Dentists have been warned about the potential danger of buying and using counterfeit and unapproved dental equipment, a regulator has said. It follows the seizure of over 12,000 different pieces of poor quality dental equipment imported into the UK from China and Pakistan and sold on auction websites such as eBay, Amazon and Alibaba in the past six months. The Medicines and Healthcare products Regulatory Agency (MHRA) - the UK's regulator for medical devices and medicines - has six ongoing investigations involving the purchase of counterfeit and unapproved dental equipment such as high-speed hand-piece drills from auction websites by UK dentists. The seized items include 24 dental X-ray machines that emit high levels of radiation, 384 hand-piece drills that could malfunction and disintegrate inside patients' mouths and 3,242 poor quality root canal files that could break. While there is no evidence to suggest that buying equipment from auction websites is a widespread or deliberate practice among dentists, the MHRA said it is concerned about the growing range of dental equipment that is being advertised to dentists at cheap prices, both online and at dental trade fairs in China. Dirty dentists put patients at risk of infection NHS dentistry is 'unfit for purpose', professionals warn 'Time bomb' in dental implants The MHRA issued a safety alert to all dentistry professionals in January, following an incident in November 2013 when a counterfeit product for drilling and cleaning teeth shattered while being used on a patient. The patient was unharmed. Alastair Jeffrey, the MHRA's head of enforcement, said: "Dentists must source their dental equipment from reputable suppliers. Purchasing from auction websites and being unable to verify the integrity of the seller has the potential to increase risks to patients and cause reputational damage to the dental profession. "The MHRA has seized large amounts of cheaply-priced, counterfeit and unapproved dental equipment. This equipment looks like the genuine product, and often has false CE approval markings but it is potentially dangerous to patients and the dental staff using it." Dr Barry Cockcroft, NHS England's chief dental officer, said: "This is important work by the MHRA. It is imperative for patient safety that dentists do not purchase equipment, from any source where they cannot be confident of the origin or quality."