Bi-directional relationship between pregnancy and periodontal disease

Oral Health, Anxiety, Depression, and Stress in Pregnancy: A Rapid Review of Associations and Implications for Perinatal Care

Research demonstrates associations between oral health and specific mental health conditions in the general population, yet these relationships remain understudied during pregnancy, despite pregnancy's profound effects on both oral and psychological well-being. Our rapid review examines current evidence on associations between oral health conditions and psychological states (anxiety, depression, and stress) during pregnancy, aiming to inform and strengthen integrated prenatal care strategies. Following PRISMA-RR guidelines, we conducted a systematic search on OVID Medline, CINAHL, and PsycINFO (January 2000-November 2024) for studies examining relationships between oral health conditions (periodontal disease, dental caries) and psychological status during pregnancy and up to one year postpartum. Systematic screening of 1201 records yielded 22 eligible studies (13 cross-sectional studies, 3 longitudinal cohort studies, 3 comparative studies, 2 prospective studies, and 1 case-control study). Analysis confirmed significant associations between oral health and psychological well-being during pregnancy through three pathways: psychological (dental anxiety directly limits oral healthcare utilization), behavioral (maternal depression reduces oral health self-efficacy), and physiological (elevated stress biomarkers correlate with periodontal disease, and periodontal therapy is associated with reduced salivary cortisol). These interactions extend intergenerationally, with maternal psychological distress showing significant associations with children's caries risk. Evidence suggests interactions between oral health conditions and psychological states during pregnancy, warranting integrated care approaches. We recommend: (1) implementing combined oral-mental health screening in prenatal care, (2) developing interventions targeting both domains, and (3) establishing care pathways that address these interconnections. This integrated approach could improve both maternal and child health outcomes.

Clinical, oral immunological and microbiological shifts during and after pregnancy

OBJECTIVES

Physiological changes and shifts in the oral microbiota composition during pregnancy may affect the maternal immune system. Uncomplicated pregnancy is associated with a T-helper (Th) 2 predominant cytokine regulation (anti-inflammatory), while oral health deterioration during pregnancy is reflected by severe gingival inflammation, a primarily Th1 cytokine phenotype (pro-inflammatory), and oral microbiome alterations. This prospective observational study aimed to evaluate Th cytokine shifts and changes in the oral microbiota composition in saliva of women before and after birth.

MATERIAL AND METHODS

Saliva (n = 96) was collected before and 6 months after birth, and medical, oral health, and periodontal status were assessed. In a multiplex immunoassay, 10 cytokines were simultaneously analyzed and cumulative Th1 and Th2 cytokine levels and Th1/Th2 ratio were calculated for all groups. Putative periodontal pathogens (n = 6) were evaluated by quantitative real-time polymerase chain reaction.

RESULTS

Th2 cytokine levels were significantly lower (p = 0.014) while pro-inflammatory cytokine levels were significantly higher (p < 0.01) during pregnancy than postpartum. Similar Th1 levels were found between the groups (p = 0.143). Th1 and Th2 cytokines positively correlated with periodontal parameters (p < 0.001) and levels of studied bacteria during pregnancy (p < 0.05).

CONCLUSIONS

This study identified a significantly increased Th1/Th2 cytokine ratio during pregnancy and a positive association with putative periodontal pathogens. This immunological and microbiological deregulation in the oral milieu during pregnancy is suggestive of a destructive inflammatory periodontal profile.

STUDY REGISTRATION

Clinical Trials.gov (Record BAP-2015).

CLINICAL RELEVANCE

Understanding altered oral immunological and microbiological regulation patterns during pregnancy may help improve the inflammatory periodontal profile in pregnant women.

Oral and general health conditions involved in periodontal status during pregnancy: a prospective cohort study

PURPOSE

Pregnancy is a period in a woman's life that has important consequences on oral health, particularly for gingival health. Present study aims to identify women at higher risk of developing periodontal disease (gingivitis and periodontitis) during late pregnancy and evaluate how this condition evolves during this period.

METHODS

Prospective cohort study was designed with pregnant women who were assessed during the first and third trimesters of gestation in a southern Spanish public hospital. Data regarding gingival and periodontal health, oral hygiene, and overall health status (obesity and diabetes mellitus) were collected. Reporting followed STROBE checklist.

RESULTS

Significantly higher number of women had the periodontal and gingival disease in the third trimester of gestation compared with in early pregnancy. In the third trimester of gestation, 42 (28.6%) and 63 (42.9%) of women presented symptoms of periodontal disease and gingival disease, respectively. Obesity (OR 2.834; 95%CI 0.919-8.741), worse oral hygiene during the first trimester of gestation (OR: 4.031; 95%CI 2.12-7.65), and periodontal disease during early pregnancy (OR: 15.104; 95%CI 3.60-63.36) most effectively predicted periodontal disease during late pregnancy.

CONCLUSIONS

Pregnancy is associated with exacerbated periodontal and gingival disease symptoms throughout the different trimesters of gestation. Obesity and oral hygiene during early pregnancy were the risk factors that most contributed to the aforementioned changes in periodontal disease.

The potential role of the gingival crevicular fluid biomarkers in the prediction of pregnancy complications

Early and minimally invasive methods are required to predict the risk of multiple adverse pregnancy outcomes. A potential technique with growing interest utilizes the gingival crevicular fluid (GCF), a physiological serum exudate found in the healthy gingival sulcus and in the periodontal pocket in inflammatory conditions. Analysis of biomarkers in the GCF is a minimally invasive method that can be feasible and cost-effective. The potential use of GCF biomarkers along with other clinical indicators in early pregnancy may provide reliable predictors of several adverse pregnancy outcomes, therefore, reducing both maternal and fetal morbidities. Various studies have reported that increased or decreased concentrations of different biomarkers in GCF are associated with a high risk of developing pregnancy complications. In particular, such associations have been commonly demonstrated with gestational diabetes, pre-eclampsia, and pre-term birth. However, limited evidence is available regarding other pregnancy complications such as preterm premature rupture of membranes, recurrent miscarriage, small for gestational age, and hyperemesis gravidarum. In this review, we discuss the reported association between individual GCF biomarkers and common pregnancy complications. Future research is required to provide more solid evidence of the predictive value of those biomarkers in estimating women's risk for each disorder.

