Police are investigating after a two-year-old girl choked to death on dental cotton as she was treated by a dentist, The Japan Times reported Tuesday.

The girl was taken to the clinic in Niiza, Saitama Prefecture by her parents Sunday, after suffering a broken front tooth in a fall at home.

She was treated by a 37-year-old dentist who told police she had used the dental cotton to stem the blood flow from the girl's gum.

The girl began choking and was rushed to hospital but died early Monday.

Niiza police will conduct an autopsy as part of a bid to discover if professional negligence was to blame.

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