A state auditor’s report has found that two dental offices owned by Dr. Samer Tahoun, including one in Northampton, improperly billed MassHealth a total of $290,417.

In a report released Tuesday, state Auditor Suzanne M. Bump found that Hampshire Family Dental, on Center Street in Northampton, and Orchard Family Dental in Indian Orchard improperly billed MassHealth for periapical radiographs totaling some $290,417 between July 1, 2010 and June 30, 2015.

A periapical radiograph is an X-ray that shows the whole tooth from the top to the jaw. MassHealth allows the X-rays to be taken as part of a full-mouth series of radiographs only once every three years, or to evaluate specific problems, such as in the instance of an infection, according to the report.

The offices were audited because of the unusually high number of bills sent to MassHealth by them for periapical radiographs.

The audit found that the offices had billed MassHealth for “unallowable” periapical radiographs as part of routine dental exams.

The report states that Tahoun said a claims representative from a MassHealth subcontractor had directed him to bill for periapical radiographs as part of routine biannual dental exams instead of including them in a full-mouth X-ray series once every three years, as is allowed by MassHealth regulations.

But Tahoun could not provide auditors with any documentation as proof, the report reads.

The auditor’s report recommends that the two offices “collaborate with MassHealth” to repay the improper payments and ensure that they do not continue to bill the agency for the X-rays as part of routine biannual exams.

In his response included in the report, Tahoun wrote that he “respectfully disagrees” with the conclusion of the audit.

He argued that the auditors did not have a statistically valid sample in arriving at their conclusion. They should have audited individual examples to arrive at a conclusion, he said.

He also disagreed with the manner in which the auditors gathered information to include in the sample.

Tahoun also said that it’s important to look at the geographical location of his offices and his patients’ dental conditions when comparing his offices’ billing practices to others.

Reached by phone, a Hampshire Family Dental employee told a reporter Tuesday evening that Tahoun had left for the day and would not be able to speak about the audit on Tuesday.

Chris Lindahl can be reached at clindahl@gazettenet.com