Brushing teeth specially after eating meal in Suhoor is of have much importance. Brushing teeth will make them clean and bright by removing plaque and colored stains. Brushing using soft brush will not harm to your enamel, and will not make your teeth vulnerable to cavities.
If you will not brush your teeth than the chances of meal with remain stuck in between teeth and gums will be much higher. And after a day or two the piece of meal will rotten. This will make your mouth a lot smell and will screw your digestive system, and a lot other problems.
So, in short, never miss brushing your teeth after taking meal especially in the month of Ramadan.
Have a healthy and safe Ramadan :)