Some vets do in fact encourage people to brush their dogs' teeth, but that's by the by. Eating foods high in sugar does not directly have an adverse effect on teeth. Dogs don't suck boiled sweets, and if you feed them sugar-laden baked beans, they'll just wolf them down. So there's less sugary stuff going to be adhering to their teeth, especially if they wash the beans down with beer. Not stout, mind, too sweet!
No. Well, not much. If you heat the central living area to your preferred temp (say 293K), the unused rooms will be kept frost-free by the waste heat from the central area leaking through corridors and walls. This will probably be enough not to need any help from the radiators in those unused rooms.
The point is that by keeping the temp in the unused rooms down you are paying *less* to heat them than you would if you were to heat them to 293K.
I do. Of course it depends on what you mean by unused. I totally agree that with current technology [*] it is impractical to adjust radiator controls all the time, if what you're trying to do is save heating costs for a room's unused portion *of each day*, but where a room is more or less permanently unused, you don't want to be keeping it at living temperature all the time.
[*] by "current technology" I don't mean what we *could* install (motorised valves remote controlled by computer -- which would be great) but what most of us *actually have* installed (TRVs).You don't need to make sure the doors are shut, because you don't actually want to prevent heat leaking into them. You simply want them to be less warm than the rest of the house, but you don't want them to be bloody cold either, so that you're not too uncomfortable when you occasionally wander into them to get at some of the junk stored there.