Ultrasonic toothbrushes

[pgk pgkParticipant @pgkpgk17461]

I suffer from chronic back problems from an old spinal asbcess. Prior to one long haul flight to Jamaica I opted to dose myself with a canine prescription analgesic because of the 10 hrs stuck in a cramped airline seat only to discover that was flavoured with sorbitol – one of the few things that affects my bowels. The flight was spent in the toilet.

I doubt the quantity in the toothpaste is significant. Xylitol is the sweetener to really avoid in dogs.

pgk

[Robin GrahamParticipant @robingraham42208]

In the absence of any compelling evidence to the contrary I'm thinking that there's nothing special about the ultrasonic toothpaste – at least two members of the hive mind here are getting good results on their own teeth with US brushes and the normal stuff, but no-one has buzzed in with a plausible explanation of why the expensive toothpaste is advantageous. I think it may well be a sales* ploy.

Trawling further through Emmident's sales stuff on their website I see that they give a hand-waving explanation of the ultrasonic cleaning process – that's fair enough, if they went on about Laplace pressure, vapour pressures, surface tension, shock waves etc they would rapidly lose their target audience. But it does seem that they cite Ruppel's images of microbubbles (which surely must be static structures given the timescale of SEM?) as evidence of cavitation – they seem to be conflating ideas of static and dynamic microbubbles. Maybe the static microbubbles in the image serve as nucleation centres and promote cavitation? That seems feasible, but if so why not just say it? I shall email them and report back if I get an explanation.

Anyhow, thanks for the discussion, I've learned some stuff.

Robin.

*Wrist slapped by a marketing manager for saying 'marketing ploy' on another forum. It's the sales people who do the bad stuff apparently.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robin Graham on 31/08/2019 00:23:24:

.[ … ]

*Wrist slapped by a marketing manager for saying 'marketing ploy' on another forum. It's the sales people who do the bad stuff apparently.

.

… That's a great line !!

In my limited experience: Marketing people are devious enough to avoid telling actual lies, whilst Sales people will say anything they think they can get away with.

The Marketing version of 'Complete Honesty' is the condensed version …

i.e. The Truth, The Whole Truth, and nothing but The Truth

I would respectfully suggest that what you are seeing on their website is the work of 'Marketing'

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

For what it's worth: **LINK**

https://worldwide.espacenet.com/publicationDetails/originalDocument?FT=D&date=20140619&DB=EPODOC&locale=en_EP&CC=AU&NR=2012342951A1&KC=A1&ND=4

MichaelG.

.

Please read carefully the closing paragraph on numbered page 1

… Is it claiming that the use of special toothpaste is avoided by this new design of brush-head ?

 

Edited By Michael Gilligan on 31/08/2019 10:41:06

[pgk pgkParticipant @pgkpgk17461]

I'm obviously getting mentally slower. It occurs that all this talk of bubbles is 'marketing' to make things sound simpler to the public. What is going on is cavitation and i don't see how that can pre-exist in any paste. There may be a point to using pastes or liquids with different surface tension/vapour characteristics to modify the force of cavitation collapse.

Whilst here it's ultrasonic energy here has to be a simple visualisation with ,say, a ship's propellor tearing through the water and inrushes to fill those low pressure areas or total disruption to vapour filled pockets. its the same imagery used below.

wikipedia cavitation

marketing and sales..ha.. sound slike the differences between advertising and promotion:

Advertising = "this is our widget it does widget stuff"

Promotion = "Buy our ultimate widget to widget better than the competion at half the price and for one day only has free postage"

pgk

[Neil WyattModerator @neilwyatt]

Posted by pgk pgk on 29/08/2019 10:14:01:

I'm still having trouble with the concept of bubbles imploding.

Goggle 'Cavitation' it's a powerful enough effect to destroy boats' propellers and pump impellers.

 

<edit> sorry, just saw your latest post…

Neil

Edited By Neil Wyatt on 31/08/2019 14:39:10

[Michael GilliganParticipant @michaelgilligan61133]

Posted by pgk pgk on 31/08/2019 12:31:21:

[ … ]

What is going on is cavitation and i don't see how that can pre-exist in any paste.

[ … ]

.

I could very easily still be wrong, but … if I may repeat my third and fourth bullet points from above:

• 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 bubbles are created by vibration, and 'imploded' by further vibration, i.e. They don't pre-exist in the tube of toothpaste…. and it seems reasonable that they might last long enough to be imaged if the vibration is stopped between those two stages.

MichaelG.