Comparison of oxidative stress markers in the saliva, gingival crevicular fluid, and serum samples of pregnant women with gestational diabetes and healthy pregnant women

BACKGROUND AND OBJECTIVE

To compare oxidative stress (OS) markers in the saliva, gingival crevicular fluid (GCF), and serum samples of pregnant women with gestational diabetes (GDM) and healthy pregnant women and to investigate the association between periodontal health/diseases and OS and GDM.

METHOD

Eighty women with GDM and 80 healthy pregnant women were included in the study. Medical and clinical anamnesis was obtained from all the pregnant women included in the study, and their plaque index (PI), gingival index (GI), bleeding on probing (BoP), probing pocket depth (PPD), and clinical attachment level (CAL) measurements were performed. GCF, saliva, and serum samples were collected for the measurements of the local and systemic total antioxidant status (TAS) and total oxidant status (TOS).

RESULTS

Clinical periodontal parameters were found to be significantly higher in the GDM group compared to the control group. The serum and saliva TAS, TOS, and TAS/TOS values were significantly lower in the GDM group than in the control group. In the analysis of the GCF samples, the mean TAS and TAS/TOS values were significantly lower and the TOS value was significantly higher in the GDM group than in the control group. The multivariate reduced model indicated that gravidity, salivary TAS/TOS, and GCF TAS were significant independent variables in the development of GDM (p < .05).

CONCLUSION

Our results indicated that the OS of serum, saliva, and GCF samples increased in patients with GDM compared to healthy pregnant women. The role of local OS parameters in GDM may be associated with elevated clinical periodontal parameters.

Oral Health Status and Literacy/Knowledge Amongst Pregnant Women in Shanghai

BACKGROUND

The changes in hormones, diet, and hygiene associated with pregnancy are associated with oral diseases. There is insufficient awareness of the importance of oral health during pregnancy. This study investigated the oral health status and knowledge amongst pregnant women in Shanghai.

METHODS

This cross-sectional study enrolled pregnant women at the Shanghai Red House Obstetrics & Gynecology Hospital in December 2020. The Fourth National Oral Health Questionnaire was used to evaluate the oral health status. Decayed/missing/filled teeth (DMFT) were the sum of the number of decayed, missing due to caries, and filled teeth. The chi-square test and Kruskal-Wallis test were used to compare the groups.

RESULTS

A total of 224 pregnant women were enrolled. The rates of dental caries were 69.8%, periodontal health was 1.8%, calculus detection was 95.6%, shallow periodontal pocket was 51.1%, deep periodontal pocket was 4.9%, regular oral examination was 22.8%, correct brushing was 49.6%, and prepregnancy oral examination was 20.1%. DMFT was 2.27, and the caries filling ratio was 45.4%. The number of missing teeth increased with age (P < .001). Only 26.3% used dental floss more than once a day, 47.3% rinsed the mouth more than twice a day, and 46.9% cleaned their tongue coating every week. In addition, 99% of the pregnant women agreed that "oral health was vital to their lives" and 97.7% agreed that "regular oral examination was necessary."

CONCLUSIONS

The oral health status amongst pregnant women in Shanghai was poor, but oral health awareness and attitudes were relatively high.

Relationship between soluble neuropilin-1 in the gingival crevicular fluid of early pregnant women and different severities of periodontitis: A cross-sectional study

Background

Pregnancy exacerbates the periodontal inflammation; however, the biological mediators involved are not well characterized. Neuropilins (NRPs) are transmembrane glycoproteins involved in physiological and pathogenic processes such as angiogenesis and immunity but its relationship with periodontal disease in pregnant women has not been studied.

Objective

To explore the soluble Neuropilin-1 (sNRP-1) levels in gingival crevicular fluid (GCF) samples during early pregnancy and its association with the periodontitis severity and periodontal clinical parameters.

Methods

80 pregnant women were recruited, and GCF samples were collected. Clinical data and periodontal clinical parameters were recorded. sNRP-1 expression was determined by ELISA assay. The relationship between sNRP-1(+) pregnant women with the severity of periodontitis and periodontal clinical parameters was determined by Kruskal-Wallis and Mann-Whitney tests. Spearman's test estimated the correlation between sNRP-1 levels and periodontal clinical parameters.

Results

Periodontitis was classified as mild in 27.5% (n = 22) women, moderate in 42.5% (n = 34), and severe in 30% (n = 24). sNRP-1 expression was higher in the GCF of pregnant with severe (41.67%) and moderate (41.17%) periodontitis compared than in those with mild periodontitis (18.8%). The sNRP-1(+) pregnant had a higher BOP (76.5% v/s 57%; p = 0.0071) and PISA (1199.5 mm2 v/s 880.2 mm2; p = 0.0282) compared with sNRP-1(-). A positive correlation between sNRP-1 levels in GCF and BOP (p = 0.0081) and PISA (p = 0.0398) was observed.

Conclusions

The results suggest that sNRP-1 could be involved in periodontal inflammation during pregnancy.

Effect of oral health promotion interventions on pregnant women dental caries: a field trial

BACKGROUND

Dental caries is a costly and very common disease, especially in pregnant women. Reasons such as not paying attention to oral health, poor diet and also lack of adequate education in this regard cause this to happen. Performing well-designed educational interventions using primary health system's forces, can improve oral health of pregnant women and help control this disease. We conducted this study to evaluate the effectiveness of some oral health interventions on pregnant women dental caries.

METHODS

A field trial study was done in comprehensive Health Centers in Varamin, Tehran, Iran to assess 439 mothers' dental health status from pregnancy up to 2 years after delivery in intervention (n = 239) and control groups (n = 200). Mothers in intervention groups received oral health-related education consisted of nutritional and behavioral messages via either of four methods: A: comprehensive method including all following methods together (n = 74), B: group discussion by dentists (n = 59), C: face to face education by primary health care providers (n = 53), and D: social network applications (n = 53); while those in control group only received routine maternal and oral health care. We used a questionnaire to collect mothers' demographic, socioeconomic and dental care behavior data and also performed oral examinations to assess their DMFT at baseline and 24 months after delivery to evaluate the effectiveness of these educational oral health interventions.

