Milking the Truth

I’ve always enjoyed “float” fizzy drinks since I was a child. If you don’t know what a “float” drink is, it’s a dark-coloured fizzy drink, usually root beer or coke, topped with some vanilla ice cream. The ice cream floats on top of the drink – thereby lending to the term “float”!

Refreshing Root Beer Float with Vanilla Ice Cream Image source

I also noticed that, if left for some time, the ice cream melts and gives the coke/root beer a kind of milky colour and texture, as seen in the picture above. The root beer has turned from black to brown. I like to compare it to adding milk to black coffee to make… well, milk coffee. Adding milk to coffee dampens its bitterness and gives a creamy finish to the taste, and so does root beer float! So a couple of years ago, I tried adding milk to coke…


Believe it or not, people are actually taking this quite seriously, and it’s startlingly interesting. This research paper is a laboratory study to determine whether adding milk to fizzy drinks can lessen the erosive potential of said fizzy drinks.

Now, for some background, fizzy drinks are VERY BAD for your teeth. They’re like the agents of destruction made with the very purpose of attacking your teeth. They are high in sugar, which leads to tooth decay. But hey, you say, what about stuff like Diet Coke? No sugar, should be good, right? Fizzy drinks in general contain phosphoric acid and citric acid, which can lead to tooth erosion. The acid demineralises tooth substance during an acid attack, so high intake of fizzy drinks will lead to worn down, ugly teeth.

According to this paper, the researchers thought that raising the drink’s calcium content by mixing it with milk could lessen the capacity for the fizzy drinks to cause erosion by suppressing demineralisation of tooth enamel.


For each drink they used 25 ml of drink with 6.25 ml UHT milk.

The pH and titratable acidity (amount of alkali required to neutralise acid, low titratable acidity means less alkali required i.e. less acidic – usually a more relevant way to measure acidity than pH) were measured.

In addition, the effects of a 60 min exposure to the drinks (+milk) upon the surface microhardness of human molar tooth substance were determined.


The researchers concluded that the addition of milk to fizzy drinks reduced their capacity to bring about erosion. Milk significantly increases their pH and decreases their titratable acidity.

They also found that adding milk lessens the reduction in surface microhardness of tooth substance following exposure to the fizzies.


We critically appraised this paper in one of our classes on Evidence-based Dentistry. So naturally I have some thoughts on this because it was taught in our course.

First of all, a lab study on pieces on teeth immersed in fizzy drinks in a test tube cannot be extrapolated to the general human oral environment. Acidic drinks tend to make you produce more saliva, which help buffer against said acids. Milk in acidic drinks may result in a reduced salivary flow so we cannot properly determine if it works in real life! Further studies need to be conducted outside the lab on human subjects in a clinical trial.

Secondly, will people accept adding milk to their coke? Do people even like it? I personally really did enjoy it. Like I said, it’s like adding milk to black coffee – gives it a certain créma! But I may be crazy, and not everyone will enjoy it. Sometimes there may even be a sedimentation reaction with coke, as shown in this picture below…

coke-milk-experiment02Image source

Doesn’t look like root beer float now, does it?

In my personal opinion, fizzy drink intake should be reduced regardless. Whether or not you add milk to it, and whether or not it is “diet” or “zero”, there is still some degree of acid erosion happening. Eliminating fizzies from your diet is the best way to stop acid erosion! Switch to alternatives such as tea & water.

HANDY TIP: Drinking fizzies is an acid attack on your teeth. Don’t brush your teeth immediately after drinking fizzies – scrubbing acids on your teeth will absolutely destroy your teeth! Wait for at least half an hour before brushing. This will give time for your saliva to buffer and neutralise the acids.

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A Sensitive Issue (Pt 2)

With the basic knowledge of the biology of dental sensitivity, this next part will be quite easy to piece together the puzzle.


Listing down things like this is part & parcel of studying dentistry. I noticed that almost all of lectures comprise of lists and lists of things i.e signs & symptoms, risk factors, clinical features etc. Since joining dental school my train of thought has always been in lists rather than in paragraphic words or in images.

Anyway, all the things below have one thing in common, that is exposed dentine.

sm2550_sensodyne_tooth_image_390w Image source: Sensodyne

1) Gum recession – gum diseases (gingivitis and periodontitis) cause the gum level to recede or inflame, exposing the root surface dentine.

2) Tooth decay – caries can cause cavitation and bore a hole in your tooth down through the enamel into dentine, once again exposing dentine.

3) Cracked tooth or leakage in filling – these are similar as they create a communication directly into the dentine from the outside world, causing fluid pressure changes etc.

4) Tooth whitening – bleaching products contain hydrogen peroxide as an active ingredient with a possible side effect of sensitivity. Take caution before getting your teeth whitened!

5) Toothbrush abrasion – intense brushing with a hard toothbrush can rub away enamel especially at the gum margins, exposing dentine. Use a soft/medium toothbrush and use circular motions as if you are massaging the gums.

6) Acid erosion – either extensive extrinsic (from acidic food and drinks such as soft drinks and orange juice) or intrinsic (from gastric reflux) causes. Can cause slow wearing away of enamel thus leading to exposed dentine.


