Lozenges, which are retained in the mouth and then swallowed are becoming more and more popular. Lozenges are soft and gentle on the mouth and there is a belief that prolonged contact with the oral mucosa mechanically stimulates saliva production.Pilocarpine: A study by Taweechaisupapong in 2006 showed no statistical significant improvement in oral dryness and saliva production compared to placebo when administering pilocarpine lozenges. Physostigmine Gel: A study by Knosravini in 2009 showed a reduction in the oral dryness and a 5 times increase in saliva following physostigmine treatment. Chewing gum increases saliva production but there is no strong evidence that it improves dry mouth symptoms. The Cochrane oral health group concluded there is insufficient evidence to determine whether pilocarpine or physostigmine are effective treatments for Xerostomia. More research is needed. Dentirol chewing gum (xylitol): A study by Risheim in 1993 showed that when subjects had 2 sticks of gum up to 5 x daily, the gum gave subjective dry mouth symptom relief in approximately 1/3 of participants but no change in SWS (stimulated whole saliva). Profylin lozenge (xylitol/sorbitol):A study by Risheim in 1993 showed that when subjects had 1 lozenge 4 to 8 x daily, Profylin lozenges gave subjective dry mouth symptom relief in approximately 1/3 of participants but no change in SWS (stimulated whole saliva).Saliva substitutes can improve xerostomia, but tend not to improve the other problems associated with salivary gland dysfunction.
Radiation therapy
Radiation therapy for cancers of the head and neck (including brachytherapy for thyroid cancers) where the salivary glands are close to or within the field irradiated is another major cause of xerostomia. A radiation dose of 52 Gy is sufficient to cause severe salivary dysfunction. Radiotherapy for oral cancers usually involves up to 70 Gy of radiation, often given along with chemotherapy which may also have a damaging effect on saliva production. This side effect is a result of radiation damage of the parasympathetic nerves. Formation of salivary gland ducts depends on the secretion of a neuropeptide from the parasympathetic nerves, while development of the end buds of the salivary gland depends on acetylcholine from the parasympathetic nerves. Sicca syndrome
"Sicca" simply means dryness. Sicca syndrome is not a specific condition, and there are varying definitions, but the term can describe oral and eye dryness that is not caused by autoimmune diseases (e.g., Sjögren syndrome). Other causes
Oral dryness may also be caused by mouth breathing, usually caused by partial obstruction of the upper respiratory tract. Examples include hemorrhage, vomiting, diarrhea, and fever.Alcohol may be involved in the cause of salivary gland disease, liver disease, or dehydration.Smoking is another possible cause. Other recreational drugs such as methamphetamine, cannabis, hallucinogens, or heroin, may be implicated. Hormonal disorders, such as poorly controlled diabetes, chronic graft versus host disease or low fluid intake in people undergoing hemodialysis for renal impairment may also result in xerostomia, due to dehydration.Nerve damage can be a cause of oral dryness.