Keeping your teeth clean is important regardless of the time of day. There is no such thing as having a stroke if you do not brush your teeth prior to going to bed. Someone must be wanting you to brush more, is all I can think.

Bacteria does enter the body if you do not brush your teeth day or night. it is important to remove the ramining food from your teeth and tongue and mouth.

Decay and bad breath can occur if you fail to brush so make it a habit to brush your teeth at least once a day.

Recent research shows something of a link between bad oral hygiene and heart disease. The link between bad oral hygiene and stroke is currently tenuous, but research is ongoing.

The best time to brush your teeth is after eating. You can also brush after drinking a liquid with sugar in it (such as soda or milk), but in that case rinsing your mouth out with water is usually enough. Brushing your teeth just before going to bed is more of a habit most people have for the sake of convenience than a requirement; in fact, if you eat and drink nothing for several hours before bedtime, you might not need to brush your teeth at bedtime.

So, no, you shouldn't get a stroke from not brushing your teeth at bedtime provided that you maintain good oral hygiene at other times.

I've written an article in response to this question:

Benefits of Nightly Teeth Brushing

Why should we brush our teeth at night before bed? — continue reading...

This is also dependent on your diet. Different foods have different bacteria levels that may or may not be harmful if they are not cleared from your mouth, in conjunction with the theory that that bacteria gets into your system. For example, vegetarians and vegans especially have to less to worry about if they don't brush their teeth. It is like how they say a dog's mouth is much cleaner than a person's; well a dog doesn't eat what we do (not that I'm telling you to eat dog food by any means, just an example), and their mouths are cleaner even though they obviously don't brush their teeth (though sometimes their owners do). If you have a pretty typical diet, you should brush your teeth. However, fluoride free toothpaste is better because the more you use fluoride, the more your teeth decay if you don't use it thereafter.