|Year : 2020 | Volume
| Issue : 2 | Page : 56-62
To evaluate the buffering capacity of various drinks commonly available in India
Vanitha U Shenoy1, Saimanaaz Shaikh1, Sumanthini Margasahayam Venkatasubramanyam1, Jayeeta Verma1, Padma Chavan2, Santosh Gawali2
1 Department of Conservative Dentistry and Endodontics, MGM Dental College and Hospital, Navi Mumbai, Maharashtra, India
2 Department of Biochemistry, MGM Medical College, Navi Mumbai, Maharashtra, India
|Date of Submission||19-Apr-2020|
|Date of Acceptance||01-May-2020|
|Date of Web Publication||19-Jun-2020|
Dr. Vanitha U Shenoy
Department of Conservative Dentistry and Endodontics, MGM Dental College and Hospital, Kamothe, Navi Mumbai 410209, Maharashtra.
Source of Support: None, Conflict of Interest: None
Introduction: Consumption of carbonated and health drinks and fruit juices containing acid, as one of the ingredients, can lead to erosion of the tooth. Aim: The purpose of this study was to measure buffering capacity of commonly available drinks and their titratable acidity. Materials and Methods: Sixteen commonly available drinks were taken and divided into four groups (sports/energy drinks, carbonated drinks, fruit juices, and water). Each group comprised four drinks. Their initial pH was measured with pH meter and their titratable acidity was measured, both by adding 0.1M NaOH into 30 mL of each drink, in the increments of 1 mL, till the pH raised to 5.5 and 7.0, respectively. Statistical Analysis: The volume of NaOH required to raise the pH to 5.5 and 7.0 was recorded in each group. The data were subjected to analysis of variance (ANOVA) followed by Tukey’s post hoc test. Results: Study groups showed significantly lower initial pH compared to the control group. Intergroup comparisons within study groups showed no significant differences with respect to their initial pH. Titratable acidity of energy drinks was found to be maximum to reach the pH 5.5 and even for pH 7. Titratable acidity was the minimum with carbonated drinks to reach pH 5.5 and with fruit juices to reach pH 7.0. Conclusion: No significant differences were observed between the energy drinks–carbonated drinks, energy drink–fruit juices, and carbonated drink–fruit juices with respect to their initial pH. Energy drinks had the most erosive potential due to their significantly greater buffering capacity as compared to carbonated drinks and fruit juices.
Keywords: Beverages, buffering capacity, dental erosion, pH, titratable acidity
|How to cite this article:|
Shenoy VU, Shaikh S, Margasahayam Venkatasubramanyam S, Verma J, Chavan P, Gawali S. To evaluate the buffering capacity of various drinks commonly available in India. MGM J Med Sci 2020;7:56-62
|How to cite this URL:|
Shenoy VU, Shaikh S, Margasahayam Venkatasubramanyam S, Verma J, Chavan P, Gawali S. To evaluate the buffering capacity of various drinks commonly available in India. MGM J Med Sci [serial online] 2020 [cited 2020 Aug 13];7:56-62. Available from: http://www.mgmjms.com/text.asp?2020/7/2/56/287165
| Introduction|| |
Dental erosion is irreversible, usually painless, loss of dental hard tissue that occurs due to a chemical process, such as dissolution or chelation, without the involvement of microorganisms, Demineralization of the tooth by erosion is caused by frequent contact between the tooth surface and acids caused by a series of extrinsic and intrinsic factors. Extrinsic factors are related to frequent consumption of acidic foodstuffs, carbonated beverages, sports drinks, red and white wines, citrus fruits, and to a lesser degree exposure to acidic contaminants in the working environment. Intrinsic factors include chronic gastrointestinal disorders such as gastroesophageal disease as well as health issues such as anorexia and bulimia where regurgitation and frequent vomiting are common. Citric, phosphoric, malic, and tartaric acids are the main dietary acids associated with erosion that is present in the beverages.,,,
During consumption, food or drink contacts only shortly with the tooth surface before it is washed away by saliva. Seow and Thong studied the erosive effect of common beverages on the extracted premolar teeth and observed that although saliva was protective against erosion, relatively large volumes of saliva were required to neutralize the acidity. Intraoral pH at the enamel surface drops rapidly following an acidic challenge and it comes back to resting pH levels only slowly.
