Brånemark’s Adamantium

I’m finally going to talk about the coolest dental invention around – implants!

If you recall my previous post Engineers on a Small Scale, I mentioned that a dental bridge is one of the options for replacing missing teeth. The other widely popular option is to go all Wolverine and put a piece of metal in your bone structure.

NEaBfb0Dqw4bch_1_b Image: Marvel Entertainment and 20th Century Fox

However, unlike our mutant friend Logan, our implants support teeth rather than claws.

Just last week, a Swiss-based implant company named Straumann sent some representatives to our school to give us a simple hands-on course on implants. Of course, as BDS undergraduates we’re not expected to know too much about actually placing implants, this hands-on course was just a simple introduction so we know what it’s all about and how to explain to patients about these fancy titanium screws.

shutterstock_74442769_Single_Implant_CrownsImage source

As we can see above, the metal screw is the aforementioned implant. It is surgically placed in the mouth by the dentist, embedded through gum and into the bone. The implant is usually made of titanium, which is a very strong metal that doesn’t corrode and has the ability to make the bone remodel & grow around it. The threads of the implant improves its ability to stay within the bone by increasing its surface area, thus providing strong support for the tooth above. After the implant is placed, a crown or bridge or even a denture can be placed on top of it. You might wonder, if its function is just to replace a missing space, why go through so much trouble moving heaven and earth to plant a screw into bone? Why not just make a bridge that sits on top of the gum?

Bridges, while ingenious, sit only on top of the gum and not within bone. This means that when you bite down on that false tooth, it doesn’t feel REAL. Implants can give that tactile sensation when you bite on it, giving the impression that it’s like a real tooth. Our teeth have the amazing ability to discern even the tiniest objects sitting between them – say, biting down on a grain of sand, or having a small piece of meat stuck between your teeth. This organic sense can never be replicated by bridgework, but implants are able to do so, to a certain extent.

Implants are expensive though. And expertise-demanding. And time-consuming. And not everyone is suitable for it. You’ll need a certain bone density to be able to do it, or else you’ll need a bone graft which in turn leads to more surgery and longer treatments. What I’m trying to say is, while it gets closest to replicating a real tooth and is considered gold standard in many regards, it isn’t a silver bullet (it’s just a titanium screw!)

Here are some pictures of the recent Straumann hands-on workshop:

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Straumann’s titanium-zirconium implant held in a sterile environment within a capsule.

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The implant removed from its capsule. The blue part is an attachment to a ratchet that I’m holding, the implant itself is the silver-and-gold screw below the blue part. In the background you can see a piece of “bone”, which has a hole surgically prepared specific to this implant’s dimensions.

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The implant screwed into the bone. At this stage, it’s nowhere near done. There are a few more stages to do after this, and may take months before a final crown/bridge is made to be placed atop it.

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I named the title of this blog post after Per-Ingvar Brånemark, a Swedish orthopaedist who is known as the founder of modern dental implants. While dental implants have been used historically as experiments, Brånemark did some landmark studies that proved that titanium could adhere with bone in a process called “osseointegration”.

 

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Autumn Update

Dear all followers of Kai Dentistry! It’s been a long while since I last blogged, so here is a recap of what I have been up to for the past few months.

Final year has begun

It all comes down to this. After all the blood and sweat of the previous 4 years, the final hurdle is finally here.

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This year we work mainly in the Total Patient Care (TPC) clinic. It combines the practice of restorative dentistry, endodontics, periodontics and prosthodontics under one roof. Before this we used to go to separate clinics to carry out different kinds of treatment. For example, we used to go to the periodontal clinic for gum treatment and prosthodontic clinic for denture treatment. Now that we have a combined clinic, it feels more like an actual dental practice. We have to think more clearly of treatment plans in handling complex treatment cases.

Summer research project

As you may know, I didn’t go back to Malaysia for my summer holidays. Instead, I spent the whole summer working on a summer research project with the university.

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The topic of the project was “quality of root canal treatments undertaken by undergraduate students”. It’s a retrospective study looking at X-rays of completed root canal treatments done by students in the school of dentistry, and grading them according to strict criteria. I’ll not divulge into the results of the findings, because it is unpublished research data I’m not allowed to share. The image above shows me posing during the early stage of the research, where I was collecting patient data from the patient records.

Of course, I wasn’t alone. I was working with my research partner Omid, who was a ball of fun (and noise!).

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And this is how the majority of the research was carried out. We were mainly working on clinic in the school of dentistry, looking at digital X-rays and patient notes, and inputting all the data into a Microsoft Excel sheet.

imag1370 Root canal selfie!

For the last few weeks of the research, we were writing a paper on the research findings. It hasn’t yet been finalised as we need to consult with consultants over some minor details. Hopefully something good will come out of it!

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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…

I’M NOT CRAZY, THERE ARE PEOPLE DOING RESEARCH ON THIS

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.

THE METHOD

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 RESULTS

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.

MY THOUGHTS ON THIS

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.

WHAT CAUSES SENSITIVITY?

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.


READ THE INGREDIENTS!

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]

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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?

References

[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.

THE BIOLOGY

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.

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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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