Oil Pulling – My New Morning Routine?

Something I may try!!!

LisaQuaschnick

How would you like to wake up, and the first thing you reach for is a big ol’ spoonful of oil to swish around in your mouth for your first waking 20 minutes?  Well, that’s what I have been doing for about a month now! 

If you have been anywhere on the internet this last month, you have more than likely seen something about “oil pulling”. According to Wikipedia, “[ancient] Ayurvedic literature states oil pulling is capable of improving oral and systemic health, including a benefit in conditions such as headaches, migraines, diabetes, mellitus, asthma, and acne, as well as whitening teeth.” 

Whiten teeth naturally?  That’s what caught my eye!  I read that several types of oils can be used, like sesame, olive, or coconut.  (organic)  So for the last month, I rise and shine, grab a tablespoon of coconut oil, set the timer on my phone, and swish away!  It’s easy to fit…

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A Look Inside Professional Whitening

While I have talked about dental bleaching throughout the term, some may not actually know what the procedure entails or what it looks like. I found this video that shows what happens during a bleaching procedure. I hate going to the dentist as is, so I think I will stick with my at-home white strips!

Suicidal Cells & Sensitive Teeth

“You’re never fully dressed without a smile”. Who said that anyway? I didn’t say it, because I feel self-conscious about my smile sometimes. Or rather, I feel self conscious about the colour of my teeth. There are times when I’m unhappy with their colour…but what are my options? I could go buy some whitening strips, but sometimes my teeth hurt afterwards. Why is this happening? Should I be concerned? As a Biochemistry student I should be able to figure out what is causing my teeth to be sensitive.

Dental bleaching has been around since the 1860’s, and over the years many different bleaching agents have been used. The two main agents used in dental bleaching products are hydrogen peroxide (H₂O₂) and carbamide peroxide. These are both highly oxidative compounds that interact with chromogens on tooth surfaces. Coloured compounds, like chromogens, typically consist of conjugated chains altering in single and double bonds, often including heteroatoms, carbonyl groups, and phenyl rings. Figure one gives an example of a chromogen found in many of the foods we eat. Either one of these peroxides is able to break one or more of the double bonds in the conjugated chain via cleavage or oxidation. These peroxide compounds produce a number of highly reactive oxygen species (ROS) depending on the temperature, pH, and light when the reaction is taking place on teeth.

This raises a red flag for me. Having reactive oxygen species floating around in my mouth doesn’t sound like my cup of tea. Those molecules must be what are causing my teeth to be sensitive. I wonder what the biochemical mechanisms are that occur in my dental tissues to induce this pain?

Brand new research published by Wu et al. (2013) from the Department of General Dentistry at the Shanghai Ninth People’s Hospital has provided some insight into a new idea for how teeth are becoming sensitive. They are proposing that H₂O₂ is able to induce apoptosis in human dental pulp cells by a specific apoptotic pathway. Pulp cells are found in the dental pulp layer of the tooth, and are often referred to as the nerve itself since it is connected to the nerves and blood vessels. Pulp cells are also involved in regenerating dentin. The researchers are aware that H₂O₂ is able to penetrate into the top two layers of the teeth (enamel and dentin) and reach the pulp chamber. This would be what is leading to sensitivity because the nerves are exposed to ROS.

Wait, I’ve heard of apoptosis before in some of my other classes. That’s cell suicide, also known as programmed cell death. It’s a highly regulated process that occurs during development, or when the cell is under stress. The plasma membrane is maintained during the process and membrane blebbing occurs, forming small vesicles containing the cytosolic contents. Another type of cell death is necrosis, but it is premature cell death. The cytosolic contents of the cell will be released after the plasma membrane loses its integrity, and this will activate the inflammatory response.

Apoptosis can occur via two pathways: the extrinsic path and the intrinsic path. Wu et al. are referring to the intrinsic pathway in their research. A simplified overview of the intrinsic apoptotic pathway is shown in Figure 2. This apoptotic pathway involves the outer mitochondrial membrane first becoming permeable after the cell has received a signal to begin apoptosis (like from a ROS). Pro-apoptotic Bcl-2 proteins are causing the membrane permeability. Many proteins from the mitochondria will now be able to go into the cytoplasm. One of the proteins is cytochrome C, which is going to form a complex with an apoptotic protease-activating factor (Apaf-1). This is depicted in Figure 3A. Apaf-1 will undergo a conformational change, and interact with pro-caspase-9, forming an apoptosome, which can be seen in Figure 3B. Caspases are proteases containing a cysteine in the active site and cleave at aspartate residues. Initiator caspases, like caspase-9, will undergo auto-cleavage to activate themselves. Then, they can activate other effector caspases via proteolytic cleavage, so these caspases can continue the apoptotic signal cascade. Caspase-3 is the effector caspase in this process.

