How to Fix Your Own Teeth (with stuff you buy from Bunnings)

Sometimes I wish I’d been a dentist.

When I’m paying my bill, that is! Boy it’s expensive!

Now, I’m always looking for ways to save myself money using my chemical knowledge (which led me to design my own way to make biodiesel, but that’s another story), and now out of necessity I’ve turned my thoughts to dentistry.

This wasn’t planned of course, but the other day I was munching on a pizza with a particularly crusty crust when I felt an almighty CRUNCH as I bit down on it. When I fished the offending item out of my mouth it was a substantial part of one of my teeth.

The tooth in question has an almighty amalgam filling in the middle of it, and so the bits around the edge don’t have a lot of mechanical support, and hence the failure.

So now I had this tooth fragment sitting in my desk as I contemplated my options. The first option of course was the dentist. From previous experience I know what she’d tell me. First it’d need a temporary repair, and then she’d take a mould, and I’d I’d have to come back for a crown.

This of course would involve a couple of thousand dollars (I think – I had one done a few years back). Since this is more than I normally spend on cars that I buy, I figured there had to be other options.

As I thought about it, it occurred to me that there was indeed another option. When we get our teeth repaired these days, amalgams are no longer used. Rather, they have been replaced by UV-curing (epoxy) polymers. They put some white stuff in your mouth, zap it with a UV light for 30 seconds or so, and Bob’s your uncle.

So all I need to do to fix my broken tooth is to find a rapidly curing polymer that can be moulded for long enough for me to hold it in place while it sets. Then it occurred to me that I had just such a product in my garage. I had bought it a while ago because I thought it looked like a useful product, although I didn’t have a use for it at the time:

Here’s how it works.

Have I mentioned that I’m not a dentist? Not sure if I’ve mentioned that yet.

Now, to fix my tooth, I had to prepare the surface correctly, as with any adhesive. This of course was a little tricky, as it was inside my mouth, and moisture was obviously going to be a challenge.

Here’s how I did it:

1. I removed any bacteria (and food) from the surface to be repaired. Anaerobic bacteria are responsible for tooth decay (they produce the lactic acid that dissolves the calcium phosphate from which your teeth are made). This was easily done with a Listerine rinse.

2. I dried the surface to be repaired. For this, I got a cotton bud and soaked it in metho. Then I just rubbed it over the surface liberally.

3. I then repeated with acetone. I was careful with this – if you get it on your tongue the sensation is rather unpleasant.

The area was now (or should have been) dry. An alternative approach would have been a gentle stream of compressed air (if I had a compressor handy), as this is what dentists use.

4. I mixed the epoxy (while holding my mouth open). Took about 30 seconds to get a consistent mix.

5. I pressed it into my tooth, and held it there with firm pressure, attempting to mould it to the approximate contour of my teeth. I poked the unused portion occasionally to get a feel for when it set (about 3 min). Then I just gently removed my fingers from the epoxy and it stayed behind.

When I did this I immediately felt the roughness of the material in my mouth. But it seemed to work, so I was happy, and I figured I’d just let it set fully and then sand it smooth the next day.

But the next day when I woke up it felt smoother. Over the next few days it seemed to smooth out naturally, and a week later it now seems to have conformed to the contours of my teeth naturally.

I haven’t been game to give it any serious bite work, but it’s OK for mushy chewing. And it’s perfectly safe chemically, as the product is certified for use with drinking materials.

And now a disclaimer or two – this technique should certainly not be used to repair a decayed tooth.

Here’s why.

Decay is caused by lactic acid, which gradually dissolves the calcium phosphate from which your teeth are made. The lactic acid comes from the breakdown of sugars, caused by anaerobic bacteria, which inhabit plaque. At the microscopic level, therefore, the cavity is a very irregular shape, with little channels and pores in which the bacteria sit, producing the lactic acid. This is why dentists drill before filling – they need to completely remove the decayed area, thus creating a smooth mechanical surface to which the filling can adhere.