Now, toothpaste manufacturers like to throw at you terms like Novamin, Pro-Argin, Pro-Relief, Pro-Expert. But what do they mean?

This part is going to be handy. I’m going to tell you some neat tips to guide you to buy what’s suitable to treat dental sensitivity.

Potassium nitrate

8957662756894 Image source: Colgate

Colgate has this product called Sensitive with Sensifoam – containing this special ingredient called potassium nitrate (KNO3).  Potassium salts act by diffusion along the dentinal tubules and decreasing the excitability of the intradental nerve fibers by blocking the generation of action potential. Also, toothpastes containing potassium nitrate and fluorides have been shown to reduce post-bleaching sensitivity. [1]

Besides Colgate, a number of other manufacturers do make toothpastes containing potassium nitrate, look out for those!

Strontium chloride

3739273 Image source: Sensodyne

The original Sensodyne made by GlaxoSmithKline was first marketed in 1961 as a desensitising toothpaste with strontium chloride. Today, Sensodyne is synonymous with tooth sensitivity, and is well-known among people with sensitive teeth. SrCl2 forms a barrier and blocks the openings of dentinal tubules, thus not allowing fluid movement within the tubules.

Arginine + calcium carbonate

This is one of  the ingredients marketed by Colgate as “Pro-Argin” and “Pro-Relief” products. It serves the same function of strontium chloride, plugging dentinal tubule openings. Arginine and calcium carbonate work together to accelerate the natural mechanisms of occlusion to deposit a dentine-like mineral, containing calcium and phosphate, within the dentinal tubules and in a protective layer on the dentine surface. [2]

Stannous fluoride

Oral-B-Pro-Expert-product-shot Image source: Oral-B

Most toothpastes that contain fluoride come in the form of sodium fluoride and sodium monofluorophosphate. Stannous fluoride, for you chemistry nerds, is tin (II) fluoride (SnF2). Oral-B’s Pro-Expert line is one of the toothpastes containing this version of fluoride.

Stannous fluoride acts in a similar fashion as that of sodium fluoride, i.e. formation of calcium fluoride precipitates inside tubules. Also, some studies have shown that stannous fluoride itself can form insoluble precipitates over the exposed dentine. [1]


FYI I’m not endorsing any particular brand nor am I paid (I wished I was!) by these companies to talk about their products. Which is why I included a pictured example of one of each brand’s products!

If you do have sensitivity, I suggest you read the ingredients list, and armed with the knowledge I have given you, make an informed decision. One man’s meat might be another man’s poison, so you may have to try different products till you find one that works for you!

There is a lot of research pouring into exploring dental sensitivity. New products come and go all the time. Who knows, in the future, we might a complete cure for sensitivity?


[1] Dentin hypersensitivity: Recent trends in management

[2] How dental products containing 8% arginine and calcium carbonate work to deliver effective relief of sensitive teeth

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A Sensitive Issue (Pt 1)

Sensitive teeth are common, really common. Sensing that this is a profitable industry, big pharmaceutical companies like Colgate, Sensodyne (GSK) and Oral-B bombard you with information about sensitivity and how their products can help with it. Now, take a step back and put your thinking caps on. These pharmaceutical companies sometimes manipulate information just to market their products a lot better. Trust me, you may not have sensitive teeth, but after seeing a Sensodyne product packaging and how well it’s made to fix sensitivity, you may think you have sensitive teeth too. That’s how good their marketing is!

I am here to write the unadulterated truth regarding sensitive teeth. I’m gonna delve into the detailed biology of it, what causes it and how you can read product packaging better. This is not coming from a pharmaceutical salesperson, this is coming from a young dental student eager to help everyone out there!

Due to the extent of the content I intend to write in this article, this post will be the first in a two-part series on dental sensitivity.


Now, you may recall that I blogged about anatomy of a tooth, I am going to build on that. The most important bit of information that you need to know is the presence of dentinal tubules in your dentine. The picture below illustrates that perfectly.

Sensitive-teeth-treatment-Dentist-PrestonImage source

Enamel is the hardest substance in the human body and is a non-living, mineralised hard tissue. So it’s basically a rock.

Dentine, on the other hand, is vital tissue. It is a living, breathing segment of the tooth and dentinal tubules are part of that vitality. These microscopic tubes connect the outermost surface of the dentine to the pulp where the nerve lives. You see where this is going?

In sensitive teeth, dentine becomes exposed, i.e. no enamel protection or gum coverage. There is a direct link between the tubules and the outside world, connecting straight to the pulp. It’s almost as if your nerve is exposed itself, yikes!

Brännström’s Hydrodynamic Theory

download Image source

This theory answers why cold & hot drinks trigger intense pain in sensitive teeth.

Dentinal tubules are filled with fluids, and lined by cells called odontoblasts on the inner surface of the dentine, surrounding the pulp. When you drink cold & hot drinks, it triggers changes in fluid pressure and movement in the dentinal tubules. These in turn trigger the odontoblasts, activating pain receptors within the pulp and sending these signals to the pain.

