( 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 . CNN 's Joe Sutton contributed to this report .
NEW : Two vials of Demerol appeared to have been tampered with , regulatory group says . NEW : Dentist had been through drug rehab , group 's attorney says . Comment: The first lawsuit against an Oklahoma dentist whose patients may have been exposed to HIV is filed .