hello and welcome, these are usual symptoms associated with abrasion,erosion and attrition. visit your dentist to get the diagnosis. if it is attrition,there will be physiologic wearing away of a tooth as a result of tooth-to-tooth contact,as in mastication.usually it occurs in elderly patients.in this case ,enamel has been completely worn away,resulting in extrinsic yellow or brown staining of exposed dentin.this usually treated by artificial replacement of teeth. if it is abrasion,there is pathologic wearing away of tooth substance.it usually occurs on exposed root surfaces of teeth and also on incisal or proximal surfaces.improper brushing technique,habitual opening of bobby pins with teeth,habitual pipe smokers,improper use of dental floss and toothpicks are the usual causes of abrasion.it is usually treated by tooth coloured restorations like glass ionomer cement.or by tissue grafting. if it is erosion,it is an irreversible loss of dental hard tissue by a chemical process that doesnot involve bacteria.dissolution of mineralised tooth structure occurs upon contact with acids that are introduced into oral cavity from intrinsic-vomiting,or extrinsic sources-acidic beverages,citrus fruits.in this case,avoid intake of excessive acidic foods or beverages. yours is more chance of erosion case-in case of dry mouth,use sugarless chewing gum or mints to increase residual salivary flow.the use of oral pilocarpine may also be beneficial. take care.