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Which tooth whiteners works best?

Which tooth whiteners works best?

Introduction: (Initial Observation)

Teeth whitening has been a process performed by dentists. Recently, many teeth whitening products are made that can be used at home. Now teeth whiteners are among the material that you can find at every supermarket, where you find other dental care supplies.
As with all other products, most manufacturers claim that their product is the best and has advantages to what the competitors offer.

Since tooth whiteners are made of different material and they are applied in different methods, their effectiveness may vary. In this project I will compare different brands of tooth whitener gels to find out which one works best.


This project guide contains information that you need in order to start your project. If you have any questions or need more support about this project, click on the “Ask Question” button on the top of this page to send me a message.

If you are new in doing science project, click on “How to Start” in the main page. There you will find helpful links that describe different types of science projects, scientific method, variables, hypothesis, graph, abstract and all other general basics that you need to know.  

Project advisor

Information Gathering:

Gather information about tooth whiteners. Read books, magazines or ask professionals who might know in order to learn about active ingredients of tooth whiteners and how they work. Keep track of where you got your information from.

Following are samples of information that you may find.

About teeth whiteners

Function: It is used to lighten tooth stains or tooth colors.

Application: Tooth whiteners may be applied in the form of strips and gels.

Active Ingredients: Oxidizing agents such as Hydrogen Peroxide or Carbamide Peroxide.


The effectiveness of tooth whiteners depends on the type and severity of the stains or the tooth colors. Thus, you should consult your dentist before purchasing the whiteners.

Since tooth whiteners contain highly concentrated peroxide which, if used carelessly, will lead to gingival inflammation, swelling and bleeding. If swallowed accidentally, it may cause injury to the body. Therefore the safe use of tooth whiteners must be made under the dentist’s supervision.

All current tooth whitening products, whether purchased in a store or used by your dentist, utilize various concentrations of hydrogen peroxide to make your teeth white. Even “light enhanced bleaching” with lasers are bound to use peroxides to create the necessary oxidation. Source….

Tooth enamel is made up of inorganic crystals known as hydroxyapatite. Only 5% of enamel contains organic material, in the form of collagen. Dentin (the next layer, which also protects the nerve tissue in the pulp), contains up to 20% of organic material. When dentin is viewed through a microscope, one notices that it is made up of small “dentinal tubules”.


There are many different products and ingredients used to whiten teeth in different ways. Products containing carbamide peroxide, sold by dentists, use an oxidizing process to whiten, are known to be the most effective.

There are a wide variety of tooth bleaching products available to you as a consumer, both from your dentist and also over-the-counter (i.e. drug stores). You might assume that any tooth whitener which is available has been approved by the U.S. Food and Drug Administration (the “FDA”) but this is not the case. The FDA does not categorize tooth whiteners as “drugs” and therefore it does not regulate them.

The American Dental Association (the “ADA”) has established a set of guidelines for tooth whiteners. These guidelines set standards for both safety and effectiveness. A manufacture can, at their own effort and expense, present to the ADA the results of their product’s research and clinical trials. If the ADA finds that the criteria of their guidelines have been met by this data they will issue to the manufacturer, for that specific product, the ADA’s “Seal of Acceptance”. Since earning the ADA’s seal is expensive and time consuming for a manufacturer, and of course totally optional, it clearly demonstrates the company’s commitment towards creating a quality product.

In the case of at home tooth whiteners, the ADA’s seal indicates that, when used as directed, a tooth whitener is not harmful to either teeth or the soft tissues of the mouth, and also that it will effectively whiten teeth. Additionally, the manufacturers of products receiving the ADA’s seal are not allowed to make claims about their product which are not supported by research or else they will lose the seal. Those manufacturers who have earned the ADA’s seal typically display it prominently on their product’s packaging.

