In our Caribbean cruise budget was a line item for a pair of sunglasses. For our dentist. We knew he'd need them because we booked a time at the Lotus Spa on the Crown Princess for a "teeth whitening."
You've seen pictures of those famous people after their teeth turn to sparkling white (which they, of course, have never been), capable of reflecting sunshine at the speed of light, and just as bright.
That was going to happen to the not-so-famous us.
We were in for a surprise. Our dental hygenist in charge of ivory headlights, Hestie, explained in the run-up to the treatment that our teeth would be au natural, although 
since she is from South Africa and not France, those weren't her exact words. But we knew what she meant.
In other words, our teeth would be close to what they were a century or so ago, before we started consuming coffee and tea and red wine, the three stars of teeth staining, in no particular order. Alas, once again we would not be mistaken for movie stars.
Hestie also explained in great detail what was going to occur, that we wouldn't feel a semblance of pain, that this particular brand of whitening process has been around for 15 or 20 years and that it is available only on cruise ships. The cynic side of us wondered how something successful could be around that long and not make it to shore, but by that point of the conversation we were in the chairs, wearing bibs and about to insert mouth guards.
Conversation became minimal.
She also mentioned something about using only "six per cent hydrogen peroxide" so as not to penetrate further into our teeth than it should (think: pain), and you can be sure the "hydrogen peroxide" perked our ears more than the "six per cent." But vanity, thy name is 2(HO) — as opposed to H2O.
The operation (bad choice of word) was supposed to take half an hour, and it turned out to be more like 30 or 35. Hestie was kind enough not to mention it was probably directly proportional to the number of staining years. During just over 20 minutes of wearing a mouthguard, we were cleansed by "my creams" (it's more like liquid) applied to the teeth, followed by 4-to-8-minute sessions of what seemed like an infrared light, all the better to penetrate our enamels.
And yes, both sets of teeth were whiter…au natural.
The cost for this is $149 per person, or $129 each if you're a couple. Quick, find a partner. The up-sell comes when you're finished: self-applied liquid treatments, without Hestie the teeth whitener. A week of it, twice a day, is highly recommended and the tab is $49 per person. Repeating that for a week every two months is another $258…
Considering that the week before we boarded the Crown Princess, one of us had a tooth filled (that's one tooth) and the bill was $311, it's not too much to pay for having your teeth look nicer.
And you do save the price of sunglasses.
Carnival Valor
7 nights
March 10, 2013
San Juan (return): St. Thomas, Barbados, St. Lucia, St. Kitts, St. Maarten
Inside: $489
Cost per day: $69
www.carnival.com