Go for scaling and polishing.

Black spots if caries can be managed with simple restorations. Yellowish teeth can be due to many reasons starting from simple food stains to plaque to early fluorosis. Will need picture to determine that.

Attach pics of teeth in question.

If it is a stain and not caries ultrasonic scaler to remove is used. And full mouth scaling advised that is full mouth cleaning. Or else if it is a dark fluorosis stain macroabrasion technique can be done and it can be made white with bleaching.

Can you share your clinical photograph of the area of the teeth in question for better consultation?

The black spot you’re mentioning could be due to a stain or a decay You’ll have to share a proper pic for better advise Yellowish teeth could be taken care of by brushing and use of mouthwash But again the natural color of teeth can’t be changed so don’t overdo brushing or don’t do hard brushing That could result in wearing off your layer of teeth and it exposed to a more yellow layer. You can visit a dentist for clinical evaluation and teeth whitening procedure

Good morning Kindly share the pic of the concerned tooth for better advise Meanwhile kindly brush twice daily for 2 mins using a flouride rich toothpaste.

For yellowish teeth brush your teeth regularly and for the black spot you should visit a dentist soon to see if you need a restoration Thank you.