Hard water, sun and what Arizona does to enamel

Patients move here from the Midwest and, within a year or two, decide their teeth have gone yellow. They book a whitening consultation. And in maybe half of those appointments, the honest answer is that whitening is not what they need.

What hard water actually does

Scottsdale's water is hard — it carries a high dissolved mineral load, mostly calcium and magnesium. That does not cause decay and it does not cause gum disease. What it does is give surface deposits something to build on. Calculus forms faster and looks denser, and the film that accumulates on enamel over a few months holds pigment from coffee, tea and red wine more stubbornly than it would in a soft-water city.

The result is discolouration that sits on the tooth rather than in it. Peroxide whitening works by diffusing through enamel into dentine and breaking down pigment molecules that are already inside the tooth. It is the wrong tool for a surface film. Scaling and polishing is the right tool, and it costs a fraction as much.

Roughly half the people who come in asking about whitening get a bigger visible change from a hygiene visit than from any gel we could sell them.

How to tell the difference yourself

Run your tongue along the inside of your lower front teeth. If it feels rough or ledged, that is calculus, and no whitening product will touch it. Look at the gumline in daylight: staining that is concentrated in a band right at the gum, and between the teeth, is usually surface deposit. Discolouration that is even across the whole visible surface, and darker toward the centre of the tooth, is more likely to be intrinsic — and that is the kind whitening addresses well.

Photographs settle it. We take a standard series against a shade tab at a first visit, clean, and photograph again. The comparison is usually decisive, and it takes one appointment rather than three weeks of trays.

The sun, and a thing nobody mentions

Arizona's other contribution is not to the teeth at all. It is to the lips. We see far more actinic damage on the lower lip here than a dentist in a cloudier state would, and the lower lip vermilion is a site where changes matter. A soft-tissue screen is part of every examination here, and if you spend your weekends outdoors, a lip balm with an SPF is a more useful purchase than a whitening kit.

Dehydration is the other one. It is easy to run mildly dry here for months at a time, and reduced salivary flow raises decay risk measurably, particularly around the necks of teeth and around existing restorations. Several common medications — antihistamines, some antidepressants, blood pressure drugs — reduce flow further. If your mouth is regularly dry, tell us, because it changes both your recall interval and what we recommend you use at home.

If it really is intrinsic

Then whitening is a good, conservative, non-invasive option and it removes no tooth structure. Custom trays made to your gum margin, carbamide peroxide overnight for ten to fourteen nights, starting at a lower concentration and stepping up only if you are comfortable. Sensitivity to cold during the course is common, dose-related and resolves; dropping to alternate nights usually fixes it. Results are not permanent — expect to top up for two or three nights once or twice a year, which costs the price of a syringe of gel if you keep your trays.

What whitening will not do is change a crown, a veneer or a composite filling. If you have a front restoration that currently matches, whitening around it will leave it looking dark. That is worth knowing before you start, not after.

The order that saves money

Clean first. Photograph. Then decide. It is a fortnight longer and it is quite often the whole treatment.

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