You may discover that the product your dentist has chosen for your use has not been granted the ADA’s seal. There can be good reasons for this:

  • As we all know, many products are manufactured as “generic equivalents”. It is very possible that your dentist has reviewed the literature detailing the properties of the product they have dispensed to you and are satisfied that it is appropriate for your use. As you might expect with a generically equivalent product, it’s manufacturer might not seek the ADA’s seal as a way of minimizing the expense of bringing their product to market.
  • The product you are using may contain more than 10% carbamide peroxide. As a result of their clinical experience and what they have read in the dental literature, your dentist may feel that a whitener with greater than 10% carbamide peroxide is indicated and appropriate for your use. In a case such as this, you should feel free to quiz your dentist so they can relate their specific thoughts and rational to you.

Facts you should know about “at home” tooth bleaching products (as of 8/17/01):

  • The only at home tooth whiteners that have yet been able to earn the ADA’s “Seal of Acceptance” are dentist dispensed products. No over-the-counter products (such as those sold in your local store) currently have earned the ADA’s seal.
  • The active ingredient contained in all of the at home tooth whiteners which have earned the ADA’s seal, and the compound which has been evaluated in the vast majority of at home bleaching studies, is carbamide peroxide at a concentration of 10%. The active ingredient found in most over-the-counter at home bleaching products is not carbamide peroxide but instead hydrogen peroxide.

Question/ Purpose:

What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.

The purpose of this project is to compare a few teeth whiteners and find out what type teeth whiteners (based on their ingredients) work best.

You can do the same project and just compare different brands.

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.

Independent variable (also known as manipulated variable) are various tooth whitening products.

Dependent variable (also known as responding variable) are the effectiveness of teeth whiteners expressed by the number of tooth shade changes (or relative effectiveness of whiteners).

Controlled variables are temperature, light.

Constants are teeth whitener amount, application method, and exposure time.


Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.

Following is a sample hypothesis:

Products with carbamide peroxide as their active ingredient will be the most effective, then products with hydrogen peroxide as their active ingredient will be less effective, products with neither of these active ingredients will be the least effective.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Experiment 1:


To test which whitener is most effective you can use denture teeth or animal teeth. To find samples of denture teeth you can get help from a local dentist. To find animal teeth, a local butcher can help. If you don’t have access to any of these, use pieces of white ceramic or china.


  1. Soak the teeth for seven days in a mixture of coffee, tea, and tobacco that had been boiled.
  2. Divide your teeth samples to 3 similar groups for testing 3 different types of tooth whiteners.
  3. Name the groups with the name or type of the tooth whiteners that you are testing.
  4. From each group keep stained teeth as a control. Do not apply any whitener to controls.
  5. Apply each whitener to its own group as directed on their package. Note that the same amount of teeth whiteners must be applied to different groups.
  6. After 1 hour, rinse the tooth samples of all groups and wash away any tooth whitener material.
  7. Compare the effectiveness of the whiteners visually or based on a tooth shade color chart.

Notes: For real stain on teeth, one hour exposure usually is not enough. Depending on your artificial stain, one hour exposure may be too little or too much. If this is the case, repeat your experiment with more or less exposure time.

Material and Equipment:

  • Samples of teeth whiteners
  • Coffee, English tea and tobacco
  • Samples of denture teeth or animal teeth for multiple experiments.

A local butcher may be able to sell you (or give you free) the teeth from animals. I bought a lamb head from a local butcher for $3.00. The teeth already had a lot of black areas so I did not have to use additional tea or coffee.

Results of Experiment (Observation):

Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.

This is a sample result for an experiment in which teeth whitener gels are compared with toothpastes containing whiteners.

After trial one, Rembrandt Plus toothpaste and Close Up toothpaste whitened most effectively. The retests of those two products whitened just as effectively. Overall, the toothpastes whitened more effectively than the gels. This might be because they contain abrasives, such as hydrated silica, which work like sand paper to scrub away the stain.

Summary of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.


Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

Related Questions & Answers:

What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.

Possible Errors:

If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.

If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.


Your references are this website and the books that you will find in your local library about dental care. You can also include the websites of manufacturers and some of the following:



A Similar Sample Project

“What Substance Most Effectively Whitens Teeth?”

by Kylie W.

6th Grade, SOAR 1998


The purpose of this experiment was to determine which cleaning product most effectively whitened teeth.

