This paper goes into great depth on the prevalent health issue of dry mouth. The major salivary glands secrete the total amount 0f 95% saliva. The saliva is composed of both organic and inorganic compounds. The quality of saliva is just as important as quantity when it comes to oral health and well-being. There will be extensive coverage on the many functions and qualities of saliva as well as its role in oral health as well as the important factors that influence salivary production. In this study saliva's role in the development of caries and the formation of bacterial plaque will be examined. There is an initial definition of dry mouth and then an investigation of its prevalence. Following is a list of the most prevalent causes of dry mouth. We will go into why dry mouth is such an issue in the following part. Finally, we will go through how to diagnose and treat dry mouth.

Saliva plays a critical role in maintaining a sound oral environment. Food is lubricated and the flavour is enhanced by saliva which also acts as a protective barrier to the mucosa of the oral cavity and help teeth from being damaged. Mucinous and glycoproteins high in proline and mucins help in the deglutition which is essential for enhancing taste sensation as well. Several antimicrobial substances found in saliva including mucin statins lysozyme and lactoferrin work in concert with certain antibodies to fight off microbes the host has come into contact with. A small amount of salivary gland secretion is influenced by hormones but the majority of salivary gland secretion is controlled by the autonomic nervous system including the major (parotid submandibular and sublingual) and minor (multiple mucous glands located throughout the mouth, particularly in the lips and soft palate). When the cholinergic system is activated, salivary flow increases but the adrenergic system slows it down all due to the increased viscosity of saliva. As a consequence, when adrenergic or sympathetic have highly activated the oral cavity becomes dry. In many drugs, the parasympathetic system is inhibited which causes the mouth to dry up. Anything that affects the glands or reduces body fluids might affect saliva production.

As the most prevalent salivary condition dry mouth (xerostomia) may be caused by a variety of factors including:

• Hyposalivation (Reduced salivary flow).

 • Changed salivary composition. 

Dry mouth (xerostomia) dental caries and a variety of disorders may all be caused by an abscence of oral secretion in people with hyposalivation (candidiasis or acute bacterial sialadenitis). Causes If an individual has hyposalivation it might be due to several factors Barbe (2018). During times of anxiety breathing by mouth occurs and as we age salivary acini diminish and secretory reserve decreases leading to a dry mouth. Because of a decrease in salivary acini dryness may have occurred. Infants born without salivary glands have a rare disorder called salivary gland aplasia or agenesis. There is a large amount of salivary gland dysfunction that is inherited from ancestors. Xerostomia or dry mouth is a prevalent ailment among researchers. The most prevalent cause is dry mouth caused by medication. After a few days of using or increasing the dose of the drugs the dry mouth usually appears (Stankeviciene et al 2021). If medication is not the cause, then people with mental health disorders may report dry mouth as an unwanted side effect (or evidence of reduced salivary flow). Some of the most prevalent reasons for reduced salivation include anticholinergic sympathomimetic and diuretic medications. Radiation therapy for head and neck tumours such as oral cancer often causes xerostomia or dry mouth. Irradiation of salivary glands with radioactive iodine (131I) used to treat thyroid diseases may cause damage to these glands.

Xerostomia a disease in which the salivary glands are unable to produce excessive amounts of saliva to keep the oral cavity wet. Disorders of the salivary glands have the potential to impair salivary gland function. HIV, hepatitis C, sarcoidosis, hepatitis B and cystic fibrosis are among the most frequent conditions (mucoviscidosis) (Botelho et al 2020). A dry mouth complaint may be due to psychogenic cause in certain individual (for example those who have xerostomia but not hyposalivation) and this should be considered when evaluating these patients.

The patient suffering from hyposalivation may have difficulty in: 

• Swallowing especially dry foods.

• Controlling dentures

 • Speaking as the tongue tends to stick to the palate leading to clicking speech. 

Additional complaints may include altered taste, lack of flavour or halitosis in the mouth of the patient (Grønhø et al 2018). These adverse effects may only be present if hyposalivation is present or they may also include dry eyes and other mucosal symptoms (nasal, laryngeal or genital). Blurred vision, light sensitivity, burning and itching are all common eye related complaints.

Diagnosis of Sjogren's syndrome may be made based on systemic signs and symptoms (such as joint pain). Tooth decay or soft tissue infections may occur when the salivary glands do not produce enough saliva (Nardone et al 2018). During the process of mastication tissues inside mouth rub against one another frothy saliva may form in the vestibule or on the tongue. Saliva may not be able to flow via the parotid ducts. Additionally, the tongue may become reddish and dry.

Complications of hyposalivation can include. 

• Dental caries 

For example, it is more likely to arise in the roots of teeth and the lower incisor area which are less prone to decay. Hyposalivation is a possibility in patients with recurrent caries that cannot be treated.

When it comes to diagnosing hyposalivation history and physical examination play a major role. It is necessary to evaluate the rate of salivary flow rates for future reference (allometry). Despite its inefficiency and lack of specificity the standard allometry procedure of collecting whole saliva (oral fluid) is still used by many practitioners (Bulthuis et al 2018). Flow rates of 1.5 ml/15 min (0.1 ml/min) or more are common in a normal person. Before the start of the test the patient is usually permitted to sit quietly for 15 minutes.