The acid content of a foodstuff or beverage can be quantified as pH or actual acidity readings, less than 7 indicate an acid. Acidity is a key factor in the taste of a drink as it balances the sweetness. However, beverages with acidic pH tend to have a greater erosive effect on dental enamel., The titratable acidity sometimes is also termed neutralizable acidity. The titratable acid content is considered more important than the pH level, which is the quantity of base required to bring a solution to neutral pH. Higher titratable acidity is consistent with higher buffering capacity. The buffering capacity of a substance is related to the resistance to pH changes. It is considered that the higher this quantity, the more potentially erosive a product is. In vitro studies showed that drinks with low pH, such as cola-based carbonated drinks and fruit juices, have been the drinks most related to dental erosion.,,, There are not many in vitro studies conducted to evaluate the pH and buffering capacity of various sports/energy, carbonated drink, and fruit juices, consumed by an average Indian consumer, in India. Thus, this in vitro study aimed to study the pH, titratable acidity/buffering capacity of various sports/energy, carbonated drink, fruit juices, and different types of water. The hypothesis of the study is that there is a difference in the buffering capacity of various commonly available drinks in India.
| Materials and methods|| |
Three test groups, each consisting of four drinks: energy drinks (Red Bull, Gatorade, Monster, and Urzza); carbonated drinks (Dukes Soda, Mountain Dew, Diet Coke, and Mirinda); fruit juices (fresh sugar cane, fresh sweet lime, Minute Maid, and Maaza); and control group of water (mineral water, boiled water, tap water, and filtered water), were chosen for the study.
Thirty mL of the freshly opened drink was dispensed in a glass beaker. It was stirred using a nonheated magnetic stirrer until a stable reading was attained. The initial pH was then measured thrice using a pH meter and the readings noted. The mean value was considered as the initial pH. The pH electrode was calibrated at the start of each session using standard buffers of pH 5.5 and 7.0. Using a pipette of 0.1M, NaOH was dispensed into the same beaker with electrodes of pH meter dipped in the same beaker containing the drink. 0.1M NaOH was added gradually till the pH meter showed a constant reading of 5.5. The volume of 0.1M NaOH used was noted at this stage. More NaOH was added until the pH meter recorded a pH of 7. Again, the total volume of NaOH used was noted. This procedure was repeated for all drinks.
The volume of NaOH required to raise the pH to 5.5 and 7.0 was recorded in each group. The data were subjected to analysis of variance (ANOVA) followed by Tukey’s post hoc test. A value of P < 0.05 was considered statistically significant.
| Results|| |
Four different types of commonly consumed beverages were evaluated for their initial pH and titratable acidity. [Table 1] shows the individual pH of all the test and control beverages, wherein it is observed that all the test beverages had an acidic pH and Urrza testing as the most acidic beverage with a pH of 2.82.
From the results, it was observed that the mean initial pH of the tested drinks was in the acidic range, whereas different types of water as control group gave an alkaline mean pH of 7.7450 and energy drink being highly acidic with a mean pH 3.3375 as shown in [Table 1] and [Graph 1]. The results of the study thus indicated that the initial pH of the control group was significantly less as compared to initial pH of energy of the energy drink, carbonated drink, and fruit juices, as shown in [Table 2] and [Graph 1].,
The multiple comparisons of the initial pH were performed using Tuckey’s post hoc test [Table 3]. The result indicates that the initial pH of the control group was significantly less as compared to the initial pH of energy drink, carbonated drinks, and fruit juices. No significant difference in initial pH was observed between energy drink–carbonated, energy drink–fruit juices, and carbonated drink–fruit juices.