RESULTS

From 454 mothers participated the examination session, 18 pregnant women discontinued during the follow-ups and 439 were remained with mean age of 27.47. In the intervention group, the frequency of daily brushing among women increased from 64% at baseline to 85.6% at the last follow-up and the mean D significantly decreased nearly 1unit at same period (P < 0.05). Most and least dental caries changes were in comprehensive intervention group and social network intervention group compared to other intervention groups, respectively.

CONCLUSIONS

Performing educational interventions during and after pregnancy using various message delivery methods and messengers (oral health professionals and trained PHCPs), could improve oral health status and behaviors of pregnant and lactating mothers in a feasible and applicable manner.

Hormonal Fluctuations and Periodontal Status in Postmenopausal Women

Introduction. While the short-term effects of hormonal events on gingival inflammation have been well described, their long-term effects on the periodontium have received less attention. Our investigation was aimed at evaluating the correlation between hormonal fluctuations and periodontal status in postmenopausal women from the profile of the Rafsanjan Cohort Study. Material and Methods. We used the data obtained from the profile of the Rafsanjan Cohort Study (RCS) as a part of the prospective epidemiological research studies in Iran (PERSIAN). The RCS includes 10,000 participants aged 35–70 years old. Among this population, the periodontal status data of 4143 women were available. Of these 4,143, the postmenopausal women were included in the study, and those who had a history of gingival treatment during the past 6 months were excluded from the study. Finally, 928 postmenopausal women were included in the present study. Periodontal status was assessed by measuring the clinical attachment loss, pocket depth, and bleeding on probing (BOP). Univariate and multivariate regression analyses were applied using three different models. Results. The results showed that 53.2% of postmenopausal women had periodontitis. There were significant differences between the participants with and without periodontitis in brushing frequency and educational status $\left(P<0.05\right)$ . After adjusting for all potential confounders, no correlation was found between hormonal fluctuations and periodontal status. Conclusion. There was no correlation between hormonal fluctuations and periodontal status.

Periodontitis and Gestational Diabetes Mellitus: A Potential Inflammatory Vicious Cycle

Periodontitis is a chronic inflammatory immune disease associated with a dysbiotic state, influenced by keystone bacterial species responsible for disrupting the periodontal tissue homeostasis. Furthermore, the severity of periodontitis is determined by the interaction between the immune cell response in front of periodontitis-associated species, which leads to the destruction of supporting periodontal tissues and tooth loss in a susceptible host. The persistent bacterial challenge induces modifications in the permeability and ulceration of the sulcular epithelium, which facilitates the systemic translocation of periodontitis-associated bacteria into distant tissues and organs. This stimulates the secretion of pro-inflammatory molecules and a chronic activation of immune cells, contributing to a systemic pro-inflammatory status that has been linked with a higher risk of several systemic diseases, such as type 2 diabetes mellitus (T2DM) and gestational diabetes mellitus (GDM). Although periodontitis and GDM share the common feature of systemic inflammation, the molecular mechanistic link of this association has not been completely clarified. This review aims to examine the potential biological mechanisms involved in the association between periodontitis and GDM, highlighting the contribution of both diseases to systemic inflammation and the role of new molecular participants, such as extracellular vesicles and non-coding RNAs, which could act as novel molecular intercellular linkers between periodontal and placental tissues.

Isobaric tags for relative and absolute quantification (iTRAQ)-based quantitative analysis of the salivary proteome during healthy pregnancy and pregnancy gingivitis

AIM

The present study aimed to investigate the salivary proteome profiles of pregnant women with gingivitis (PG) or without gingivitis (HP) and non-pregnant healthy controls (HC) by employing iTRAQ-based proteomics.

MATERIALS AND METHODS

Saliva samples were collected from 30 Chinese women comprising 10 subjects in each of the three groups (PG, HP, and HC). The samples were subjected to iTRAQ-based proteomics analysis, and ELISA was performed to validate the results. The subsequent observations were validated in a cohort of 48 subjects.

RESULTS

Pathways associated with neutrophil-mediated immune response and antioxidant defence mechanism were significantly higher in PG than HC. The abundance of salivary cystatins (S, SA, and SN) and antimicrobials were significantly decreased in PG and HP, while cystatin C and D were additionally decreased in PG. Cystatin C was mapped to all the major catabolic pathways and was the most re-wired protein in pregnancy gingivitis. Further validation demonstrated cystatin C to be significantly lower in PG than HC.

CONCLUSIONS

While the decrease in levels of salivary cystatins and antimicrobial proteins may predispose healthy pregnant women to pregnancy gingivitis, it may cause persistence of inflammation in pregnant women with gingivitis.

Periodontology and pregnancy: An overview of biomedical and epidemiological evidence

Women are particularly susceptible to developing gingival problems during pregnancy. In addition, periodontal disease in pregnant women may lead to adverse outcomes for both mother and infant, which have serious clinical and public health implications. Both scenarios have been extensively researched, helping to bring attention to pregnant women as an important and vulnerable population as it concerns periodontal health. The increase in gingival inflammation caused by hormonal changes in pregnant women is undisputed and has been studied and documented since the 1960s, although the exact etiology is not fully understood. The relationship between periodontal disease during pregnancy and adverse pregnancy outcomes is less substantiated, because of conflicting evidence. This review of the biomedical and epidemiologic literature provides an overview of both sides of this relationship and examines the potential mechanisms for developing periodontal disease during pregnancy and the proposed mechanisms by which periodontal disease leads to adverse pregnancy outcomes.

Oral Microbiota: A Major Player in the Diagnosis of Systemic Diseases

The oral cavity is host to a complex and diverse microbiota community which plays an important role in health and disease. Major oral infections, i.e., caries and periodontal diseases, are both responsible for and induced by oral microbiota dysbiosis. This dysbiosis is known to have an impact on other chronic systemic diseases, whether triggering or aggravating them, making the oral microbiota a novel target in diagnosing, following, and treating systemic diseases. In this review, we summarize the major roles that oral microbiota can play in systemic disease development and aggravation and also how novel tools can help investigate this complex ecosystem. Finally, we describe new therapeutic approaches based on oral bacterial recolonization or host modulation therapies. Collaboration in diagnosis and treatment between oral specialists and general health specialists is of key importance in bridging oral and systemic health and disease and improving patients' wellbeing.