Wu et al. thought H₂O₂ could be triggering this intrinsic apoptotic pathway, and they attempted to build some evidence for their hypothesis. They first cultured human dental pulp cells and treated them with various concentrations of the bleaching agent for four hours. Once the cells were ready, they tested cell viability and saw that H₂O₂ treated cells were unable to thrive in the environment compared to the untreated group. They concluded this bleaching agent to be cytotoxic to the pulp cells.

What else did they find? After a Flow Cytometry test where they stained cells with Annexin V and propidium iodide (PI) their evidence grew. Annexin V only stain cells undergoing apoptosis. This is because it binds to phosphatidyserine, a lipid that is translocated from the inner side of the plasma membrane to the surface when apoptosis is occurring. PI stain can’t penetrate membranes, so it stains cells that are undergoing necrosis or that are in the late apoptotic phase. The researchers found higher percentages of apoptotic cells in those that were treated with H₂O₂. The highest concentration they tested was 100µmol/L, and there was a large percentage of these cells undergoing necrosis.

So this means higher concentrations of the ROS will induce our inflammatory response. This list of reasons why I don’t want to use H₂O₂ on my teeth is starting to grow. But wait, there’s more. Once Wu et al. knew apoptosis was occurring, they wanted to ensure it was by the intrinsic pathway they proposed. They did a Western Blot analysis to look at protein amounts, more specifically the amounts of activated caspase-9 and caspase-3. Both of these proteins were found to have increased expression in cells treated with H₂O₂ compared to the control group. These proteases are specific to the intrinsic pathway, and therefore they concluded apoptosis is indeed occurring in these human dental pulp cells when they are exposed to H₂O₂.

My cells are committing suicide when I try to make them whiter. Those poor pulp cells are dying and my dentin isn’t being regenerated. That’s probably why when I drink something cold or hot I feel sensitivity; my soft tissue is becoming more and more exposed. No wonder my teeth hurt after I wear those white strips. At least now I have an understanding of what is happening at a scientific level.

The discovery that the intrinsic apoptotic pathway is being induced is opening the door for a potential new target for improving the effects of bleaching agents on tooth sensitivity. Maybe one day I’ll be able to be “fully dressed” with a smile that doesn’t hurt so much.

 

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See References page for related articles on this post.

Shedding Some Light on the Matter: How the Use of Tetracycline Can Drastically Alter Your Teeth

In today’s world, people care a lot about their physical appearance. For job interviews, or for important events people want to make a good first impression, and as unfortunate as it is, their image is something most will remember.  People want white teeth; it’s a fact.  I know that for me, taking care of my teeth is something I take pride in. But maintaining white teeth can be a tricky task, seeing as there are so many factors that can cause tooth discolouration. Your habits and food sources can greatly alter the colour of your teeth.

Mind you, that does not stop me from drinking my daily coffee. Things like coffee and tobacco use cause extrinsic stains, which is probably more familiar to most people. These stains are caused by chemical interactions taking place on the enamel surface of your teeth from polyphenol compounds interacting with chromogens to create coloured compounds. Enamel is the top layer on your teeth, and is the most susceptible to extrinsic stains (Figure 1). It is the toughest tissue in the entire body,and its thickness varies across tooth surfaces. Amelogenesis, the process of enamel formation, involves the development and orientation of calcium phosphate crystals called hydroxyapatite crystals. If enamel gets damaged, there is no way to regenerate it. When it’s gone, it’s gone forever.

So most of us are aware of the fact that our daily habits, plus food and beverage choices can affect the colour of our teeth from staining enamel. Something we are not aware of is a type of staining that occurs during tooth development: intrinsic stains. In this case, some sort of internalized stimulus is causing teeth to become stained on the outside.

A particular type of intrinsic staining caught my eye, and an antibiotic called tetracycline causes it. As a student who is interested in going into Pharmacy, this intrigued me. Tetracyclines were first introduced back in 1948, and consist of four fused cyclic rings. These drugs are effective against both Gram-positive and negative bacteria and act as bacteriostatic agents, meaning they stop bacterial reproduction. At higher concentrations they can act as bactericidal agents. Tetracyclines are used to treat a variety of bacterial infections including pneumonia, acne, and urinary tract infections. Derivatives of tetracycline arise from alterations in the substituents attached to the ring structure (Figure 2).

