Female Hormones and Periodontal Health:
Oestrogen and Progesterone
© Juliette Reeves 2011
Introduction
Many of the clinical changes that occur throughout the life stages of the female patient are the result of the genetic and hormonal differences between the sexes. These hormonal differences can result in more frequent and more exaggerated responses to oral bacteria, which initiate gingival and periodontal lesions. (1)
The biological changes that occur in the tissues of the periodontium during puberty, the menstrual cycle, pregnancy, menopause, and oral contraceptive use have increased our interest in the relationship between sex steroid hormones and periodontal health. The aetiologiy of periodontal disease is multi- factoral, however, periodontal pathologies may also be a consequence of the actions and interactions of sex steroid hormones on specific cells found in the periodontium, not the least being alveolar bone.
Steroid hormones are derivatives of cholesterol and can be further divided into three principal sets: corticosteroid hormones (glucocorticoids, and mineralocorticoids), calcium regulating steroid hormones (vitamin D and its metabolites), and gonadal or sex steroid hormones (oestrogens, androgens, and progesterone).
This article primarily discusses the influences of sex steroid hormones, predominantly oestrogen and progesterone, on the periodontium, with particular interest in bone remodelling, resorption, and alveolar bone loss. The question of whether osteoporosis and alveolar bone loss have a linear relationship remains the subject of much research. Recent studies, however, indicate that low BMD and female hormone deficiency can indeed influence alveolar bone loss.
Tezal et al (2) reported that skeletal BMD is related to interproximal alveolar bone loss and, to a lesser extent, clinical attachment loss, implicating post-menopausal osteopenia as a risk indicator fro periodontal disease in post-menopausal women. Bone modelling and skeletal consolidation result from a sequence of hormonal and nutritional interactions. Because nutrition is a modifiable pathogenic factor in bone loss, which has important practical and oral health implications, this too is a factor which may contribute to oral bone loss.
Oestrogen and Bone Loss
The function of oestrogen in maintaining bone mass was established over 60 years ago by Dr Fuller Albright who first showed that postmenopausal women had an accelerated rate of bone loss. (3) Several theories exist as to the mechanism by which oestrogen blocks bone resorption. Oestrogen deficiency has been shown to affect serum calcium (Ca+) homeostasis. With the development of oestrogen deficiency, increased bone resorption occurs due to an increased responsiveness of bone to parathyroid hormone (PTH). This hormone stimulates the breakdown of bone to release calcium into the blood, thereby correcting plasma Ca+ concentration and decreasing PTH output. Decreased serum PTH also decreases tubular Ca+ reabsorption. Both decreased Ca+ absorption and increased renal calcium loss normalise the serum Ca+ concentration. Thus the serum Ca+ concentration is maintained , more by bone loss, however, than by absorbed dietary Ca. Studies have shown that oestrogen therapy reverses this sequence. (4)
In addition, oestrogen has been shown to increase the secretion of insulin-like growth factor 1 and transforming growth factor b in sufficient amounts, which could inhibit osteoclast recruitment or function. (5) In addition oestrogens appear to inhibit the release of interleukin 1 and interleukin 6 from mononuclear cells. (6) Manolaglas et al (6) also reported that oestrogen deficiency stimulates production of proinflammatory IL6, which stimulates growth of osteoclasts and bone resorption. Oestrogen deficiency in rats is also associated with production of proinflammatory PGE2 in bone, which also stimulates bone resorption. Oestrogen lowers PGE2 production in bone and may therefore reduce bone resorption. (7)
Alveolar Bone Loss
Recent research by Civitelli et al (8) has suggested that the positive effects of hormone/oestrogen replacement therapy (H/ERT) on post cranial bone density are accompanied by similar positive effects on alveolar bone mass. Dr Robert Civitelli conducted a three year , double-blind, randomised, placebo-controlled study of 135 post-menopausal women who had no previous history of periodontal disease. Both groups also took daily calcium and vitamin D supplements. At the end of the study, the researchers found that the women who received H/ERT in addition to the supplemental micronutrients had a “significantly” greater increase in alveolar bone mass (1.84%) compared to the women who took the placebo. (0.95%).
