Utah dentist Elbert O. Thompson worried he'd have to give up his career because of back problems.

He didn't want to leave the cavity-filling and the teeth-pulling behind because he cherished his hard-won diploma, earned during the Depression in the pre-student-loan era from Chicago's prestigious Northwestern Dental School.In Utah in the 1950s, dental patients sat up in straight chairs. Dentists were forced to stand over their patients, kicking an electrical current regulator on one side of the chair, then bending like a corkscrew to look into the patient's mouth.

This gymnastic display occurred because patients, who were sitting up, had to leave the chair in order to spit. Thompson figured the spittoon was at the spine of his dentistry-related back problems. He began considering efficiency studies and bothering equipment people for new equipment.

"I determined with time-and-motion studies that as the dentist stands there and watches the patient spit, he's wasted enough time to buy a Cadillac every year. It's a stupid waste of time.

"One day - I don't know how I had the courage to do it - (but) I laid a patient way back in the chair with pillows and used my belt to stabilize her knees." At the same time, Thompson started tinkering with plastic tubing, trying to figure out a way to use suction and water to eliminate the need for the cuspidor.

His first suction contraption had a major flaw: noise.

So he fiddled with motors. For a time, he used a milking machine from Sears & Roebuck. Then he tried a surgical pump, which proved too strong. "You could get a hold of a cheek with one of those things and it would produce hematomas." Eventually, he developed a suction pump powered by the same principles that operate a sewing machine motor.

Now 80, Thompson retired from his Holladay practice about 13 years ago. But his futuristic vision hasn't dulled.

And Thompson remembers back nearly 40 years, when he started experimenting with ideas that eventually revolutionized his entire profession.

Thanks to back pain, Thompson modernized his field with what was labeled the "washed field" technique, a term for the suction evacuation system used with warm water. Thanks to this technique, the dental assistant became more than an appointments secretary.

"We would work like a dancing team. She would stay out of my way. She would entrap the excrements - the solids, the slurries, the saliva and sometimes blood. She would pull so fast and so clean that the operating field was presented with much greater excellence in vision."

Starting in 1954, Thompson lectured about his ideas all over the world. When he returned from trips to stacks of mail and stacks of dental appointments, he tinkered with new ideas, testing them on his patients.

Beyond the inventing, Thompson hunted through encyclopedias and dictionaries to coin terms for his ideas. It took him about 10 years to discover "euthenthics," a word that means movement to improve the human species through control of environmental factors.

Euthenthics Dentistry, a term Thompson copyrighted, includes many of his ideas for accelerated efficiency, including four- and six-handed dentistry, high-speed dentistry, sit-down dentistry, the therapeutic dental office and using water properly during dental procedures.

Apathy was the immediate reaction to Thompson's then-radical ideas, except for the dental-supply companies, the cuspidor peddlers, who were in outright opposition. During an early lecture to the College of Physicians and Surgeons, Thompson remembers, a televised football game was turned on through his entire speech.

Thompson found a word for that attitude, too: "xenophobia," or fear of anything foreign or strange.

Thompson's experiences as a dentist and inventor are featured in a historical program published for the Utah Dental Association's winter meeting.

The February meeting of the Utah Dental Association celebrated a century of Utah dentistry, marking historical high notes such as Thompson's inventions. The association was founded in 1891, five years before the state entered the union.

Other notables in Utah dentistry include Alexander Neibaur, a German immigrant to the United States in 1841 who became the first dentist to practice in the Territory of Deseret. Neibaur seldom received money for his services of cleaning and plugging teeth, as well as inserting artificial teeth. Instead, he was paid in cornmeal, molasses and pigweed greens.

Utah's first woman dentist, Rose Ellen Valentine, held a dental license from 1903 to 1960.

Valentine started as a bookkeeper and accountant for L.H. Berg, a Brigham City dentist and surgeon. Her starting salary was $12 a week. "I accepted his offer," Valentine wrote in her memoirs, "but told him that `I'll never pull a tooth.' "

Came the reply from her new employer: "We'll talk about that later."

One day, a woman brought her small daughter into the office to have a tooth extracted. The dentist wasn't in, so Valentine looked at the tooth and decided to pull it out with dental floss. "When Dr. Berg returned, I told him what I had done. He smilingly exclaimed, `Never let such a thing happen again. Use a forcep.' "

But Valentine writes that she was intimidated by the forceps, until Berg forced her to pull five teeth in one day.

For years, Valentine, a slip of a woman just topping 5 feet tall, was the only woman dentist practicing in Utah.

One 250-pound farmer from western Box Elder County laughed at her. "Go ahead, I don't think you could hurt me, even if you can't pull the tooth."

"Without too much effort I extracted the tooth, which was an upper six-year molar. He was further chagrined, but glad, and as long as I practiced in Brigham City, he remained my patient," Valentine wrote.

Another Brigham City dentist, Mary Petersen Reeder, passed her dentistry examination in 1940, the only woman in her class. During World War II, according to an article published in the dental association's magazine, it was difficult to get quality equipment, such as drills and burs.

After the war, she got married, and rare in those times, kept her practice. "I had a job that I loved, and a good practice." She maintained a two-chair office, complete with its own lab, and employed three dental assistants.

Pregnancy offered some interesting challenges for the dentist. "When I was pretty big with child No. 1, she kicked one of my male patients . . . hard enough for both of us to feel it. That's when I decided I would quit until she was born."I determined with time-and-motion studies that as the dentist stands there and watches the patient spit, he's wasted enough time to buy a Cadillac every year." "Two of my children have spots of white, about the size of a quarter in their heads, and one has a mark on his toenail, which are probably due to taking X-rays without a lead apron when I was pregnant," Reeder writes.

Just as with today's working mothers, Reeder had some problems finding child care. A woman she hired called the day she was to start tending, saying she couldn't baby-sit because her own children had contracted chicken pox.

With dental patients on the way, the busy mother-cum-dentist ad-libbed. "I grabbed the baby, her diaper bag and food, and ran into the adjacent apartment and said, `I have a patient in 30 minutes, and you will have to keep my baby for about a month, at least, until these kids are through with chicken pox,' " Reeder writes.

Reeder, who practiced for 25 years and has been retired for 25 years, said she was lucky, as her emergency baby sitter became a longtime employee.

"In some ways, I feel that the quality of dentistry we did 50 years ago was as good as it is at its best today. We had X-rays, good dental assistants and many dentists who were specialists in their field."