The mechanism of these drugs involves high affinity binding to the 30S subunit on bacterial ribosomes. This inhibits aminoacyl-tRNA from binding and as a result, protein synthesis is inhibited. This is interesting and all, but how does this relate to changing the colour of your teeth? Well, tetracyclines have the ability to penetrate bone or dental hard tissue that is calcifying during development. These antibiotics form complexes with Ca²⁺ ions on top of hydroxyapatite crystals that are present in dental tissues, mainly the enamel (Figure 3). This mechanism is referred to as chelation, and the final product is a stable tetracycline calcium orthophosphate complex. These complexes get deposited into the dentin layer of the tooth, which is the most susceptible to becoming stained.

If the binding of Ca²⁺ to tetracycline occurs before the calcifying teeth erupt from the gums, the tetracycline calcium orthophosphate complexes will initially form a yellow discolouration on the teeth. If the teeth are already erupted from the gums, tetracycline will oxidize over time to form a brown colour due to light exposure. Researchers have characterized the coloured compound as 4α, 12α-anhydro-4-oxo-4-dedimethylaminotetracycline (AODTC, Figure 4), and teeth that are more exposed to light will darken the most due to tetracycline undergoing photochemical oxidation to reach this product. A neat way researchers have compared this progressive colour change is to think of it as bruising; tooth colour can vary from pale yellow to dark purple over time.

The intensity of the intrinsic stain caused by tetracycline is related to a number of factors such as the dosage, the frequency, the duration of administration and the stage of odontogenesis (tooth development). Primary teeth begin to calcify at the embryonic stage of life and stop between eleven and fourteen months of age. Calcification of permanent teeth begins after birth and continues until around the age of eight. The problem is that tetracycline is capable of crossing the placental barrier, and therefore prenatal administration of tetracycline or administration before age eight is not recommended by health care professionals.  In many cases it was found that staining is more frequent in developing dentin when the dosage was over three grams or if the administration was for more than ten days.

While the intrinsic staining theory of tetracycline antibiotics has a lot of evidence behind it, recent research has proposed an extrinsic theory of staining caused by tetracyclines. The proposed mechanism is that the antibiotic attaches to glycoproteins in dental pellicles (a film covering the enamel surface). This causes demineralization and remineralization processes to occur and in turn, oxidation of tetracycline occurs upon air exposure or bacterial activity. Degrading the ring structure ends up forming a black quinone product. Interesting, but if I had to put money on it, I would go with the intrinsic theory of tetracycline staining.

Now, are there ways to remove stains caused by tetracycline antibiotics? There are certainly ways of managing it. Certain tetracyclines that cause coloured banding patterns on teeth have shown to be more difficult to treat. Long-term bleaching treatments can take up to twelve months to reduce the side effects of tetracyclines, with the risk of sensitivity setting in. Despite having bleaching treatments available to correct the effects of teteracycline stains, some will only last for a few years at a time. For tougher stains that have no improvement from bleaching, there are options such as dental porcelain veneers, which are shells that cover the tooth surface and improve appearance. Replacing the crowns on effected teeth is another option to improve tooth colour. Obviously, more invasive treatments would be less appealing to people, and procedures called “crown replacements” scream expensive. It is definitely not cheap to treat tetracycline stains.

After all of this, tetracycline is still being prescribed in today’s world. For adults and children above the age of eight, this should be fine since it can’t stain teeth at this stage of development. But what about the people who are still impacted by the side effects of tetracycline? There was a recent debate in the past year or so involving a man who was prescribed teteracycline as a child for pneumonia. He attempted to blame the drug company for his stained teeth, Pfizer, who created and patented tetracyclines. He started a petition to try and get the company to pay for his dental bills for any cosmetic treatments he had to undergo to improve the staining—quite ambitious of him. He also mentioned how living with tetracycline stains affected his self-esteem and increased his insecurities throughout life. He admitted to not applying to certain jobs due to the stains on his teeth. Pfizer came clean saying the side effects were caused by the antibiotic but denied the company’s responsibility for the damage. They said it is up to the patient and physician to discuss the risks and benefits of the drug and the physician’s judgment on whether or not to prescribe the drug to a particular patient.

What do you think? Should this drug still be prescribed knowing the effects of teeth staining? What if parents and physicians say it’s okay to take it? Children obviously aren’t able to make the decision on their own. In any case, tetracycline is still available and people need to be informed before making decisions. Knowing what it does to developing teeth and how expensive treatments are is something I would definitely consider before allowing a young person to use it.

Refer to References Page for the references used for this blog post!
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