A mouthwash of 0.5 teaspoon sodium bicarbonate to 250mls water is a good way to both keep the mouth clean and neutralise any acidity, especially after taking something like Ensure or other acidic drinks. Milk on its own is a safe drink for teeth as it is not acidic, also taking some natural yoghurt after eating acidic things would help neutralise the acidity. My consultant recommended Soda bicarb solution during my treatment, and I still make sure I always have a bottle handy with it made up. It also refreshes the mouth when feeling dry. Saves a lot of money on other mouthwashes, and can be used if you have a bit of heartburn by sipping some rather then spitting out. Some people recommend adding 0.5 teaspoon salt while the mouth is sore during treatment.

I have read that flossing at the end of the day is the most important time as the bacteria are most active over night.

I am also fairly obsessed about saving my teeth so I do brush with high fluoride toothpaste 3 or 4 times a day and floss at night. But I think it is important to be gentle with them. I remember being very confused as advice for what to eat to cope with a sore mouth/throat and problems of a dry mouth seemed often to contradict what was good for teeth! The important think is that you seem to already be aware of the need to look after your teeth, so many people do not understand this (my oncology dentist loves seeing me as I do as I am told, many of her patients come in to see her with a bottle of coke in their hand!) so I think now concentrate on getting through the treatment with eating and drinking plenty and leaving the worry about your teeth for now.