The story behind Dr. Bass

Aug. 1, 2003
One of the most difficult adjustments I had to make in dental hygiene school was changing my tooth brushing technique.

By Trisha O'Hehir

One of the most difficult adjustments I had to make in dental hygiene school was changing my tooth brushing technique. In my senior year in high school, I attended a career day at the University of Minnesota School of Dental Hygiene, where one of the hygiene students taught us how to properly brush our teeth. We were told to brush them the way they grow ... down on the uppers and up on the lowers. I was thrilled to finally learn proper technique and wondered why no one had taught this before.

I was feeling miles ahead at the start of dental hygiene school, already knowing proper brushing. Imagine my dismay when I found out that the method had changed in the intervening months. The Roll technique was out and the Bass technique was in — so I was already behind and I had just started!

I've used and taught the Bass technique for years, just as I'm sure you have. But I didn't really know who Dr. Bass was. I just figured he was a dentist who was interested in prevention and made money selling his special toothbrush and floss ("The Right Kind," as they were called). Boy, was I wrong.

A few months ago, I had the privilege of meeting Dr. Bass's grandson and a couple of wonderful "old-timers." I hate to say that, as you may already think of me as an "old-timer" after 37 years in dental hygiene. Dr. Wayne Lott is a retired dentist from Arkansas who knew and studied with Dr. Bass. He told me stories of the cantankerous physician who, upon retirement from his position as dean of the medical school at Tulane University, spent the next 32 years on a mission to discover the cause of dental disease and design a program to prevent it. Many people consider him to be the "Father of Preventive Dentistry," despite his open attack of dentists and lack of recognition by the dental profession.

Dr. Bass lived to be 100 years old, finally retiring at the age of 97. He made his mark in medicine with successful treatment of hookworm in children. His microscopic studies of malaria and efforts to eradicate the organism made it possible for workers to construct the Panama Canal.

His study of amoebas led him to dentistry and the false conclusion that periodontal disease was caused by Endameba buccalis. As we know today, some microorganisms inhabiting periodontal pockets are simply opportunistic, and not the cause of disease. The dental profession refuted his 1915 book on periodontal disease, which advocated injections of emetin to treat periodontal disease. In many cases, these injections left people with arms too sore to brush their teeth. The treatment worked for dysentery, but not for periodontal disease.

After this rebuke, Dr. Bass turned his attention back to medicine and was appointed dean of the Tulane Medical School in 1922. To his great credit, Tulane was the only medical school with a dental division teaching oral hygiene to medical students and he expected them to teach their patients.

When he retired as dean at the age of 65, he remained at the school as Professor Emeritus and returned to his study of dental disease in earnest. He gathered all of the published material available and began searching for the cause of dental disease. He was also spurred on by the sudden loss of two of his own teeth, due to periodontal disease. He gathered extracted teeth and evaluated them under the microscope and looked in many mouths to find the answer. He published 32 articles on the subject — 26 published between the ages of 71 and 94. Still an outcast with the ADA, most of his publications were in medical journals.

He studied the epithelial attachment and plaque accumulation, identifying what he termed the "zdec" or "zone of disintegrating epithelial attachment cuticle," which he felt was the battlefield where the war against gum disease needed to be waged. He saw that plaque took 24 hours to form, and concluded, "A clean tooth does not decay and periodontoclasia does not occur about a clean tooth." His "sound bites" of the 1950s are still valid today — a clean tooth won't decay and gum disease won't occur in a clean mouth.

To clean the teeth, Dr. Bass developed what he called the "right kind" of brush and floss. He was inspired by the writings of the inventor of dental floss, Dr. Levi Spear Parmly, who, in 1819, recommended thorough brushing with salt and cleaning between the teeth with waxed silk floss. Dr. Bass developed precise specifications for his brush and floss. The brush was to be six inches long, 7/16 of an inch wide, and three rows of bristles, six tufts per row, 80 bristles per tuft, and each bristle 0.007 inch in diameter with a rounded end. His floss was to be unwaxed nylon, 170 filaments, and wound with three to four turns. The many filaments acted as individual cutting blades, rather than a single waxed cord.

Dr. Bass invested his own money in the development of these products and he chose not to receive any financial benefit. His commitment was to the promotion of oral health and prevention of dental disease — a true ivory tower academic. He once expressed the wish that his epitaph would read: "He designed and promoted an effective method of personal oral hygiene."

In 1960, Dr. Bob Jones of Tulsa, Okla., gathered together other followers of Dr. Bass and founded the Society for the Preservation of Oral Health. In 1969, a national group of followers formed the American Society for Preventive Dentistry, with regional chapters. The first National Prevention Convention was held in 1971 in Chicago, with Dr. Bob Barkley as the keynote speaker. Awards were presented to Dr. Bass, Dr. Barkley, and Dr. Sumter Arnim of Texas, a Bass follower and protégé. (More about Drs. Barkley and Arnim in future columns.)

In the mid-1970s, I was a member of the Board of Directors of the Western Society for Preventive Dentistry, a chapter of the national organization. I'm sad to say that, in 1977, the organization died from lack of interest in prevention! The restorative and practice management focus of continuing education was stronger than prevention.

Dr. Bass's story wouldn't be complete without some indication of his cantankerous nature, which set the ADA against him. Seems he lashed out at public health dentists and criticized the military dentists for not teaching prevention. He felt that those in the military should at least be taught how to prevent dental disease while in the service. He was also a staunch antifluoridationist, adamantly opposed to fluoride of any kind. The dental community didn't take kindly to a physician telling them what to do.

Now you know a little about the man behind the prevention movement of the 1950s. Dr. Jones was an eloquent speaker on the subject of oral health; Dr. Arnim continued the teachings of Dr. Bass at the University of Texas; and Dr. Barkley picked up the prevention torch and ran with it. A plane crash cut Dr. Barkley's life short, but the briefcase left behind holds many exciting tales. I've only had a brief look at the contents. During the next few months, I'll take a closer look and let you know what I find.

Trisha E. O'Hehir, RDH, BS, is a senior consulting editor of RDH. She is also an international speaker, author, instrument designer, inventor, and oral health detective. Her Web sites are and She can be reached at (800) 374-4290 or at [email protected].