[Robin GrahamParticipant @robingraham42208]

Posted by Michael Gilligan on 31/08/2019 10:26:02:

For what it's worth: **LINK**

https://worldwide.espacenet.com/publicationDetails/originalDocument?FT=D&date=20140619&DB=EPODOC&locale=en_EP&CC=AU&NR=2012342951A1&KC=A1&ND=4

MichaelG.

.

Please read carefully the closing paragraph on numbered page 1

… Is it claiming that the use of special toothpaste is avoided by this new design of brush-head ?

 

Edited By Michael Gilligan on 31/08/2019 10:41:06

It appears so Michael – the need for a special ultrasonic toothpaste is clearly one of 'the aforementioned problems' listed in paragraph three. But then on numbered page 7, describing how the invention is to be used, they give the first stage in the process as follows:

– distribute ultrasonic toothpaste lightly on the insides and outsides of the teeth

So ultrasonic toothpaste is still necessary? I'm even more confused now!

pgk, I agree with your last post and your earlier one when you suggested (I think) that the defining quality of 'ultrasonic toothpastes' might be to do with viscosity/surface tension. But Michael's tentative explanation of Ruppel's SEM image could be right. If so, we need to know how the 'implosion' (yes, I noted your inverted commas Michael) of bubbles in fluid might enhance the ultrasonic cleaning process.

Pending a response from Emmident I shall later today try the toothbrush on a piece of rusted steel with normal and ultrasonic toothpastes to see if I can detect a difference. I'll get it in the neck from the Mrs if I knacker the brushes, but sometimes one has to suffer for science.

Robin

 

 

 

Edited By Robin Graham on 01/09/2019 01:09:06

Edited By Robin Graham on 01/09/2019 01:16:52

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robin Graham on 01/09/2019 01:02:34:

[ … ]

It appears so Michael – the need for a special ultrasonic toothpaste is clearly one of 'the aforementioned problems' listed in paragraph three. But then on numbered page 7, describing how the invention is to be used, they give the first stage in the process as follows:

– distribute ultrasonic toothpaste lightly on the insides and outsides of the teeth

So ultrasonic toothpaste is still necessary? I'm even more confused now!

[ …]

Pending a response from Emmident I shall later today try the toothbrush on a piece of rusted steel with normal and ultrasonic toothpastes to see if I can detect a difference. I'll get it in the neck from the Mrs if I knacker the brushes, but sometimes one has to suffer for science.

Robin

.

I share your confusion, Robin … but I think the four lines on numbered page 8 might help

It seems that there are two processes involved in the use of this super brush-head

1. Wide-are Ultrasonic cleaning by microbubble implosion, and
2. The mechanical intervention of the bristles into awkward locations around orthodontic braces

MichaelG.

.

Good luck with the experiment

[SillyOldDufferModerator @sillyoldduffer]

Posted by Robin Graham on 26/08/2019 09:52:13:

Posted by Neil Wyatt on 26/08/2019 01:29:13:

Posted by Robin Graham on 25/08/2019 23:11:28:

The only credible candidate in the ingredient list is hydrated silica. Further research is needed!

…

Neil

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….

Robin.

 

I don't think Hydrated Silica is the only credible ingredient, but I agree the mix looks very much like an ordinary toothpaste.

The active ingredients are Silica, Tetrapotassium Pyrophosphate, Sodium C14-16 olefin sulphonate and possibly Glycerin, which although it promotes bubble formation I suspect is just a sticky sweetener.

Sorbitol, Saccherin, and Disodium pyrophosphate are controlling the flavour, presumably so the dog doesn't take a violent dislike to the taste. Aroma is managing the smell, I guess to avoid annoying both animals involved in brushing the furry friend's teeth.

Xanthan gum and Sodium methylparaben extend the storage life of the mixture.

The Titanium Oxide is to please the human animal; would you spend good money on a grubby yellow toothpaste or trust it? Humans believe toothpaste must be bright white unless it also comes with red go-faster stripes.

I suppose it's possible someone experimented in a lab to find the chemical proportions that produce best cavitation, and why not? Otherwise I think it's just doggy toothpaste.

I wonder what it tastes like – I prefer peppermint!

Dave

Edited By SillyOldDuffer on 01/09/2019 10:55:31

[pgk pgkParticipant @pgkpgk17461]

When it comes to pharmacetical and feed companies ideas of taste/smell I remain cynical (as ever). In the early days of promotions for doggy toothpastes one company did provide a range of flavours which included biscuit flavour. Now that one tasted exaclty like the filling in a custard cream and one found staff sticking their fingers in the demo pot for another taste – it was lovely but less popular with the patients.

