic.
Salivary sugar clearance for candy group was statistically significant after 5, 10, 15, 20, and 30 min of consumption. It was found that the maximum clearance of salivary sugar was seen with respect to mango-flavored candy (mean difference-5.6) and for hard milk candy (mean difference-4.4) at 30 min, suggesting mango-flavored candy to be less cariogenic.
When three groups were assessed, it was observed that salivary sugar clearance was statistically significant at all the time intervals (P < 0.05). Fruit and nuts chocolate had a maximum clearance of salivary sugar making it least cariogenic followed by mango-flavored candy, and the least fall in salivary sugar clearance was recorded with dark chocolate followed by milk chocolate making it most cariogenic [Table 3] and [Graph 2][Additional file 2].
|Table 3: Descriptive statistics of salivary sugar clearance of three groups at different time intervals|
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When the intergroup comparison of salivary sugar clearance of three groups was done at different time intervals, it was seen that the comparison between Group I and II, Group II and III, and Group III in relation to Groups I and II was statistically significant at baseline, 5, 10, 15, 20, and 30 min, respectively, except at the baseline between the Groups I and II where the comparison was not significant [Table 4].
|Table 4: Multiple group comparison of salivary sugar clearance rate values|
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| Discussion|| |
Chocolates have been found to be associated with dental caries both positively and negatively, even though no significance has been proved for or against chocolates.  In this study, subjects aged 10-15 years were included as the maximum chocolate consumption will be seen in the children and adolescents when compared to that of the adults.
Chocolates are commonly available as different types in the market. Studies were done on chocolates have primarily focused on cariogenic potential; however, the cariogenic potential of chocolates depends on other factors such as sugar content, high frequency of intake, bedtime consumption, reduced salivary flow, and critical pH. Reduced salivary flow during sleep limits natural cleaning and buffering, so caries risk of the child increases significantly. However, children who take sticky chocolates infrequently are also at a risk if they do not follow the oral hygiene measures.
Decreased salivation and lack of masticatory movements during night increase the cariogenic potential of chocolates. Information regarding the relation between viscosity and dissolution of dental hard tissues is few in the literature and also shows variations in the results of studies. This may be due to using minimum pH and time and areas under given pH values.
A substrate which do not cause any drop in plaque pH has shown no detrimental effects on teeth substance was evident. The amount of time that pH remains acidic and the time spent under different pH conditions is an important indicator of food retention in the oral cavity, which in turn causes caries. 
Different appraisals of "critical pH" varies from 5.7 to 5.5 or even lower. Dissolution of enamel occurs as a combination of changes in the plaque, pellicle, and enamel. This varies among individual to individual and also among different oral sites within the same individual. ,
In a study done by Hegde et al.,  where unfilled chocolate was compared to milk chocolate, the latter had a maximum pH drop. It has been suggested that when milk is added to the chocolate to make milk chocolates, the milk may cancel out the beneficial properties of cocoa mass, which is seen in all the chocolates and can make it more cariogenic than the rest. 
However, in our study, the results were found to be contrary; the milk chocolate had least drop in plaque pH when compared to other chocolates making it least cariogenic. This can be supported by the fact that milk contains casein which is a milk phosphoprotein and it stabilizes calcium and phosphate ions within the tooth, making it least susceptible to the process of demineralization. 
Mango-flavored candy had the maximum fall in plaque pH making it most cariogenic followed by dark chocolate. Previously, dark chocolates were reported with lesser cariogenicity which may be because of the fact that dark chocolate boost up the antioxidant levels and also have higher concentrations of unsaturated fatty acids such as oleic acid, fatty acid, palmitic acid, and stearic acid. ,, But, the results of the present study are found to be conflicting to the previous findings about dark chocolates.
When the filled chocolates were compared, the chocolate with wafer showed the maximum drop in pH [Graph 1]. This could be due to its texture which enables it to be more retentive and therefore possibly more acidogenic. Chocolates with fruit and nuts also had a fall in plaque pH, but not as low as that of wafer chocolate. This fall in pH with fruit and nuts chocolates could be due to the longer retention ability of the fillings and also due to the sucrose concentration of the fruits which additively makes it more acidogenic. 
When the plaque pH values for candy group was evaluated, it showed that all the candies in the group showed a fall in the levels of pH and it was more significant with mango-flavored candy when compared with hard milk candy, suggesting mango candy to be more cariogenic and hard milk candy to be less cariogenic in the candy group. This may be due to the presence of mango flavor additive in the mango candy which lowers its pH and makes its more cariogenic, and nonretentive property and easy cleansable nature of the hard milk candy when compared to that of other chocolates made it cariogenic. 
The time course of clearance of sugars from saliva can be signified in a number of ways: As a clearance rate, that is, the amount cleared per unit time and volume of saliva, as the total sugar cleared in each time interval or, best of all, as a percentage of total clearance. 
To attain a relation between the incongruent units, the sugar cleared in each time interval was therefore expressed as a percentage of the total cleared over 30 min. Whichever way it is expressed, one phenomenon can always be recognized with all sugars, it is that the clearance is high at first and falls rapidly with time, confirming the validity of Lanke's  exponential equation for the rate of sugar clearance.
The observation that salivary sugar clearance is distinctive of an individual is also in agreement with Lanke  and is in accordance with Dawes  concept that clearance is a function of parameters which vary within a narrow range for any given subject such as unstimulated salivary flow rate and the volume of saliva present in the mouth immediately before and after swallowing. Lagerlφf et al.  reaffirmed that oral carbohydrate clearance is an individual property stable over an extended period of time, confirming the validity of the study results. 
In the present study, when the chocolates of all the three groups were assessed, it was seen that the salivary sugar clearance was statistically significant at all the time intervals. Fruit and nuts chocolate had the maximum clearance of the salivary sugar making it least cariogenic followed by the mango-flavored candy. The least fall in the salivary sugar clearance was recorded with dark chocolate followed by milk chocolate making it most cariogenic.
Parents should be informed about the importance of primary dentition and also they should be advised on the need to give these chocolates at mealtimes rather than between meals or before bed time. Health workers should be informed regarding the cariogenic potential of chocolates so as to guide parents and guardians to introduce oral hygiene measures after consumption of the chocolates.
| Conclusion|| |
- Mango-flavored candy had the maximum fall in plaque pH making it most cariogenic followed by the dark chocolate, and the least fall in plaque pH was recorded with milk chocolate making it least cariogenic.
- Fruit and nuts chocolate had the maximum clearance of the salivary sugar making it least cariogenic followed by the mango-flavored candy, and the least fall in the salivary sugar clearance was recorded with dark chocolate followed by milk chocolate making it most cariogenic.
- Even though mango-flavored candy had the maximum fall in plaque pH, its salivary clearance was high. Hence, consuming high amounts of mango-flavored candies over prolonged periods of time may enhance its cariogenic properties.
- Dark chocolate had a high fall in pH along with least salivary sugar clearance and milk chocolate had low salivary sugar clearance which signifies that unfilled chocolates are more cariogenic when compared with that of other chocolates (filled chocolates and candies).
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]