If an existing part of a denture such as a clasp, a tooth, or a flange is broken and replaced or repaired, it's a 'Repair of a denture' and is free of charge to the patient irrespective of the charge paying status.
There's no time restriction with regards to how long after the original appliance was made for a repair to the denture be provided.
If the open Course of Treatment (CoT) is a Band 3, the denture repair would be expected to be claimed as part of this Band 3 CoT.
A separate claim for denture repair could be made where there is already an open Band 1 or Band 2 CoT.