Interview Transcript
Excerpts of Interview with 938Live
Topic: Teeth Whitening
Presenter: Today we will be taking a look at tooth whitening or bleaching. Now we know that there are a number of Hollywood stars, whom we'd see on magazines, who have wonderful smiles. Some of us perhaps have considered going for the procedure to whiten our teeth to get a lovely smile. And perhaps we've got discolouration of teeth as well. We're going to be finding out about teeth whitening procedures, as well as some of the differences, such as home kit systems and in-office systems where it is done in the dental clinic. Dr Christina Sim, a Senior Consultant with the Department of Restorative Dentistry of the National Dental Centre joins us today.
First of all, I would like to find out, people going for teeth whitening don't really have very white teeth. Is this a big problem in Singapore? Do you know a lot of people who have discolouration of teeth?
Dr Christina Sim (Dr Sim): 10 years ago, where tooth whitening wasn't as popular as today, the patients I saw had really dark teeth, some even going beyond the tooth shade guide scale. However, 10 years on, now, even those with relatively lighter teeth are more conscious about the shade of their teeth. Therefore, they come in to seek our advice. There is a increasingly awareness, not because their teeth is very dark but because they know or had seen their friends who have lighter sets of teeth and that is what they want too.
Presenter: Was there a specific reason why these people from the earlier days tend to suffer more from discolouration?
Dr Sim: It is not that they tend to suffer more, but those who seek treatment have very dark teeth. But now, those that seek treatment do have relatively lighter teeth as compared to before. I do want to qualify that, 10 years ago, there were quite a lot of patients with very dark teeth, like tetracycline-stained teeth. That's because tetracycline was widely used as an antibiotic in the very early years. With increasing awareness of not taking tetracycline when one is either pregnant, or for very young children, we see less of occurrence of such stained teeth.
Presenter: Now, there are different types of stain that can result from various things such as the tetracycline stain you mentioned. They produced different colours. Tell us about the various colours that people can have on their teeth.
Dr Sim: Taking a step back, let's look at what types of stains are present on the tooth surfaces. We can divide the stains into 2 broad categories, intrinsic stains which mean they are embedded within the
tooth structure and extrinsic stains which mean they are stains deposited on the tooth surface itself. How we manage intrinsic or extrinsic stains will be different.
For extrinsic stain, which are stains deposited on the tooth surface. These are brought about by daily drinking and eating of your foods and beverages such as coffees, teas, curries, red wine and colas. In smoking, nicotine stains can be deposited. There are other forms, like those who work in industries where they are exposed to chemicals. If they are exposed for long period of time, they may have some staining on their teeth. Then there is also external staining cause by chromogenic bacteria, which are oral bacteria with colour in them, that had been deposited on the teeth surface. For example, actinomysis, which can stain black and others like the penicillin, which, can stain green. Sometimes the penicillin can be found on the children teeth. So on the chomping teeth, we can find a shade of green on the cervical aspect, the tooth surface towards the gum line. These are the wide range of extrinsic stains that can be present.
Presenter: They are also the easier to treat?
Dr Sim: That's right because they are on the tooth surface, basically a thorough and professional cleaning, polishing and regular maintenance will be able to remove the surface stain.
Presenter: Why do people brushing their teeth everyday and drinking coffee everyday at the same time, but they are not able to remove those stains just by brushing their teeth regularly.
Dr Sim: Tooth surfaces are not flat, so there is a technique on how one needs to brush. It is not just brushing alone; as the toothbrush cannot reach the in-between (proximal) surfaces thus flossing comes in. Flossing is very important to clean the those areas but not everybody flosses their teeth. When stains starts to get deposited, first they are external stains but when they remain on the surface and get absorbed in to the tooth structure. Over time, teeth will tend to get darker. It is also part the physiological aging because teeth do get darker as you age.
Presenter: What about people with yellow type of teeth?
Dr Sim: Yellow teeth mostly likely mean natural aging and those are one of the easiest stains to be managed.
Presenter: Please tell us more about the intrinsic type of stains.
Dr Sim: The intrinsic stains are stains that are embedded within the tooth structure. Thus with the help of professional cleaning, polishing and tooth brushing will not remove those stains. They are brought about by several factors. Firstly, you are genetically born with it. Secondly, it may be due to chemicals or drugs as mentioned earlier. When there are excess intakes of tetracycline, the tetracycline compound gets embedded into the tooth structure, while the teeth were being formed and so these give rise to a whole range of colours. The mild tetracycline stains can be yellow brown, then ranging from dark brown to dark grey and in the severe form, can present in bands. That's more difficult to manage than just homogenous discolouration.
