An ex-dentist has been jailed for using laughing gas on women and girls to molest them.

Content warning: This post contains themes of sexual assault and child abuse some readers may find triggering.

Some girls and young women wanted Rodger Garry Leighton to give them laughing gas so they could cope with their fear of dentists.

Instead, they and other patients faced a worse nightmare as he sexually molested them while they were immobilised by the nitrous oxide gas as they reclined in his Sydney dental chair.

On Monday in Sydney’s District Court, Judge Chris Craigie jailed the frail 81-year-old retired dentist for eight years with a non-parole period of three years for his “brazen” predatory crimes.

He had pleaded guilty to molesting five girls, aged between 10 and 14, and three young women between 1974 and 1983 at his surgery at Jannali in Sydney ‘s south.

Last year, the same jail judge jailed him for at least one year one month after a jury found him guilty of indecently assaulting three other girls.

The new sentence is partially accumulative on his previous term – meaning he will be eligible for release on parole in March 2019.

The judge stressed that he was bound by penalties applicable at the time of the offending, penalties which were now much tougher for such crimes.

“For some 40 years, the offender had gone unpunished” while his vulnerable victims had to relive the humiliation and distress he caused them, he said.

Leighton continued on with his life, with the social status and standing in the community that was given to professionals such as him.

He was in his late 30s and early 40s,when he administered the gas under “the pretence it was solely for the purpose of legitimate dental treatment”. But it also facilitated his opportunistic offending aimed at his own sexual gratification.

Retired Jannali dentist Rodger Garry Leighton is in his cell tonight right alongside notorious underworld killer Neddy Smith. #7News pic.twitter.com/OWOAuXm8OQ

— 7 News Sydney (@7NewsSydney) July 24, 2017

Describing the offending as a “gross breach of trust”, the judge said the molestations occurred when his dental nurse was out of the room.

Sometimes, the nurse would call out to see if Leighton was ready to continue the treatment and he would reply no, so he could keep on assaulting the patient.

Leighton, who uses two walking sticks, had a “constellation of health problems’ and had previously been subjected to threats of physical assaults by other inmates.

When he became eligible for parole last year, he was not released because of “the unusual circumstances” that no accommodation could be found for him in the community.

His wife suffered from numerous medical conditions, including Parkinson’s Disease, while one of his sons now had nothing to do with him and another had only very limited communication.

If you or someone you know is experiencing sexual abuse, Mamamia urges you to seek help and contact 1800 RESPECT. If you are in immediate danger, please call 000.