(CNN) -- The Arkansas Department of Health says it has begun contacting about 100 patients -- ranging in age from 14 to 22 -- who were treated by Dr. William Jarrod Stewart at six dental clinics around the state between November 20, 2011, and February 20, 2012.
The department is recommending that patients who fall into that time frame be screened for infection.
Based on information received from the U.S. Drug Enforcement Administration, the health department has concluded that some of the drugs used by Stewart may have been contaminated with infectious material, the department said.
Stewart had a substance abuse problem and completed a lengthy rehabilitation program in 2010, said Bill Trice, an attorney for the Arkansas Board of Dental Examiners.
Stewart died on February 29, 2012, according to health department spokesman Ed Barham. After his death, the DEA conducted an audit and found two vials of the sedative Demerol that appeared to have been tampered with, Trice said. He said he could not confirm what infectious diseases may be involved, and it is not clear whether Stewart had any diseases.
"Some level of testing was performed on the vials, and so far no diseases have been found," Trice said.
The warning, therefore, is mostly precautionary, he said.
If Stewart were alive, the board of examiners would bring him in for testing, Trice said.
In March, Oklahoma dentist Dr. W. Scott Harrington surrendered his license after that state's health investigators said patients may have been exposed to HIV and hepatitis at his suburban Tulsa clinic.
The first lawsuit in that case -- which affects 7,000 patients -- was filed Monday.
Christina Quin, whose wisdom teeth were removed by Harrington in 2009, filed a lawsuit seeking damages of more than $75,000 in Tulsa County. The lawsuit alleges that she became ill with an infection after the procedure.
It took six weeks for Quin to recover from the unspecified infection, her attorney Patrick Carr said. She linked the infection to Harrington's office after hearing reports about it in March, the lawsuit said.
"We see this as a public safety matter ... there needs to be some investigation to see what happened," Carr said. "This is the primary reason for filing this lawsuit."
Carr said his client does not have HIV or hepatitis.
CNN's calls to Harrington's attorney James Secrest were not returned.