Periodontitis Is Associated With Risk of Conventional Stent Restenosis: Pilot Case-Control Study

Objectives: Percutaneous coronary angioplasty with stent implantation has been established as the main form of treatment of atherosclerosis. However, 16 to 44% of patients may evolve with stent restenosis. Periodontitis is an inflammatory condition associated with bacterial infection, that may lead to periodontal tissue destruction and tooth loss. This study aimed to evaluate the association between stent restenosis and periodontitis.

Materials and Methods: Coronary angiography exams presenting stent imaging with and without restenosis were analyzed. Patients meeting the inclusion and exclusion criteria were selected and allocated in 2 groups: case (restenosis) and control (without restenosis). We evaluated if systemic and periodontal variables were predictors of restenosis (primary outcome) using a multivariable stepwise logistic regression. Additionally, we compared clinical and periodontal conditions between the control and case groups (secondary outcomes) using Chi-square test and ANOVA test.

Results: Data from 49 patients (case n = 15; control n = 34) were analyzed. The results showed that stages III and IV periodontitis and lack of physical activity were significant predictors of stent restenosis (OR 5.82 and 5.98, respectively). Comparisons regarding the diagnosis of periodontal conditions between control and case groups did not present significant differences in the incidence of periodontitis and alveolar bone loss.

Conclusion: Stages III and IV periodontitis increased the incidence of stent restenosis. These findings suggest that advanced stages of periodontal disease might lead to the occurrence of negative outcomes after coronary angioplasty with stent placement.

Pregnancy and Dentistry: A Literature Review on Risk Management during Dental Surgical Procedures

Background: Pregnancy is a unique moment in a woman’s life, accompanied with several physiologic changes that have an impact on oral health. Aim of the study: The purpose of the present study was to conduct a critical review of published literature regarding pregnancy and dentistry, the most frequent oral diseases that are encountered during pregnancy, their correlation to adverse pregnancy events, and safe dental treatments that can be performed during pregnancy. Methods: A Medline/COCHRANE search was carried using specific keywords and MeSH terms, combined with the boolean operators “OR” and “AND”. Results: The search led to 146 publications including guidelines, meta-analyses, systematic and non-systematic reviews, published between 2000 and 2021. Discussion and conclusions: Due to the increased inflammatory and immune body response that characterizes pregnancy, periodontal conditions are often aggravated during pregnancy and periodontal disease encountered frequently in pregnant patients. There are conflicting study results in the literature regarding the association between periodontitis and adverse pregnancy outcomes. Periodontal treatment did not show a significant reduction in the adverse outcomes. Many dentists, often due to lack of information, are reluctant to provide dental treatment to pregnant women. However, preventive and restorative dental treatment is safe during pregnancy. Diagnostic radiographs may be performed after the first trimester if absolutely necessary. Analgesics (such as paracetamol) and anesthetics (such as lidocaine) are also considered safe. In case of infection, antibacterial drugs such as amoxicillin, ampicillin, and some cephalosporines and macrolides can also be prescribed. Organogenesis takes place in the first trimester, the time during which the fetus is susceptible to severe malformations (teratogenesis). The ideal time to perform dental treatment is the second trimester (week 17 to 28). However, acute pain or infections make the intervention of the dentist absolutely necessary and emergency treatment can be performed during the whole pregnancy period.

Regulation of matrix metalloproteinases-8, -9 and endogenous tissue inhibitor-1 in oral biofluids during pregnancy and postpartum

OBJECTIVE

During pregnancy, mothers undergoe considerable physiological changes affecting the whole body including periodontal tissues. Susceptibility to gingival inflammation during pregnancy could be mediated by modulation of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). Therefore, the aim of this study was to investigate salivary and gingival crevicular fluid (GCF) levels of MMPs and TIMPs during the second and third trimester of pregnancy and postpartum.

DESIGN

Saliva and GCF samples were collected from 96 pregnant women (PW) before and after giving birth. The sixty matched non-pregnant women (N-PW) were recruited as a control group and full-mouth periodontal examination was performed. The levels of MMP-8, MMP-9 and TIMP-1 were determined by immunofluorometric and enzyme-linked immunosorbent assays.

RESULTS

The PW group exhibited significantly higher levels of MMP-8 and MMP-9 in their saliva than the N-PW group while corresponding salivary TIMP-1 levels were significantly lower in NPW compared to the postpartum stage. This resulted in significantly higher MMP-8/TIMP-1 and MMP-9/TIMP-1ratio in the saliva from PW before and after birth than in that from N-PW. MMP-8, MMP-9 and TIMP-1 levels were higher in GCF from PW and postpartum than in that from N-PW.

CONCLUSIONS

MMP-8 and MMP-9 levels in saliva and GCF reflect inflammatory burden during pregnancy. They could be used for monitoring the inflammatory state of gingival tissues during pregnancy.

[Treatment strategy for pregnancy epulis]

Pregnancy epulis is a tumor-like lesion with high prevalence in China. The local lesion, the general condition of the pregnant patient, and the complications during treatment should be taken into consideration when making a treatment plan for pregnancy epulis. In this study, three representative pregnancy epulis cases were presented, and related studies at home and aboard were reviewed to summarize the etiology, differential diagnosis, treatment, and prevention of pregnancy epulis and share the clinical experience in the treatment of pregnancy epulis.

Is periodontal disease a risk factor for severe COVID-19 illness?

Periodontal disease (PD) comprises a group of diseases involving inflammatory aspects of the host and dysbiotic events that affect periodontal tissues and could have systemic implications. Diverse factors and comorbidities have been closely associated with PD such as diabetes, obesity, aging, hypertension, and so on; although, underlying mechanisms or causal associations have not been established completely. Interestingly, these same factors have been widely associated with progression or severe coronavirus disease 2019 (COVID-19), an illness caused by coronavirus SARS-CoV-2. Since inflammatory and dysbiotic factors as well as comorbidities affect systemic health, it is possible that periodontal status indicates the risk of complication of COVID-19. However, assessment of oral health history including periodontal status in COVID-19 patients has not been reported. Knowing PD is associated with severe COVID-19 could help identify risk groups and establish pertinent recommendations.

