A federal judge has denied the Arizona Department of Corrections' motion for summary judgment in a class-action lawsuit over the quality of health care in the state's prisons.

The suit seeks adequate medical, mental health and dental care for prisoners and challenges the use of use of solitary confinement in Arizona's prison system.

Corrections officials had argued that the plaintiffs, in their words "received constitutionally adequate" medical and dental care and "any deficiencies in the provision of medical care are not system-wide."

The ruling by U.S. District Court Judge Neil Wake in Phoenix sets the stage for an Oct. 20 trial on behalf of 33,000 prisoners in the state's 10 prisons.

The American Civil Liberties Union, ACLU of Arizona and the Prison Law Office filed the federal lawsuit in 2012.

Wake certified the case as a class action in March 2013. The Ninth U.S. Circuit Court of Appeals unanimously affirmed a lower court ruling in June.