"Apparently 400 years ago, people used to go to the barber's to get acid applied to their teeth. I'm not sure how well that worked," says Dr. Jonathan Liu of The Dental Studio as he was preparing for an in-clinic Zoom teeth whitening procedure.
"But modern times? In the '60s it was discovered that peroxide applied to teeth will lighten its colour. And in the '70s they started adding energy sources like heat to try to accelerate the process. That didn't work very well." Later in the late '80s, laser whitening treatments came about. It was a successful treatment modality but the heat generated from the laser proved to be too painful for the clients. In the '90s, a light-activated whitening system paired with peroxide came about. And it remains "the system which is still used today".
For the past 20 years in his dentistry practice, Liu watched the consumer trends of teeth whitening ebb and wane. The peak came about 15 years ago in Singapore, "when we were doing an insane amount of whitening. There was a fad, but fads are not good, right?"
Yet, there's a similar teeth whitening fad happening right now. There are home teeth whitening kits sold everywhere online, be it on Amazon, eBay, Carousell, or even Instagram.
Liu advises consumers to be cautious of these products. These online-bought kits are starkly different from the ones sold in local pharmacies and drug stores. "If you buy it off the shelves in Singapore, it's probably going to be safe because those are regulated." The ones sold online are, however, likely unregulated.
"So why is it dangerous to buy these kits online and whiten my own teeth?" I ask Liu.
He replied, explaining that it's more than the fact that they are unregulated. When it comes to self-administering teeth whitening kits, the individual's dental health status and the peroxide concentration within these kits play a part.
"First of all, gum disease? The gums will bleed. And tooth decay? The peroxide can enter the cavity and end up closer to the nerve and damaging the tooth," explains Liu. "All that should be protected first."
The active ingredient in teeth whitening gels is hydrogen peroxide. "Upon contact with the teeth, it gives off free oxygen radicals which then penetrates the tooth structure and breaks the bonds between the stains and the tooth," Liu continues.
However, when peroxide is in high concentrations, "it can burn your lips, or your gums, or any of the oral tissues. Which is why when we do procedures like that, we actually cover up everything else, only exposing the teeth, so that's safe," says Liu. "But when you're on your own, you don't have any of these protections." If unregulated, the hydrogen peroxide potency in these products may stretch from zero to a startling four percent.
"So we should leave teeth whitening to the professionals?" I ask Liu.
"Definitely, for safety reasons that we just talked about," he replies. At Liu's dental clinic, he offers both in-clinic and customised take-home whitening kits for his patients — the latter involves a customised teeth tray for the patient and a thorough coaching session by the dentist. The former in-clinic treatment is called Zoom, a more potent and time-efficient option. When it comes to Zoom, Liu spends a good 20 minutes cleaning the patient's teeth and covering the gums before coating the exposed teeth with a 25 percent-strong peroxide formula and accelerating the whitening process with blue light from a LED lamp.
Both the gel and lamp are left on for 15 minutes before the lamp is switched off, the peroxide gel cleaned away, and the process is repeated again for a total of three cycles. In the 45 minutes spent under the peroxide gel and the LED lamp, the Zoom procedure, on average, whitens an individual's teeth by eight shades — only I didn't last that long in the dentist's chair.
Either it was my irrational fear of dentists or the teeth sensitivity that got to me, I surrendered at the end of the second cycle to Liu's dismay.
"You are four to five shades up now but we could do better," he encourages.
"No," I shook my head like a stubborn child.
The sensitivity was gnawing at my teeth. Like a paper cut, the smallest prick is the most unbearable of all pains. Sensitivity is apparently a common complaint amongst those who have been through a Zoom whitening procedure but the majority consensus has it that there is no treatment more effective than this on the market right now.
Liu sent me home with a syringe of desensitising gel. He explains that over the next 24 hours, saliva will gradually coat the now-bare teeth with a layer of mucus again, alleviating the sensitivity.
Two months later, the daily Americano took a toll — the whitened teeth grew a shade or two yellower. Why not try a home kit? I picked up a home teeth whitening kit and carefully squeezed the gel into the whitening tray before leaving it on for a recommended 30 minutes. "My gums feel funny," I thought. But ten minutes in, it morphed into a stinging pain. "Damn, I burnt my gums," I realised. "Should have left it to the doctor."
Dr. Jonathan Liu is based at The Dental Studio, 290 Orchard Road, Paragon Tower 1.
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