Just a toothbrush is not enough

To clean your teeth perfectly, not only do you need a toothbrush (manual or sonic), but it is really necessary to use interdental brushes and dental floss. If you want, you can also use a mouth shower.
This will prevent many problems such as tooth decay, bleeding gums and subsequent periodontal disease.
It is important that you use the right size interdental brush to make the cleaning really effective. A properly sized interdental brush fills the space between your teeth perfectly with its fibres and cleans it well. If it's small, it won't clean the spaces, using it will be an unnecessary effort and if it's big, it can damage your gums.
So it is best to consult a dental hygienist or a dentist. They will recommend the right size of interdental brush for you and explain how to use it.
One last tip, brush first with an interdental brush and then with a toothbrush, the interdental spaces will be free and the toothpaste will get into the interdental spaces.