Why they ever came out with raspberry bubblegum flavour for one antibiotic is a mystery – probably the company just had a huge vat of the stuff left over…

The pet food manufacturer looking for new flavour ideas wasn't keen on my suggestions of Robin with Mouse flavour cat food or Horse dung and decaying rabbit dog food although they did admit that they once made a promotional run of a dog food so tasty no dog refused it— unfortunately owners who opened the tins and got a whiff were throwing it away as 'being off'.

When we had to find ways to trick pets into eating drugs the owners couldn't dose then for dogs it was easiest to mash it in marmite +/- peanut butter or for cats with pilchards. Oddly my cat patients seemed to prefer pichards in tomato sauce rather than oil.

Mint falvour is traditional and likely expected by adults but remember kids like thir punch and judy type flavousr of banana etc. Just wait for the marketeers to hit the millenial or gen Z customers with quinoa and goji berry toothpaste or something equally bizarre.

[MeunierParticipant @meunier]

My take from all the above interesting discussion – whilst not reading every link – is that perhaps the purpose of the 'special toothpaste' may be to promote the formation of micro-bubbles rather than just bubbles, which then fulfil the function of cavitation and hence cleaning. (what is the pH of this toothpaste ? ) A similar effect, perhaps, to my adding 5ml of dish-washing-liquid in my domestic ultra-sound cleaning tank which apparently lowers the surface tension of the water thus promoting the formation of more numerous, smaller sized bubbles.
DaveD

[Robin GrahamParticipant @robingraham42208]

Posted by SillyOldDuffer on 01/09/2019 10:54:11:

Posted by Robin Graham on 26/08/2019 09:52:13:

Posted by Neil Wyatt on 26/08/2019 01:29:13:

Posted by Robin Graham on 25/08/2019 23:11:28:

The only credible candidate in the ingredient list is hydrated silica. Further research is needed!

…

Neil

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….

Robin.

 

I don't think Hydrated Silica is the only credible ingredient

…

I wonder what it tastes like – I prefer peppermint!

Dave

Edited By SillyOldDuffer on 01/09/2019 10:55:31

Dave, I thought (before reading MichaelG's credible hypothesis about foaming) that Ruppel's SEM image must be of a solid structure and hydrated silica seemed the best candidate given that it's odd, amorphous stuff. Maybe I should have said 'most' rather than 'only'. Do you see an alternative if the image is of a solid in the toothpaste?

The doggy utrasonic toothpaste is indeed peppermint, which our dogs detest. We also have enzymatic (non-ultrasonic) dog toothpaste which is flavoured with 'poultry extract' – I try not to think too much about that means! Problem is they like it so much that they want to eat the toothbrush.

Sadly I didn't get the opportunity to test the brush on rust today but I did look up ultrasonic derusting in case it was a crazy idea. It seems that it should work – I'll give it a go when I can.

pgk – I reckon you could be onto a winner with your quinoa and goji berry idea. But:

The pet food manufacturer looking for new flavour ideas wasn't keen on my suggestions of Robin with Mouse flavour.

Over my dead body mate.

Robin

 

Edited By Robin Graham on 02/09/2019 01:32:24

Edited By Robin Graham on 02/09/2019 01:37:20

[pgk pgkParticipant @pgkpgk17461]

pgk – I reckon you could be onto a winner with your quinoa and goji berry idea. But:

The pet food manufacturer looking for new flavour ideas wasn't keen on my suggestions of Robin with Mouse flavour.

Over my dead body mate.

Robin

The ultimate in recycling?

You're probbaly aware that pelleted dog/cat food is an extruded mix that has the flavour sprayed on at the end of the process. They call that flavour 'digest' and while one hopes it's steam produced and analagous to boiling up a chicken carcase (or whatever) for soup then i guess the best that can be said is that its no worse than a turkey twizzler.

As another light hearted but true comment: we were given trial cans of venison cat-food which was actually god stuff asa novel protein for possible allergy cases. As usual we got sent an awful lot of cans to give away early December. I put a sign up "Feed your cat Rudolf for Christmas"

pgk

[mark costello 1Participant @markcostello1]

I always thought "mouse in a can" would be a viable idea.

[Michael GilliganParticipant @michaelgilligan61133]

Resurrecting this thread:

About 17 minutes into this: **LINK**

The Secret Life of Waves: http://www.bbc.co.uk/iplayer/episode/b00y5jhx

there is a short piece at University of Southampton, which may be relevant.

MichaelG.

[Robin GrahamParticipant @robingraham42208]

Thanks for that Michael – interesting stuff. Keen as I was I didn't do my 'rust removal with an ultrasonic toothbrush' experiment because on reflection I thought domestic disharmony might ensue. It turned out that dog had a rotten tooth which has now dropped out – whether by nature or with the assistance of ultrasound I don't know. The animal is now chomping happily and the toothbrush has become redundant – it'll find it's way to my workshop I expect. In due course.

