Ultrasonic toothbrushes

Like other things in this category Neil - it's only a sin if you enjoy it!

I did indeed Michael - I followed the link but wasn't quite sure what I was looking at. In the English translation the author says of his SEM image:

"it clearly shows the formation of micro bubbles which will implode in the process".

In my first read through I took 'formation' to mean 'bringing into being' rather than 'existing in a particular shape' as, for example, in 'a rock formation'. Then I realised that SEM could hardly capture cavitation on the timescale of a 1.6 THz oscillator. So the micro bubbles must be static features in the toothpaste. The only credible candidate in the ingredient list is hydrated silica. Further research is needed!

Johnnyboy25 - first thing I said to my wife when she suggested it, ultrasound, it'll drive the animal mad. But it seems these things work at much higher frequencies than dogs can hear.

XD 351 - dog was rescued from a bad place - we're just trying to get her back to the state of normal dogness where toothpaste and bogpaper are unnecessary.

Robin.

Edited By Robin Graham on 25/08/2019 23:16:57

In a non-abrasive toothpaste? Shome mishtake shirley?

Plants have silca crystals in them as a defence against herbivores, which is why herbivore teeth don't stop growing with age...

Neil

I did some digging-around yesterday, but couldn't find a specific research paper about the toothpaste.

Manfred Ruppel was the specialist SEM operator at Goethe: **LINK**

https://www.bio.uni-frankfurt.de/43227763/Über_M__Ruppel

and appears well-respected.

The image on the available copy of that confirmatory letter is difficult to interpret, but it is important to note the 300nm length of the scale bar: These are very small bubbles.

More if/when I can find anything 'technical'

MichaelG.

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Edited By Michael Gilligan on 26/08/2019 07:04:05

Here's a patent for what I assume to be the brush: **LINK**

https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=DE&NR=20218605U1&KC=U1&FT=D&ND=3&date=20030605&DB=EPODOC&locale=en_EP

Assistance from a forum member fluent in German would be appreciated.

MichaelG.

Edited By Michael Gilligan on 26/08/2019 08:07:59

We feed our dogs on Raw, perfect pearly whites due to The bone content, plus a host of other benifits.

Well, yes. But ingredients are Aqua, hydrated silica, sorbitol, glycerin, disodium pyrophosphate, tetrapotassium pyrophosphate, xanthan gum, sodium C14-16 olefin sulphonate, sodium methylparaben, sodium saccharin, aroma, CI 77891. CI 77891 is TiO2.

All very mysterious!

Thanks for further digging Michael - I wasn't disputing Ruppel's credentials, it's just that he doesn't give us much context for the image.

Coincidentally I am expecting a someone who earned her crust by translating German tech documents to drop by tonight. l'll ask her about the patent.

Robin.

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Context appears to be that it was commissioned SEM imaging work, to support the customer's own research.

Still hoping to find something 'published' but I suspect the details might be 'Commercial in Confidence'

MichaelG.

Drifting only slightly off-topic ... I've just found this brief exchange: **LINK**

https://electronics.stackexchange.com/questions/190556/how-can-i-make-a-ceramic-piezo-operate-at-a-specific-frequency

Circuit Schematic and a Patent reference

MichaelG.

I'm still confused how they say:

" In contrast to standard products, our special toothpaste is free of abrasive particles that could permanently damage your teeth’s enamel. "

and:

" in the ingredient list is hydrated silica. "

One could also wonder whether to consider hydrated silica to be one of the nano-materials that isn't in their toothpaste.

Edited By Neil Wyatt on 27/08/2019 22:51:10

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Let's try analysing their statement for abiguity:

Robin qoted the following:

Toothpaste without abrasive particles

While you could theoretically forego using toothpaste when using a conventional toothbrush due to the brushing motion, using the special ultrasonic toothpaste for micro cleaning with emmi®-dent is a must. In contrast to standard products, our special toothpaste is free of abrasive particles that could permanently damage your teeth’s enamel. This is why ultrasonic toothbrushes not only prevent gum inflammation and periodontitis, but are perfect for people with sensitive gums or with pre-existing gum problems.

I have emboldened one key sentence which is open to interpretation:

1. In contrast to standard products, our special toothpaste is free of abrasive particles that could permanently damage your teeth’s enamel.
2. In contrast to standard products, our special toothpaste is free of abrasive particles that could permanently damage your teeth’s enamel.

The distinction is subtle, but:

If the particles in [1] are small enough; they might legitimately claim that they could not permanently damage the enamel.

Whereas, in [2] they would be claiming that the paste is entirely free of abrasive particles.

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My understanding, however, is that the active part of the cleaning process is the implosion [sic] of microbubbles that are formed and then destroyed by the ultrasonic vibration.

No ... I don't understand how it all works, and

Yes ... I am intrigued !

MichaelG.

**LINK**

https://en.m.wikipedia.org/wiki/Hydrated_silica

MichaelG.

