who to removed Yellowish on the teeth. in how may months or days without medical advise i.e ingredient to use easily?

Ans: Hi
External stains are usually caused by food colours in the food or beverages we consume on a daily basis. She should try to identify and cut out the offending item from her diet. And, of course, brushing after every meal helps.

Ans: HiThe color of teeth varies from person to person. Fun fact: Darker skinned people have whiter teeth. And vice versa.Please note Scaling and polishing can only eliminate external stains. Not make your teeth whiter

Ans: Hello Manoj
I'm afraid there's no effective home remedy for a cavity in your teeth. Except, maybe, to give very temporary relief from pain. You need to consult your dentist soon. He'll restore your decayed tooth with a filling after eradicating the decay. The method of treatment will depend upon the extent and severity of decay.
As always prevention of cavities by maintaining proper oral hygiene is desirable

Ans: Hello
Your dentist, after a clinical examination, will tell you why your teeth are discolored. It's possible that there are accumulated stains and/or tartar. If that's the case, a simple procedure called Scaling and polishing (cleaning) will restore your teeth to whiteness. If your teeth have always been yellowish - if they're naturally yellowish - they cannot be whitened by cleaning alone. You may need to get your teeth bleached.
Please go by your dentist's advice.

Ans: Hello
At the age of 20, you're much too young to start losing teeth. I suggest you consult a dentist soon. It may still be possible to save the tooth with "the very large cavity" if you consult a dentist soon.
As for your other "very dirty" teeth, there could be external stains or deposits (called calculus or tartar - the result of inadequate or ineffective brushing) which can be easily removed. At worst, there could be multiple cavities caused by tooth decay which can also be restored with fillings or crowns.
Please note that a proper brushing technique and regular brushing will help keep your teeth healthy regardless of which brand of toothpaste you use.