Sunday, November 22, 2009

How To Making Your Teeth Whiter.

In this article, I'll give an update on my latest "discoveries" in this ever-changing field.

1. Chairside or DIY
No change here. I always recommend DIY whitening. It's more economical and it works just as well. Some say it works even better than chairside whitening.

2. Effectiveness
Recently, a Japanese dentist published a paper on what kind of teeth bleach better than others and I found it a really interesting read. He mentions (surprisingly) that dentine doesn't actually bleach. It's the enamel that bleaches. I tend to agree with that because in many of my bleaching cases where dentine is exposed due to abrasion cavities, that part of the tooth won't whiten.

If it's true that only enamel bleaches, then it will mean that people with worn out and yellowed teeth are unlikely to benefit very much from bleaching. It also means that areas where the enamel is thicker, like near the incisal tip, will whiten much better than the necks of the teeth where the enamel is thinner. Hence, the location of the staining is very important. If the tooth is darker around the tips, then they will bleach well. If they are darker around the gum area, then they may not bleach well.

The bad news is, Asians tend to have thinner enamel than their Causasian counterparts. This means that Asian teeth will not bleach as well as Caucasian teeth. Many of the claims by the manufacturers of bleaching products are actually based on Caucasian teeth.

3. New Products
For our DIY kit, we're now using 9.5% hydrogen peroxide. We are no longer using 22% carbamide peroxide. The new product is clearly more effective than the old. Besides that, additives like amorphous calcium phosphate go into the new packaging. ACP has been shown to be capable of remineralising demineralised teeth by cauing calcium phosphate to precipitate. It's supposed to help control sensitivity.

Patient feedback confirms that a reduced level of sensitivity is experienced with the new formulation. Our 9.5% hydrogen peroxide take-home kit is the most popular bleaching kit at our office today. It may take a bit longer than chairside whitening, but it's more cost-effective.

For chairside bleaching, we are still using 38% hydrogen peroxide. Not much "improvement" in that area as hydrogen peroxide in those concentrations is highly caustic. For lasting results, all chairside whitening procedures must be followed up with the take home kit. The way I look at it, there's really no point in doing chairside whitening.

4. Procedures

No change in that department. Impressions are first taken and a set of customised bleaching trays are made. If you book your appointment in advance, the trays will be ready in 1 hour.

The mixing tip is attached to a double syringe. As the plunger is pushed, the two chemicals are mixed together and activated. Each syringe contains enough material for 3 upper and lower applications. 3 syringes give 9 applications.

The activated gel is placed into the customised bleaching tray. The trays are worn over the teeth for one hour 2 times a day. They are quite comfortable and are almost invisible. However, the trays must be pushed in for a snug fit. The flexible tray is pressed against the teeth to clear voids in the gel. Excess gel on the gums is wiped off.

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