Presenter: How do we distinguish the different types of stains? For example, can we just by looking our teeth in the mirror and determine the type of stains or can it only be done professionally by the dentist?
Dr Sim: Generally, if one is doing all he/she can to maintain good oral hygiene, brushing, flossing and going for the professional cleaning every 6 months and yet the tooth colour is unsatifactory, then most probably, it is intrinsic staining. If one sees the black stain deposited or the stain becoming larger, then it could be external staining.
Presenter: Are intrinsic stains treatable?
Dr Sim: Yes, but it would go beyond merely cleaning and polishing. First the dentist will identify the type and cause of discolouration as well as the intensity if discolouration. It is by identifying these can the dentist then formulate and create a treatment plan, which could include a series of different procedure to achieve what you desire.
Presenter: It possible to achieve as white a shade as if you had an extrinsic type of stain, or somebody with an intrinsic stain will never be to achieve that wonderful shade like somebody with an extrinsic stain could have with treatment?
Dr Sim: Everybody's teeth come in different shades. It may not be possible for you to want your friend's light teeth if your own teeth are sark brown instead of light yellow-based. It also depends on what type of treatment you are prepared to do. If you are able to accept very drastic treatments and are prepared to sacrifice tooth structure in order to get to the lightest shade, then there are methods to do that, such as partially removing tooth structure to replace with something artificial (eg. a crown) which will allow the dentist to create the colour you want. Nevertheless, you need to consider if it is worth sacrificing very healthy tooth structure in order to achieve that whiteness. Therefore, there must be a balance of what you wish to achieve and what is required of you to achieve that result.
Presenter: How much can changes in your appearance, for example somebody with stained teeth now had white teeth after this procefure. How much will it change the appearance of the person you think?
Dr Sim: You will be quite surprising. Even conservative procedure like tooth whitening, which doesn't require any removal of tooth structure, will cause a huge change. Once, i had a patient come in, saying that he/she is actually a little shy about smiling because their friend ask whether he/she smoke as the person have yellow teeth. Through a simple procedure of tooth whitening, the teeth shade change to a lighter shade. It may not be white as what we are expecting but it is a lighter shade of its original colour. You will be amazed on how it can change the person personality, as that person is more cofidence now, he/she is smiling. These translate into everything, socially and how the person behavior.
Presenter: Will there be any group of people who will not benefit at all from teeth whitening procedure?
Dr Sim: Those who will not benefit from teeth whitening will then have discoloured teeth that are not suitable for the whitening procedure. Some of the causes are tooth decay, which can cause discolouration not treatable with whitening, and pulpal death. The latter means the pulp tissue containing the blood vessels and nerves are necrosed. There will be underlying infection that needs to be treated by root canal treatment prior to going for another form of tooth bleaching procedure. However, in the case of the pulpal death, after root canal treatment is carried out, then non-vital tooth whitening procedure will used. Such causes are difficult for the person to identify themselves, unless they experience severe toothache.
Presenter: What kinds of techniques are being used nowadays to whiten teeth?
Dr Sim: There are several techniques, broadly divided into dentist-prescribed bleaching method, or the in-office bleaching method.
In the dentist-prescribed home bleaching method, the dentist will then take a mould of the patient's teeth to make a very accurate and customized bleaching tray. With the bleaching tray, the patient will place the bleaching gel and wear the trat daily for a couple of hours until the teeth lighten. Throughout the weeks, the teeth will gradually lighten.
In-office bleaching is for those who are not very disciplined or lack the patience to carry out the home processes for weeks. This is a one-visit clinic appointment where bleaching is carried out for an hour. The most important part of the process is the diagnosis of the cause of the discolouration to ensure this in-office treatment is appropriate. After the dentist had diagnosed that the type of tooth discolouration is amendable to bleaching, some preparatory work will be done and the entire treatment will take about 1.5 hour. A significant lightening effect can be seen by the end of the visit immediately.
Presenter: Does it get whiter with time or what do you see at the end of the treatment is the finally colour.