After the initial pH evaluation, the amount of NaOH required to raise the pH up to 5.5 and 7.0 was calculated for all the test beverages and it was observed that Red Bull required the maximum NaOH to raise pH to 5.5 and 7.0 (17.5 and 33.2 mL, respectively) [Table 4].
|Table 4: Initial pH and amount of NaOH required to raise pH to 5.5 and 7.0|
Click here to view
The descriptive statistics of the amount of NaOH required to raise the pH to 5.5 of each of the test group beverages is as shown in [Table 5] and [Graph 2], with energy drinks requiring the maximum and carbonated drinks the least.,
The multiple comparisons of the amount of NaOH required to raise the pH to 5.5 were performed using the Tuckey’s post hoc test [Table 6] and it was observed that there was a significant difference (P < 0.05) between energy drink and carbonated drink (P = 0.01) and energy drink and fruit juices (P = 0.029).
The descriptive statistics of the amount of NaOH required to raise the pH to 7.0 of each of the test group beverages is shown in [Table 7] and [Graph 3], with energy drink requiring the maximum and fruit juices the least.,
The multiple comparisons of the amount of NaOH required to raise the pH to 7.0 was performed using the Tuckey’s post hoc [Table 8] and it was observed that there was a significant difference (P < 0.05) between energy drink and fruit juices (P = 0.013).
| Discussion|| |
The public perception is that sports/energy drinks and fruit juices are healthy and will not cause tooth destruction, but evidence appears to contradict this view., The results of this study show that all the commonly available drinks tested had an acidic pH as compared to the control water.
Dental erosion is a condition that occurs in the absence of plaque. Dental plaque is known to have a much higher buffering capacity than saliva and may actually protect the tooth surface from acids of nonbacterial origin.
The erosive potential of a drink or food is codetermined by its chemical and physical properties and biological factors such as pH, which is a measure of the initial hydrogen ion the concentration of a beverage alone is not predictive of its potential to cause erosion. Apart from its pH value, the ability of an acidic solution to dissolve enamel or dentin depends on its ability to keep pH unaffected by the dissolution of tooth mineral and dilution with saliva (i.e., buffering capacity).
Titratable acidity is the parameter that determines the actual hydrogen ion availability for interaction with the tooth surface, is associated with the undissociated acid in drinks and foods. Undissociated acid diffuse into the hard tissues of the teeth and act as a buffer to maintain the H+ concentration. Consequently, the driving force for demineralization at the site of dissolution is maintained., This parameter, therefore, may be a good indicator of the erosive potential of a food or drink especially after exposure for a certain time. The greater the buffering capacity of the drink, the longer it will take for saliva to neutralize the acid and then the more apatite may be dissolved before a higher pH value is reached and dissolution ceases. Thus, a more realistic and accurate method for predicting erosive potential is by the measurement of a beverage’s total acid content.
Food acidulants in the form of phosphoric and citric acid are common, but malic, carbonic acid, and other organic acids may be present in the beverages. These additives found in sports/energy, soft drinks, and packed fruit juices add to the taste profile of the drink and balance the sweetness. These acids are added as a preservative and provide antibacterial action as well.
The presence of polybasic acids in these beverages is important because of their ability to chelate calcium at higher pH levels could cause a significant enamel dissolution through a calcium chelation effect rather than a simple acid attack. These acids thus remove the beneficial effects of calcium in the mineralization process, promoting a decreased buffering effect of saliva and thus increased tooth destruction. When the acids in the beverages lower the pH of saliva, calcium ions are extracted from the enamel/dentin into the saliva to compensate for this low oral pH environment, leaving a softened matrix for additional destruction by caries process or by mechanical abrasion.
In this study, it was observed that the sports/energy and carbonated drinks showed an initial pH in the range of 2.82–4.56, with a mean of 3.3–4.0. The amount of NaOH in mL required to bring the pH to 5.5 and 7.0 was the highest with Red Bull, thus indicating the erosive nature of the beverage. All the beverages whether they were the energy or carbonated or fruit juices presented with an initial acidic pH; however, fresh sugarcane juice requiring the least amount of NaOH in mL for it to reach a pH of 5.5 and 7.0
Thus, the type of acid, its calcium chelating properties, exposure time, and temperature are also the other important factors concerning the erosive quality of beverages.