This study concurs with an earlier study from Payne (9) who was able to show a positive effect of 17b Estradiol (E2) on alveolar bone density. Overall interproximal changes revealed E2 sufficient women exhibiting a net gain of alveolar bone density and E2 deficient women a net loss. These two studies demonstrate the effect of oestrogen specifically on alveolar bone .
Progesterone and BMD
Evidence is increasing that progesterone and its analogues also play a role in bone remodelling. (10) (11) Progesterone receptor sites have been discovered in human osteoblast cells. 12,13) Prior (12) has presented evidence that progesterone does have receptors in osteoblasts cells and is more likely, therefore, to effect new bone formation. She suggests progesterone deficiency as playing an important role in bone loss. (14) Natural progesterone is not to be confused with synthetic analogues such as medroxyprogesterone acetate (DMPA). Natural progesterone is produced by the corpus luteum in the ovaries during the latter half of the menstrual cycle. The adrenal glands also produce progesterone in small amounts. Progesterone is synthesised by the body from cholesterol.
Hormone Deficiency
It is evident from the papers reviewed that hormonal influences on both alveolar and skeletal bone density are not without significance. As far as bone density is concerned, oestrogen deficiency has been shown to affect both systemic and alveolar bone density. To date it appears that little research exists to show the direct effects of natural progesterone on alveolar bone density. In a study carried out by the College of Stomatology, Western China (15) , elevated progesterone was associated with an increase in alveolar bone formation during orthodontic movement, in Adult female Sprague-Dawley rats. In the immunohistochemical staining, the osteoblasts were positive-stained cells and they exhibited deeper stain and higher percentage in the progesterone group. The study concluded that progesterone influences the periodontal reconstruction on orthodontic tooth movements in pregnant rats and may be helpful in alveolar bone formation. In the light of the research conducted to date on the effect of progesterone on skeletal bone, it would not be unreasonable to reason that natural progesterone may also have a positive influence on both systemic and alveolar bone density. Deficiency of either of these two hormones, therefore, could predispose an individual to periodontal disease or modify the progression of a pre existing condition. Considering the hormone balance of such a patient can have benefits.
Balancing Female Hormones
The female hormones are extremely complex. There are multiple factors that can cause an imbalance within the delicately controlled female cycle. Female hormone homeostasis can be disturbed by nutritional deficiencies, stress (emotional, physical, work, environmental), exposure to xenoestrogens, sub-optimal liver function, endocrine disorders, and genetic predisposition. The first step in addressing female hormone imbalance is to consider nutrition and lifestyle. It is now known that progesterone will not enter the cell without the presence of glucose.Nakajima et al (17) showed that following a large meal there is a transient and large increase in the metabolic clearance rate of progesterone. Improvement in progesterone uptake by balancing blood glucose with a 3 hourly starch diet has been demonstrated.(18) Balancing blood glucose therefore plays an important part in maintaining female hormone balance.
Natural Hormone Supplementation
Over the last decade growing media interest and the publication of books on natural hormones has fuelled an increase in women using natural hormones by self-prescribing over-the-counter progesterone (as well as oestrogen) skin creams.
Progesterone augmentation by the use of “natural progesterone creams” is becoming more and more popular amongst women wishing to alleviate many of the symptoms associated with hormonal imbalance or menopause. However the use of natural hormones as a therapy for endocrine related symptoms remains controversial, and the application of natural hormones should not be taken casually. Hormonal therapies are extremely potent and inappropriate application of natural hormones, even in small doses, can lead to adverse symptoms such as depression, loss of libido, weight gain, lack of energy, irregular menstrual patterns and unplanned pregnancy. Unless adequately qualified, a dental professional should liaise with the patients GP over hormonal therapy. Natural hormone therapies should only be used, prescribed and monitored under the supervision of an adequately qualified heath professional. Furthermore, the monitoring of any natural hormone therapy through saliva samples is important to ensure correct doses are being administered.
With the advances in scientific research into female health, it is becoming clearer that the female hormones, as well as good nutrition and a healthy lifestyle, play a pivotal role in the health and well being of women. As a profession we are in a good position to detect female hormone deficiency or imbalances through the effect on the oral tissues. We are also able to provide advice and support through the life stages of the female patient.
References
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