Abstract
Although dry mouth and hypersalivation are opposite sensations, they can both occur in association with stress. We investigated the difference between dry mouth and hypersalivation based on sex, age and the amount of saliva at the first report. Approximately 937 patients were assigned to the dry mouth group (Group D), while 93 patients were assigned to the hypersalivation group (Group H) ； all of the patients had been treated in the past 9 years. The frequency of hypersalivation was approximately one-tenth of the frequency of dry mouth. Group D showed a female predominance, while Group H showed a male predominance. In Group D, the amount of saliva at rest actually decreased in 63.0% of the patients, and did not decrease in the remaining 37.0% of the patients. On the other hand, in Group H, the amount of saliva actually increased in 25.3% of the patients, and did not increase in the remaining 74.7%. The sensations of dry mouth or hypersalivation sometimes occur independently of the actual amount of saliva, and may be affected by the individual's state of mind. The sensation of dry mouth is a type of discomfort that leads to a sensation of shortage or dissatisfaction, while the sensation of hypersalivation is a type of discomfort that leads to a sensation of excess and which sometimes occurs in association with neurosis or depression. We performed a gum test to examine the effect of stimulating salivation. The act of chewing gum also has the effect of reducing stress. Thus, the gum test can be considered to reduce stress. We hypothesize that both the patients in Group D who showed dry mouth at rest and normal findings in the gum test, and the patients in Group H who showed hypersalivation at rest and normal findings in the gum test were affected by stress. As the amount of saliva is affected by individual differences and age-related changes, a diagnosis of dry mouth or hypersalivation should not be made based on the amount of saliva alone ； rather, this should be regarded as one element in the diagnosis. Although the amount of saliva decreases with age, patients do not usually consult a medical institution for this reason alone. Rather, they tend to make such consultations when these symptoms occur in association with stress. Paying attention to the amount of saliva alone can lead to a misdiagnosis. Some patients complain of hypersalivation after meals or due to various conditions. It is difficult to diagnose patients based on the amount of saliva alone, without stimulation ； however, combining a gum test can yield clues that are useful for making a diagnosis. When examining patients who complain of dry mouth or hypersalivation, we need to listen to the patient's detailed medical history, observe the of patient's posture, perform a swallowing test and consider other aspects of their condition. We should consider the possibility that stress might be involved in the patient's condition, irrespective of the amount of saliva. If we respond to the patient's psychological condition, we can expect an improvement in their symptoms, even if the amount of saliva remains unchanged.