Early pregnancy levels of gingival crevicular fluid matrix metalloproteinases-8 and -9 are associated with the severity of periodontitis and the development of gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is increasing worldwide and women with a history of GDM are at risk of developing type 2 diabetes which is a risk factor for periodontitis. The aim of this study was to explore the association between the concentrations of matrix metalloproteinase (MMP)-8 and -9 in gingival crevicular fluid (GCF) during early pregnancy with the periodontal diagnosis and the risk of GDM development.

METHODS

A prospective cohort study, including 314 women, enrolled at 11 to 14 weeks of pregnancy was conducted. A complete maternal/obstetric and periodontal exam was performed, and GCF samples were obtained for the MMP-8 and -9 determination by Multiplex Elisa Assays. Mann-Whitney test; Spearman's correlation and log-binomial regression model estimated the association between MMPs concentration in GCF and GDM.

RESULTS

Fourteen percent of the pregnancies were diagnosed with GDM. An increase in the concentration of MMP-8 and -9 in women with periodontitis stage III and IV compared to periodontitis stage I was observed (99.31 ng/mL [IQR: 85.32] versus 71.95 ng/mL [IQR: 54.04], and 262.4 ng/mL [IQR: 312.55] versus 114.1 ng/mL [IQR: 184.94], respectively). Women who developed GDM showed increased concentrations of MMP-8 and -9 in GCF since the beginning of pregnancy (P = 0.0381; P = 0.0302, respectively). MMP-8 concentration in GCF was associated with GDM (RR: 1.19; P = 0.045; CI 95% 1.00 to 1.40; and RR: 1.20; P = 0.063; CI 95% 0.99 to 1.45 in the adjusted model).

CONCLUSION(S)

GCF concentrations of MMP-8 and -9 at early of pregnancy are increased in women with severe periodontitis and associated with the GDM development.

Periodontal disease and adverse pregnancy outcomes

Periodontal diseases are considered not only to affect tooth-supporting tissues but also to have a cause-and-effect relationship with various systemic diseases and conditions, such as adverse pregnancy outcomes. Mechanistic studies provide strong evidence that periodontal pathogens can translocate from infected periodontium to the feto-placental unit and initiate a metastatic infection. However, the extent and mechanisms by which metastatic inflammation and injury contribute to adverse pregnancy outcomes still remain unclear. The presence of oral bacteria in the placenta of women with term gestation further complicates our understanding of the biology behind the role of periodontal pathogens in pregnancy outcomes. Epidemiological studies demonstrate many methodological inconsistencies and flaws that render comparisons difficult and conclusions insecure. Therefore, despite the fact that a number of prospective studies show a positive association between periodontal diseases and various adverse pregnancy outcomes, the evidence behind it is still weak. Future well-designed explanatory studies are necessary to verify this relationship and, if present, determine its magnitude. The majority of high-quality randomized controlled trials reveal that nonsurgical periodontal therapy during the second trimester of gestation does not improve pregnancy outcomes. From a biological standpoint, this can be partially explained by the fact that therapy rendered at the fourth to sixth months of pregnancy is too late to prevent placental colonization by periodontal pathogens and consequently incapable of affecting pathogen-induced injury at the feto-placental unit. Thus, interventions during the preconception period may be more meaningful. With the increase in our understanding on the potential association between periodontal disease and adverse pregnancy outcomes, it is clear that dental practitioners should provide periodontal treatment to pregnant women that is safe for both the mother and the unborn child. Although there is not enough evidence that the anti-infective therapy alters pregnancy outcomes, it improves health-promoting behavior and periodontal condition, which in turn advance general health and risk factor control.

Periodontitis and placental growth factor in oral fluids are early pregnancy predictors of gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) affects around 7% to 10% of all pregnancies. Early detection of predisposition to GDM is the first step in developing efficacious preventive treatment. The objective of the present study was to establish the utility of placental proteins presents in oral fluids (gingival crevicular fluid [GCF] and saliva), and periodontal disease status as early pregnancy predictors of GDM.

METHODS

A nested case control within a prospective cohort was conducted. Pregnant systemically healthy women, aged between 18 and 40 years at 11 to 14 weeks gestation were included. Samples of oral fluids were collected and a complete maternal/obstetric and periodontal history was obtained. The concentration of placental growth factor (PlGF) and soluble Fms-like tyrosine kinase 1 (sFlt-1) were measured by enzyme-linked immunosorbent assay in a nested case control sample of the prospective cohort. Multiple logistic regression models assessed the association. The evaluation of the diagnostic accuracy of the biomarkers was performed through receiver operating characteristic (ROC) curves by calculating the area under the curve (AUC).

RESULTS

There were recruited 212 pregnant women at 11 to 14 weeks of pregnancy, of these, 14 women (i.e., 6.6%) developed GDM, and displayed significant greater bleeding on probing (BOP) [P = 0.0003]; periodontal probing depth (PD) [P = 0.0028]; clinical attachment level (AL) [P = 0.0008] and periodontal inflamed surface area (PISA) [P = 0.0001]. Similarly, initial glycemia and GCF-PlGF concentrations were significantly greater in women with GDM [P = 0.0012, and P = 0.0019, respectively]. When data were subjected to ROC curve analysis, the combination of initial glycemia and GCF-PlGF concentration delivered an area under the ROC curve of 0.897. Multiple logistic regression analyses demonstrate an association between glycemia (OR 1.21, 95% confidence interval [CI] 1.06 to 1.38; P = 0.005) and GCF-PlGF concentrations in women who developed GDM (OR 1.68, CI 1.05 to 2.68 P = 0.03).

CONCLUSIONS

Within the limitations of the present study, the results support that first trimester maternal glycemia combined with GCF-PlGF concentrations could be a surrogate biomarker for the future development of GDM in pre-symptomatic women.

Periodontopathogenic microbiota, infectious mechanisms and preterm birth: analysis with structural equations (cohort-BRISA)

PURPOSE

The association between periodontopathogenic microbiota and preterm birth (PTB) has been overly studied. However, the biological mechanisms involved are little known. The objective is to evaluate the effect of periodontopathogenic bacteria burden (PBB), periodontal disease and other infections during pregnancy on preterm birth (PTB), through Structural Equation Modeling.

