It is theoretically possible that alcohol trapped in the mouth as a result of ill fitting dentures may cause an elevated breath alcohol reading.
The burden would be on you to establish that this has happened although this would not present a defence. It could potentially persuade the court to exercise its discretion to find 'special reasons' and not disqualify. It must be demonstrated that:
1. The amount of alcohol consumed would, in ordinary circumstances, not have been sufficient to mean that you would have produced a reading in excess of the legal limit;
2. On each occasion you blew into the device (there would have to be two positive excessive readings for a charge to be brought) the residual alcohol was present in your mouth; and
3. Were it not for the presence of that 'mouth alcohol' you would have been over the legal limit.
It is important to consult an expert forensic toxicologist to assist with this approach