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.)

IF YOU HAVE A MISSING TOOTH…

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.

NEW IS ALWAYS BETTER?

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.

12339421_10207878843790738_464352848781518507_o

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!

renandrey-large

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

REFERENCES

[1] Laser Use in Dentistry – WebMD

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Amalgam – A Story of Lustre and Glory

This is an article about amalgam – a story of lustre and  [REDACTED]  mercury.

Ah, the controversies and conflict of choice when it comes to picking a filling material. There have been numerous researches on which is a better filling material, and for what purposes. But I’m not going to delve into those: anyone can use Google and find out more. (But be warned! The internet is a hodgepodge of wacky and satirical information – read and learn with a pinch of salt!) I am, however, going to take on this topic from the patient’s point of view – and how, as a patient, you can make an informed decision.

So the other day I had a patient who had a mouthful of amalgam (silver fillings). He told me he wanted to get them all out, to be replaced with composites (white fillings). He claimed that this was not because he wanted to look good – the amalgam fillings were all in the molar teeth, way behind the smile line – but because he was reading articles about the controversies of amalgam and health. This was clearly an informed patient who knew quite a lot of stuff. However, I could not guarantee him that his fillings would be replaced with composite – different teeth may require different material choices. I hope that he was not too disappointed.

So what is AMALGAM?

LifeCare-Dental-Amalgam-Fillings-924x400 Pic source

Amalgam is an alloy of metals containing silver, tin, copper, zinc and mercury. Wait, what! Mercury? The toxic material?

Relax, mercury in amalgam is not going to kill you. Amalgam has been around for a really long time. Scientific evidence, accumulated over decades, supports the view that there is no clinical evidence of mercury poisoning in people who have amalgam fillings in their mouths. [1] This is because the main exposure to mercury from dental amalgam occurs during placement or removal of restoration in the tooth. [2]

So in any case, if there were to be mercury poisoning, it would be the dentists – who are exposed to mercury and its vapour for many many years. So far so good, no old dentists seem to suffer from any form of mercury poisoning. This is because the levels of mercury in amalgam are so minimal they are unlikely to do any kind of damage to the human body. Nevertheless, if you have the time, read the research paper in link no. 2 about it at the references section below.

Ughh, but it’s still so ugly. Why do dentists still use amalgam!

Well, it depends on which tooth the cavity is, and how the cavity is shaped. Of course, your front teeth will definitely not be the ones having amalgam – we almost always have a consensus that composite white fillings are better. Nobody wants a piece of metal sticking out of their smile in a selfie!

However, the front teeth is hardly the place for decay to occur, requiring fillings. By far the most common tooth decay is seen on the biting surfaces of the molar teeth. And this is where amalgam is at its best.

It is a metal – so it can withstand strong biting forces. Molar teeth have extremely strong forces acting on each other when biting and chewing. And perhaps for importantly, it survives for a very long time. Studies have shown that amalgam survives longer than composite (in the molar teeth) and is less likely to fail as a filling. [3]

If the decay on a molar tooth is small, composites will be used instead. Amalgam requires some degree of cohesion in the cavity for it to function properly.

FUN FACT!: Placing an amalgam filling requires excellent hand carving skills. We need to carve the filling to try and match the original tooth shape. Dentistry is as much an art as it is a science.

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I am still in the midst of my crown course, and I will hopefully be blogging about crowns really soon!

References

[1] http://www.poison.org/articles/2010-dec/do-fillings-cause-mercury-poisoning

[2] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3388771/

[3] http://www.ncbi.nlm.nih.gov/pubmed/17545266

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Episode IV

It was a very quick Summer after the end of third year and voila! I’m in fourth year now. I haven’t blogged since June, as I was busy enjoying my Summer holidays back home in KL. I hope my avid readers aren’t bored to death during the hiatus!

We’ve been told by clinical staff in our school that as a fourth year, we are “senior dental students”. Still feels surreal to be known as “senior”, as I feel like it was not long ago when I started first year. Ah, the good old days of first year, studying human anatomy and basic physiology.

Nevertheless, the dentistry is becoming more challenging and rewarding at the same time. I have to say I thoroughly enjoyed third year. First-hand patient contact and performing treatments, third year was a ridiculously good experience. The dean of our school, Professor Burden, said this: “Dentistry is the only undergrad programme where we actually treat real life patients ourselves.” Yes, and it is most enriching.

