An abusive culture developed at the £4,000-a-week Veilstone care home in Bideford, and Gatooma, in Holsworthy, in 2010 and 2011.
Vulnerable residents were left alone in rooms for hours on end with little food or water by managers and staff at the homes in Devon.
The rooms, which had no heating, furniture, toilet or television, were known as either the "garden room" or the "quiet room".
The conditions were brought to the attention of watchdog, the Care Quality Commission (CQC) in July, 2011. The police then became involved, following which the CQC carried out unannounced inspections.
Last year 24 defendants were prosecuted during four trials at Bristol Crown Court and proceedings concluded on Wednesday when the Crown offered no evidence against the final two accused. Those convicted included company directors, managers and care staff.
They included co-director Jolyon Marshall, 42, his wife Rachel, 32, and several managers. Paul Hewitt, 71, the founder of Atlas Project Team, was convicted of a health and safety offence.
Prosecutor, Andrew Langdon QC, said: "Whatever the original purpose, these two rooms were used by staff to control - perhaps to even punish - residents at a time that was not only unacceptable by professional standards of care but was also quite unnecessarily cruel."
Health campaigners have since called for changes in how society treats adults with learning disabilities following the scandal at the two care homes in Devon.
Specialist disability rights lawyer, Richard Copson of Slater and Gordon, said: “Some six years on from the scandal of abuse at Winterbourne View, this case provides a shocking reminder of the need to monitor and deal with not only truly appalling treatment of vulnerable people, as in this case, but also any poor care and inadequate care providers.
“It’s always essential those powers are used effectively and swiftly to protect vulnerable people with high care needs who deserve to live and be cared for with respect and dignity. At all times.
“The CQC has robust powers to deal with poor care environments, the local authorities have equally robust care and safeguarding powers and the deprivation of liberty authorisation regime can deal with all elements of care for people living in residential care living in care who lack capacity.”