BIOLOGY PROJECT (2012-13)
Effect of different toothpastes on bacteria
Prepared by:
Ishita Rupapara
11 C
S. N. Kansagra School
Biology Department
CERTIFICATE PAGE
A PROJECT REPORT ON –
Effect of different toothpastes on bacterial growth.
PROJECT SUBMITTED FOR FULFILLING THE REQUIREMENTS OF GROUP
PROJECT FOR THE CCE EVALUATION, ISC YEAR I (2012-13)
PROJECT PERFORMED BYKinnari Ashar and Ishita Rupapara
PROJECT SUBMITTED BYIshita Rupapara
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TEACHER
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PRINCIPAL
Index
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Introduction
Hypothesis
Variables
Materials used
Procedure
Precautions
Raw data
Data presentation
Graphs
Conclusions
Evaluations
Limitations of experiment
Suggestion for improvement
Bibliography
Remarks
Introduction
Toothpaste is a paste or gel dentifrice used with toothbrush. Toothpaste helps
to remove plaque, a sticky, harmful film of bacteria that grows on teeth that
causes gum disease and eventual tooth loss if not controlled. Toothpaste
contains fluoride, which makes the entire tooth structure more resistant to
decay and promotes remineralisation, which aids in repairing early decay
before the damage can even be seen. Special ingredients in the dentifrice help
to clean and polish the teeth and remove stains over time.
Ordinary toothpaste may only contain sodium fluoride as an active ingredient;
tartar control toothpaste may also contain triclosan. Triclosan is an
antibacterial and antifungal organic compound found in many antibacterial
soaps, deodorants, toothpastes, acne medications, and other antibacterial
applications.
Bacteria reside in great numbers in many places, both inside and on the
surface of the human body. In many cases, like in the gut, the presence of
bacteria is beneficial. Bacteria in the mouth cause the formation of cavities,
and can increase the chance of other disease and illness. Many different types
of bacteria live in the mouth, and some types simply pass through depending
on the types of food consumed.
Dental hygiene
There are plenty of bacteria and other micro-organisms living in our mouth.
These bacteria attack the food leftovers that stick to, and in between our
teeth. They cause our teeth to decay, forming plaque and causing bad breath.
When they digest sugar and starch that stick to our teeth, they produce acids
that will dissolve tooth enamel.
Brushing our teeth everyday with toothpaste is very important for dental
hygiene. Using toothpaste together with the proper brushing techniques can
help in getting rid of plaque and also remove bacteria so that gum disease and
loss of teeth can be prevented. Some types of toothpaste are even able to
prevent bacteria growth and plaque formation.
The most important ingredient in toothpaste is fluoride. It helps in
strengthening the tooth surface and prevents bacteria growth. It also helps to
repair tooth decay in the early stages. Another ingredient in toothpaste that
helps in fighting bacteria is Triclosan, an antibacterial agent.
Bacteria in our Mouth
There are various types of bacteria in our mouth, harmful and helpful.
These types of bacteria include:
Streptococcus
Staphylococcus
Neisseria
Haemophilus
Streptococcus pneumoniae
Porphyromonas gingivalis
Diphtheriod
Fusobacteria
Streptococcus mutans
Hypothesis
My hypothesis was that Colgate Total would reduce the amount of bacteria
most.
I based my hypothesis on the fact that Colgate Total has the ingredient
Triclosan which is a strong antibacterial/antimicrobial agent.
Variables
Controlled variables:
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Size of pit
Amount of toothpaste
Incubation time
Temperature of incubator
Media
Independent variable:
 Different types of toothpastes
Dependent variable:
 Zone of inhibition of bacteria
Materials used
 5 different toothpastes
 Colgate
 Pepsodent
 Sensodyne
 Optifresh
 Glister
 2gm Agar Agar
 5.6gm Nutrient Agar
 10ml Nutrient Broth solution
 10-15 sterile test tubes with cap
 2-3 sterile sugar tubes with cap
 2 burners
 Sterile cotton swabs
 Sterile pipette nibs
 100µl micropipette
 2 conical flasks
 Sterile distilled water
 Autoclave
 Incubator (having constant temperature of 37°C)
 2 Nichrome loops
 Methanol
 Glass spreader
 Weighing machine
 Borer
Different types of toothpastes
Petri dish showing bacterial growth and zone of inhibition
Procedure
 Take 200ml of distilled water in conical flask and add 5.6gm Nutrient
Agar and 2gm Agar Agar to it. Make a solution by stirring it till both the
contents are completely dissolved.