Just to summarise what I’ve learned in third year:

  • Restorative work (fillings, build-ups etc)
  • Root canal treatment/endodontics
  • Extractions
  • Partial denture design & prescription
  • Scaling (with ultrasonics and root planing)

And a few things we will learn in fourth year:

  • Minor oral surgery
  • Suturing
  • Crowns
  • Complete denture design & prescription
  • Adjusting orthodontic appliances
  • Treating children (yay!)
  • And possibly many more that I don’t know yet…

For the first week of class, we are having a short course in minor oral surgery. Minor oral surgery is undertaken when there are defects present in the oral cavity that needs surgical intervention to remove. So for example, during extraction, a root cracks and a part of it is left in the socket. In some cases the root may be left inside the socket, if it’s small and unlikely to cause infection. However, if it is at risk of developing an infection, the root has to be removed. But how? The root is buried within the bone, which is further covered by gum soft tissue.

Enter minor oral surgery. This would involve cutting a gum flap with a scalpel right down to the bone, and peeling back the soft tissue. This reveals the bone. The bone is drilled with some burs to reveal the leftover root in its socket. The root is pried out with some instruments, and the gum flap sutured (stitched) back into place. I’ve had a go at this on phantom heads, it is mighty interesting. I’ve even learned the technique of suturing, but it would take a lot of practice to be proficient at it.

I will update when I learn more stuff from school. For now, bye peeps! Here’s to fourth year of dentistry!

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My Thoughts About Grinding

bruxismThese are my teeth. Notice the red arrows? My teeth have been flattened after of years of grinding teeth in my sleep. I never realised this until a friend of mine pointed this out to me back during my A-levels days.

“Hey!” he said, “why are your canines flat?”

I have a condition known technically as bruxism. And I am not the only one. It’s a very common condition and we as dental students are gaining awareness of it as we see more and more cases of bruxism.

Bruxism – clenching and grinding of teeth

The grinding mostly happens at night when one is unconscious. It is often a tapping/chomping movement and a side-to-side sliding movement. Clenching happens in the day, and also not within conscious control. Only when pointed out do people realise that they’ve been clenching. Clenching is common when one is anxious or stressed, but constant clenching is a sign of bruxism.

People who have bruxism often have sore muscles around the mouth (muscles of mastication – the muscles that help you chew your food) especially the masseter muscle at the sides of the lower jaw. This can lead to an enlargement of this muscle caused by intense “workouts” every night so bruxers have large squarish faces. Some patients even have headache caused by soreness of the temporalis muscle (it can be felt if you place your hand on your temples and clench). I was told by a lecturer that night-grinding can often involve strength of muscle movements that are beyond normal conscious control.

Most dentists are able to detect bruxism by looking at one’s teeth. We call it tooth wear, or more specifically, attrition. Teeth like mine are prominent signs of severe bruxism but most people have milder versions.

Why does bruxism happen?

Actually, to this day, nobody knows.

Some people have proposed theories such as stress. Here’s the reasoning: if we clench when we’re stressed, so we should grind when asleep because of stress too! It is quite true that in today’s urban lifestyle with economic recession, job insecurities and household debt, people are more stressed than ever before.

Me personally? I don’t think I am that stressed up all the time. I do however get stressed up when exams are upon me or when I’m nervous. And if I were chronically stressed I would have had anxiety problems and depression which would pose a larger problem than having flat teeth!

Okay so to the title of this blog post: my thoughts about bruxism. I feel that since muscle motor control is handled by the brain, it occurs to me that there has to be something wrong in the motor centres of the brain that is causing bruxism.

Take epilepsy for example: people who suffer from epilepsy get seizures and convulsions due to abnormal electrical discharges in the brain. Part of a tonic-clonic seizure is the uncontrolled biting/chewing. Convulsing patients often bite their own tongue and it is wise to not put anything into the mouth of a convulsing patient, as they might bite off the object or even your finger! [1] Tongue biting is also used as a diagnosis of an epileptic seizure. [2]

DISCLAIMER NOTICE: These are only my thoughts about the subject. Nothing I say here can be taken as fact. So don’t quote me on this! We have to wait until scientists figure it out.

My theory is this: tongue-biting in a seizure may be similar to bruxism. It involves the involuntary unconscious contraction of the muscles of mastication. What if bruxism is like a “mini seizure” (partial seizure?) caused by abnormal electrical brain activity? I do agree that stress may contribute to the abnormality of brain activity – like how during a stressful exam season, we so often have nightmares about doing badly. If stress is able to cause our brain to make nightmares, it can definitely lead to further brain disorders like electrical discharges.

Don’t worry, fellow bruxers. This is only my theory. You have no brain disorders and neither have I. Let’s just hope that further research into brain wave activity by neuroscientists can clear this up soon enough and determine the true underlying physiology of bruxism. I will blog about the treatment methods for bruxism some time in the future – it’s surprisingly interesting!

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References

[1] http://www.webmd.com/epilepsy/what-to-do-during-a-seizure

[2] http://www.ncbi.nlm.nih.gov/pubmed/7487261

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