The erosive protective functions of saliva include the following:
Dilution and clearance of erosive substances from the mouth.
The neutralization and buffering of acids.
Slowing down and maintaining a supersaturated state next to the tooth surface due to the presence of calcium and phosphate in saliva.
Providing calcium and phosphate necessary for remineralization.
Both quality and quantity may be responsible for some observed differences in susceptibility of different pH to erosion. Studies have supported the protective value of saliva, with the strongest association found between dental erosion and low salivary flow rate and low buffering capacity.,
Other biological factors affecting erosion include the anatomy of the teeth and soft tissues that may influence the retention/clearance pattern of erosive agents. The proximity of the tooth surfaces to the salivary duct orifices is of overriding importance; also soft-tissue movements of the tongue and buccal mucosa and swallowing patterns can influence clearance rate.
Thus, when an acidic liquid contacts tooth surface, a sudden rapid drop of pH occurs at the tooth surface, which then slowly rises over the next 20–30min (recovery phase) due to neutralization and clearance of acidic solution by the normal salivary flow. During this time, the mineral content that has been dissolved is replaced if adequate saliva (containing calcium and phosphate) is available. Another exposure to the acidic solution during this time causes another rapid drop in pH extending the total period of tooth surface demineralization. Calcium, phosphate, and fluoride contents have a protective effect, for example, yoghurt has a low pH of 3.8, yet it has no erosive potential due to its high calcium and phosphate contents.,
The method used in this study to determine titratable acidity has been used in a number of studies,, and is known to give a realistic measure of buffering capacity of drinks by quantifying the amount of alkali required to bring the pH to a chosen value. Various end points have been used in previous studies from pH 5.5 to 10. The definition of the exact value of pH below which enamel dissolution may occur is controversial as in the mouth it is the degree of undersaturation with respect to tooth mineral that is the crucial point. The end point chosen, therefore, for this study was pH 7. This end point is nevertheless limited as it lies in an area where there is a rapid rise in pH.
High levels of acidity are interpreted as being potentially the most harmful. The consumption of an acidic drink will, however, stimulate salivary flow. It is possible, therefore, that a more acidic drink may be either cleared from the mouth or neutralized more rapidly, due to the increased salivary washing action and buffering capacity, and so will spend less time in contact with the teeth. Clearance of a drink from the mouth will also depend on the ability of a drink to adhere to the enamel. A more viscous drink is likely to adhere and will, therefore, be held in the mouth for longer. A diluted juice will have lowered viscosity due to increased proportion of water, and with salivary stimulation remaining unaffected due to the low pH dilution may aid clearance from the oral environment.
von Fraunhofer and Rogers made certain projections based on an average daily consumption of 25 ounces of soft drink and a residence time in the mouth of 5s. The total exposure time to beverages would equal 22,750s (380min or 6.3h) per year. However, it is more likely that the exposure time for a beverage on the dentition is closer to 20s before salivary clearance occurs; this would make the annual exposure of dental enamel to soft drinks approximately 90,000s (i.e., 1500min or 25h) per year.
The increased rate of erosion has been linked to growth in consumption of dietary acidic intake particularly soft drinks, fruit juices, and sports drinks. The consumer must keep in mind the negative effects of these beverages and use measures to see to it that the negatives effects of these do not affect teeth.
| Conclusion|| |
Within the limitations of this study, the following conclusions can be drawn:
- No significant differences were observed between the energy drinks–carbonated drinks, energy drink–fruit juices, and carbonated drink–fruit juices with respect to their initial pH.
- Energy drinks had the most erosive potential due to their significantly greater buffering capacity as compared to carbonated drinks and fruit juices.
- Energy drink > carbonated > fruit juices.
- Monsters had the most erosive potential and sugar cane fruit juice had the least.
Erosion has been linked to growth in consumption of dietary acidic beverage intake particularly soft drinks, fruit juices, and sports drinks. However, more in vivo studies need to be carried out to understand the correlation to the clinical scenario.
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Conflicts of interest
There are no conflicts of interest.
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[Graph 1], [Graph 2], [Graph 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]