A Course of Treatment (CoT) is:

(a) an examination of a patient, an assessment of their oral health, and the planning of any treatment to be provided to that patient as a result of that examination and assessment

(b) the provision of any planned treatment including any treatment planned at a time other than the time of the initial examination to that patient.

The CoT will also include any treatment that's discovered during the course, even at a later date to the initial assessment.

This information is also available in The National Health Service (Dental Charges) Regulations 2005.