Hello,       Cleaning or scaling is the process of removal of deposits from and around the teeth . Bleaching is the process of improving the shade of tooth chemically. Scaling will remove the yellow flaky deposits around the teeth.Scaling or cleaning will promote health of gums. The time taken depends on the amount of deposits you have got.  After the tooth is being cleaned of the deposits it's health will improve and if  you had those yellowish or yellow brown flaky deposits then after cleaning the appearance of the teeth shall improve but it will not whiten the teeth. Mild discomfort may be felt when cleaning is done between teeth and gums,( subgingival scaling).

Hello, good that you are planing to take care of your teeth and gums by getting cleaning done. How much will it take depends upon amount of stains and deposits present on teeth surface. It's an absolutely painless procedure. You might just feel little sensitivity during procedure which is normal. After teeth cleaning, natural colour of your teeth will be visible. After cleaning if u want you want to make your teeth more bright or white in colour, you can ask your dentist for bleaching. Both are totally different procedures.

Time will depend on the amount of deposits u have on your teeth. If u have any gum infection it may pain a little for that u can ask your dentist to give topical spray anesthesia. Jus with cleaning teeth will not become total white for that u should get bleaching only