First of all I will highly appreciate you for your concern about ur oral health. The problem your are facing is non griveous but it may damage your teeth.Al though it's not clearly possible with out clinically examination your teeth but if your are having recurrent plaque formations inspite of being maintained proper hygiene you must go for and periodontist.
Next Steps
Recurrent plaque and staining may indicate the presence of stain forming bacteria.They are very difficult to be removed from your oral cavity.
Swab test may be done to identify the bacteria.
Health Tips
But I would recommend you that firstly you must go for a comprehensive oral prophylaxis with abrasive polishing.
gingival curretage may be beneficial for you.
I am prescribing you certain medications.Start using them from today. After that you go for a good dentist and undergo the above mentioned procedures.
Rx,
1.Clohex Ads
1:2 thrice a day for 15 days
2.Doxycilline dispersable tablet
dissolve two tablet in a glass of water and rinse your entire oral cavity for 2 min with 4 frequency for 1 week.
you can also buy some disclosing agents.You can apply them to your teeth .If it changes it colour it indicates the persistence of plaque and bacteria.
Hope you understand and your problem is solved.
don't worry dear
thank you.