Generally, dentists have always stated that we should have our teeth professionally cleaned twice a year. Between cleanings, it is always essential to have good oral hygiene to prevent build up (tartar) which can lead to gum disease or periodontal disease. This is done by frequent brushing and the use of dental floss to prevent accumulation of plaque and bacteria between the teeth.

Flossing
Dental floss is just as important as tooth brushings if not more. Periodontal disease usually starts between the teeth, so It is best to make sure flossing is done before bedtime. Bacteria work hard while we sleep in our mouths because it provides a the perfect environment for growth because is moist, warm, and dark. Proper technique is essential! Make sure that the floss does stimulate the gum tissues as well as the toothbrush.

Tongue cleaning

The tongue does carry bacteria so don't forget to brush the tongue with either a toothbrush or a tongue scraper. 

Gum care
Massaging gums with a soft toothbrush is recommended for good oral health. Flossing is recommended at least once per day, preferably before bed, to help prevent receding gums, gum disease, and cavities between the teeth.

Oral irrigation
Oral irrigators are good stimulators but not good for replacement of toothbrush or dental floss. Plaque is a very sticky substance and needs to be manually removed with a toothbrush and floss, not just an oral irrigator alone.

Electric toothbrushes vs. manual toothbrush
I always say it is not what you use, but how you use it. Even though one uses an electric toothbrush, you have to make it work for you. See directions for proper use of all electric types of brushes.