I think you have periodontitis cleaning (scaling) your teeth by dentist then use snowdent toothpaste for teeth whitening
use mouthwash for maintent your oral hygiene.
Any toothpaste is ok. Just brush twice daily and floss every night. Flossing is very good because usually cavities start in-between teeth where brush doesn't reach. Get dental check up every year.
toothpaste r only cleaning agents n do not cure any dental probs. they help clean ur teeth. various brands differ only in colour n flavour. using proper brushing techniques with any toothpaste 'll b sufficient.