 The specialist may be needed to: Study and document the degree of salivary dysfunction, arrange future dental care although much of this can be undertaken in the primary care environment. Investigations may be indicated to exclude systemic disease particularly, imaging (mainly to exclude Sjogren’s syndrome sarcoidosis or neoplasia), determine the cause, salivary gland biopsy (if there is suspicion of organic disease such as Sjogren’s syndrome), ophthalmic exam (for example Schirmer test mainly to exclude Sjogren’s syndrome), viral infections (hepatitis C, HIV), sarcoidosis, diabetes, blood tests (mainly to exclude diabetes Sjogren’s syndrome sarcoidosis hepatitis and other infections), Sjogren’s syndrome and connective tissue disorders.

It is possible that in some people who complain of a dry mouth there is no evidence of decreased salivary flow or an anomaly in saliva production (Marín et al 2021). A psychological component might also be at play.

Sjogren's syndrome is a disorder of dry mouth and dry eyes (also termed as keratoconjunctivitis sicca). Evidence of an autoimmune reaction may be found in blood autoantibodies or by performing a biopsy of the labial salivary gland (Baldini et al 2018). Sjogren's syndrome may be present in any individual at any moment however middle age or later it is the more common. Female patients make up the significant bulk of the cases. It is an autoimmune disease affecting the salivary lacrimal and pancreatic glands. Viruses and inherited factors may have a role in the development of the disease. As a result of secondary Sjogren's syndrome which is most often accompanied by rheumatoid arthritis or another connective tissue illness, dry eyes and a dry mouth are common (RA). Often referred to as sicca syndrome primary Sjogren's syndrome may develop without the presence of a connective tissue illness Bowman (2018.). Both types however are long-term and may harm glandular regions other than the salivary glands such as the pancreas. Prolonged activation of B lymphocytes may lead to B cell neoplasms like lymphoma.

Itching, dryness, fuzzy vision and light sensitivity are just some of the eye-related concerns that SS has to deal with. Inflamed conjunctivae and soft crusts may be seen on the angles if the eyes are red (keratoconjunctivitis sicca). Lacrimal gland enlargement is one of the most common feature. Symptoms of oral cavity includes: 

• Xerostomia 

• Swollen salivary glands 

These include chronic sialadenitis (as part of the autoimmune process) “ascending bacterial sialadenitis myoepithelial sialadenitis” (myoepithelial pseudolymphoma) and cancerous lymphoepithelial lesions.

A comprehensive study of the patient's medical history and symptoms as well as an examination of the salivary glands is required before a diagnosis can be made. Specialized institutions utilise a variety of international standards to validate the diagnosis (Mavragani and Moutsopoulos 2019). No treatment for SS has yet been developed however hyposalivation may be treated with medicine However maintaining excellent dental health and seeing the dentist regularly are essential.

It is important for those who suffer from xerostomia to treat any underlying issues that may be contributing to the condition such as drugs that cause dry mouth. As part of the treatment patients should be educated on how to keep the oral cavity moist and avoid dryness in the first place (Ozek et al 2018). A saliva substitute may be able to assist reduce discomfort. There is a slew of choices accessible including:

 • Water or ice chips; frequent sips of water are generally effective.

 • Synthetic salivary substitutes.

 People with objective xerostomia are at a greater risk of developing dental caries if they do not maintain a healthy diet and practise good oral hygiene. Without consistent use of topical fluoride medications, the long-term therapy would be inadequate (Monsalve and Anaya 2020). Sugarless candy or chewing gum could help to alleviate condition (containing sorbitol or xylitol not sucrose). If an individual is prescribed with cholinergic drug such as pilocarpine or cevimeline he or she should only use it under medical supervision. 

Drooling of saliva is entirely normal for infants. If an individual is prone to excessive salivation several variables might be to blame including menstruation pregnancy, eruption of teeth and irritation in oral cavity as well as foods and drugs that affect the salivary glands Güvenç (2018). True salivary hypersecretion is the most prevalent cause of excessive salivation. True hypersalivation may be caused by a lack of swallowing skills (false sialorrhea) or a pharyngeal or oesophageal blockage (such as a tumour) rather than by excessive saliva production itself as is the case with Parkinson's disease cerebral palsy or learning disabilities (Miller et al 2019). Behavioural and antisialogogues should be employed in addressing the underlying reason that is not possible (Kalma et al 2021). Sometimes it is essential to perform surgery to redirect the ducts of the salivary glands into the oropharynx.

The production of saliva is essential for the maintenance of healthy oral health. It is most obvious and critical function is to help in digestion by providing flavour and lubrication for food while also protecting the mucosa and teeth from damage. Saliva is composed mostly of water and mucins as well as proline-rich glycoproteins lubricates and aids in the swallowing of food and is required for proper taste perception. Saliva contains components of antimicrobial like mucin statins lysozyme and lactoferrin as well as particular antibodies to a variety of micro-organisms that the host has encountered during the infection. In addition to its cleaning activity saliva contains particular antibodies to a variety of micro-organisms that the host has encountered during the infection. In addition, as previously stated it is important to recognise that some patients who complain of a dry mouth do not show any signs of diminished salivary flow or a salivary illness. The problem is likely the result of psychogenic variables such as stress. The use of xerostomia-inducing medications should be phased out in favour of safer alternatives and underlying conditions such as diabetes should be treated. Patients should be educated on the need of avoiding situations that may increase dry mouth as well as the necessity of keeping the mouth moist. In the near run salivary substitutes may prove to be effective.