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https://www.sciencedirect.com/topics/chemistry/hydrated-silica

Edited By Michael Gilligan on 27/08/2019 23:58:54

I wondered if the the confusion might be because MichaelG's link was to Emmi-dent (the version for humans) but the ingredient list I quoted came from the back of a tube of Emmi-pet.  Not so - further research reveals:

Ingredients

Aqua, Hydrated Silica, Sorbitol, Propylene Glycol, Tetrapotassium Pyrophosphate, Xanthan Gum, Sodium C14-16 Olefin Sulfonate, Aroma, Titanium Dioxide, Sodium Fluoride, Sodium Saccharin, Allantoin, Limonene, Mentha Arvensis Leaf Extract, Chamomilla Recutita Flower Extract, Salvia Officinalis Leaf Extract, Sodium Methylparaben.

for Emmi-dent. So essentially the same formula, but with the omission of sodium fluoride in the pet version presumably because of the toxicity problem JasonB highlighted. So still mysterious and possibly mendacious - though I suppose it might depend on how 'abrasive' is defined.

The German version of the patent for the toothbrush yields no more pertinent information than the summary in English. It says that there is an ultrasonic transducer in the head of the device which is connected to a battery and pressing the button causes the thing to work. I'm surprised that the patent was granted (if it was) - prior art surely? Ultrasonic cleaning has been around since the 1950's it seems.

My Teutophone friend translated Manfred Ruppel's letter for me and came up with 'clearly shows the presence of micro bubbles' rather than the 'clearly shows the formation of ...' in the English version of the letter which Michael found. I don't know if that's significant, but I do know that Ruppel's observations are scientifically valueless in the absence of information about what exactly he has imaged, and under what conditions (ie context).

I'm no further forward in understanding how Emmi-pet/dent toothpaste enhances the mechanism of ultrasonic cleaning. I suspect it's a sales ploy.

Robin.

Edited By Robin Graham on 28/08/2019 01:29:30

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That's probably helpful to know, Robin

MichaelG.

General info. for those interested in Robin's conundrum:

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**LINK**

https://www.emag-germany.de/impressum/

**LINK**

https://www.emag-germany.de/downloads/

**LINK**

https://www.ultrasonic-world.co.uk/ultrasoniccleaner.html

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MichaelG.

Edit: ... and translated, using DeepL, from this page:

https://www.emag-germany.de/die-emag-ag/

Our ultrasound device for micro tooth cleaning, Emmi®-Dental, is also a pioneer in the future: ultrasound is guided into a special ultrasound toothpaste. This creates tiny bubbles which, through implosion, remove all impurities, tartar and bacteria. The unique Emmi®-Pet series was developed for gentle and thorough tooth cleaning in dogs.

Edited By Michael Gilligan on 28/08/2019 07:51:23

I retired long enough ago to be out of them loop on contemporary innovations. But if a novel product was launched then I'd have expected published documentation to support it's premis and if that seemed unconvincing then most companies would have a veterinary advisor one could speak to.

I have posed a question on one of the veterinary professional boards to see if such evidence exists.

On lighter off topic notes:

Back in history I wondered whether the oral product for ladies intimate thrush treatments might be of use in canine nasal aspergillosis cases ( a difficult but uncommon condition to treat.) Somehow the company switchboard routed my call to the wrong department and a surreal conversation regarding fungus up a puppy's nose before i twigged that I was on the ladies' helpline and they thought i was using euphamisms.

The comment about biscuits to clean teeth - believe it or not but the first marketing ploy was to provide a screwdriver and tippex. Coat the screwriver and then jab it into a biscuit to show how well it cleans the screwdriver. Yeah - that really just proves that if you paint your dogs teeth with tippex then the biscuits will clean it off...

pgk

Pending pgk's discovery of the truth ... here is my hypothesis:

• The novelty claimed in the patent is that an ultrasonic generator, built into a toothbrush, excites the bristles in such a manner that they act as an array of 'stingers'
• Modal analysis, or modelling, will probably have been done [but may not have been disclosed]
• The resulting vibrations, in individual bristles, are such that they 'foam' the toothpaste with microbubbles
• Continued vibration then causes these [very small] bubbles to 'implode' generating a multitude of local shock events
• The toothpaste itself may, or may not, be classed as abrasive; depending upon how you choose to define that term ... but; since there is [in the normal sense] no brushing action involved, it is probably a moot point.

I wait in eager anticipation to learn just how wrong I am.

MichaelG.

pgk - thanks for your interest in this conundrum and for taking the time to consult your professional colleagues - I'll be interested to hear what they say. Thanks also for the aspergillosis tale - that made me laugh, a welcome relief from my wearying worries about dog toothpaste.

MichaelG - I'm sort of almost half convinced by your hypotheses , but I wonder where Ruppel's image fits in with your scheme. I don't know much about SEM, but I think exposure times are far too long to capture a 'snapshot' of cavitation, or even foaming on that scale - small bubbles in fluids are pretty unstable. I might be wrong about these things, but that's why I thought his images must be of solid structures and the only candidate seemed to be the hydrated silica.

Robin.

+1

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I'm guessing that it fits between the third and fourth bullets in my hypothesis

... note that my fourth starts with the word 'Continued'

MichaelG.