From mundane to momentous

Hildebolt went from filling teeth to defining a human species

Charles F. Hildebolt, Ph.D., is not fond of routine.

Fifteen years into his career as a dentist in Beavercreek, Ohio, he quit to go back to school and try something else.

“Dentistry is OK — it’s a great profession for people who have that temperament — but once I’d done procedures several thousand times, I just … I used to grit my teeth,” says Hildebolt, professor of radiology. “Thank goodness my wife went along with my selling my dental practice and putting all that behind us.”

At the time, Hildebolt had been active for many years in exploring Mammoth Cave in Kentucky, the world’s longest known cave system.

“Just about every trip we were on, we explored and mapped virgin caves — caves humans hadn’t been in before that weren’t on any of the maps,” he says.

On the trips, Hildebolt met and became lifelong friends with Patty Jo Watson, Ph.D., and Red Watson, Ph.D., two WUSTL faculty members who are now retired. Patty Jo, the Edward Mallinckrodt Distinguished University Professor Emeritus, was an anthropologist at the Mallinckrodt Institute of Radiology, and Hildebolt was occasionally able to help her on digs in Mammoth Cave.

“They knew that I wasn’t too happy with what I was doing, and Red and I used to exchange long letters,” Hildebolt says. “He knew I was interested in taking courses in archaeology and anthropology, and he said, ‘Well, maybe you should think about graduate school.'”

(From left) Dean Falk, Ph.D., the Hale G. Smith Professor and chair of anthropology at Florida State University; Rokhus Due Awe, Emanuel Wahyu Saptomo, Thomas Sutikana (part of the team that discovered the Hobbit and co-authors on Hobbit articles); and Charles F. Hildebolt, Ph.D., in the Liang Bua cave on Flores Island, Indonesia, where Hobbit was discovered.

After exploring a number of options for graduate study, Hildebolt was most intrigued by WUSTL’s physical anthropology program and the possibility of studying under Stephen Molnar, Ph.D., an expert in dental anthropology who now is professor emeritus of anthropology in Arts & Sciences.

Teeth might seem like an odd focus for an anthropologist, but their durability and the information they can reveal about eating habits and nutrition have made teeth a rich source of insights into humanity and its ancestors.

When he earned his doctorate from WUSTL in 1987, Hildebolt was hired as faculty.

“The University is such a great place to work,” he says. “You get to work with the brightest and the best, the resources are the best in the world, and I’m never, ever bored.”

Defending a discovery

In recent years, much of the excitement in Hildebolt’s professional life has centered on a skeleton found in a cave on the Indonesian island of Flores in 2003. The skeleton came to be known as the “Hobbit” because her short stature and enormous feet (nearly as long as her lower leg bones) evoke the diminutive protagonists in J.R.R. Tolkien’s “Lord of the Rings” trilogy and its prequel, “The Hobbit.”Hildebolt wasn’t a member of the team that originally unearthed the Hobbit. He became involved through Dean Falk, Ph.D., the Hale G. Smith Professor and chair of anthropology at Florida State University. Falk had examined a cast of the Hobbit’s skull and agreed with the theories of the researchers who found the Hobbit: She said the skeleton likely was proof of a previously undiscovered species of human ancestors.

But claims of new human ancestors have historically been greeted with aggressive skepticism. Both to better test the group’s hypotheses and to help prepare for heavy criticism, Falk asked Hildebolt and his colleagues to build a digital model of the Hobbit’s skull with CT scans and other advanced imaging techniques. Because the living brain’s structure shapes the interior of the skull, researchers could use their digital analysis of the inside of the Hobbit’s skull to produce a three-dimensional approximation of her brain structure known as an endocast.

(From left) Son, Sean; daughter, Nea; wife, Louise; and Charles Hildebolt in Holden Beach, N.C.

Skeptics had suggested the Hobbit was just a regular human suffering from microcephaly, a condition where the brain is abnormally small. Others, including the fossils’ original discoverers, had wondered if the Hobbit was simply a pygmy form of a known human species rather than a distinct species. But when the Hobbit’s virtual endocast was compared to endocasts of a pygmy brain and a microcephalic brain, scientists found very few similarities.

Since then, the skeptics have kept coming, and Hildebolt, Falk and others still are writing rebuttals.

“In this field, debates like this can go on for years, if not decades,” Falk says with a wry chuckle. “Charles, who is one of the smartest people I know, has this wonderful sense of humor and is really sensitive to the nuances. This lets him present our side of the debate in a way that’s reasoned and does not give offense.”

Investigating dental health

When he’s not active in efforts to defend the Hobbit from skeptics, Hildebolt’s research focuses on the effects of vitamin D on periodontal disease. He recently started analyzing data from a small pilot study where the experimental group was given regular oral supplements of vitamin D and calcium to see if these treatments promoted dental health.”Vitamin D is known for its ability to reduce weakening of bones,” he says. “But it also has anti-inflammatory effects, and these may be more important in terms of preventing periodontal disease.”

Cavities are caused by oral bacteria, Hildebolt says, but the actual damage to the teeth is inflicted by immune inflammatory cells that attack those bacteria. In addition, scientists have recently learned that vitamin D can trigger the release of natural antibiotics that may help eradicate the bacteria causing the problem.

Charles F.Hildebolt

Family: wife, Louise, 60; daughter, Nea,29, a jewelry manufacturer and clothing designer living in Bali,Indonesia; son, Sean, 27, a new-home salesman in St. Louis

Book that helped inspire his career change: “Human Variation: Races, Types, and Ethnic Groups” by Stephen Molnar

Favoriteplace to eat: Annie Gunn’s, Chesterfield, Mo.

Hobbies: soccer andscuba diving

Education: B.S.,microbiology, 1966, Ohio State University; D.D.S., 1970, Ohio StateUniversity College of Dentistry; M.A., physical anthropology, 1985,Ph.D., physical anthropology, 1987, WUSTL

Early results suggest that the experimental group had improved dental health as a result of the vitamin D supplements. Hildebolt suspects that the recommendations for dietary intake of vitamin D will soon be going up.

“To get the maximum benefit from vitamin D, you need high blood serum levels of it, and the current recommended intake levels just aren’t enough to reach those thresholds,” he says.

Traveling adventures

Hildebolt holds an adjunct appointment in anthropology, where Glenn Conroy, Ph.D., professor of physical anthropology and of anatomy and neurobiology, credits him with “service above and beyond the call of duty to students and colleagues.”

As an example, Conroy says that Hildebolt volunteered to go to Ethiopia in 1990 with Conroy’s wife, Jane Phillips-Conroy, Ph.D., professor of physical anthropology and of anatomy and neurobiology. Their mission was to trap wild baboons and give them dental X-rays.

Hildebolt’s adventuresome ways have slowed somewhat as he has aged. Now 64, he no longer goes on spelunking expeditions. And he hasn’t been mountain climbing since his first child — his daughter, Nea — was born in 1978. Hildebolt’s wife, Louise, a physician’s assistant, was pregnant when he went to the summit of Mount McKinley with the Ohio State Mountaineers that same year.

“We were on the mountain for 37 days and spent something like 10 days in a snow cave,” he says. “Another group on the other side of the mountain couldn’t find a snow cave, and several people died. That was the last mountaineering trip I ever went on.”

Hildebolt’s primary hobby now is soccer. He plays in five “noncompetitive” soccer games most weeks, including one with his son, Sean, on Tuesdays.

“I used to go the gym, but I didn’t like that. It’s boring and much too routine to just run around a track,” he says. “I figured, why not do the stuff I loved to do when I was a kid? You know, run around, chase the ball and kick it? That’s hard to beat.”