I became interested in this idea when I got my braces put on in May of 1997. The orthodontist had told me that I needed to use a toothpaste that contained some amount of whitener.

The information gained from this experiment should benefit people in two ways; the cleanliness and healthiness of the person’s teeth and obtaining the best product for their money.


My hypothesis is that the baking soda mixed with a little peroxide will work better than the Mentadent, Aquafresh Whitening and Rembrandt.

I base my hypothesis on the fact that the dentist I go to, Dr. Kinney, and the hygienists there recommend baking soda with a little peroxide for getting good results on whitening a person’s teeth.


The constants in this study were:

Soaking the teeth in the same types of liquid stain and for the same length of time.

Checking the whiteness using a shade guide.

Using the same brand of toothbrush and number of strokes.

Using the same type of tooth (wisdom teeth).

My manipulated variable was the type of cleaning/whitening substance used.

My responding variable was how white the cleanser made the stained tooth when brushed.

To measure the responding variable I visually compared the tooth to a shade guide that I obtained from dental hygienist, Nicolai Kreger



12 Teeth

4 Pair Latex gloves

1 Shade guide

1 Magnifying glass

12 Styrofoam cups

1 Coffee tin full of coffee

4 Tea bags

1 jug Grape juice

  • 1 tube Mentadent
  • 1 bottle Hydrogen Peroxide

1 box Baking soda

1 Ruler

1 Graduated Cylinder

  • 24 Ziplock Baggies

4 Toothbrushes


  • Get 12 styrofoam cups of the same size (approximately 250 ml.). Cut the top half of each cup off and discard. Set bottoms of cups on table.
  • Label four cups with the letter A, four with B, and four with C.
  • Get grape juice, coffee and tea ready. I made the coffee by using 250ml. of water and 22.5ml. of the folgers coffee mix. I made the tea with 250ml. of water and one tea bag of Peoke flavored tea.
  • Put on latex gloves.
  • Pour 30 milliliters of grape juice into one Styrofoam cup labeled A.
  • Pour 30 milliliters of coffee into one Styrofoam cup labeled B.
  • Pour 30 milliliters of tea into one Styrofoam cup labeled C.
  • Find what color each tooth would match on the shade guide with a magnifying glass and then record that data.
  • Put one tooth in each liquid.
  • Let each tooth remain in its liquid for 3 hours.
  • Remove tooth from liquid while wearing latex gloves.
  • Put tooth on a small, clean piece of plastic.
  • Check teeth on shade guide to see which color they are after being stained.
  • Make up plaster, keep stirring so that the plaster does not dry.
  • Put each tooth in plaster, let it set until dry.
  • Put 1.0 cm of the toothpaste on the toothbrush.
  • Use one specific cleanser (Aquafresh, Rembrant, Mentadent, or peroxide/baking soda mixture) to brush one tooth. Brush each tooth 20 strokes back and forth.
  • Repeat steps 11 and 12 using the same cleanser for the other 2 teeth in that test group.
  • Examine each tooth with a magnifying glass while it is lying on the “Tooth Shade Guide”.
  • Compare the tooth to the shade guide. Record this shade and any other noteworthy observations.
  • For later reference, put each tooth in a separate baggie labeled with the stain and the toothpaste used to brush it.
  • Repeat steps 4-16, until each cleanser has been used for each stain.





My study of teeth whiteners may be helpful for people trying to choose a toothpaste that whitens their teeth. The following information may better help people understand their teeth, home whiteners and bleaches, oral surgery and different toothpaste’s.

Dental History

Mouth related diseases have been a problem from the beginning of time. Scientists have found two jawbones that had two holes drilled through the bone. They think this was done to drain an abscessed tooth. Early dentistry was practiced as a part of general medicine.

Aristotle wrote about ointments that helped to treat diseases of the teeth and oral tissues. He also talked about tooth extraction and the use of wires to keep jaws in place and bind loose teeth. A Roman named Celsus wrote of oral diseases, including bleeding gums and ulcers of the oral cavity.

Arabian doctors designed special instruments to better clean teeth in the ancient days. Italian sources mention the use of gold leaf as a dental filling material.

