A surprise inspection of Harrington's practice on March 18, prompted by a patient's positive test for HIV and hepatitis C, revealed the use of old needles and rusty instruments, as well as the practice of pouring bleach on patients' wounds until they "turned white," according to the complaint filed by the Oklahoma Board of Dentistry.
"The basic things that everyone knows -- follow CDC guidelines, use clean syringes, don't reuse multi-dose vials in multiple patients, don't use rusted equipment -- those are things even non-physicians know," board president Susan Rogers told ABC News at the time. "Those are basic things. That part makes it egregious."
Instruments used for patients who were known to carry an infectious disease were given an extra dip in bleach on top of normal cleaning methods, according to the complaint. But the tools had red-brown rust spots, indicating that they were "porous and cannot be properly sterilized."
Harrington, who has been practicing for more than 30 years, voluntarily surrendered his state dental license and could face criminal charges. A license revocation hearing before the state dentistry board is set for Aug. 16.
The Tulsa Health Department has set up a hotline at (918) 595-4500 for people with questions.
ABC News' Dr. Richard Besser contributed to this story.