Hello Sugumaran ,very well said .the condition is known as XEROSTOMIA ie - dry mouth.patients with this condition when meet a dental surgeon ,first we rule out the cause of it ,as it can be due to age- physiological ,normal 2-due to drug induced ,3-radiation .etc .as a home regime I advise patients sip water,unsweetened drinks frequently.and here comes your LEMON as it acts on our salivary glands to produce saliva.