Although there are more women than men in the United States, women have long been underrepresented in medical research. To respond to this crucial need, the National Institutes of Health (NIH) in 1990 established the Office of Research on Women's Health (ORWH), which developed a research agenda to correct the gaps of knowledge in women's health. As a result, a record number of studies have been conducted, and more are underway, into areas such as heart disease, female cancers, gynecologic health, and osteoporosis, thus improving both the body of knowledge and therapeutic strategies for gender-specific disorders. The ORWH has specified research priorities for the 21st century that include research on: the health of girls and women across the life span; sex and gender factors; biomedical, behavioral, and psychosocial factors; socioeconomic and geographic factors; women with disabilities; and the advancement of women in biomedical research careers [5].

The members of the dental health team can provide factual information and clarify any myths or misconceptions about menstruation that their young female patients may have. There are also changes associated with menstruation that can have a direct bearing on oral health. When young women enter puberty, the changes in estrogen levels can be reflected by changes in the gingival tissues. The relative proportions of anaerobes in the subgingival plaque may change, coinciding with fluctuations in the normal hormonal cycle. Symptoms of gingivitis often follow a pattern that coincides with the menstrual cycle [16]. Nodular hyperplastic reactions that are histologically similar to inflammatory hyperplasia may take place. These areas frequently involve the interdental papillae and can be very red and exuberant in appearance. Patients with a familial history of juvenile periodontitis should be closely monitored for signs of periodontal disease, and appropriate therapy should be initiated at the earliest possible time. Referral for specialty evaluation is highly recommended [17].

Bleeding can become more extensive after oral surgery during the time of menses, and salivary glands may swell. A small rise in tooth mobility may also be detectable. Many women report that oral aphthous ulcers tend to appear during the luteal phase of their menstrual cycle [18]. These changes, however, are not universal and may vary in severity from one woman to another as levels of estrogen and progesterone fluctuate during the normal cycle. Dentists, hygienists, and dental assistants should educate patients on the importance of good dental hygiene and effective plaque control that can minimize the increase in gingivitis during menses.

There is an increased risk of several potentially serious conditions for patients taking OC. These include thromboembolism, myocardial infarction, stroke, hepatic neoplasm, and gallbladder disease. The risk, however, is very small in healthy women without other underlying risk factors, such as hypertension, hyperlipidemias, obesity, and diabetes. Smoking is a substantial risk factor in the incidence of myocardial infarction for patients 35 years of age and older who take OC [30,31,32].

Gingival inflammation is a common side effect among women taking birth control pills, apparently due to changes in the microcirculation. There is also an alteration in the relative proportions in the established bacterial flora associated with the intake of these hormones. Prevotella species may overgrow disproportionately through a favorable increase in its nutritional supply, as female sex hormones may stereochemically resemble and substitute for the naphthoquinones needed by Prevotella [16,33,34]. Reports have also shown shifts in the makeup of saliva in women taking OC and other sex hormones. Salivary flow may change as well, with alteration in the rate of parotid and submandibular salivary secretions. There are also conflicting reports of chronic dry mouth in some women [35,36].

Published studies have indicated a greater incidence of postoperative localized osteitis in women taking OC after they have had their mandibular third molars removed. One retrospective review found that alveolar osteitis occurred in 37.9% of women taking OC and in 8.9% of women not taking OC at the time of third molar extraction [37]. This may be related to the effect that birth control pills have on blood clotting. In one study, 40% of patients experiencing postoperative complications after third molar removal were users of OC [33]. It was speculated that the increase of fibrinolytic activity associated with the use of OC accounted for the high incidence of postoperative complications. Such an increase was speculated to be associated with lysis of the formed clot and subsequent "dry socket" formation. As a result, some researchers have suggested that the risk of developing postextraction osteitis may be reduced by performing extractions on days 23 to 28 of the pill cycle, which are nonestrogenic days [33,38,39,40]. One study found that socket irrigation following extraction significantly increased dry socket formation [41]. A systematic review of surgical techniques suggested that placing platelet rich plasma or platelet rich fibrin in sockets may reduce the incidence of osteitis [42]. A study evaluating the impact of OC on women's periodontal health found that women who used OC had higher gingival-index scores and clinical attachment loss than nonusers [43].

In addition to generalized gingival changes, a solitary, tumor-like growth, frequently referred to as a "pregnancy tumor" or "pregnancy granuloma," may appear. This lesion is often found associated with anterior interdental areas and has a histologic appearance similar to a pyogenic granuloma. Often, the lesion will regress after delivery, so decisions about surgical removal are best delayed until some time postpartum. Also, removal of the lesion during pregnancy may result in a recurrence [18].

