Conclusion and evaluation :
3.1 Conclusion
3.1.1 and 3.1.2: Analysis of raw and processed data to identify trends and patterns and
describe findings
The mass of neutralizing agent of toothpaste samples and the number of moles of HCl each
toothpaste sample neutralized based on figure 2. The results indicated that sample 4 with the
active ingredient silicon dioxide, had the highest mass of neutralizing agent (0.41 kg 10-3).
Sample 5, with the ingredient of sodium bicarbonate, contained a succeeding highest mass of
neutralizing agent (0.25 kg 10-3). This was followed by sample 2 (0.16 kg 10-3) with the
active ingredient dicalcium phosphate. Both sample 1 (0.07 kg 10-3) and sample 3 (0.03 kg
10-3) contained the active ingredient calcium carbonate which appeared to have the lowest
mass of neutralizing agent compared to the other toothpastes. The mass of neutralizing agent
in sample 1 and sample 3 only varied by 0.04 kg 10-3, possibly because both the toothpaste
samples contained the same active ingredient. When comparing individual numerical results,
there appeared to be a dramatic difference of the mass of neutralizing agent between sample
4, with the highest mass, and sample 3, with the lowest mass. The high difference of mass of
neutralizing agent of 0.38 kg 10-3 was surprising as it shows how the neutralization
capacity of toothpaste vary in response to differing active ingredient present.
When analyzing the bar graph with the line graph in figure 2, a trend between number of
moles of HCl reacted and the mass of neutralizing agent present. The number of moles of
HCl reacted is higher in the toothpaste samples containing the highest mass of neutralizing
agent. For instance, sample 4 with the highest mass of neutralizing agent had the highest
number of moles of HCl reacted. Whereas sample 3, with the lowest mass of neutralizing
agent had the lowest number of moles of HCl reacted
3.1.3 Conclusions based on data
From the data it can be concluded that the higher the quantity of the neutralizing agent added
to the toothpastes the higher the amount of HCl reacted. Sample 4, colgate cavity protection
contained the highest mass of neutralizing agent and also reacted the highest amount of HCl.
Toothpastes that contain high amounts of such ingredients leave lesser amounts of acid
unreacted compared to toothpastes with lower amounts of neutralizing ingredients. This
therefore supports the hypothesis that the toothpaste with the highest mass of neutralizing
agent will neutralize the highest amount of HCl and therefore have the highest neutralization
capacity.
3.1.4 Finding and conclusion compared to literature
The study conducted by Dodamani and Khairnar found that overall, toothpastes were
effective in increasing the pH of the saliva by reducing the salivary levels of glucose. This
was tested by testing the pH of samples of saliva from participants before and after brushing
with toothpastes. There was a huge increase in pH after the participants brushed their teeth,
additionally there was also a significant decrease in levels of salivary glucose. Even though
the current experiment cannot be correlated with this literature study due to vast differences
in methodology, the theory that toothpastes contain effective agents that neutralize acids
formed in the mouth is supported. Their conclusion that use of toothpaste reduced levels of
salivary glucose can be used to support the conclusion of the current study. The break down
of glucose increases the acidity of the mouth, toothpastes work to increase the pH of the
mouth by neutralizing these acids
3.1.5 Quality and reliability of data
Standard deviation suggests the quality of the data by indicating how reliably conclusions can
be made from results. When analysing standard deviation (SD) bars in the raw data of the
mean volume of NaOH used to titrate different toothpaste, the generally small SD indicates
that there is a low spread of data clustered around the mean. In order to clearly compare the
reliability of the raw data acquired, the RSD can be analysed. All toothpaste sample 1-5 had
very low percentage of RSD (0.80, 1.02, 0.47, 0.85 and 1.32 respectively), since they were all
less than 33% the results are said to be reliable, allowing conclusion to be reliably drawn.
The quality of the raw data could further be indicated through the analysis of the uncertainties
due to the apparatus used in the experiment. Since the final uncertainty of the mass of
neutralising agent ranged from 4.33 106 kg 10-3 to 2.42 104 kg 10-3 is small,
it indicates that the systematic errors in the experiment were also minimal, providing more
reliability to the conclusions reached.
