“I really can’t recommend it enough.”

My dental hygienist had just finished fifteen minutes of brain-rattling tooth-scraping and was now trying to pitch me on a procedure involving lasers.

“Lasers?” I said lamely. “What are, uh…, the benefits of lasers?”

The DH swiveled and looked at me above her protective glasses—a look that indicated she pitied my profound gingival ignorance. “It zaps away all of the bacteria from the roots of your teeth. Amazing technology. I’d recommend it to anyone with your level of periodontal disease.”

“I have periodontal disease?” That sounded serious.

“Not yet,” she said, her voice filled with deadly caution. “But you have pre-periodontal disease. If it gets worse you’ll have full-blown periodontitis.” She mic-dropped her latex gloves into the trash.

“How much does it cost?” I asked, a little sheepishly. It seemed gauche to talk about money when my gum health was hanging on by a thread.

“Well unfortunately your insurance won’t cover it,” she said. “So it’ll be about four-hundred dollars.”

“Four…hundred…dollars?” My eyebrows hit the ceiling.

“Yup!” said the DH cheerfully. “Trust me, it’s worth every penny.”

“…”

The rest of our conversation was an awkward blur. Somehow I managed to fend off the DH and her expensive laser, but as I was leaving she mentioned—in an unmistakably threatening tone—that she’d made a note in my file and that I should strongly consider laser therapy at my next visit. I left the office feeling like I had postponed the inevitable.

But as I walked home my guilt turned to indignation. How was I supposed to make this decision? On the one hand I go to the dentist because they’re the experts—but on the other hand I know that dental offices are businesses like any other, driven by the cold logic of capitalism to foist as many treatments onto their patients as possible. So how can I make sure that this laser thing is worth the cost?

Laser bacterial reduction (LBR) is just one example of the many high-stakes medical decisions that you and I and everyone else are forced to make constantly.

In the pre-Szaszian era, medicine was something that happened to you. You would put your health in your doctor’s hands and they would unilaterally decide your course of treatment. But in today’s patient-centered world, doctors are more like consultants: they provide suggestions, you Google those suggestions and provide counter-suggestions, your health professional Googles your counter-suggestions, etc. Medicine has become a three-way negotiation between you, your doctor, and The Algorithm.

In addition, most of today’s health decisions are made outside of MD-earshot. You’re vegan and wondering if you should take a B12 supplement. You have a headache and aren’t sure what painkiller to take. You want to avoid COVID and aren’t sure what kind of mask to buy. These are all health decisions! And most of them are made by individuals, not by medical professionals.

Which brings me back to my dental hygienist and her expensive laser. I have six months until my next cleaning—that’s six months to figure out if this treatment is worth it. But where do I start?

Hahaha just kidding. You’re reading this in a year that starts with “2” so the only possible starting point is Google. Let’s see what Google has to say about “laser bacterial reduction” (LBR):

The first thing I notice is the Google Scholar widget at the top. Nice! I’m all about evidence-based medicine, and the fact that Google’s top results are three peer-reviewed articles is A+.

Or so I thought. The first study (Moritz 1997) is a small pilot study with only 50 subjects. It found that lased subjects had fewer bacteria around their gums—but there’s no direct evidence that laser therapy fights periodontal disease.

The second study (Moritz 1998) is actually just a 6-month follow-up with the subjects from the first study. This study has some promising info: pocket depth (a direct measure of periodontal disease) was 1.9 mm shallower in lased patients than non-lased patients. But again, this was a 1998 pilot study with 50 subjects. Not exactly definitive.

The third study (Dewsnup 2009) is an in vitro study on 55 extracted teeth, comparing an erbium, chromium:yttrium-scandium-gallium-garnet laser (what?) with a sodium hypochlorite wash. I’m interested in a diode laser, on still-very-firmly-attached teeth, versus no treatment, so this isn’t remotely relevant to my problem.

So far this is pretty weak evidence. But my gums are on the line here, so let’s keep scrolling.

The next section is the “People also ask” section. It has four questions:

• Is laser bacterial reduction worth it? Answer: “The benefits of Laser Bacterial Reduction make the treatment a worthwhile investment.” Source: A dentist’s office named, in all seriousness, “Fidler on the Tooth.” There is zero evidence cited by Dr. Fidler’s page, which exists to advertise the laser bacterial reduction offered by her office.

• How long does laser bacterial reduct