Julia L F Goldstein

How Are You Changing the World?

X-rays and Toothpaste

Mar 24, 2015 by Julia L F Goldstein

My new dentist (let's call him Dr. X) is a very smart man. I asked him why his office had not migrated from film to digital X-rays, and I was impressed with the thoroughness of his research on the topic. He seriously considered buying digital equipment when he moved to a new office several years ago, but decided against it for several reasons:

1. Digital plates have poorer resolution than films, making it more difficult to see details in images. This makes diagnosis more challenging.

2. In an effort to improve resolution in the newest generation of digital cameras, technicians often increase radiation dosage.  This was surprising news to me, as the general trend in medical imaging is toward technology advances that enable lower doses. For example, PET scanners being built today use higher resolution radiation detectors than those in older machines, allowing lower doses of radioactive tracers to be injected into patients.

3. Digital sensors are becoming smaller, but they are still rigid components built on silicon chips. In contrast, film-based systems are more flexible and can better conform to the patient's mouth. The promise of all sorts of flexible electronics, including sensors, is supposed to have solved this problem, but truly flexible sensors remain an expensive option that hasn't reached volume production.

I was surprised that Dr. X did not mention cost as a reason for delaying the move to digital imaging. Instead, he's waiting for smaller, flexible, more sensitive sensors.

Dr. X also knows a lot about toothpaste. He is concerned about the proliferation of toothpastes with extra features, including the fad of whitening toothpastes. While it is true that these products can be effective in the short term by polishing stains off of tooth enamel, in the long run they may have exactly the opposite effect.

Toothpaste is mildly abrasive, but the newest fancy pastes contain much more aggressive abrasives. These act like sandpaper, eventually wearing down the outer layer of tooth enamel after long-term use. The dentin underneath the outer surface has a yellower tone, so many years of whitening toothpaste may result in teeth that are far from white. Dr. X recommends a plain toothpaste, which major manufacturers still sell. It costs less, and it is probably better for the teeth.