Dr Sim: The treated teeth doesn'y get whiter over time, in fact it gets dark darker over time. That's part of the natural physiological process (teeth will become darker naturally with time). Even with any tooth whitening procedure, if you compare the colour of your teeth a few years down the road, you will find that your teeth are darker than what it used to be. That's why tooth-whitening procedures cannot be permanent and touch-up procedures are needed to keep the teeth colour light.
Presenter: I am not sure if everybody has a uniform type of discolouration on every tooth. If it isn't, how does the procedure treat each tooth differently? I am sure that you don't want to have some teeth whiter than the rest after the procedure.
Dr Sim: That's a very good question because naturally teeth by themselves, are not of uniform shade. If you take a closer look, the front teeth are lighter than teeth at the back of your mouth. On the tooth, the biting edge is usually lighter than areas near the gum line. Therefore, when one bleaches his or her teeth, the teeth surfaces are bleached at the same rate so the shade nuances will still be present. If using the tray bleaching method and you find that your back teeth are still darker than the front, and you are unsatidfied with that, you can still bleach those teeth.
Presenter: You mean we couldn't do this in-office type method?
Dr Sim: In the in-office type light-activated bleaching, the light will be activated for all the upper and lower teeth at the same time. There are other in-office bleaching methods where we can just bleach a specific tooth.
Presenter: Are the in-house type bleaching system different from what we can get from the pharmacy?
Dr Sim: They are definitely different. The concentration of the bleaching gel is very much higher for the in-office kits than what is available in the pharmacy. If one needs the higher concentration of bleaching gel, he/she can only get it from the dentist. In addition, the bleaching tray that is made by the dentist is customised to fit the individual. Each of our jaws have different size and shape; our teeth are also positioned differently. Although similar tray-like products are available at retail pharmacies but these are one-size-fits-all. The downside of such trays are that not all surfaces of your teeth have contact with the bleaching gel and the gel may even have contact with your gum tissue. This can cause some sensitivity and for some patients, could be quite severe.
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Call-in
Caller 1: How often should one do whitening? I had never done it before, and i was quite fascinated when doctor said that it'll not be permanent. If i were to do a whitening procedure next week, when should i go for my next session?
Dr Sim: Your teeth will darken naturally over time after your first whitening treatment, depending on what food and beverage you consume and how you maintain your oral hygiene. The rate of discolouration varies among individuals. On average, patients that i treat come back for touch-ups after about 3 years. This is not because the teeth shade had reverted back to their original colour, but more due to the fact that they had experienced whiter teeth, which they are very happy with. When it starts to darken perceptibly, enought for the darkened shade to be noticeable, then that is when the patients usually decide when they need something to be done. Therefore, when to come back for touch-ups is really the individual's choice.
Caller 1: Is there any particular food or beverages that i should avoid to prevent my teeth from darkening?
Dr Sim: Well, if i am going to tell you all the food or beverage that is going to discolour your teeth, life will be really boring for the sake of just having white teeth! I would usually tell them to go ahead to have their coffee and tea but understand that these are possible causes for tooth discolouratation. Remember that extrinsic stains are deposited onto the tooth surface and so good oral hygiene practices such as brushing after each meal and flossing well will ensure these stains do not remain on the tooth surface. This will slow down the natural process of tooth darkening with time.
Presenter: Now we come to a major question about sensitivity because hydrogen peroxide is used as the main bleaching agent. You know when we talk about bleaching clothes, floor and etc, people always know how acidic it can be and they thought it would cause a great sensitivity, is this true?
Dr Sim: Well, the active agent bleaching agent is hydrogen peroxide, but if one uses the tray method, the formulations come mostly with carbamide peroxide, which then breaks down in a controlled manner into urea and hydrogen peroxide. Furthermore, manufacturers try to make the formulations as pH-neutral as possible to minimize sensitivity. The sensitivity is usually transient and goes away; it should not be permanent. I usually warn my patients to be prepared for some common side effects like sensitivity or gum irritation, which affects about nearly 60 - 70% of patients. It should not cause you to develop tooth sensitivity. If one does have sensitivity, then it is probable that one may have an underlying undetected cause that needs to identified. It also does not erode tooth enamel. It is important to know that the formulation used for your procedure are well established ones. Another caution is not to use bleaching gel daily as you would with makeup, to maintain the whiteness of his/her teeth. Once teeth have been lightened, stop using the bleaching gel so your teeth are not unnecessarily exposed to the gel. Your whitened teeth will remain light for a fair period of time. Take a break until a few years later, and do a touch-up procedure when you truly want to.
END