Human Mouth Tissue

[billybog]

What compounds are similar to the human mouth tissue?

For example, gelatin is similar to human skin because gelatin contains bones, skin, and different tissues of cows, pigs, and other animals.

So what would be similar to the human mouth tissue?

[SciB]

I don't think there is any substance that you could use to mimic the epithelial lining of the mouth and gums. If you want to do an experiment that gives you real data then you need to use the actual cells, not a model.

It is easy to get cheek cells by scraping the inside of your cheek with a wooden Popsicle stick or a spoon. To see the cells you would need access to a microscope with 400X magnification, but most school labs have one of those. You can stain specific organelles or membranes in the cells using dyes and even use a phone camera to take pictures through the eyepiece of the microscope.

I don't know what you are interested in but you could look at the effects of various kinds of mouthwashes on the cheek cells. Some mouthwashes have a lot of alcohol and this could damage cells. You might be able to detect that under the microscope.

These are just some ideas for you. Let us know what you want to do and we can make some more suggestions.

Sybee

[billybog]

I was actually doing an experiment on Colgate Optic White toothpaste, and Crest 3D White toothpaste. When you search up reviews for the Colgate toothpaste, many people complain about how it burns their mouth or they get blisters in their mouth. So I looked into the ingredients of the toothpastes and found out that Colgate Optic White uses an ingredient called tetrasodium pyrophosphate which contributes to the burning.

Now I want to test if that is actually the ingredient that burns peoples mouths. Since the Crest 3D White toothpaste has similar compounds as the Colgate Optic White, I am going to add tetrasodium pyrophosphate into the Crest (it can be bought in a powder form). This will tell us if it is actually the tetrasodium pyrophosphate that causes the burning or not.

I cannot test this on a human because if something reacts within the toothpaste and the person is harmed in any way, then I wouldn't know how to fix it. So this is why I need a model to test this experiment on.

[SciB]

The best model of the mouth would be cheek cells as I suggested. You can use your own and those of your family.

A 'burning' sensation in the mouth and blistering sounds pretty serious and bad for sales. Can you send a link to the reviews you are talking about.

Why do you think the pyrophosphate in the toothpaste causes burning? Do you have a reference or link that you can post? Your school could order sodium pyrophosphate from a chemical company and you could test it directly on some cheek cells on a microscope slide then stain them and examine them for changes.

Here are some links to sites with information about staining and photographing human cells:

http://www2.mrc-lmb.cam.ac.uk/microscop ... ncheek.php
http://serc.carleton.edu/microbelife/re ... stain.html
http://www.biologycorner.com/worksheets ... cheek.html
http://www.instructables.com/id/Take-di ... without-a/
http://howto.wired.com/wiki/Take_Microphotographs

Sybee

[billybog]

Here are a few links in which people were complaining about the burns:

http://www.amazon.com/Colgate-Optic-Whi ... geNumber=1
http://www.consumeraffairs.com/cosmetics/colgate.html

I asked my teacher if I could use cheek cells for this project and he said that we won't be able to see any damage at that level of magnification.

Here are the links for the tetrasodium pyrophosphate:
http://www.dentalbuzz.com/2014/12/30/to ... than-good/
http://www.trustedhealthproducts.com/6H ... ste-xs.pdf

I'm not sure if it's actually the tetrasodium pyrophosphate that causes the burning. That's what I'm experimenting on.

Thank you for the links and for all the help so far.

[SciB]

Hi,

I read several of the negative reviews about Colgate OpticWhite toothpaste and now I see what you meant. Of course, you have to be skeptical of what is written in reviews. That's why you do experiments like what you are planning.

I did a search for 'is pyrophosphate harmful to the mouth' and found one source that said: "Tartar control toothpaste also contains the ingredient sodium pyrophosphate which can make normal teeth hypersensitive and sensitive teeth extremely sensitive to hot and cold liquids." (http://www.dentalgentlecare.com/toothpaste.htm)

Several of the reviewers complained of tooth sensitivity so the pyrophosphate that the toothpaste contains may be the cause.

