W. Scott Harrington voluntarily surrendered his dental license on March 20.

Story highlights

One case of patient-to-patient transmission of Hepatitis C linked to dental practice

Four cases of HIV have been identified and are undergoing genetic testing at the CDC

Investigators shut down W. Scott Harrington's practice in March

CNN  — 

An investigation into an Oklahoma dentist accused of potentially exposing patients to disease confirmed one case of patient-to-patient hepatitis C transmission, health officials said Wednesday.

A total of 89 of W. Scott Harrington’s patients tested positive for hepatitis C, but at this point only the one case has been directly tied to his dental practice in suburban Tulsa, officials said.

Four cases of HIV were also found in his patients; the CDC is conducting genetic testing to determine whether those cases are tied to the dental office.

“This is the first documented report of patient-to-patient transmission of hepatitis C virus associated with a dental setting in the United States,” state epidemiologist Dr. Kristy Bradley said. “While dental procedures are generally safe, this reinforces the importance of adhering to strict infection control procedures in dental settings.”

State health investigators shut down Harrington’s dental practice in March – and asked 7,000 of his patients to be tested for hepatitis and HIV – after health officials found sterilization and other infractions at the oral surgeon’s offices.

Investigators observed “unauthorized, unlicensed” employees using IVs to sedate patients and improper handling of needles. The drug cabinet was also rife with issues, they said.

“I will tell you that when … we left, we were just physically kind of sick,” Susan Rogers, executive director of the Oklahoma Board of Dentistry, told CNN earlier this year. “That’s how bad it was, and I’ve seen a lot of bad stuff over the years.”

The dentistry board launched its probe after one of Harrington’s patients came down with hepatitis C. The Oklahoma Public Health Laboratory has since completed testing for 4,202 of his patients. An unknown number of patients also sought testing though their private health providers, health officials said.

Scores of Tulsa dental patients tested for hepatitis, HIV exposure

Anyone who was treated at Harrington’s dental practice should contact Oklahoma’s patient information hotline between 8 a.m. and 5 p.m. at (918) 595-4500 with questions.

Hepatitis C is a contagious liver disease that can lead to liver failure and death, according to the Centers for Disease Control and Prevention. Approximately 70% to 80% of people living with the virus do not have any symptoms. Hepatitis B is a similar liver disease that can range from a mild illness to a serious, chronic condition.

Hepatitis is of particular concern for the Baby Boomer generation – people born between 1945 and 1965. This population is five times more likely to have hepatitis C than other generations, the CDC says.

More than 55% of Harrington’s dental patients who have been identified as having hepatitis C were over the age of 50, the Tulsa Health Department reports.

CNN’s Joe Sutton, Jacque Wilson and Jennifer Bixler contributed to this report.