From the late 19th century dentists in New Zealand cities began to set up dental practices with the latest technology. This included adjustable dental chairs, equipment to administer nitrous oxide or 'laughing gas' for pain relief, and dental drills operated by a foot pedal. In this dentist's surgery in Taranaki just before the First World War, nitrous oxide is being delivered by one dentist, while another prepares to do some dental surgery, probably one or more extractions. Skilled dentists at that time could remove an entire set of teeth in just three minutes – which was necessary, as administering the gas for longer than this made patients ill and could kill them. Two female dental assistants are also in attendance, and dental equipment is laid out, much as it might be for medical surgery. In the foreground is one of the adjustable chairs that made it much easier for dentists to work with patients.