Introduction

Xerostomia, lichen planus, Sjogren's syndrome, burning mouth syndrome (4), menopausal gingivitis, stomatitis, and a decrease in the height and density of the alveolar bone are some examples of these changes (5). The prevalence of oral disorders in menopausal period is various (8, 10, 11).

Wordrop investigated 149 patients using a questionnaire and concluded that the prevalence of oral disorders in postmenopausal women is definitely higher than premenopausal women (12). Hoseini and Karbasi measured the quantity of the stimulated parotid saliva in 158 postmenopausal women and compared it with men of the same age. They concluded that the volume of stimulated parotid saliva does not change after menopause (13). Amirian compared the quantity of unstimulated whole saliva in postmenopausal women with the men of the same age and realized that the mean volume of saliva in women was less than men, and xerostomia was more frequent in postmenopausal women when compared to men of their age (14).

Asplund investigated the relation between xerostomia and menopause by means of a questionnaire.

They concluded that %17.8 of the premenopausal women, %23.2 of women who are in first five years of the menopause period, %29.2 of women who are in five to nine years after menopause and %34.5 of women in whom at least 10 years has passed from the beginning of their menopause suffer from xerostomia (15). In Elinsson's study in Sweden, the increase in the age was not found to be correlated with a decrease in the saliva (16). In Hoseini's research no meaningful difference in the volume of stimulated saliva was reported between postmenopausal women who suffered from xerostomia and the ones who did not have related complaints (17).

 In another study conducted by Hoseini and Mirzai the mean flow of unstimulated saliva in postmenopausal women who suffered from xerostomia was considerably less than the ones who did not have any related symptom (18). In Johnson's study done using a questionnaire, the prevalence of xerostomia increased in the ages between 50 and 70, especially in women (19).

The goal of this study was to compare the volume of unstimulated saliva between postmenopausal
(50-70 years old) and premenopausal subjects
(20-50 years old).

Materials and Methods

This descriptive-analytic study was done by a
case-control method. 80 patients (40 patients in each group) were chosen from the patients who were referred to the gynecology department of Shahid Sadoughi Hospital that is under the supervision of Shahid Sadoughi University of Medical Sciences of Yazd using a convenience sampling method. Chosen patients in both groups were not supposed to have systemic diseases, any history of smoking/ allergy, or a history of consumption of any medications. Women who were confirmed by a gynecology specialist as being in a state of menopause (at least one year had passed from the last menstruation) were chosen as appropriate cases. To cooperate in this study, patients were supposed to agree to the terms of study and sign a written consent. In the study group, after entering the biographic information in a special questionnaire and asking for the patient's level of satisfaction, the patient's psychological condition and her complaint of xerostomia were estimated by HADS and a certain questionnaire (10, 20, 21).

After that, the patients' volume of the unstimulated whole saliva was measured in the same condition by the proper process.

This was accomplished using the spitting method
(22-24). Samples of the patients’ saliva were collected between nine and 11 o'clock. The patients were asked to avoid eating and drinking from 90 minutes before sampling. For collecting samples, patients were asked to keep the saliva in their mouth for five minutes and then spit in the graded test tubes one to two times per minute. The volume of the saliva was written down on the basis of ml/min (milliliter per minute) (23).

In order to evaluate the patients’ psychological condition, HADS (Hospital Anxiety and Depression Scale) was used (25, 26). Raw data was analyzed by SPSS11 software using Chi Square, Mann Whitney
(for comparing the existence of xerostomia), and
 Kruskal-Wallis (for comparing the mean volume of the saliva and the stress degree of people) tests. In the present study, the volume of unstimulated whole saliva less than 0.1 milliliter was considered as identical to xerostomia (23).

Results

In the current research, 80 patients in two groups of postmenopausal (50-70 years old) and premenopausal (20-50 years old) women were investigated. The mean HADS scale grade did not show any significant difference between postmenopausal (12.7±6.9) and premenopausal (13.3±6.3) women.

The mean volume of the unstimulated whole saliva in postmenopausal and premenopausal women was 0.35±0.04 and 0.3±0.03, respectively (with no statistically significant difference).

%30 (n= 20) of postmenopausal and %15 (n=6) of premenopausal women suffered from the defined xerostomia. A significant difference between the two groups is recognizable in this part (P= 0.026).

