Dr M. McCullough, Australian Dental Association, comments:
An acute feeling of dizziness following prolonged dental treatment is not uncommon in dental practice. Sudden changes in blood pressure following postural changes after prolonged periods in a supine dental chair may be responsible. Usually, if patient and dentist are aware of this possibility, then treatment procedures can be kept to shorter duration, with rest breaks during the procedure.
Postural hypotension is unlikely to explain the episode occurring two days after the dental procedure. Possible explanations to consider include tooth extraction and subsequent haemorrhage with breakdown of haemostasis, infection and acute dental pain causing decreased nutrition or hydration.