Hi.. You might be having attrition of teeth. In the condition volume of teeth decreases. It will also start looking slightly yellow because of exposure of dentin and loss of enamel. You need prosthetic correction using caps for teeth. Visit a nearest dentist. We should rule out- Gastritis GERD Bruxism Regards

Do you have chronic gastritis, or acidity problems? One of the main causes of the problems you've mentioned is acid reflux. So the teeth can be made smooth but they will become sharp again unless you can control the acid reflux. Thinning of teeth expose the inner layers which are naturally yellowish in color. The correction of the same will be possible only after clinical assessment. Take care.