Critical thinking

A problem arises if professionals espouse false information, due to their lack of critical thinking about their own scripts.

A problem arises if professionals espouse false information, due to their lack of critical thinking about their own scripts.

With his finger on the palatal aspect of number 10, the patient said with a lisp, "The last time I had my teeth cleaned, she put something on my tooth. Thith on righ ere."

"I donno wha she did," he continues to complain, with his tongue touching the offensive part of the tooth. "But, it feels like she put some kind of glue on it and then it solidified on the tooth.

"I know it wasn't there before," the patient says adamantly. "She must have picked something up from somebody else, or the tray, and it got there accidentally," he conjectured, trying to bring himself from irate to irritated. He seemed appalled and grossed out that something from someone else got onto his tooth three months ago at his last prophy appointment.


Had the patient used his critical thinking skills, he would have understood that the story he told was impossible. The difference he felt with his tongue was a coincidence of timing if anything. Hygienists have been cleaning his teeth for years and never put anything that flows onto his teeth, even accidentally.

How often do professionals get stuck in this wayward thought track? It's one thing when a patient comes to us with a far-out dental story. This is our turf; we're educated to have an understanding in a situation like this. A problem arises if professionals espouse false information, due to their lack of critical thinking about their own scripts.

Here is a list of critical thinking rules/attributes from the book, Challenging Your Preconceptions: Thinking Critically about Psychology.

  1. Critical thinkers are flexible — they can tolerate ambiguity and uncertainty
  2. Critical thinkers identify inherent biases and assumptions
  3. Critical thinkers maintain an air of skepticism
  4. Critical thinkers separate facts from opinions
  5. Critical thinkers do not oversimplify
  6. Critical thinkers use logical inference
  7. Critical thinkers examine available evidence before drawing conclusions

The author goes on to say, "Critical thinking is a logical and rational process of avoiding one's preconceptions by gathering evidence, contemplating and evaluating alternatives, and coming to a conclusion."

Had this patient been able to tolerate ambiguities as listed in rule No. 1 and had he identified his initial assumption as highly unlikely, he would not have come up with the working theory that he lived with during the preceding three months. Had he been able to separate facts from opinions and realized he was oversimplifying, he would have concluded that, while something had changed on tooth number 10, it could not have come from his hygiene appointment.

In the book, How We Know What Isn't So, the author describes the problem of assuming too much from too little data. The main point of the book is that people, for various reasons, too often make assumptions — even leaps of reason — that later become known as facts.

For example, take the idea of "adoption equals conception." The author evaluates the notion that, quite frequently, after adopting a child, couples conceive a child of their own, even after years of trying in vain. While the evidence does not support the widespread belief that couples conceive easier after adopting, many people know a couple where this has happened. Or, they may know someone that knows a couple who has experienced this. Our attention is drawn to those unusual cases that become embedded in our long-term memory.

Without further mental labor, the legend is born.

Examples of this lack of critical thinking also exist within the profession of dental hygiene:

  • The active ingredient in Listerine® is alcohol
  • Power brushes = gum recession
  • Water jets are harmful and not beneficial
  • Flossing treats gum disease
  • PSR scoring isn't as good as full-mouth perio charting

While Listerine® has alcohol in it, alcohol is not the active ingredient. The dental industry stopped using alcohol as a surface disinfectant over a decade ago because it doesn't work.

PSR, a great little tool for busy practices, has a funny reputation of not being as good as full-mouth perio charting. In reality, six readings per tooth must be taken in order to obtain the score for the sextant. Using logical inference as a critical- thinking device, we can see that these two positions fall under the heading of oversimplification. The ideas simply were not thought through!

Sometimes, no matter how we think things through and no matter how much information we gather, we come to the wrong conclusion.

Marilyn Vos Savant wrote a book on that very issue. She calls the phenomenon "counter-intuitive thinking." In her book, titled The Power of Logical Thinking, she takes some of the mind-bending puzzles published in the Parade section of the Sunday newspaper and proves over and over again how intuition can get us into big trouble.

Some answers go so violently against the "gut" that virtual word wars were waged. Some of the premium minds in this great country are buckled into a configuration that won't allow defeat, no matter how much evidence there is to support a different answer. Some of those great minds from premium universities took a dive into gender bias, claiming that Ms. Vos Savant used "woman's logic" instead of taking an active roll in understanding.

Intuition can be very useful, but when it comes to the sciences, it does not always work. Knowing this can open a dusty corner in a brain. It can let the moths out into the sunshine of truth and knowledge.

The patient in the opening sequence of this column oversimplified the change in his tooth; his intuition failed him. In reality, the margin of the composite restoration on that tooth had broken down, causing a different feel to it. The restoration was, of course, tooth-colored, and the majority of it was on the inside of the tooth.

As we all know, the tongue doesn't have an eye (such a shame). This man did not have all the available information. He failed to come to a more logical conclusion. Not only did the patient have limited information, but his attention was focused on that tooth every day for three months.

To a hygienist, with the information available to him or her, listening to the account sounded ridiculous. To the patient, though, with the information he had available, it was logical; he did not know he did not have all the information.

The same thing can happen to anyone. Without critical thinking skills — or even the knowledge that there are critical thinking skills — people do not look further than their own nose. As a professional, an expert in a field, the rules are different. Critical-thinking skills are vital, not only when communicating with patients, but also to make the entire profession shine.

Shirley Gutkowski, RDH, BSDH, has been a full time practicing dental hygienist in Madison, Wis., since 1986. Ms. Gutkowski is published in print and on Internet sites, and speaks to groups through Cross Links Presentations. She can be contacted at dentwrite@aol.com

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