METHODS

This was a case-control study nested in a prospective cohort called BRISA, including 330 pregnant women, 110 cases and 220 controls. This study included the following variables: cytokines interleukin-10 (IL-10) and transforming growth factor beta (TGF-β), periodontal disease, PBB, age, socioeconomic status (SES), systemic infections and PTB. The correlations between variables were analyzed using Standardized Coefficient (SC).

RESULTS

Greater PBB interfered positively with the occurrence of periodontal disease (SC: 0.027; p: 0.011), but these were not associated with the cytokines studied, nor with PTB. The lower serum levels of IL-10 (SC - 0.330; p 0.022) and TGF-β (SC - 0.612; p  < 0.001), and the presence of other systemic infections during pregnancy (SC 0.159; 0.049) explained the higher occurrence of PTB.

CONCLUSION

It is possible that only the more severe periodontal disease and other systemic infections are capable of altering the cascade of cytokines regulating the inflammatory process and have an effect on the occurrence of PTB.

Tongue coating in relationship to gender, plaque, gingivitis and tongue cleaning behaviour in systemically healthy young adults

OBJECTIVES

The purpose of this observational study was to investigate the relationship between tongue coating (thickness [Tc] and surface discoloration [Td]) and gender, plaque, gingivitis (bleeding on marginal probing [BOMP] and bleeding on pocket probing [BOPP]) and tongue cleaning behaviour.

MATERIALS AND METHODS

A total of 336 participants were screened for this cross-sectional study, from which 268 (150 male, 118 female) were found to be eligible. Aspects of tongue coating were visually assessed. Additionally, BOMP, BOPP and the plaque index (PI) were scored. To ascertain the tongue cleaning behaviour, the Oral Hygiene Behavior questionnaire was used.

RESULTS

Most tongue coating was found at the posterior sections of the tongue surface. A thin coating and white discoloration were most prevalent as highest score for both males (92.7%) and females (87.4%), as well as white discoloration for the whole group of participants (50.2%). A gender difference was observed for TC and Td (P < .001). Analysis did not reveal a relationship between Tc and PI and between Td and PI. Also, no relation was detected between tongue cleaning behaviour and Tc or Td. However, tongue cleaning was associated with lower BOMP and BOPP scores.

CONCLUSION

BOMP, BOPP or PI score did not appear to be linked to Tc and Td. A significant gender difference was found for Tc and Td. Self-reported tongue cleaning behaviour was associated with slightly lower BOMP and BOPP scores.

Oral health awareness and practices in pregnant females: A hospital-based observational study

Background:

The aim of this study was to assess the oral health awareness, methods adopted to maintain hygiene, prevalent myths regarding oral health in pregnancy, and importance of oral health during pregnancy, to help formulate oral health program for pregnant females in partaking hospital.

Materials and Methods:

A total of 225 pregnant females participated in the study. After complete demographic assessment of participants, a questionnaire was provided to them. Questionnaire included simple multiple choice questions on how they maintained oral hygiene, their oral health status, visit to the dentist, and barriers in seeking treatment. This was followed by a questionnaire regarding common myths and understanding of the importance of oral health during pregnancy which had three choices: true, false, and do not know. The results were expressed in percentages, and one sample t-test for percentages was applied where ever required.

Results:

Majority of participants self-reported some form of oral health problems with bleeding gums as a chief complaint leading the survey. Around half of the participants had never visited a dentist, and an abundant number of pregnant females reported safety concerns for developing the child as a reason for not taking any treatment during pregnancy. A highly significant number of participants were unaware of the importance of oral health during pregnancy and believed in age-old myths.

Conclusion:

The oral health care still remains on the backseat in care provided to pregnant female. A complete overhaul of understanding through individual, family, and community counseling is required to spread awareness.

Periodontal Disease and Breast Cancer: A Meta-Analysis of 1,73,162 Participants

Objective: To investigate the correlation between periodontal disease and breast cancer. Materials and Methods: PubMed and China National Knowledge Infrastructure (CNKI) databases were searched up to February 8, 2018 for observational studies examining the association between periodontal disease and breast cancer. Study selection was conducted according to predesigned eligibility criteria, and two authors independently extracted data from included studies. Meta-analysis was performed using the Comprehensive Meta-Analysis v2 software and risk estimates were calculated as relative risks (RRs) with corresponding 95% confidence intervals (CIs). Results: A total of 11 study were included. Meta-analysis indicated that periodontal disease significantly increased the risk of breast cancer by 1.22-fold (RR = 1.22, 95% CI = 1.06-1.40). Amongst participants with periodontal patients and a history of periodontal therapy, the risk of developing breast cancer was not significant (RR = 1.23; 95% CI = 0.95-1.60). The association results between periodontal diseases and breast cancer were found to be robust, as evident in the leave-one-out sensitivity analysis. Conclusions: Periodontal disease may be a potential risk factor for the development of breast cancer among women, and thus effective periodontal therapy may present as a valuable preventive measure against breast cancer.

Periodontal Disease, Inflammatory Cytokines, and PGE2 in Pregnant Patients at Risk of Preterm Delivery: A Pilot Study

Periodontal disease is an infection that, in pregnant women, can act as a risk factor for preterm delivery by increasing local and systemic inflammatory responses. Objective. To analyze the presence of periodontal disease, proinflammatory cytokines, and prostaglandin E₂ (PGE₂) in pregnant patients at high risk for preterm delivery. Materials and Methods. Pilot study for a case-control study. We included 46 pregnant patients (23 patients at risk of preterm delivery as cases and 23 patients without risk of preterm delivery as controls). We excluded patients who received periodontal treatment, antibiotics, or antimicrobials over the last 3 months as well as those with infections or diseases such as diabetes or hypercholesterolemia. The patients underwent a periodontal assessment, and their levels of cytokines (interleukin- [IL-] 2, IL-6, IL-10, and tumor necrosis factor- [TNF-] α) and prostaglandin E₂ (PGE₂) were quantified. Results. Patients with periodontal disease showed higher levels of cytokines (IL-2, IL-6, IL-10, and TNF-α) and PGE₂. Patients at high risk for preterm birth showed higher IL levels compared with patients at low risk for preterm delivery. PGE₂ increased with the severity of periodontal disease. PGE₂ was higher in patients at low risk for preterm delivery, although this difference was not significant. Conclusion. Periodontal disease can increase the systemic inflammatory response as well as the levels of PGE₂ and inflammatory cytokines in pregnant patients.

