Hey
If you don't have a radiography qualification then you shouldn't be taking rads, i know it is acceptable to press the button for the clinician if supervised and told when to, but you should not be placing the film in the mouth and taking the x-ray with no qualification.
The notes are ultimately the responsibility of the clinician, but i always write all the notes i can in as much detail as i can and they should be checked by the dentist or hygiene/therapist before being saved and charged through. if the notes are written wrong it will not come back on the nurse.
Most places do not use paper notes at all anymore. Most if not all paperwork that the patient has is scanned onto the notes on the computer and the paper work shredded.
with regards to the impression taking, is the practitioner who is signing you off qualified to take impressions? are you sure you've not been enrolled on a course? as you do usually have to take 10 sets of impressions for the course?
hope this helps? have you spoken to the practice about your concerns? x