Merja Laine

Effect of pregnancy on periodontal and dental health

Clinical studies have shown that oral tissues can be affected by pregnancy. Pregnancy-related changes are most frequent and most marked in gingival tissue. Pregnancy does not cause gingivitis, but may aggravate pre-existing disease. The most marked changes are seen in gingival vasculature. Characteristic of pregnancy gingivitis is that the gingiva is dark red, swollen, smooth and bleeds easily. Women with pregnancy gingivitis may sometimes develop localized gingival enlargements. The gingival changes usually resolve within a few months of delivery if local irritants are eliminated. The inflammatory changes are usually restricted to the gingiva and probably do not cause permanent changes in periodontal tissues more often than those in the non-pregnant state. Although it is widely believed that pregnancy is harmful to the teeth, the effect of pregnancy on the initiation or progression of caries is not clear. Previous studies, however, indicate that the teeth do not soften, i.e. no significant withdrawal of calcium or other minerals occurs in the teeth. It is mainly the environment of the tooth that is affected. The number of certain salivary cariogenic microorganisms may increase in pregnancy, concurrently with a decrease in salivary pH and buffer effect. Changes in salivary composition in late pregnancy and during lactation may temporarily predispose to dental caries and erosion. Although their underlying mechanisms of action are not fully understood, pregnancy-related changes in the oral environment may have some untoward temporary or permanent effects on oral health. Most of these effects could be avoided by practising good oral hygiene.

Pregnancy-related changes in human whole saliva

Flow rate, pH, buffer capacity, viscosity, sialic acid, selected proteins (amylase, lysozyme, peroxidase, lactoferrin) and anions (thiocyanate, hypothiocyanite) were analysed in paraffin-stimulated whole saliva of 16 women during the three trimesters of pregnancy and post partum. Salivary pH and buffer capacity decreased towards late pregnancy, followed by a rapid and significant (p less than 0.01) increase after delivery. The specific activity of salivary peroxidase increased significantly (p less than 0.05) during the third trimester, thus supporting the concept of oestrogen-dependency of this enzyme. None of the other parameters changed significantly during pregnancy or lactation. The results suggest that the composition of human saliva is influenced by female sex steroids during pregnancy.

Minor gland and whole saliva in postmenopausal women using a low potency oestrogen (oestriol)

Many women undergo hormone replacement therapy in order to relieve menopausal and postmenopausal symptoms. Oral discomfort is common among these symptoms and studies have shown that the stimulated whole saliva flow rate is increased after combined oestradiol and progesterone replacement therapy. There is, however, no data regarding the effect of other oestrogens or of oestrogen alone on whole and minor gland saliva. In the present study, the flow rate from minor salivary glands (buccal, labial and palatal) and the secretion rate and buffer capacity of whole saliva was examined in 18 postmenopausal women (61-76 years) prior to, and during 1 year of a low potency oestrogen (oestriol) use. The ability of whole saliva to aggregate and mediate bacterial adherence as well as subjective feelings of dry mouth was also examined. For comparison, the same variables were examined in nine peri- and postmenopausal, non-medicated women (reference group, 53-61 years). During hormone treatment, the labial saliva flow was significantly increased and the complaints of dry mouth reduced. Increased stimulated whole saliva flow was seen in both the hormone and reference groups. This was also true for the stimulated whole saliva buffer capacity, which was increased parallel to the flow rate. The secretion rates were generally lower in the hormone group compared to the reference group throughout the study period. Except for stimulated whole saliva, statistical analysis at baseline revealed no age-related reduction of the saliva flow rates. The ability of whole saliva to mediate aggregation of Actinomyces naeslundii was significantly decreased after hormone treatment. Thus, the present findings indicate that a low dose oestrogen (oestriol) may affect the flow rate of labial salivary glands and the bacterial aggregation activity of whole saliva.

Hormone replacement therapy and some salivary antimicrobial factors in post- and perimenopausal women

OBJECTIVES The effect of hormone replacement therapy (Cyclabil) on non-immunoglobulin (peroxidase) and immunoglobulin (total IgA, IgG, IgM) antimicrobial factors as well as on total protein and microorganisms in whole saliva was assayed in 19 postmenopausal and 8 perimenopausal women. METHODS Paraffin-stimulated whole saliva was collected before as well as 3 and 5 months after the onset of the treatment. Time- and group-related differences between post- and perimenopausal women were analyzed. RESULTS Peroxidase and total protein output per min increased significantly (P = 0.004 and 0.001) during the treatment in both groups. No significant time- or group-related differences in the mean concentrations of the respective variables were found. The mean concentrations of salivary IgA and IgG showed a significant time-related decrease in both groups (P = 0.012 and 0.010). Salivary IgM concentration in perimenopausal women also showed a significant time-related decline (P = 0.017) and the difference in changes of salivary IgM between the two groups was significant (P = 0.033). Total IgA output per min increased in perimenopausal whereas it decreased in postmenopausal women (interaction; P = 0.021). Hormone treatment had no effect on the amount of salivary bacterial floras. CONCLUSIONS The composition of saliva in post- and perimenopausal women was found to be estrogen-dependent. The second finding was that all women participating in the study reported a sense of enhanced oral well-being including relief of oral dryness.

