Súc miệng bằng nước muối (Không bắt buộc).

Given the above summary, write a detailed text in English for it.
Saltwater kills the bad bacteria on your teeth.  There is a rumor that saltwater is acidic and can erode teeth if used too often.  It's better not to use it too often, as, like anything, too much of anything is bad. For complete antibacterial protection rinse with a chlorhexidine mouthwash before going to bed, but do not use it for longer than two weeks in a row.