Pregnancy, parity and periodontal disease

Many women believe that their dental condition deteriorated during pregnancy or as a result of having children. Epidemiological studies have reported an association between higher parity and tooth loss, and higher parity and periodontal attachment loss. Several possible explanations for this association exist. First, hormonal changes during pregnancy affect the immune response to bacterial plaque and drive vascular and gingival changes that may contribute to heightened gingival inflammation. These changes are transient, without irreversible loss of periodontal attachment, and post-partum resolution can be expected for most women. For women with destructive periodontal disease, the effects of pregnancy and parity are unclear. Second, it is also plausible that parity and socioeconomic position (SEP) have shared risk factors, increasing the incidence of disease or influencing its management. Education, one aspect of SEP, is an important determining factor for women's fertility rate, with a gradient of fewer children with higher educational attainment. Higher levels of education are also favourably associated with behaviours conducive to oral health, and a lower incidence of damaging health behaviours. Thus, the potential for confounding is considerable. This review examines the literature on the association between pregnancy, parity and periodontal health, and explores sociobehavioural mechanisms for the observed association.

Comparison of Serum Levels of Endothelin-1 in Chronic Periodontitis Patients Before and After Treatment

INTRODUCTION

Endothelin-1 (ET-1) is a potent vasoconstrictive peptide with multi functional activity in various systemic diseases. Previous studies indicate the detection of ET-1 in gingival tissues and gingival crevicular fluid.

AIM

The aim of this study was to estimate the serum ET-1 levels in clinically healthy subjects and subjects with chronic periodontitis, before and after treatment, and correlate it with the clinical parameters.

MATERIALS AND METHODS

A total of 44 patients were included in the study. Group I comprised of 20 subjects with clinically healthy periodontium. Group II comprised of 24 subjects with chronic periodontitis. Group III comprised of same Group II subjects following periodontal management. Serum samples were collected from the subjects and an Enzyme Linked Immunosorbent Assay (ELISA) was done to estimate the ET-1 levels. The ET-1 levels were then correlated among the three groups with the clinical parameters namely, Plaque Index (PI), Sulcus Bleeding Index (SBI), probing pocket depth, clinical attachment loss and Periodontally Inflamed Surface Area (PISA). The independent t-test and paired t-test were used for comparison of clinical parameters and Pearson's correlation coefficient test was used for correlating the ET-1 levels.

RESULTS

ET-1 levels in chronic periodontitis subjects were significantly higher compared to healthy subjects (p<0.001). However, the clinical parameters did not statistically correlate with the ET-1 levels. There was a significant decrease in ET-1 levels following treatment (p<0.001).

CONCLUSION

Serum ET-1 is increased in chronic periodontitis and reduces after periodontal therapy. Further studies are required to establish ET-1 as a biomarker for periodontal disease.

The Role of Nutrition in Periodontal Health: An Update

Periodontal health is influenced by a number of factors such as oral hygiene, genetic and epigenetic factors, systemic health, and nutrition. Many studies have observed that a balanced diet has an essential role in maintaining periodontal health. Additionally, the influences of nutritional supplements and dietary components have been known to affect healing after periodontal surgery. Studies have attempted to find a correlation between tooth loss, periodontal health, and nutrition. Moreover, bone formation and periodontal regeneration are also affected by numerous vitamins, minerals, and trace elements. The aim of this review is to critically appraise the currently available data on diet and maintenance of periodontal health and periodontal healing. The effects of nutritional intervention studies to improve the quality of life and well-being of patients with periodontal disease have been discussed.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Evaluation of the gingival inflammation in pregnancy and postpartum via 25-hydroxy-vitamin D3, prostaglandin E2 and TNF-α levels in saliva

BACKGROUND

Physiological changes and immunological modifications occur during pregnancy. The clinical and biological features of periodontal infections are affected by pregnancy. The aim of the present study was to evaluate saliva levels of 25-hydroxy-vitamin D3 (25(OH)D3), prostaglandin E2 (PGE2) and TNF-alpha (TNF-α) in pregnancy, postpartum and non-pregnant controls.

METHODS

Whole saliva samples together with full-mouth clinical periodontal recordings were obtained from 59 pregnant, 47 post partum and 70 systemically healthy non-pregnant women. Groups were also evaluated according to the periodontal health status. 25(OH)D3, PGE2 and TNF-α levels in the saliva samples were determined by enzyme-linked immunoassays. Data were statistically tested by nonparametrical tests.

RESULTS

Saliva TNF-α and PGE2 levels were significantly lower and 25(OH)D3 levels were significantly higher in the pregnant group than postpartum group (p<0.0001). Saliva TNF-α and 25(OH)D3 levels were significantly higher and PGE2 levels were significantly lower in the control group than postpartum group (p<0.0001). In the pregnant healthy, gingivitis and periodontitis groups saliva TNF-α levels were significantly lower than postpartum and control counterparts (p<0.0001, p=0.032, p=0.003 and p=0.013; p=0.027; p=0.007, respectively). In control healthy, gingivitis and periodontitis groups saliva 25(OH)D3 levels were significantly higher than the postpartum counterparts (p<0.0001, p<0.0001, p=0.002, respectively). In the control healthy and gingivitis groups saliva 25(OH)D3 levels were significantly higher than pregnant healthy and gingivitis (p<0.0001).

CONCLUSIONS

In conclusion, within the limits of the present study it seems that pregnancy have an effect on parameters in saliva in relation to the periodontal status of the women. Further studies are required for better understanding of the impact of periodontal diseases on pregnancy or otherwise.

Oxidative stress markers in saliva and periodontal disease status: modulation during pregnancy and postpartum

BACKGROUND

Periodontal diseases may affect local and systemic inflammation, and reactive oxygen species (ROS) levels. This systemic health burden could compromise the outcome of pregnancy in expectant mothers. The aim of the present study was to evaluate oxidative stress markers, including glutathione peroxidase (GPx), thiobarbituric acid-reactive substances (TBARS) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), and total bacterial loads in the saliva of pregnant and postpartum women, and to investigate their association with periodontal disease severity.

