Response to FOI - rbh 730
The type of information requested is not kept in any easily searchable data base so would mean obtaining the hospital notes of the last 50 or so patients treated and looking at each case individually before compiling a summary. This would therefore exceed the cost limit laid out by the Act.
Audit projects have been undertaken on orthodontic retention and have been published by the British Orthodontic Society, which has a good website, in an Audit journal. I have included the link below.