A manual toothbrush can be difficult for an individual with ALS to use quite early in the course of the disease. The narrow diameter of the brush makes it difficult to grip; the need to hold it carefully and move it back-and-forth is a further liability.
An electric toothbrush is a considerable advantage for an individual with muscle wasting in their hands and arms. As long as it can be brought to the mouth and held up for long enough, the brush itself can do most of the work while it is simply held. Pressing the on/off button may pose a significant challenge, however.
Using string floss is extraordinarily difficult with weak hands. Water flossing using an oral irrigator such as a Waterpik™ is a viable alternative.
An assistant helping with flossing should be careful to avoid pressing the individual's lips against their teeth with their fingers, as this could injure the lips or insides of the mouth.
Mouthwash should be avoided in individuals with difficulty swallowing.