Ask her to visit a good Dentist

The yellow material is called as tartar or calculus which keeps forming on the teeth on a regular basis. Scaling and polishing is done to remove the tartar and to delay its re formation.

As u said some thing is ovelapping, thn it has to be calculus, it is one of the causes for bad breath, she needs professional cleaning of her teeth, this must remove bad breath, and if the problem of bad breath persists thn u have to look into the other causes and may need an advice from a physician. Hope this solves ur problem best of luck

Hi, that yellow material which is overlapping teeth is known as calculus. It's difficult to remove calculus with brush. You need professional help from dentist for removing this plaque and calculus. Also calculus harbours bacteria which decomposes food producing bad smell leading to baad breath. Visit your Dentist and get scaling done. It will solve your problem.

Tartar or calclus, it is a kind of deposit on teeth that can't be removed by brushing, if the deposits are superfecial just cleaning (scaling with ultrasonic machine) and polishing will be sufficient, if deposits r deep involving deep structures like periodontium and bone ur friend may need laser deep cleaning, or flap surgery, nowadays laser treatments are available for patient comfort kindly ask your friend to visit nearby dentist to check at wt stage the diseases is then can plan accordingly.

Normal brushing cannot remove the tartar and calculus for which ultrasonic scaling has to be done so ur friend needs to visit a dentist for the same.and if yellowish discoloration of tooth a also there for that bleaching techniques can be done . Bad smell will also go once scaling has done and mouthwash is used.

Your friend has to do scaling of her teeth. If she wants to change the color of her teeth then she can go for bleaching.