Dental clinic in Hamilton accused of improperly sterilizing instruments over a nearly 6-year period

A dental professional examines the inside of a patient's mouth. (Pexels)

Hamilton dental patients at a clinic on the city’s east mountain may have been exposed to various infectious diseases like hepatitis due to improperly sterilized instruments.

Hamilton Public Health Services (HPHS) says it has “identified infection prevention and control concerns” at Dentistry At Fennell & Ottawa at 1134 Fennell Avenue East near Upper Ottawa Street.

HPHS says patients who received treatment at the office operated by Dr. Merenisa Gonzales-Diaz between July 25, 2019 and Feb. 20, 2025 may have been exposed to improperly sterilized instruments.

They say while the risk of infection is low, the instruments could have transmitted infectious diseases like hepatitis B, hepatitis C and HIV to patients.

Patients who received any dental procedure such as cleanings, crowns, restorations, extractions, veneers, or dentures may be at risk of possible exposure to blood-borne infection, according to HPHS.

Anyone who received care during the specified period are advised to get testing.

HPHS says as of Feb. 24, the Dentistry At Fennell & Ottawa clinic now meets the required infection prevention and control standards and no cases of blood-borne infections have been linked to the office.

In a statement to CTV News Toronto, the Royal College of Dental Surgeons of Ontario (RCDSO) says it is looking into the matter.

“Infection prevention and control (IPAC) is a critically important part of safe patient care. Public health units will typically inform us about lapses and concerning IPAC inspections in dental practices. If the College receives information that raises concerns about IPAC compliance, that can prompt a Registrar’s Investigation.”

HPHS says the issue was referred to the regulatory college.