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The oral cavity is a major portal of entry for pathogens that may lead to changes in the normal microflora [1]. The homeostasis of the oral cavity is maintained by saliva, an extracellular fluid produced by salivary glands and secreted in the mouth through openings called salivary ducts [2]. There are three pairs of large salivary glands and hundreds of small (minor) glands; the main glands are the parotid (located in front of and just below each ear), the submandibular (located below the jaw), and the sublingual glands (located under the tongue)(Fig 1). Human saliva is 99% water, and it is estimated that a healthy person produces 600 mL per day; however, during sleep, the amount drops to nearly 0 [3, 4]. Saliva fulfills key functions in the mouth, including maintenance of oral hygiene, lubrication, chewing, and swallowing of food (Fig 2). Additionally, saliva contains several important enzymes such as amylase, lysozyme, and lipase, and therefore, the process of digestion starts the moment food enters the mouth [4]. Importantly, saliva is crucial for defense against microbial species, as it is rich in antimicrobial compounds such as hydrogen peroxide, lactoferrin, and lysozymes [3, 5]. Consequently—in addition to affecting taste, chewing, and swallowing—disruptions in saliva secretion increase the frequency of oral conditions such as oral candidiasis, gum disease, and tooth decay (caries), as well as respiratory tract infections [4, 6]. Xerostomia (a subjective feeling of oral dryness) and salivary hypofunction (a clinically objective decrease in saliva production) are the most commonly reported side effects of medications; however, HIV-AIDS and autoimmune …