Immunohistochemical demonstration of androgen receptors in human salivary glands

Androgen receptors were demonstrated in human salivary glands by immunohistochemistry using polyclonal antibodies. Fresh, clinically healthy salivary gland samples (two from minor, seven from parotid and eight from submandibular glands) of both sexes were used. Frozen tissue sections were incubated with the antibody against human androgen receptor and visualized by an indirect immunoperoxidase technique. Androgen receptors could be detected in all salivary tissues studied. Positive staining was confined to nuclei of almost all acinar cells as well as to the majority of nuclei in ductal cells. Very few of the nuclei of connective tissue and endothelial cells stained positively. The presence of androgen receptors in human salivary glands suggests possible direct effects of androgens on these tissues.

Salivary carbonic anhydrase VI and its relation to salivary flow rate and buffer capacity in pregnant and non-pregnant women

OBJECTIVE Previous studies have shown that pregnancy may have unfavourable effects on oral health. The pH and buffer capacity (BC) of paraffin-stimulated saliva, for example, have been found to decrease towards late pregnancy. Salivary carbonic anhydrase VI (CA VI) probably protects the teeth by accelerating the neutralization of hydrogen ions in the enamel pellicle on dental surfaces. Since estrogens and androgens are known to regulate CA expression in some tissues, we studied here whether salivary CA VI concentration shows pregnancy-related changes. DESIGN Paraffin-stimulated salivary samples were collected from nine pregnant women 1 month before delivery and about 2 months afterwards and assayed for salivary CA VI concentration, BC and flow rate. The enzyme concentration was determined using a specific time-resolved immunofluorometric assay. The control group consisted of 17 healthy non-pregnant women. RESULTS The results indicated that salivary CA VI levels varied markedly among individuals, but no significant differences in mean concentrations were seen between the samples collected during late pregnancy and postpartum. BC values were lower during pregnancy, however. CONCLUSIONS Our findings suggest that CA VI secretion is not significantly affected by the hormonal alterations associated with pregnancy, and confirm the earlier reports that CA VI is not involved in the regulation of actual salivary BC.

The effect of hormone replacement therapy on salivary calcium concentrations in menopausal women.

Hormone replacement therapy in menopausal women is known to affect the general calcium turnover of the body. No information is available about the effects of hormone therapy on salivary electrolytes and on calcium in particular. A group of 16 healthy peri- and postmenopausal women, all recommended to start hormone replacement therapy, were studied longitudinally for 5 months. Paraffin-stimulated whole saliva was collected at baseline, at 3 and at 5 months after the onset of therapy, and analysed for calcium, sodium and potassium concentrations. In response to hormone replacement therapy, calcium concentration decreased (p = 0.037), that of sodium increased (p = 0.019), while no change was observed in the potassium concentrations during the follow-up period.

Effects of low-dose oral contraceptives on female whole saliva

The composition and flow rate of paraffin-stimulated whole saliva were analysed in 22 women, of whom 11 used oral contraceptives and 11 did not. Ten men served as the controls. The salivary samples were collected during one month (oral contraceptive users and men), or during one menstrual cycle (non-users). The saliva analyses included flow rate, pH, buffer effect, sialic acid, thiocyanate, peroxidase, lysozyme, amylase, immunoglobulins A, G and M, total protein, mutans streptococci, lactobacilli, yeasts and total numbers of aerobic bacteria. The salivary buffer effect of oral contraceptive users was significantly (p less than 0.005) higher than that of non-users. All the other constituents showed intra- and interindividual variation in all groups, but with no apparent hormone-dependency.

Immunohistochemical detection of androgen receptors in human oral mucosa

Oral mucosal biopsies from 11 healthy volunteers, 7 women and 4 men, were analysed for the localization of androgen, oestrogen and progesterone receptors. The samples were dissected as quickly as possible and immediately frozen in liquid nitrogen to be stored at -70 degrees C. Only androgen receptors could be detected by the methods used. These were mainly located in the nuclei of basal epithelial cells, and to some extent in the nuclei of fibroblasts and endothelial cells. Failure in the localization of oestrogen and progesterone receptors might have been due either to low numbers of receptors or to the insensitivity of antibodies used. The method is thus suitable only for detecting androgen receptors.

Evaluation of salivary markers during the menstrual cycle: Peroxidase, protein, and electrolytes

Abstract Considerable variation in many salivary components was observed during the menstrual cycles of 12 women. Whole saliva peroxidase activity increased significantly during the preovulatory period; the highest activity was measured 3.8 ± 2.4 days before ovulation. The increase of activity tended to coincide with the increase in serum estrogen level. Large cyclic variation without any clear tendency occurred in salivary α-amylase and sialic acid concentrations; minor cyclic variations were found in thiocyanate, calcium, potassium, and protein. None of the measured compounds proved to be a reliable marker for ovulation. From a clinicochemical point of view, the remarkable cyclic variation is important to know because whole saliva is frequently used as a diagnostic aid in the treatment of oral diseases.