The Harvard School of Dental Medicine announced on Wednesday that it will launch an investigation into the work of one its faculty members , after an environmental watchdog group accused the professor of ignoring research conducted by one of his own students that linked fluoride to bone cancer in boys.

Chester Douglass, chair of the dental school’s Oral Health Policy and Epidemiology Department, reported in a recent study that was based on research funded with government money that there is no correlation between flouride and bone cancer in boys, ignoring findings by one of his doctoral students that such a correlation did in fact exist.

In a letter sent Monday to the National Institute of Environmental Health Sciences (NIEHS), the Washington-based Environmental Working Group (EWG) claimed that Douglass had committed “serious misrepresentations of research results” in his report.

Douglas did not respond to requests for comment this week.

Douglass is also the editor-in-chief of the Colgate Oral Care Report, a professional newsletter for dentists subsidized by Colgate Palmolive, the company that makes Colgate toothpaste—which contains fluoride.

The newsletter’s official e-mail, colgateoralcarereport@hms.harvard.edu—is within the Harvard internet domain hms.harvard.edu.

“It’s really duplicitous when you find out the chair of [one of the departments of] the Harvard School of Dental Medicine has a double life,” said Richard Wiles, EWG’s vice president, referring to Douglass’ employment by Colgate. “It borders on deception.”

The two-page report Douglass delivered to the NIEHS­—a branch of the National Institutes of Health (NIH)—was only an outline of the research he and other scientists performed; a final report is slated for release sometime this year.

But parts of the preliminary report show Douglass reported finding no significant connection between fluoride and osteosarcoma, a rare but deadly form of bone cancer that strikes early in life.

“The analysis carried out...reported an Odds Ratio of 1.2 to 1.4 between fluoride and Osteosarcoma that was not significantly different from 1,” Douglass’ report stated.

That claim, Wiles said, directly contradicts the 2001 research of Elise B. Bassin, a doctoral student at the Dental School whom Douglass himself advised.

Bassin’s manuscript has never been published, although Wiles called it a “fabulous piece of epidemiology.”

Bassin has requested that no copies of the text be made without her permission, said Jack Eckert, a librarian at Countway Medical Library where the dissertation is kept. Eckert said that some doctoral students are hesitant to allow their unpublished theses to be copied, “especially if it turns up in some other person’s publication.”

But portions of Bassin’s thesis have been posted to the internet. In it, Bassin wrote that “among males, exposure to fluoride...was associated with an increased risk of developing osteosarcoma. The association was most apparent between ages 5-10 with a peak at six to eight years of age.”

Douglass’ report to the NIEHS, which is undated, did not discuss any evidence in favor of a link between fluoride and osteosarcoma. But it included a citation to Bassin’s 2001 dissertation in a section titled “Publications,” which was appended to the report in a way that made the citations appear to corroborate, not question, Douglass’ research.