Dr Mark Spigt, Associate Professor at Maastricht University, looks back at the statements belonging to his PhD thesis.

“Regular check-up of the teeth by the dentist is screening, and should therefore comply to the recognized rules for screening, before it is implemented on a large scale.” Mark Spigt, December 2004

The idea for this proposition came from a professor at our department; Paul Knipschild. He wondered how the dentists were able to lobby so successfully, that everybody more or less agrees that checking your teeth every half year is a good idea. There are many things in our body that can be checked and fixed. In fact, dental check-up is screening and before we start implementing screening programs we normally need to know whether the screening and subsequent treatment is (cost-)effective. But in the case of filling dental caries lesions, there is no trial showing that filling the caries is effective. I started reading about the topic and found some very critical papers that really urged the dentists to stop filling caries the way they do it now; otherwise the society will turn against us…. They argued that the diagnostic process is very weak; it is very difficult to judge whether the observed caries needs to be filled or not. Caries is not a linear process. The demineralization of the tooth can be restored, so that early caries can be reversed. About taking x- rays to diagnose the caries, the papers were very critical. The filling itself is a definitive damage to the tooth. If caries is filled unnecessarily, the damage is certainly irreversible and often the filling has to be replaced or near the sides of the filling new caries develops. 

When I visited a dentist in that period, after having not been to a dentist for several years (and with an obvious hole in one of my teeth…), you can imagine I had a hard time. I asked my dentist whether she could do the consultation without an x-ray, since the evidence base for this procedure was very weak. She said she couldn’t…. I went to another dentist and I showed her the critical papers and asked her to take notice of these papers. She smiled and took the papers. But she also convinced me more or less that I really had to do something about that hole, and that she really needed to check my other teeth as well. She filled the hole, and also two other holes she found on the x-ray…. These other two holes still bother me. 

It felt like bringing your car to a garage that you don’t trust. They tell you what is wrong with the car and that it needs to be repaired, but you cannot judge whether they are right, or just want to earn some extra money. But I was lucky. I learned from my mother in law, that she was very happy with her dentist. Her dentist once said to her: “I think there is some caries in that tooth, but let us wait half a year to see how it progresses”. That was the dentist I wanted, and I asked him whether he had a place left in his practice, and since then I am very happy with my dentist, and he doesn’t complaint that I only come once a year and not twice… 

After my  PhD there seems to be some change in the way dentists treat caries. A paper(1) from The Lancet from 2007 shows that the critical attitude towards filling has spread. In that state-of-the- art paper it is written that it is widely known that the validity of dental caries diagnosis is weak, also for the x-ray and that dentists can still misclassify sizeable numbers of sound surfaces as decayed. The same story I agree, but this time the paper is not written by whistleblowers, but by authors that have the authority to write for the Lancet. The authors say that “a major challenge for the clinician is to detect lesions at an early stage, before surgical intervention is needed”. And there is much more focus on prevention and choosing the least invasive measures first. But it also states that “In dentistry, the promotion of evidence-based care and the production of clinical guidelines to support appropriate care for individual patients is now possible”. Some things develop slowly…

1.      Robeh H Selwitz, Amid I Ismail, Nigel B Pitts; Dental caries. The Lancet; Vol 1369, January 6, 2007
Mark Spigt