Robin

[Howard LewisParticipant @howardlewis46836]

Probably throwing the thread somewhat off topic, the implosion of bubbles can be quite damaging, or effective, depending on the context..

The manufacturers of engines with wet cylinder liners had problems with what was called "waterside attack". This caused the cylinder liner to become porous, allowing coolant to make its way into the sump, via the microscopic holes in the liners. The problem was that as the piston reversed direction at top and bottom of the stroke, the skirt slapped the wall. This caused the coolant to cavitate, presumably because of minute deflections of the liner. When the resulting cavitation bubble imploded, it knocked the ferrite out of the liner.

One solution was to move the gudgeon pin off the centreline of the bore, to reduce the slap. Others chromium plated the liners, but ultimately the cavitation still made its way to the liner!

So US should be a good way to clean Fido's teeth, as long as not overdone. Possibly, water would be an effective conveyor of the US pulse, since this basically the main constituent of some US cleaning baths.

Give a product a fancy name and you can sell it for a vastly inflated price.

Or am I a cynic?

Howard

[Michael GilliganParticipant @michaelgilligan61133]

I think it’s time to revive this thread:

The Royal Microscopical Society has launched a YouTube channel, and the videos include this ultra high speed video of cavitation bubbles : **LINK**

MichaelG.

[Mick B1Participant @mickb1]

Posted by mark costello 1 on 02/09/2019 17:17:00:

I always thought "mouse in a can" would be a viable idea.

In the 60s there was a cat food called (IIRC) 'Dine' which was a canfull of silvery compressed whole fish in jelly.

Fluff loved it, but parents wouldn't buy it having seen (and smelt) it once.

[Robin GrahamParticipant @robingraham42208]

Posted by Michael Gilligan on 13/06/2020 09:42:13:

I think it’s time to revive this thread:

The Royal Microscopical Society has launched a YouTube channel, and the videos include this ultra high speed video of cavitation bubbles : **LINK**

MichaelG.

That's amazing Michael. I see that the work dates from 2015 – have further advances in speed been made since then?

Apart from the astonishing microscopy it's interesting to see how the cavitation pattern changes with distance between the active and 'passive' elements. Maybe I should send these guys a sample of dog toothpaste!

Do you have any references to the original research? Couldn't see anything on the (obviously fledgling) RMS site.

Robin.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robin Graham on 13/06/2020 23:04:59:

 

Do you have any references to the original research? Couldn't see anything on the (obviously fledgling) RMS site.

Robin.

 

.

I found this page, Robin : **LINK**

https://www.birmingham.ac.uk/staff/profiles/clinical-sciences/vyas-nina.aspx

… but haven’t yet followed-up the list of her publications.

MichaelG.

.

Edit: Here we go:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4775067/

Edited By Michael Gilligan on 13/06/2020 23:31:28

[Graham StoppaniParticipant @grahamstoppani46499]

Posted by Howard Lewis on 14/11/2019 19:53:06:

So US should be a good way to clean Fido's teeth, as long as not overdone. Possibly, water would be an effective conveyor of the US pulse, since this basically the main constituent of some US cleaning baths.

Give a product a fancy name and you can sell it for a vastly inflated price.

Or am I a cynic?

Howard

My company used to sell Ultrasonic baths – I'm not an expert in this area though. From what I can remember, plain old water worked just fine. Some additives would compliment the the cleaning through chemical action acting alongside the cavitation while others would reduce the cavitation. Can't remember which now as its around 25 years ago.

With regards the damage ultrasonics can do, a simple test to ensure the bath was working was to dip a piece of aluminium baking foil in the bath for a couple of minutes. If the bath was working there would be pin holes punched in the foil by the cavitation.

[Michael GilliganParticipant @michaelgilligan61133]

Robin,

Here are some details about the camera they used: **LINK**

https://photron.com/wp-content/uploads/2014/07/FASTCAM_SA1.pdf

MichaelG.

.

https://photron.com/

Edited By Michael Gilligan on 14/06/2020 10:37:08

[Robin GrahamParticipant @robingraham42208]

Thanks Michael. Pretty impressive technology. It looks like Dr Vyas is still working at Birmingham Uni – I may contact her to enquire about the influence of cavitation media. As she works in Dentistry it must be something that they have considered. I'm sure there must be funding opportunities from toothpaste manufacturers!

Dog owners might be interested to hear that the ultrasonic brush/toothpaste combination appears to have worked – the animal is munching happily again. However it's possible that she may have had had a rotten tooth which fell out in the course of nature. Perhaps stimulated by ultrasound – we'll never know.

Robin

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