**2. Definition and evaluation**

Xerostomia (dry mouth, oral dryness, and mouth dryness) is the dryness of oral cavity and can be caused by lower salivary flow or the complete lack of saliva [6]. Based on the etiology, the xerostomia can be classified as true xerostomia (xerostomia vera, primaria), caused by the malfunction of the salivary glands and pseudo xerostomia or symptomatic xerostomia (xerostomia spuria, symptomatica), which is described as the subjective sensation of oral dryness, despite normal secretory function of the salivary glands [7]. The xerostomia, as a symptom, is more common in older populations, but its causes are not related to aging. It has been shown it is related to some specific diseases, drugs, or therapies associated [8]. The prevalence of xerostomia varies from 13 to 28% in older populations, and increases up to 60% in patients living in long-term care facilities [9–11].

Xerostomia, although not considered a disease, may imply the presence of changes directly related to the salivary glands or be the result of systemic diseases [12]. In order for a suitable treatment to be instituted in a timely manner, it is important to carry out a thorough evaluation of the patient with the dry mouth condition, determining, if possible, the cause of the xerostomia. The patients with xerostomia, who are present with salivary gland hypofunction, are at risk of many oral complications; the persistence over time of low rates of salivary secretion causes changes in the oral environment and affects the hard and soft tissues of the mouth. Xerostomia can also be a consequence of systemic disease and its recognition is a valuable aid in the treatment [13]. It is a potentially debilitating condition that can affect up to 1 in 5 oncology patients, with higher prevalence in women and the elderly. There is evidence that the use of multiple medications may increase the risk of xerostomia [13]. This symptom represents a strong impact on the quality of life of the people affected. Over 87.6% of people with xerostomia were worried if they had to spend the rest of their lives with the dry mouth sensation [14]. The dry mouth (xerostomia) sensation has a higher incidence on individuals over 60 years old (12–40%), up to three times higher than on younger adults. It does not seem to be directly related to the normal aging process, but to some chronic diseases or treatments [15, 16]. It is estimated that about 20–30% of the 20-year-old population has xerostomia and the cause may be the increased use of antidepressants, since xerostomia is associated with depression and anxiety. In United States, up to 40% of the 20-year-old population may have xerostomia. The high consumption of antidepressants and other medications, as well as alcoholic beverages and tobacco may explain the increase in people with this condition [17].

Although xerostomia, as a symptom, entails many problems for patients who suffer from it, especially in relation to their quality of life, the decrease in the amount of saliva due to its multiple properties is what brings more consequences at the oral level. Saliva is composed of 99% water and electrolytes. The rest of the composition is organic and includes immunoglobulins, digestive enzymes such as amylase and lipase, and antibacterial and antifungal enzymes, as well as mucins [14]. Ninety-three percent of its volume is secreted by the major salivary glands and the remaining 7% by the minor glands. Saliva production is controlled by the autonomous nervous system, mainly by parasympathetic nerve signals [18]. Saliva is very important for the preservation of general and oral homeostasis. It has a participation in digestives functions, cleaning, sense of taste, oral mucosa hydration, and defense of teeth trough pH control and its remineralizing potential. In addition, it has antimicrobial properties and controls the composition of oral microbiota by its antibacterial, antiviral, and antifungal capacities [14]. A summary of the Saliva components and functions can be seen in **Table 1**.

Several short and long-term conditions can interrupt salivary secretion, leading to xerostomia. Xerostomia can thus result from three basic causes:



**Table 1.** Saliva components and functions.

that limits many functions of day-to-day life, and often does not find response or effective treatment. Regards the complexity of xerostomia and its importance in dental practice, this chapter reviews the relevant data about etiology, diagnosis, consequences, and the current

Xerostomia (dry mouth, oral dryness, and mouth dryness) is the dryness of oral cavity and can be caused by lower salivary flow or the complete lack of saliva [6]. Based on the etiology, the xerostomia can be classified as true xerostomia (xerostomia vera, primaria), caused by the malfunction of the salivary glands and pseudo xerostomia or symptomatic xerostomia (xerostomia spuria, symptomatica), which is described as the subjective sensation of oral dryness, despite normal secretory function of the salivary glands [7]. The xerostomia, as a symptom, is more common in older populations, but its causes are not related to aging. It has been shown it is related to some specific diseases, drugs, or therapies associated [8]. The prevalence of xerostomia varies from 13 to 28% in older populations, and increases up to 60% in patients

Xerostomia, although not considered a disease, may imply the presence of changes directly related to the salivary glands or be the result of systemic diseases [12]. In order for a suitable treatment to be instituted in a timely manner, it is important to carry out a thorough evaluation of the patient with the dry mouth condition, determining, if possible, the cause of the xerostomia. The patients with xerostomia, who are present with salivary gland hypofunction, are at risk of many oral complications; the persistence over time of low rates of salivary secretion causes changes in the oral environment and affects the hard and soft tissues of the mouth. Xerostomia can also be a consequence of systemic disease and its recognition is a valuable aid in the treatment [13]. It is a potentially debilitating condition that can affect up to 1 in 5 oncology patients, with higher prevalence in women and the elderly. There is evidence that the use of multiple medications may increase the risk of xerostomia [13]. This symptom represents a strong impact on the quality of life of the people affected. Over 87.6% of people with xerostomia were worried if they had to spend the rest of their lives with the dry mouth sensation [14]. The dry mouth (xerostomia) sensation has a higher incidence on individuals over 60 years old (12–40%), up to three times higher than on younger adults. It does not seem to be directly related to the normal aging process, but to some chronic diseases or treatments [15, 16]. It is estimated that about 20–30% of the 20-year-old population has xerostomia and the cause may be the increased use of antidepressants, since xerostomia is associated with depression and anxiety. In United States, up to 40% of the 20-year-old population may have xerostomia. The high consumption of antidepressants and other medications, as well as alcoholic beverages

and tobacco may explain the increase in people with this condition [17].

Although xerostomia, as a symptom, entails many problems for patients who suffer from it, especially in relation to their quality of life, the decrease in the amount of saliva due to its multiple properties is what brings more consequences at the oral level. Saliva is composed of 99% water and electrolytes. The rest of the composition is organic and includes immunoglobulins,

available treatments to this condition.

16 Salivary Glands - New Approaches in Diagnostics and Treatment

**2. Definition and evaluation**

living in long-term care facilities [9–11].
