I’m a big fan of prevention, understanding that everyone dies of something, and not all health problems are preventable. That said, it’s crazy how our fears about illness and death overwhelm our better judgment from time to time, and how people with a service to sell sometimes let their ambition get in front of the science, even when it is just an ambition to prevent every illness and disease.
Take dental cleanings, an arena in which I am a patient, not an expert. My dentist said I needed deep cleanings by a periodontist and that it was covered by my insurance. Of course, I couldn’t find a periodontist who takes insurance, so I decided to have it done anyway, pay out of pocket, and then submit to Blue Cross. $1360! Which Blue Cross denied because the periodontist was out of network. (You really can’t make this up. Kafka lives, reincarnated as health insurance companies.) The periodontist then said I ought to have four cleanings a year. So, I said, wait a second, walk me through the evidence that cleaning four times a year is better than three times a year. Or two times a year. Or once a year.
At which point, the periodontist hedged. Well, he said, it’s been seven years since I took my boards, so I probably can’t quote the studies. Or study. Because, he said, cleaning hasn’t been well studied, at least recently. People study bone grafts and tooth implants now, but not dental cleanings, which are regarded as settled science.
But how can you have settled science when there haven’t been studies? I asked. I’m interested in a single outcome – do dental cleanings impact tooth loss? I’m 72 years old. So my teeth need to last me about twenty years, not fifty years. If I’m going to spend $500 to $600 a year on dental cleanings (which is more than most of us pay for primary medical care, just saying) and then $1360 every few years on deep cleanings, I ought to know that there is going to be a return on my investment.
Well, the periodontist said, they don’t really study the number of cleanings and how that is associated with tooth loss. More frequent cleanings reduce the need for deep cleanings. People report less gum infection, aka gingivitis. And less gum bleeding when you floss. But I don’t know the evidence about tooth loss. And these are old studies, so I don’t know if they are any good.
Okay, I said. Let me see what I can find. Understanding that the periodontist was truly concerned about the health of my gums and my teeth, but I still wanted more data. (I’m a little unclear about any financial interest dentists do or don’t have in dental cleaning, but, after a lifetime of watching the profit motive undermine health care, I’m always cautious.)
Great, the periodontist said. Let me know what you find if you can find out more.
(Yikes, I said to myself. How comfortable am I about getting a recommendation that isn’t based on knowledge of the evidence?)
So I asked colleagues, and I looked around. Here’s what I found, with their help.
It turns out cleanings have been studied at least twice, in 2013, including by a group that included the current dean of Harvard Dental School, and a group in Great Britain: the US group looked at the records of 5,117 adults, going back 16 years, and found that there is no evidence favoring two dental cleanings a year over one cleaning a year to prevent tooth loss except in higher risk individuals – people with diabetes, smokers, and those with a genetic construction called interlukin-1composite genotype, which is found in about one third of Caucasian adults, but few of us know whether we have that risk. There was a reduction in the risk of tooth loss for higher risk people with two visits a year. The British study found essentially the same thing. I couldn’t find evidence that anyone has studied three or four cleanings a year, which was what my periodontist was recommending.
It also turns out there is an older review article (2002) that looked at deep cleaning aka scaling and planning, that suggested deep cleaning is associated with improvement in gingivitis – but did not look at deep cleaning and tooth loss. Most dentists and lots of experience suggests that gingivitis is associated with dental carries and the development of severe gum disease, which in turn can lead to tooth loss – but there isn’t good evidence that deep cleaning actually prevents tooth loss, just gum disease. Dentists just think it does. Remember, the absence of evidence isn’t evidence of absence – just because the impact of deep cleaning on tooth loss hasn’t been studied doesn’t mean there isn’t some impact. (Just to mess us all up, there isn’t good evidence that flossing reduces tooth loss in the short run (over 1 year) but there is some evidence that it works if you do it regularly over five years.) All that said, gum inflammation and infection is actually associated with heart disease, which is more significant if you have diabetes or smoke – or are over fifty. And severe gum disease is often thought to be the cause of heart valve infection, which is life threatening, but relatively rare.
So what’s a human being to do? I’m 72, which means I likely have 18 to 20 years of life left. I’m in good health, no heart disease or no diabetes (yet) and I’m not a smoker. I exercise daily. I brush a couple of times a day.
So I’m going to get a dental check-up and cleaning once a year, not four times a year. If I need deep cleanings every few years, I might do that. If I was 30 or had diabetes or was a smoker, however, I’d probably do two or more cleanings a year if that was recommended by a dentist I knew and trusted.
But here’s the rub on prevention. The effectiveness of prevention is related to risk. Higher risk people benefit more, vis-à-vis dental cleaning and tooth loss, but also in other arenas. One size does not fit all. We tend to overdo prevention from time to time, sometimes out of an excess of caution, but sometimes when there is financial benefit involved. So relationships matter. Choose your professionals well. Choose people you know and trust and then ask questions so you know that the benefits you want are likely to result from the time and money you expend.
What’s crazy, in these days of RFK Jr, is that you are too often left to figure this stuff out for yourself. We could do better than this — and make a health care system that is for people, not for profit, with trustable recommendations from independent authorities like CDC and FDA, like we tried to do, once, however imperfectly. It’s crazy we didn’t make what we had better, by making the whole thing not-for-profit. And it’s crazy we are losing the trustable authorities we had, to politics.
PS I no longer have Blue Cross. Getting rid of them was quicker and easier than fighting with them. I sent this data to my periodontist. I haven’t heard back from him yet.
You can find Michael Fine’s commentaries and short stories on
https://michaelfinemd.substack.com/and on http://www.michaelfinemd.com
