As a consumer, “they” push every sort of teeth whitening light or laser on you, trying to make you believe they actually work. They don’t.
I’m talking about from small little gimmick hand-held lights you see in stores, on social media and online sellers; to major corporations’ high intensity, high cost lights and lasers used by dentists in their offices. It’s marketing spin, pure ‘n simple.
I’ve been a teeth whitening scientist since 1977, and I can tell you, if the laws of science don’t agree with what’s claimed in the marketing hype, the hype’s not true. You can’t change the laws of physics or chemistry, no mater how much you want to.
Everyone tends to assume that when you add energy (via heat, electricity, photon/light, etc.) to a chemical reaction, it speeds up the reaction. Think back to high school chemistry. You put two different things into a little beaker…and nothing happens. But then you put the beaker over a Bunsen Burner to add heat (energy) to the mixed brew, and WHOOSH!, the reaction happens. That is called an “endothermic reaction”. You put energy into the endothermic reaction to make the reaction go faster.
Well, heat is very damaging to the pulps (nerves) of the teeth, so you can’t add heat energy to the teeth whitening gel. But you can add photon energy via lights and lasers. So, according to the companies that make and sell these lights & lasers, when you shine the light on the whitening gel, the light energy makes the peroxide break down faster; therefore more effectiveness.
That might actually work…IF the breakdown of peroxide was an endothermic reaction. But it’s not. The breakdown of peroxide is what’s called and “exothermic reaction”. In other words, the reaction must get rid of energy for the reaction to proceed. If you’ve ever mixed up plaster, you’ve seen that as it hardens, it gets hot. As the plaster is setting, it needs to give off energy in the form of heat. That is an exothermic chemical reaction.
According to Le Chatelier’s Principle of Chemical Equilibrium, if you try to push energy back into an exothermic reaction that is trying to get rid of energy, it will not help the reaction and could even slow down the reaction.
So why in the world would you really want to use a light or laser on teeth to supposedly make the peroxide breakdown teeth whitening process work better? The only reason could be marketing spin and hype. Remember, you can’t change the laws of physics or chemistry.
But here’s the real kicker:
A scientific study published in the Journal of Endodontics December 2008 showed that not only do lights and lasers not add to teeth whitening results; the combination of lights and lasers with the high concentration hydrogen peroxide whitening gel on the teeth causes the release of something called Substance P in the pulp (nerve) of the teeth. Substance P is a neurotransmitter, causing pain nerves inside the teeth to fire. The only job of Substance P is cause inflammation and pain. OUCH!
The only saving grace here is that usually the pain goes away after hours or a couple days. But that’s not much consolation to having useless lights or lasers used (with no improvement of teeth whitening results), only to cause excruciating pain in your teeth during and after the teeth whitening process.