Reversible xerostomia
This condition is characterised by detectable residual glandular activity, allowing for stimulation or regulation of salivary secretion.
Reversible xerostomia can be caused by factors such as medications, stress, an unbalanced diet, or public speaking.
### Irreversible xerostomia
There is irreparable damage to the glands that prevents them from functioning. This clinical picture can be found in patients diagnosed with Sjögren's syndrome or patients with head and neck cancer who receive high doses of radiation therapy.

Dry and irritated mouth.
Nighttime dryness and difficulty sleeping.
Tooth sensitivity.
Halitosis (bad breath).
Difficulty chewing, swallowing and speaking.
Burning mouth and tongue.
Taste alterations that lead to the perception of a metallic taste.

Public speaking: increases the need for saliva to facilitate clearer vocalisation.
Stress, anxiety and depression: impact the central nervous system, affecting various organs and glands throughout the body, including the salivary glands.
Diabetes and other systemic diseases also affect the entire body, altering glandular activity.
**Certain medications: **antihistamines, antihypertensives, diuretics and cancer treatments, etc.
Absence of teeth: diminishes stimuli in the mouth, resulting in lower saliva production.
Unbalanced diet characterised by excessive carbohydrates and a lack of fruits and vegetables.
Tobacco and alcohol consumption: can decrease salivary secretion by inhibiting nerve impulse transmission.

A lack of moisture in the oral cavity can lead to various clinical manifestations that diminish the quality of life of patients suffering from xerostomia:
- Dryness, redness, irritation and cracks in soft tissues, which can make them more susceptible to opportunistic microorganisms.
- Inflammation of the mucosa (stomatitis) and of the gums (gingivitis).
- Painful ulcerations and local infections caused by fungi, such as candidiasis, as well as fissures in the lips or halitosis.
- Pharyngitis, laryngitis, dyspepsia or constipation.
- Carious lesions and tooth sensitivity.

Additionally, since this condition may be linked to other systemic diseases, its management often requires the collaboration of multiple healthcare professionals, including dentists and medical specialists for each specific condition.