hello good afternoon since you are complaining about bad breath since 3-4 yrs and also dark gums..lets divide the your query into two parts que 1 : bad breath que 2 : dark gums. lets see the solution for your que 1 for the first issue you need to undergo 1. teeth cleaning also known as scaling 2. maintainence of proper oral hygeine by two means    A. learning proper brushing techniques and instructions from the dentist and     B . use of additional interdental brushes also known as proxa brushes.     C. use of chlorhexidine mouthwashes two times a day which will help you a lot in  controlling the prevention of deposits. Que 2 : Dark gums for this u can undergo for 1. gum depigmentation by using either laser or surgical depigmentation... www.smilecuredentalclinics.com 9916206200/08042050580 E-mail : smilecuredentalclinic@gmail.com

For bleeding gums and bad breathe  you need to undergo  professional  scaling that is cleaning. For dark gums it can be rectified  by laser depigmentation treatment. Visit your dentist for more detailed  analysis and treatment.