 Take 10ml distilled water and a pinch of Nutrient Broth in a test tube
and make its solution.
 Plug the flask with cotton swabs and newspaper on it and the test tube
containing Nutrient Broth with a cap.
 Cover all the Petri dishes and the beaker containing pipette nibs with the
newspaper. Also cover all test tubes and sugar tubes with cap.
 Put all the covered Petri dishes, beaker containing nibs, test tubes, sugar
tubes and the two flasks in an autoclave for sterilization.
 After cooling, pour 20ml (approximate) of solution from flask in each
Petri dish.
 Allow the solution in Petri dish to solidify.
 Select a prominent germy area and swab that area with the help of
cotton.
 Slightly rub the cotton swab over the prepared N-Agar plate and cover
the Petri dish.
 Put the Petri dish in incubator having constant temperature of 37 °C for
a day or two to allow the bacterial growth.
 Isolate an individual colony from the mixture of different colonies
obtained in the Petri dish with the help of loop.
 Put the loop having an isolated individual colony in a test tube which
contains Nutrient Broth.
 Place the test tube in incubator to allow the bacteria to grow for few
hours.
 Pour the solution from the test tube in each of the remaining 6 Petri
dishes and spread it over the prepared N-Agar plates with the help of
spreader.
 Mark 3 parts on each of the 6 Petri dishes.
 With the help of a borer, make a pit which is equidistant from each other
and the walls of the Petri dish.
 Make a solution of each toothpaste by taking 1gm of toothpaste in 2ml
distilled water.
 Pour 100µl of 5 different toothpaste solutions in 5 different pits with
the help of micropipette.
 In first Petri dish 3 different toothpastes are taken i.e. Glister, Sensodyne
and Optifresh where as in second Petri dish Pepsodent and Colgate are
taken in 2 pits and third pit is filled with sterile distilled water which acts
as a control.
 Two more sets are prepared and three such trials are done.
 All the Petri dishes are kept in incubator (37°C constant temperature) to
allow the growth of bacteria for 1-2 days.
 The Petri dishes are removed from incubator and the zone of inhibition
of bacteria is observed and measured with the help of scale.
 All the 5 toothpastes are compared by taking the average obtained from
each of the three trials.
Precautions
 After sterilizing, mostly the experiment is performed between the two
burners so that the area around the burners is sterile.
 After spreading the N-Broth (having bacteria) with the help of spreader,
the spreader is dipped in methanol and passed from flame to any
possible bacteria stuck to the spreader.
 The nichrome loop is also burnt and so that it is not infected by bacteria
and cooled so that high temperatures doesn’t kill the bacteria that are to
be taken in the loop.
 Hands should be washed with dettol to make them free of bacteria and
germs.
 While performing the experiment near the burners , care should be
taken that it is performed safely.
Raw data
Sr.no.
