Visit your dentist.after clinic evaluation he can decide the correct path of treatment.There are so many options for the solution of your problems.

The colour of the teeth is determined mainly from an inner layer of tooth called the dentin. Over which is the enamel through which the colour of the dentin shows thus determining your tooth colour. Stains on the tooth could be intrinsic or it could be extrinsic . Some changes in tooth colour and shape could be from birth or they could be acquired. Depending on the kind /nature of the stain your treatment can be planned. Treatment options are plenty, Bleaching or whitening of teeth is a safe option. Other options include microabrasion , macroabrasion,composite or ceramic veneer .

Dear Sir, The yellow lines present in your teeth could be due to fluorosis or medicine related. Do not worry, please visit a dentist and get a clinical examination done to know the best treatment plan for your teeth. The dark lines may be removed with the help of bleaching or with cosmetic procedures like porcelain veneers, lumineers etc.

Daily brushing cannot remove stains or calculus , it has to be removed using special instrument called as scaler, kindly visit your nearby dentist for cleaning , if it is an internal stain then it won't go by cleaning and RCT with crown might be required , in some cases just bleaching is required so kindly visit your nearby dentist so that he can see and plan treatment accordingly to create your beautiful smile