A number of studies have indicated that women with periodontal disease have an increased risk of preterm births [18,62,63,64]. A PLBW baby is defined as one born before the 37th week of gestation, weighing less than five pounds, six ounces. In a study of 124 pregnant or postpartum mothers at the University of North Carolina School of Dentistry, those who delivered preterm newborns were more likely to have significantly worse periodontal disease than a comparable group of women who delivered normal birth weight infants. The researchers concluded that periodontal disease is a statistically significant risk factor for preterm low birth weight, with an adjusted odds ratio of 7.9 [62]. Another study of 870 women with pregnancy-associated gingivitis conducted by the Department of Conservative Dentistry in Santiago, Chile, found that periodontal treatment significantly reduced the incidence of preterm labor and/or low birth weight infants [65]. However, the results of more recent studies find limited and/or insufficient evidence to conclude that periodontal disease or its treatment led to a reduction in PLBW infants [66,67]. Nevertheless, the American Academy of Periodontology has recommended that periodontal evaluations be a part of a woman's overall healthcare program as periodontal disease can impact a woman's health in a variety of ways throughout her life [68].

The most common type of gynecologic cancer is cancer of the uterus, and approximately 66,200 women will be diagnosed with uterine cancer in 2023 [104]. The three layers that comprise the uterus are the inner layer or lining, which is called the endometrium, the middle muscular layer, which is called the myometrium, and the layer of tissue that coats the outside of the uterus, which is known as the serosa. Most uterine cancers begin in the endometrium. Endometrial cancer occurs around 60 years of age on average. Uterine cancer is uncommon in women younger than 45 years of age [104].

Breast cancer is the most common cancer in women, but it is also one of the most treatable if detected early. The risk to American women of developing breast cancer in their lifetime is reported as one in eight [110]. Nodal involvement remains the best prognostic indicator for long-term survival. The ACS has reported the five-year survival rate as 99% for localized, 86% for regional, and 29% for distal [111]. These survival rates underscore the importance of rigorous, consistent screening for all women.

But in 2002, surprising results from a major clinical trial, the Women's Health Initiative (WHI), were published in the Journal of the American Medical Association [134]. The study was designed to evaluate the health benefits and risks of the most commonly used estrogen-plus-progestin hormone preparation in more than 16,000 menopausal women. The trial was halted after a mean follow-up of 5.2 years because of the apparent increased risks of coronary heart disease, stroke, pulmonary emboli, and invasive breast cancer associated with HRT. The authors of the study reported that the rate of women experiencing coronary heart disease events rose 29% in women taking HRT, compared to placebo. Stroke rates were 41% higher in the HRT group, while the rate of venous thromboembolism was about double in the drug cohort [133,134]. A 2005 Cochrane review of the data from ten clinical trials (two involving healthy women; eight involving women with heart disease) reported similar findings [140]. A 2015 Cochrane review of data from additional new trials concurred with these previous findings [141].

Osteoporosis is one of the most serious long-term concerns of perimenopausal and postmenopausal women, affecting approximately one in four women [132]. The loss of bone mass accelerates after menopause and causes bones to become brittle and at increased risk of fractures. Hip fractures among elderly women are not only costly and debilitating, but women often die from subsequent complications within a year. Studies have shown that long-term estrogen use protects women from postmenopausal bone loss and osteoporosis [122]. Estrogen therapy slows the demineralization process, but it cannot restore bone that has already been lost. In addition, once estrogen replacement stops, bone loss resumes. The WHI trial did show that women taking the estrogen-plus-progestin formulation experienced a one-third reduction in hip fractures and a 24% decline in total fractures [133].

Observational studies have indicated that long-term estrogen deficiency seems to be related to a higher risk of developing Alzheimer disease, but the reason why remains unknown [150,151]. Among the 6.5 million people 65 years of age and older in the United States with Alzheimer disease, 4 million are women and 2.5 million are men [152]. Women also suffer more severe cognitive impairment [153]. The finding that women with Alzheimer disease have lower levels of estrogen than do those without Alzheimer disease seems to indicate that there is a relationship that bears further investigation; however, HRT is not recommended for cognitive improvement or maintenance in women with Alzheimer disease [151,154,155,156].

Bisphosphonate drugs, such as alendronate, may retard the progression of alveolar bone loss associated with periodontitis. In one double-blind, placebo-controlled clinical study, alendronate lowered the risk of progressive loss of alveolar bone loss; during the nine-month trial, the relative risk of the loss of bone height and density was reduced to 0.45 in the alendronate group [166]. A study from 2019 found no improvement in maintaining alveolar bone level with the use of bisphosphonates but did suggest that its use may be promising as an adjunctive local delivery medication for management of periodontal diseases [167]. Two other studies support the assertion that bisphosphonates may be useful for periodontal treatment; however, existing information on this potential is limited [168,169,170]. However, bisphosphonate drugs are known to cause medication-related osteonecrosis of the jaw (MRONJ) in some patients, particularly those who underwent IV bisphosphonate therapy, who were taking bisphosphonates for extended periods of time, and/or who underwent dental procedures while taking bisphosphonate drugs [171,172].

Because most postmenopausal women have some degree of osteoporosis, they should take steps to prevent further bone loss. The best preventive measures are early education to encourage positive lifestyle habits before the disorder develops (ideally, well before menopause). The following methods have been identified as being helpful to prevent bone loss [158,173,182,183]:

The National Health and Nutrition Examination Study (NHANES I) evaluated more than 9,000 people for a median of 14 years and found that individuals with periodontitis had a 25% greater likelihood of developing CHD (an association found to be statistically significant). Poor dental hygiene characterized by extensive dental debris and calculus also increased the risk of CAD [196]. A 2021 literature review found that the prevalence of heart disease is more common among individuals with periodontitis [197]. A systematic review published in 2022 concluded that periodontal disease may be an important nontraditional risk factor for acute coronary syndrome [198].