Postmenopausal women suffer from xerostomia significantly more often than premenopausal women (%45 versus %17.5) (PV= 0.003).

Discussion

One of the main complaints of the patients who recourse to dental offices is xerostomia; a symptom that can be caused by various etiologies such as systemic disorders, salivary glands diseases, or certain drugs side effects. However, in some groups of these patients, such as postmenopausal women, nothing can be found as the cause of this complaint in the patient's medical history.

Oral disorders during menopausal and postmenopausal periods may be due to the changes in the quality and quantity (or both) of saliva
(4, 7, 10, 18, 27). The aim of the current study is to investigate the quantity of unstimulated whole saliva in postmenopausal women So, two groups composed of the same number of subjects were studied to unravel the effect of menopause on the aforementioned symptoms.

Similar to the majority of peer studies, the same number of patients was selected for the two groups in this research. The number of studied patients is the same as some of the previous studies (9, 12, 27-29). It must be noted that the number of patients was limited, due to the elimination of interfering factors such as systemic diseases, medications, smoking, and allergy.

This research seems to be more reliable than Wardrop's, Ben Aryeh's, and some others' studies
(9,12,27-32) since in those studies, patients receiving medications were not excluded. In the present study, since the special instrument needed for measuring stimulated saliva was not accessible, unstimulated whole saliva was measured by the spitting method.

This method is both safe and repeatable. In the previous researches in which the volume of unstimulated whole saliva was studied, no meaningful difference between postmenopausal and premenopausal women was found (22-24). Ellison did not find any relation between age and decreased saliva volume, either (16).

In Ben Aryeh's study, the volume of the saliva in postmenopausal women was not different from the younger control group, though whole protein of saliva and the density of IgA were considerably higher (30).

These two studies used the same method as ours.

Rivera Gomuz investigated 30 postmenopausal women and compared them with the control group.

They concluded that there was no difference in the mean volume of whole saliva between these two groups (33).

In Hoseini's study, 42 women in two groups were investigated. No meaningful difference was found in the volume of stimulated whole saliva (17).

Ahadian investigated postmenopausal women and compared them to the men of the same age. They concluded that the volume of unstimulated saliva decreases during menopause (14). Sex may be the reason of this difference. In the present study, %15 of women between 20 to 50 years old and %30 of women between 50 to 70 years old complained from identical xerostomia (the volume of unstimulated whole saliva less than a milliliter per minute). The observed difference is statistically significant (P= 0.026). This result is consistent with Tarkkila's (31) and Eugin del Valle’s studies (27). Asplund's study showed that xerostomia increases after menopause as well (15).

Al-Dwuiri and Lynch also reported that an increase in age is associated with a rise in xerostomia prevalence (34). In the current research, postmenopausal women complained about xerostomia statistically more frequently than the control group (%45 versus %17.5, P= 0.003).

Regarding the statistically significant difference, identical xerostomia of these two groups can be explained; change in the quality of saliva can increase xerostomia in postmenopausal women, as well.

In Eugin del Valle’s study, %60 of the study population suffered from xerostomia (27). In another research, Tarkkile reported that %19.9 of the study population suffered from xerostomia (31). The differences in the results of the aforementioned studies may be due to the difference in the research methods.

In Wardrop's study, %43 of postmenopausal and %6 of premenopausal women had oral symptoms (12). The difference between the results of that research and ours may be due to the difference in the ages of the two groups.

The same can be said about the women who used certain medications in Wardrop’s study.

In the current study, the subjects' psychological condition was evaluated by HADS to check for nervousness which is an interfering factor in the salivary flow.

Consequently, no statistically significant difference was found between the two groups of study. HADS had been previously used in Hoseini's (17) and Ahadian' studies (14) and none other.

Our study exclusion criteria such as systemic diseases, history of medication use, allergy, and smoking background in both groups posed certain limitations, especially in choosing the subjects.

Providing the same conditions for measuring the saliva caused further difficulties. More investigation can be carried out to study the quality and the components of the saliva.

This may help us discover the true mechanism of xerostomia in postmenopausal women.

Conclusions

The volume of unstimulated whole saliva does not change after menopause, and the psychological conditions of postmenopausal women do not make any considerable difference in either the prevalence of the symptoms or the intensity when compared to the premenopausal ones.