1
2
3
4
5
toothpastes
Colgate
Pepsodent
Sensodyne
Glister
Optifresh
trail 1
2.5
2.3
3.5
3.0
1.5
trial 2
3.5
3.0
2.0
3.1
2.3
trial 3
3.1
2.6
1.8
2.0
2.6
Data presentation
Sr.no. toothpastes
trail 1
trial 2
trial 3
mean
maxmean
mean- standard
min
deviation
1 Colgate
2.5
3.5
3.1
3.03
0.47
0.53
2 Pepsodent
2.3
3
2.6
2.63
0.37
0.33
3 Sensodyne
3.5
2
1.8
2.43
1.07
0.63
3
3.1
2
2.7
0.4
0.7
1.5
2.3
2.6
2.1
0.5
0.6
4 Glister
5 Optifresh
0.34361315
A bar chart showing effect of different toothpastes on bacteria
Error bar shows the range
4
zone of inhibition [in cms(+/-1mm)]
3.5
3
colgate
pepsodent
2.5
sensodyne
2
glister
optifresh
1.5
1
0.5
0
colgate
4
pepsodent
sensodyne
glister
toothpastes
optifresh
A bar chart comparing the effect of different toothpastes on
bacteria
Error bar shows Standard Deviation
zone of inhibition [in cms(+/-1mm)]
3.5
3
colgate
pepsodent
2.5
sensodyne
2
glister
optifresh
1.5
1
0.5
0
colgate
pepsodent
sensodyne
glister
toothpastes
optifresh
Conclusion
Some bacteria cause diseases and other infection. The bacteria that cause
sickness are harmful to human health. Most bacteria in the mouth are bad and
eat away at teeth, causing tooth decay. Toothpaste, floss and various other
items are used to reduce the amount of bacteria I human mouth. Toothpaste
that effectively reduces bacteria should contribute to dental health. Thus from
the experiment performed and results obtained we conclude that Colgate has
the best effect on bacterial growth out of the 5 toothpastes that wee taken.
Evaluation
According to my hypothesis, Colgate would affect the bacterial growth the
most. The results obtained from the experiment performed, I conclude that
Colgate is the most effective toothpaste on bacterial growth.
The media that was poured in the Petri dishes was poured on an average and
was not measured accurately.
The toothpaste solution though taken in micropipette might not have been
accurately taken.
Due the constant temperature of incubator, the bacterial growth in all Petri
dishes was even.
By providing enough Nutrient Broth, the bacteria were able to grow properly.
Amount of toothpaste solution was enough to have its effect around the pit.
Limitations of experiment
 The time to perform the experiment was less due to which the
experiment was only performed once and the results obtained were not
precise.
 The trials done were less due to which there was difference in the result.
Suggestion for improvement
The experiment performed can be improved by taking care of following steps:
 The solution poured in Petri dish should be poured after measuring and
not poured approximately.
 The trials performed should be more so that the zone of bacterial
inhibition obtained is more precise.
 The zone of bacterial inhibition should be measured with a more precise
scale instead of a daily used ruler.
 The transferring of solution should be done in minimum time possible so
that he Petri dish that is opened is not infected with bacteria.
Bibliography
 http://www.sciencebuddies.org/science-fairprojects/project_ideas/MicroBio_Agar.shtml
 http://www.cliffsnotes.com/study_guide/MicrobialCultivation.topicArticleId-8524,articleId-8424.html
 http://www.google.co.in/imgres?num=10&hl=en&sa=X&biw=1272&bih
=627&tbs=itp:clipart&tbm=isch&tbnid=4825LOK4IuSbvM:&imgrefurl=ht
tp://chemlifemalavish.blogspot.com/&imgurl=http://3.bp.blogspot.com/_t7Ijf45rR3s/
Sm8chhvDSNI/AAAAAAAAAAc/tdwzDkhrh8/s320/toothpaste.jpg&w=274&h=320&ei=NEAUI7mDsS3rAeHioDYCw&zoom=1&iact=hc&vpx=1014&vpy=188&dur=99
5&hovh=243&hovw=208&tx=103&ty=115&sig=11322561579418195481
2&page=1&tbnh=105&tbnw=98&start=0&ndsp=24&ved=1t:429,r:7,s:0,i:
97
 http://www.livestrong.com/article/161300-what-are-the-differenttypes-of-bacteria-found-in-the-human-mouth/
 http://jac.oxfordjournals.org/content/45/2/153.full
 http://www.selah.k12.wa.us/soar/sciproj2006/RainanV.html
 http://www.colgateprofessional.co.uk/products/Colgate-TotalToothpaste/details
 http://www.sciencedaily.com/releases/2010/04/100413121334.htm
 http://www.all-science-fair-projects.com/print_project_1294_104
 http://sandwalk.blogspot.in/2009/03/bacteria-in-your-mouth.html
Remarks