Latest to the addition of the regular brush for people above 50 years is a inter-dental brush, which is like very small bottle brush. It can be pushed into inter dental space where the food stagnates especially the vegetable and meat fibers.
Dental Brush is useful to use if before retiring to bed.
In sum total if you brush your teeth only in the morning you are accumulating the food debris after every meal and when you rise up in the morning you find the mouth foul smell, because the food debris in the
oral cavity will under go purification because the oral flora which is teeming with millions of micro-organisms produce foul smell, which is very offensive. On the other hand if you clean the mouth before returning to bed, there are no foods particles present except saliva which is part of the physiological process.