Oral whitening surgery

Oral whitening surgery is done by a dental physician. A dentist needs to go under the tooth and insert a whitening liquid. This is always an optional treatment. Something that causes the need to have this surgery are some kinds of acne treatment. The only way then to whiten the teeth is to have the oral surgery. It depends on the person’s tooth as to how many times this will need to be performed.

Bleaching and home whiteners

The most common whitener is toothpaste. There are other means of whitening teeth. One recommended treatment is the baking soda peroxide mixture. Each tooth whitener is different so you can get results that differ from medical information. This does not mean that you have performed the treatment wrong. Everybody has different teeth. There are different ways of bleaching. People use a tray that is formed to the shape of their teeth, then they put the recommended liquid into the tray and they also use whitening kits that may contain different choices of whiteners. Different people resort to different types of whitening systems according to their expectations.


All teeth typically have three layers. The inner layer of the tooth is called dentin. The gumline is covered with enamel (the crown) . This part of the tooth is extremely hard and the root of the tooth is covered by a bonelike substance called cementum.. The root is connected to the jawbone.

The twenty primary teeth consist of four central incisors, four lateral incisors , four cuspids (canines) and eight molars. They are all replaced by 32 permanent teeth, four central incisors, four lateral incisors, four cuspids , eight bicuspids and twelve molors. There are four wisdom teeth that grow in later. Not all people have four wisdom teeth. Some people don’t have wisdom teeth at all.

Types of Toothpaste

The different types of toothpastes consist of many different ingredients. In almost every new toothpaste today, one of the most helpful and main ingredients is fluoride. Rembrandt is probably one of the most popular whitening toothpaste on the market today. People depend on toothpaste to clean their teeth effectively. The types of toothpastes that I used had varying results. My results can vary from another person’s experiment. In my experiment I could tell which toothpaste was doing the best job just by looking at the teeth. The results on one person’s teeth can vary greatly. No person will get the exact same results as another person, even when they use the same toothpaste.


As you can see, results vary from person to person. If you are someone who has unhealthy teeth you are not alone. It’s amazing how technology has changed the world of dentistry. It’s hard to believe a world without the technology for fixing a persons teeth.

Bleaches and home whiteners can be very helpful to anyone who thinks that using them is necessary.

Oral surgery also can be helpful. I would recommend that you make sure it is absolutely necessary before the surgery is performed. Remember that it is an optional choice.

I hope that you have learned something about your teeth. You can now tell people about your teeth.


The original purpose of this experiment was to see what substance most effectively whitened teeth.

The results of my experiment were, the Rembrandt toothpaste worked the best on whitening the coffee, tea and the grape juice. The next best toothpaste was the baking soda peroxide mixture, Aquafresh Whitening was third, and the least effective was the Mentadent


My hypothesis was that the baking soda mixed with a little peroxide would work better than the Mentadent, the Aqua fresh Whitening and the Rembrandt.

The results indicate that my hypothesis should be rejected because the Rembrandt toothpaste worked the best on whitening, and the baking soda peroxide mixture was second on whitening the teeth.

Because of the results of this experiment, I wonder if advertising claims were true.

If I were to conduct this experiment again I would take more observations of the teeth to make sure that I didn’t miss anything. I think that using the shade guide was a bad choice because it didn’t tell the color of the grape juice. The better choice may have been using the colorimeter. The color of purple did not show up on the shade guide, so I also think that that was a bad choice for a stain.



Clark L. Fields. “Soda,” World Book Encyclopedia, 1995

“Cleaning the Teeth” World Book Encyclopedia, 1995

Kreger, Nicolai, Dental Hygientist, Kinney Bruce P. DDS, December 9, 1997

Kenneth, Kalkwarf, D.D.S. “Dentistry”, Grolier Interactive Inc., 1998

Gerald, Shklar. “Teeth”, Grolier Interactive Inc., 1998

Church and Dwight Co, Arm and Hammer Dental Care Product Guide, Princeton, New Jersey, 1997

Clinical Research Associates, Clinical Research Associates Newsletter, Provo, Utah, 1989