Why a toothbrush is not enough
After eating, a soft film of bacteria stays on the tooth. For the first 24-48 hours a brush removes it easily. But if it stays, minerals in your saliva harden it into tartar. From that point no brush and no toothpaste will shift it — only an instrument will.
The problem is that tartar does not stop at the tooth. It grows under the gum, pushes the gum away from the tooth and forms a pocket. Inside that pocket the bacteria are unreachable, inflammation becomes permanent, and bone loss begins — periodontitis. That, not decay, is the main reason people lose teeth after 40.
Most importantly, this whole process is painless until the late stages. By the time a tooth starts to loosen, a significant amount of bone is already gone, and it does not come back.