Flow Rate of Saliva
salivary flow rates are highly variable and stabilize after the age of 15 years ; therefore they should be interpreted in a clinical context.27,28 The numbers depicted in this section are averages projected from studies on the general population. The range of normal unstimulated salivary stream is 0.1 mL/min and above ; in the stimulate state, it is 0.2 mL/min and above. On median the unstimulated flow rate is 0.3 mL/min, and the stimulated menstruation rate is 7 mL/min at maximum. Stimulated saliva is thought to contribute angstrom much as 80 % to 90 % of the average daily salivary output. This leads to an average daily saliva secretion of around 1000 to 1500 milliliter or an average flow of 1 mL/min.29,30 Salivary flow in the unstimulated state is produced primarily by the submandibular glands ( 71 % ) ; the parotid and sublingual glands produce 25 % and 3 % to 4 % of the flow, respectively.30 The child salivary glands account for trace amounts of saliva. once stimulated, the relative contributions of the parotid and submandibular glands are reversed, and the parotid gland supplies two-thirds of the salivary flow.27,31 Studies that have specifically addressed hypofunction of the salivary gland have defined the critical range that separates a person with normal gland serve from person with salivary gland hypofunction as unstimulated hale salivary flow rates between 0.12 and 0.16 mL/min.32 The diagnosis of salivary hypofunction is frequently unmanageable to make, given the wide stove of salivary menstruation rates that are accepted as convention. A more reliable means of diagnosing hypofunction is potential if an individual base record of saliva stream has been established. salivary gland hypofunction can then be defined as a 50 % reduction in the individual al-qaeda saliva flow rate. About 30 % of the population reports some degree of dry mouth. In general, oral-related effects of salivary hypofunction are reduced readiness of food for digestion and taste and an increase susceptibility of oral structures to disease.33 Although decrease concentrations of salivary mucins and decreased resting salivary menstruation rates have been associated with increasing senesce, in general, no substantial age-related changes in the secretory responsiveness of salivary cells are apparent.34,35 Furthermore, factors endemic to the geriatric population—such as polypharmacy, poor nutritional condition, and systemic diseases—also lend to salivary gland hypofunction.36 At present, the accurate function of advancing age on the average day by day product of saliva and xerostomia is unknown.
salivary secretion is controlled by a salivary center in the medulla, which is triggered by specific stimuli that include the mechanical act of chewing and gustatory and olfactory stimuli. The stimulation of salivary menstruation with chew is thought to be a reflexive pronoun reaction mediated by receptors in the oral mucous membrane, muscles of chew, and temporomandibular joint. These receptors stimulate the salivary nucleus, which in turn increases the parasympathetic nervous system foreplay to the salivary glands, resulting in increased salivary flow.37 Interestingly, the increase in salivary flow is thought to be directly proportional to the applied chew force.38 Gustatory stimulation are the most potent stimuli to the salivary center and elicit a much as a 10-fold increase in salivary stream. acidic tastes lead to the greatest increases in saliva flow, whereas sweet tastes are the least induce. smell is the weakest of the salivary center triggers. furthermore, addiction is thought to occur with reprise presentation of the like food cues, which leads to a decrease in foreplay of the saliva kernel and saliva flow. Dishabituation occurs with the presentation of novel food cues.39–42