One review said the toothpaste reduced their sense of taste and that might be due to the sodium lauryl sulfate (SLS) it contains:
http://www.drdexter.com/whats-on-your-t ... our-mouth/
"SLS has a reputation for being a skin irritant, and in a study located in the U.S. National Library of Medicine, it was found that a significantly higher frequency of aphthous ulcers (canker sores) was demonstrated when the patients brushed with an SLS-containing toothpaste.The ingredient is also responsible for the unpleasant taste of orange juice after you brush your teeth. SLS desensitizes the taste buds that pick up sweetness, so your tongue is getting only the sour and bitter flavors."

OK, I think testing this toothpaste is a great idea for a project--but the big question is how to do it. I have to disagree with your teacher who says you won't be able to see any changes to cheek cells under the microscope. As a scientist, I would not categorically assume that something is impossible without testing it. What you will be able to see is going to depend on how you treat the cells with the toothpaste and what stains you use to identify the changes.

I do not know what the effects of this toothpaste will be on check cells, but if it alters the cell membranes (there is a stain for membrane lipids) this can have a large affect on how the cells function or even if they survive. There is a vital dye called trypan blue (https://www.thermofisher.com/order/cata ... t/15250061) that can be used to see which cells have damaged membranes. It comes as a 0.4% solution and you add it to the cells and 5-10 minutes later you count the cells that are blue. The trypan dye molecules can only enter cells that have holes in their membranes, so blue cells are damaged ones. You count all the cells in the microscope field then count the blue ones and express that as a percentage. That is a very good measure of the health of the cheek cells.

There are other stains for specific cell functions and organelles and you can find out more about them by doing some reading online. I can help you understand the technical details.

Do you have a lab that you can do these experiments in? That would make your work much easier.

I hope this helps to focus your project and get you started. Post again when you have more questions and we will get back to you.

Sybee

[billybog]

Thank you so much for the help. My teacher did agree to the idea of using the dye, except he's not sure if we're allowed to use human tissue/cells for the experiment. It may be against the rules.

Could this be tested on bacteria instead?

[billybog]

Can trypan blue work on bacterial cells? I tried researching that, but I couldn't find anything.

[billybog]

Now I am going to test this on bacterial cells using methylene blue because I wasn't sure if trypan blue would work on bacterial cells.

Using human tissues was against the rules so that is why we have to use bacterial cells. This works fine because humans carry 10x more bacterial cells than actual human cells.

Methylene blue works just fine as well because even though it stains all cells, the cells that aren't damaged have active enzymes that get rid of the colour. We would have to test this a few times though because some dead cells have enough active enzymes to get rid of the colour.

Once again, thank you so much for your help. I really appreciate it, and don't know how I would have done this without you. Thank you!

[SciB]

Hi,

The cells you are using are your own cheek cells! I don't think they would be harmful to you. After you stain and photograph the cells just put the slide into alcohol.

No, trypan will not stain bacteria. Besides, your whole idea is based on the effects of toothpaste on human cells, not bacteria. This will tell you nothing.

There are projects to test the effectiveness of mouthwashes on killing mouth bacteria but you will have to change your hypothesis and experimental methods.

Sybee

[billybog]

I know I tried convincing my teacher to use cheek cells because the results will not be the same, but he said no. Apparently it's against the rules even if they're just out of your mouth.

I could change my experiment to how tetrasodium pyrophosphate affects bacteria, but that won't be so exciting.

[SciB]

Are you allowed to grow bacteria from swabs on agar if the Petri dishes are sealed? If you can't do that then you will have to get a list of what you ARE allowed to do and choose something from there.

[billybog]

Yes we are allowed to grow bacteria with agar in a petri dish. My teacher said it shouldn't be a problem if we use bacteria since humans have more bacterial cells rather than animal cells. But I don't think the results will be the same because the cells have different parts to them.

[SciB]

OK. So now you're using bacteria. My next question--are you allowed to use bacteria from your mouth or only the usual E coli K12?

I googled antibacterial toothpastes and found that there are a few. They contain an antibacterial compound called triclosan (http://www.colgateprofessional.com/prod ... paste/faqs). You could test a couple of different toothpastes, with or without triclosan, and a couple of different antibacterial mouthwashes to see which one works best on mouth bacteria.

You can find information about how to test compounds for antibacterial activity here:

1. https://www.sciencebuddies.org/science- ... p014.shtml
2. https://www.sciencebuddies.org/science- ... p019.shtml
3. https://www.sciencebuddies.org/science- ... #procedure

Sybee

[billybog]

We have to grow the bacteria ourselves. I don't think it matters where we get it from.