In this month's proderm story, our interviewer wants to know everything there is to know about oral health, from sensitive teeth to bad breath. Our project manager and resident artist Caroline Manger, who has managed a great variety of oral health studies at proderm, was not only available to illustrate a very sensitive tooth, but also to answer all our questions about oral health!
Oral health at proderm - The whole, naked tooth
Hi Caro! I think the initial question is pretty clear: What kind of oral health studies are we commonly doing here at proderm?
We mainly do cosmetics and consumer care studies. But we can absolutely also do pharmaceutical and medical device studies.
Ok, what would be typical products in consumer care studies?
Well, toothpastes, toothbrushes, mouthwashes, tooth whitening products. We had one that was a tooth paste in combination with some sort of LED device.
Tooth whitening products?
Oh yes – Testing tooth whitening properties of products is one of the most common things we do in oral care!
So, the subjects need to have discolored teeth, I suppose?
That's not a problem. People drink a lot of tea and coffee.
So how do you measure that - Is there something like a tooth color scale?
Oh yeah! The Vita shade guide - It's like a card where there are lots of little plastic plates with different colors. You usually use these at the dentist when you need to ensure dentures fit in with the rest of the teeth in terms of color, for example.
But the way we usually assess coloring of teeth is by taking photos and evaluating the pictures photo-analytically. They are not like cool marketing photos, though, as people have to wear these cheek retractors.
Ah, photography and image analysis seem to be some sort of core competency at proderm
Yes, of course we always try and use that, as that's actually what makes us special - with the many photo devices and photo systems that we have.
So what else is there?
Well, plaque and gum health. It's a bit of a departure from the cosmetic impact; it's also about health, a healthy oral cavity and healthy gums.
For plaque scoring we virtually paint the teeth with a blue color like you do with children at the dentist to show them how bad they are at brushing their teeth.
I think I've seen that in TV commercials.
Exactly! At the end of the day, it's always a visual assessment. Gum health assessment goes a bit in the same direction. You always have a visual assessment, which is just a bit nastier, because you basically go along the gums with this probe thing until it bleeds and then you assess the strength of the bleeding visually. And that is also the crux of both plaque scoring and gum health assessments. It is really challenging to show product differences in such studies because these are usually minimal differences and you need super good evaluators.
Then how do we do it?
First of all, you need a tried-and-tested panel of evaluators, which we have now expanded a bit. All very experienced and trained dentists!
So how do we ensure the assessment is done uniformly? Wouldn't everybody do this a bit differently?
In all the studies where we have visual assessments, the evaluators are always very well trained. It's really difficult and it's super important to have trained and "well calibrated" evaluators. We go through a lot of effort to get that right before each study.
I mean, apart from the scoring, when testing tooth brushes, people also brush their teeth very differently. How do we deal with that?
Oh that's not so difficult to standardize. You just ensure subjects brush each side for a specific amount of time.
We are still on the subject of the most common oral health studies at proderm, is there anything else that comes to mind?
Sensitive teeth! We do a common study design where you look at how sensitive the teeth are to pain. There are toothpastes that have ingredients that try to fill up pores in the enamel, so that the nerve endings are not so exposed. Sponsors like to claim that their products make the teeth less sensitive. One way to test this is to poke the tooth with a device called Yeaple probe that helps measure the force needed for people to begin feeling discomfort in their teeth.
Yeaple Probe sounds like something you would have found in a toy shop in the nineties or something.
Ha ha, no it's a device for measuring dentinal hypersensitivity that can apply force to a tooth in discreet increments of 10g, so this helps to harmonize measurements across investigators, which is very important if you want to show that a product really protects the teeth from pain.
OK, let's move on - What are some more exotic study designs we do?
So at proderm we do a lot of sniff studies for deodorants for example, but sometimes we also apply this technique to oral health related topics, namely bad breath or halitosis, not only natural bad breath but also for example bad breath caused by things like smoking or certain kinds of food for example. We can do this employing the same sniffers who work on our deodorant studies, but we also have an OralChroma device that can objectively measure volatile sulfide compounds in breath.
OK, apart from smelly breath, anything else we do that is a bit more exotic?
Ok, one kind of crazy study type we can offer are in situ de-mineralization and re-mineralization studies.
I think you should try and explain what an in situ de-minil… de-minali… de-min-
Yeah, that's where you always get hung up, that's exactly why you try to avoid having to say it at all.
… explain what an in situ demineralization and remineralization study is..
There you go!
So basically, the idea is that the tooth enamel is attacked by acid and that it demineralizes and thus offers a surface for attack for bacteria to get in there and cause caries.
The idea is to re-mineralize it somehow so that it remains resistant and cannot be attacked. Basically to show a protective effect, we can use a relatively simple method of testing that is purely physical.
There are special machines for testing the hardness of surfaces. You have a clamp holding the material that you want to test and then you have a bolt that comes in from above, pressing with a certain pressure and the tip of this bolt has a specific pyramid shape and the softer the enamel, the bigger the imprint, which you can analyze under a microscope.
But it's hard to clamp subjects' teeth into the device while they are still attached to the person... So you do it with enamel from bovine teeth.
Really? Like, from a cow?
Yes, and um, in situ basically means you pretend that this piece of cow tooth is the tooth of the test person, because you put it in their oral environment. You can take them out afterwards and have them examined in the laboratory.
Where do you even get cow teeth?
Exactly, yes, that was quite fun. The last time we did a study like this, we got them from a company in England. And that wasn't so easy.
First off, we had the Corona lockdowns going on so everything that was supposed to be delivered somehow took a gazillion years, then we were in the middle of Brexit time, where it was also not quite clear how what was going to be processed and all.
But you managed to import them eventually?
It all worked out in the end and we didn't even have to postpone the study. But there definitely was a certain thrill factor.
And when you get the cow teeth, what happens next?
You make dental impressions, like you would do for a dental cast or a retainer. This thing that people "love" so much at the dentist or orthodontist- that feeling when the impression material it's running down the back of your throat. Retainers are made for each subject to carry the enamel pieces within the oral cavity, on the upper palate between the teeth. People are supposed to wear these all day, except when eating.
How long do people need to wear this?
That depends on the protocol, mostly around a couple of days to a week, something around that time frame.
Isn't that super annoying?
We were most worried that the subjects would have trouble speaking if they had for example a job that requires them to talk a lot, but that didn't seem to be a problem at all! But all in all, it's a great way to study de- and remineralization claims with products like toothpastes!
Ah, ok, so if people brush their teeth they also brush the cow teeth, so to speak?
So, we can do something like that again at any time?
Thank you very much!