If you just plonk an epoxy on top, the bacteria are free to continue their decaying process, and probably at a greater rate, as the lactic acid is not now being washed away.

So I would only use this technique, as I have, for a situation where the failure was purely mechanical, and I was attaching the epoxy to a clean, undecayed surface.

Once again, I am not a dentist, so I’m not recommending this to anyone – I’m just telling you what I did.

Just thought I’d mention that….

One other thing – chemical safety. Is this stuff safe to put in your mouth? As it happens, it is – if you look on the documentation for this stuff it says that it’s safe to use on drinking utensils. The reason is that it’s a thermoset polymer, which means that the polymerisation process is irreversible – it sets into an inert solid that has no chemical toxicity whatever.


Hardware Chemicals #1: Hydrochloric Acid

Hydrochloric acid is an extremely useful and versatile chemical that has many uses around the home.

Its usefulness comes from the fact that it is a very strong mineral acid that is nonetheless generally safe to have around. This is because its bark is worse than its bite. In its concentrated form you’ll see white fumes coming off it, and if you catch a whiff of it it’ll hit you in the nose like a sledgehammer. This property alone is a strong deterrent for children and pets.But these fumes are only an irritant – they are not toxic.

If you get it on your skin it’ll sting, but it won’t burn (like sulfuric acid). And if you got it in your eyes, they’d probably survive, although it’d sting like hell. But you should be wearing safety glasses and gloves when handling it anyway.

And it’s cheap. A 20L drum from the hardware store will only set you back about $45. And because it’s concentrated, it’ll last you a long time.

So what can you do with it?

For a start, it is an excellent weed and grass killer. Make it up at about 10% (500mL in a 5L garden sprayer), add a few handfuls of salt, make the whole lot up to the 5L mark and away you go. Spray it on weeds and grass that you want to kill and you’ll start to see results within 24hr. And it doesn’t matter if some gets on the soil – there are plenty of things in the soil that will neutralize it.

And if you find something that will survive this brew (unlikely) then just increase the concentration.

It’s also an excellent chemical for rejuvenating driveways. Cement is essentially an alkaline composite. As it’s exposed to the sun and air it develops a coating of cement dust, largely composed of limestone (calcium carbonate). A 10% solution of hydrochloric acid will strip off this layer and restore it to pristine condition. A clean with a high pressure water cleaner afterwards will remove any water marks and give it a uniform look.

Have you had tiles put down and the tilers have smeared grout over the tiles? No problem – a 5% solution of hydrochloric acid will get it off easily.

What are Acids?

I think my first experience of acids was an episode of batman, where the penguin demonstrated the potency of the acid that he was about to dunk Batman in by inserting his umbrella in it. When he pulled it out, the part that had been inserted had completely dissolved.

And this is the view of acids that most people have – potent, nasty chemicals that dissolve everything in their path.

Well, although there are acids that can dissolve all sorts of things, there is no acid that will do to the penguin’s umbrella what happened on the show.

Essentially we can place acids into two categories – mineral acids and organic acids. Mineral acids attack metals mostly, whereas organic acids attack organic material.

Also, acids may be categorised according to their strength, with the vast majority of acids being weak acids, and our bodies are full of them – amino acids, fatty acids and so on.

There actually aren’t many strong acids, and only one of them (hydrochloric acid) is available to the general public in a concentrated form. Other strong acids are sulfuric, nitric, perchloric, and hydrofluoric. That’s pretty much it, although there are several mixtures that are used to provide extra potency. Aqua Regia is a mix of 1 part nitric to 4 parts hydrochloric. Piranha solution is a mix of hydrogen peroxide and sulfuric acid, and chromic acid is a mix of sulfuric acid and potassium or sodium dichromate.

Tomorrow we’ll look at hydrochloric acid and see what it can be used for around the home.