But the Crown alleges Hirini's abuse was ongoing, finally coming to light on July 3, 2012 after she assaulted him at her mother's house at Patutahi.
During that incident she verbally abused him, scraped the inside of his mouth with a roasting fork, cut his finger with a butcher's knife, and struck him about the head with a sharpening steel, knocking out and fracturing more of his front teeth, which she had previously damaged in a similar way.
The boy fled to a friend's workplace about 500 metres away where, according to a witness, he arrived shaking, terrified and bleeding. The witness, a friend of the complainant's, said in evidence she had previously seen him with other injuries.
She once asked him about a swollen hand and disfigured jaw line, but he just "shrugged it off".
A doctor and dentist who examined the boy after the alleged incident on that day in 2012 gave evidence to the trial.
The dentist said damage to the teenager's teeth was the worst he had ever seen at one time.
The teenager's three top front teeth were knocked out by the roots. One of his upper canine, or eye teeth, which were the strongest teeth in the head and the hardest to damage, had been fractured through. It would have been extremely painful.
The boy's lower four front teeth had been smashed off and a lower canine had also been fractured through -- but those injuries were older. They would have been too sore to clean, the dentist said.
The pulps of those lower teeth had begun to die off, which would have taken weeks or months. Gangrene had begun to set in. All the breakages could only have been caused by extreme force with an object, the dentist said.
"You could see [similar damage] with a sporting injury caused by a hockey stick or a cricket bat -- you would need an object, you are not going to do that with a fist," the dentist said.
He had since spent "hours and hours" on remedial work in the boy's mouth, including denture and root canal work.
The doctor told the court she made a record of acute new and older injuries apparent on the complainant but it was not her to role to try to determine how they occurred.
She noted injuries at different stages of healing all over his body, including 14 linear healed wounds to the front of his body and 13 scars on his back.
The acute injuries included linear abrasions to the roof his mouth and inner cheek, swollen lips, a finger laceration which required stitching, an inflamed eye and a mildly inflamed eardrum.
There were two areas of swelling and bruising with abrasions to the overlying skin on his head.
Five bald patches on his head were due to areas where hair follicles had been damaged and not regrown.
There was a damaged fingernail on a middle finger -- allegedly caused by a blow from a hammer.
In a police interview with the complainant shown to the jury on day one of the trial, the teenager claimed Hirini mistreated him "like a dog" and used him as her "bitch" for household chores.
He estimated Hirini hit him about 200 times with a knife sharpening steel during his time in her care.
She made him sleep naked in a bathroom or locked him in a bedroom and gave him a milk bottle in which to urinate and defecate. She made him wear a nappy at nights.
In cross-examination, Mr Maynard put it to the boy that Hirini looked after him well. He had his own bedroom with a king-sized bed, stereo, TV set and PlayStation.
She supported him when he got into trouble at school, which occurred frequently. He had been expelled from one high school and was only allowed to attend at his next when Hirini, who worked there, was on site, Mr Maynard submitted.
There was no incident at Hirini's mother's house. Having found out the teenager was roaming the streets after the elderly woman was asleep, Hirini had simply gone there to take him home, defence counsel said.
The trial in front of Judge Tony Adeane is expected to end later this week.