One hypothesis explaining the possible mechanism responsible for the link between CVD and periodontitis centers on bacterial products, such as lipopolysaccharides (LPS), that can enter the bloodstream and affect the cardiovascular system. Several studies have reported the presence of periodontal bacteria in cardiovascular specimens [199]. It has also been postulated that micro-organisms normally present in the oral cavity, including P. gingivalis and Streptococcus sanguis, enter the bloodstream through local action that induce bacteremias, grow within the vascular plaques, and have the potential to induce platelet aggregation [200]. A study of carotid atheromas using polymerase chain reaction found that 42% of atheromas contained at least one of the periodontal micro-organisms studied and 72% contained the bacterial DNA of one of these micro-organisms [201]. Although periodontal treatment as a means to prevent CVD is not recommended, the emergence of periodontal infection as a risk factor for CVD should lead dental and healthcare professionals to recognize that patients cannot be healthy without good oral health [14,202].

Gonorrhea, which is caused by the bacteria Neisseria gonorrhoeae, was once the most prevalent STI in the United States. Gonorrhea is one of the most common infectious diseases, with an estimated 677,769 persons in the United States acquiring the disease in 2021, an increase of 45% from 2016 [203]. After a decline in the incidence of the disease from 1975 to 1997, the national rate for gonorrhea has been steadily increasing. This STI is transmitted vaginally, orally, or anally by sexual activity or from the mother to newborn during delivery. The majority of women are asymptomatic early in the disease. When symptoms do occur, they may include burning on urination and increased vaginal discharge. In the oral cavity, the disease manifests as a stomatitis and may exhibit a clinical appearance similar to the oral lesions of erythema multiforme, erosive lichen planus, or herpetic stomatitis [203,204].

Syphilis is a bacterial STI caused by the spirochete Treponema pallidum. Like gonorrhea, syphilis is transmitted vaginally, orally, or anally through sexual activity, and via maternofetal transmission. In some cases, the disease has been acquired by dentists and hygienists providing dental treatment for a patient with syphilis during a contagious stage of the disease. Universal precautions apply, with the routine use of gloves, mask, and eye protection. Although syphilis is not as widespread as gonorrhea, its incidence is on the rise, which is especially ominous because of the harmful effects the untreated bacterium has on the heart, eyes, and central nervous system [203]. An estimated 133,945 cases of syphilis were reported in 2021, up 52% from 2016 [203].

Eating disorders, such as anorexia nervosa and bulimia nervosa, can significantly impact oral health through a lack of proper nutrition and the effects of repetitive vomiting [209]. Although eating disorders occur more often in women/girls (3% to 4% lifetime prevalence) than men/boys (0.3% to 1.0% lifetime prevalence), they do occur in males in all age groups and in non-Western countries and are a particular concern for oral health [210]. Both anorexia nervosa and bulimia nervosa may carry a five or more times increased risk of mortality [210].

The frequent, self-induced vomiting in conditions like bulimia, typically after periods of binge eating, can have a destructive effect on the teeth. The regurgitated gastric contents can cause decalcification, softening of the enamel, and loss of tooth structure. Most often, this erosion occurs on the maxillary anterior teeth—specifically, on their palatal surfaces. A loss of occlusal anatomy can be observed when the posterior teeth show evidence of damage [211,212]. In one small study, the prevalence of severe malocclusion was high in women with anorexia and bulimia nervosa and resulted in a negative oral health-related quality of life [213]. Dental manifestations may not be immediately apparent, most often appearing after about two years of chronic vomiting.

The obvious signs are the physical ones, including the loss of or injury to teeth. Injuries may also range from bruises, cuts, black eyes, concussions, broken bones, and miscarriages, to permanent injuries, such as damage to joints, partial loss of hearing or vision, and scars from burns, bites, or knife wounds. Typical injury patterns include contusions or minor lacerations to the head, face, neck, breast, or abdomen. These are often distinguishable from accidental injuries, which are more likely to involve the periphery of the body. In one hospital-based study, domestic violence victims were thirteen times more likely to sustain injury to the breast, chest, or abdomen than accident victims. Abused women are also more likely to have multiple injuries than accident victims. When this pattern of injuries is seen in a woman, particularly in combination with evidence of an old injury, physical abuse should be suspected [219,220,221].

After identifying a victim, dentists and other healthcare professionals should immediately implement a plan of action that may include providing a referral to a local domestic violence shelter to assist the victim and the victim's family. The acute situation should be referred immediately to local law enforcement officials. Other resources in an acute situation include crisis hotlines and rape relief centers. After a victim is introduced into the system, counseling and follow-up are generally available with counselors who specialize in the care of battered women and their spouses and children. These counselors may include social workers, psychologists, psychiatrists, other mental health workers, and community mental health services. The goals are to make the resources accessible and safe and to enhance support for women who are unsure of their options [225,227].