So this is how dental sensitivity works. The key concept here really is the exposed dentine, dentinal tubules and the hydrodynamic fluid changes within these tubules. Now, take a moment be in awe of the intricate details of this biological design. This is why I love biology so much.


I do realise that people have relatively short attention spans these days, so this is the end of part 1 on dental sensitivity. Stay tuned for part 2, where I will talk about the causes of dental sensitivity, and the practical part of choosing the right toothpaste!

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Engineers on a Small Scale

Dentists and engineers have one thing in common: we build bridges!

My dad is a civil engineer, my brother is an architect. As expected, many people naturally speculated that I would follow their footsteps to pick up a career in engineering or construction. Here’s the plot twist: I didn’t really enjoy doing maths, but excelled in biology and chemistry. Ergo, the career option for engineering therefore went out the door. (I realise I theoretically could have done chemical engineering, but that’s up to an alternate universe to tell.)


As a dentist I could still do one thing that an engineer does: design and build bridges! No complex calculations, just pure dentistry and an eye for aesthetics.

Bridges are one of three methods of replacing permanently lost teeth. The other two are dentures and implants, which I shall talk about on another day.

Here’s how dental bridges work…

bridge00002 Image source

The picture above is an excellent illustration of a conventional dental bridge. There is a missing tooth down the middle. The two teeth beside it are drilled down in size and shaped to serve as abutments for the bridge to sit on.

An impression is taken of the drilled-down teeth and of the gums, and is sent to the dental lab to manufacture a bridge. If you know what dental crowns are and how they work, this is a similar thing: crowns joined together to form a bridge across the missing tooth gum region. The bridge is then cemented onto the abutment teeth and it would look as if the tooth was never missing in the first place.


bridge-new-img1 Image source

As you can tell from the previous example of a conventional bridge, the drill-down process of the natural teeth does a lot of unnecessary damage of the existing teeth. In modern day dentistry we try to conserve as much natural tooth as possible. So a new technique was used to “glue” bridges to the adjacent teeth – this is called adhesive bridges.

This requires only very minimal drilling to the back surfaces of the abutment teeth. After this, an impression is taken and sent to the lab, where they make the bridge as shown above – an artificial tooth (we call in a pontic) flanked by two metal wings. The wings are bonded to the adjacent teeth using a strong resin cement.

Adhesive bridges are much more commonplace these days than conventional bridges. They are less damaging to natural teeth and requires less chairside drilling. In fact, I just did one for my patient the other day, to replace a missing canine tooth! He went home a happy man, and can finally smile with confidence!

I thought it’d be interesting to share with everyone out there, explaining what dental bridges are and how they work. And also to talk a bit about my experience in giving a patient a bridge – it was a win-win!

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Lightsaber Dentistry

Happy new year 2016!

Recently Star Wars: The Force Awakens came out, and it generated so much hype that people started adding lightsabers to their Facebook profile faces. I decided to use my (albeit limited) creativity to make some lightsaber pictures too, not on my face – instead, on my teeth!

This picture below illustrates some form of mad dentist’s dream, and it garnered quite a number of likes on my Facebook profile.


Light-scaling or light-burningawaytoothdecay. Is this possible? 

Laser dentistry

Lasers fascinated me as a young boy and I’m very sure I’m not the only one fascinated by what lasers can do. So it only got me more excited when I found out that lasers do have a place in dentistry!

Lasers are used by dentists to treat:

  1. Tooth decay – Lasers are used to remove decay within a tooth and prepare the surrounding enamel for receipt of the filling.
  2. Gum disease – Lasers are used to reshape gums and remove bacteria during root canal procedures.
  3. Biopsy – Lasers can be used to remove a small piece of tissue (called a biopsy) so that it can be sent to a lab to be examined in detail.
  4. Teeth whitening – Lasers are used to speed up teeth whitening procedures. A bleaching solution, applied to the tooth surface, is ”activated” by laser energy, which speeds up the whitening process.
dental-laser Pic source

No kidding, this is real!

Like a tiny lightsaber, lasers work by delivering energy in the form of a powerful light. When used for dental procedures, the laser acts as a cutting instrument that vapourises tissues that it comes in contact with. When used for “curing” a filling, the laser helps to strengthen the bond between the filling and the tooth. When used in teeth-whitening procedures, the laser acts as a heat source and enhances the effect of tooth-bleaching agents.

Lasers are reported have these benefits too, compared to the traditional dental drill:

  • May cause less pain in some instances
  • May reduce anxiety in patients without the use of the drill
  • Minimize bleeding and swelling

On the downside, laser equipment are usually very expensive, and so too will the procedures. Dentists will also need to be appropriately trained in handling laser devices as these are extremely high powered and dangerous when used wrongly.

There are a number of exciting advances in applications for lasers in dentistry listed here. Some of these are not widely used yet as they have not been scientifically proven to be any better than traditional methods of dentistry.

However, I choose to remain optimistic that someday I will be a dentist and at the same time, a laser beam wizard! Heck yea, pew pew!


Kylo Ren just wants to look at her teeth. He’s secretly a dentist. Rey happens to not like dentists very much.

Pic source: Disney, Star Wars


[1] Laser Use in Dentistry – WebMD

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