A Dutch dentist who was extradited to France to face charges of mutilating patients has admitted responsibility for his actions, according to French newspaper L’Express, quoted by news agency ANP.

Mark van Nierop appeared in court in the French town of Nevers on Tuesday, charged with mutilating 120 patients without medical need between 2008 and 2012 at his practice in Chateau-Chinon. Van Nierop is said to have pulled healthy teeth, broken people’s jaws and left broken bits of equipment in patients’ gums.

Van Nierop, 51, was tracked down in Canada in September 2014 and extradited to the Netherlands on an international arrest warrant. A Dutch court ruled then he could be sent to France for trial.

Van Nierop challenged the extradition, saying he suffered from ‘psychological problems’ and had suicidal tendencies which could only be treated in the Netherlands.

The trial is expected to last 10 days.

The Dutch public prosecution department is currently investigating events at the practice he had in The Hague before moving to France, ANP said.