METHODS

A total of 187 women were originally recruited for this case-control study, assigned to the following groups a) pregnant group, b) postpartum group: the pregnant group re-evaluated 6 months after giving birth, c) control group: systemically healthy and non-pregnant women. The levels of the studied oxidative stress markers in saliva were measured by commercially available kits.

RESULTS

The levels of salivary 8-OHdG were significantly elevated in the pregnant, compared with the control group. Although salivary 8-OHdG levels slightly decreased after giving birth (postpartum group), the difference did not reach significance. In contrast, the activity of antioxidant enzyme GPx in saliva was significantly lower in the pregnant than the control group. Although no differences in lipid peroxidation (represented by TBARS) were observed between the pregnant and control groups, after giving birth TBARS levels were significantly lowered. Only in the postpartum and control groups did clinical measurements of periodontal disease severity correlate with oxidative stress markers. Interestingly, there were no such correlations with TBARS in the pregnant and postpartum groups.

CONCLUSIONS

The present study shows changes in the oxidant/antioxidant balance in saliva during pregnancy and after birth, which may be affected by periodontal health status in the latter case. Whether this is associated with adverse pregnancy outcomes, or not, remains to be elucidated. Early identification of ROS markers in saliva may be of clinical value in the periodontal management of pregnant women.

Using risk assessment in periodontics

Risk assessment has become a regular feature in both dental practice and society as a whole, and principles used to assess risk in society are similar to those used in a clinical setting. Although the concept of risk assessment as a prognostic indicator for periodontal disease incidence and activity is well established in the management of periodontitis, the use of risk assessment to manage the practical treatment of periodontitis and its sequelae appears to have less foundation. A simple system of initial risk assessment - building on the use of the Basic Periodontal Examination (BPE), clinical, medical and social factors - is described, linked to protocols for delivering care suited to general dental practice and stressing the role of long-term supportive care. The risks of not treating the patient are considered, together with the possible causes of failure, and the problems of successful treatment are illustrated by the practical management of post-treatment recession.

Sociodemographic disparities and behavioral factors in clinical oral health status during pregnancy

OBJECTIVES

Although oral health (OH) problems are common during pregnancy, little is known about individual characteristics or behaviors relating to clinically assessed OH during pregnancy. This cross-sectional study describes the clinical OH status of a sample of pregnant women, examines relationships between sociodemographic factors and OH, behavioral factors and OH, and the influence of behavior on the relationships between sociodemographic clusters and OH. Baseline data were utilized from a pilot intervention study promoting OH during pregnancy.

METHODS

Participants (n = 99), recruited from CenteringPregnancy(®) prenatal care groups completed questionnaires addressing race/ethnicity, income, education, dental insurance, oral hygiene practices, and dental care utilization; and clinical examinations for periodontal probing depths (PD), bleeding on probing (BOP), plaque assessment, and visual detection of untreated decay. Chi-squares and one-way anovas with Tukey's studentized range test of planned comparisons were conducted to examine bivariable relationships between both sociodemographic and behavioral characteristics to OH status. Multivariable logistic regression analyses tested whether the effects of sociodemographic variables on OH status might be mediated by behaviors, including self-reported oral hygiene and recent dental visits.

RESULTS

Forty-five percent of the sample had untreated decay and the mean percentage of sites with BOP = 18%. Bivariable analyses of sociodemographic factors indicated that compared with Whites, Hispanic women had greater % of sites with: BOP, PD ≥5 mm plus BOP, and Plaque Index (PI) scores of ≥2, all P = 0.05; and greater untreated decay (Chi-square 13.3, P < 0.001). Lower income was related to greater untreated decay (Chi-square 7.6, P < 0.01). Compared with the highest education level, the lowest level group had higher % BOP, P < 0.05. Public dental insurance (versus private) was associated with greater % BOP, PD ≥5 mm plus BOP, both P < 0.05, and greater untreated decay (Chi-square 16.9, P < 0.001). Regarding behaviors, lacking a past 6-month dental visit was related to greater: BOP, PD ≥5 mm plus BOP, and PI ≥2 (F range 6.2-8.7, P < 0.01-0.05); and greater untreated decay (Chi-square 12.0, P < 0.001). Self-reported optimal oral hygiene was related to lower % BOP and PD ≥5 mm plus BOP (F range 4.5-6.7, both P < 0.05). Mediation analyses indicated that there were significant indirect effects of racial/ethnic differences on OH outcomes via having a recent dental visit (OR range 1.2-1.9). However, significant differences between the Hispanic and White groups remained.

CONCLUSIONS

This study highlights sociodemographic disparities in clinical OH during pregnancy, the importance of dental care, and provides useful findings for tailoring interventions for expectant mothers and their infants.

Periodontology: past, present, perspectives

Periodontitis is an infectious disease that affects the tooth-supporting tissues and exhibits a wide range of clinical, microbiological and immunological manifestations. The disease is associated with and is probably caused by a multifaceted dynamic interaction of specific infectious agents, host immune responses, harmful environmental exposure and genetic susceptibility factors. This volume of Periodontology 2000 covers key subdisciplines of periodontology, ranging from etiopathogeny to therapy, with emphasis on diagnosis, classification, epidemiology, risk factors, microbiology, immunology, systemic complications, anti-infective therapy, reparative treatment, self-care and affordability issues. Learned and unlearned concepts of periodontitis over the past 50 years have shaped our current understanding of the etiology of the disease and of clinical practice.

The ambit of periodontal reproductive endocrinology

A preface on the historical background, scope and clinical importance of the effects of reproductive endocrinology on the periodontium is presented. Furthermore, deductive explanations of intuitive observations evaluating the influence of reproductive endocrinology on the periodontium are discussed.

Symbiotic bacteria appear to mediate hyena social odors

All animals harbor beneficial microbes. One way these microbes can benefit their animal hosts is by increasing the diversity and efficacy of communication signals available to the hosts. The fermentation hypothesis for mammalian chemical communication posits that bacteria in the scent glands of mammals generate odorous metabolites used by their hosts for communication and that variation in host chemical signals is a product of underlying variation in the bacterial communities inhabiting the scent glands. An effective test of this hypothesis would require accurate surveys of the bacterial communities in mammals' scent glands and complementary data on the odorant profiles of scent secretions--both of which have been historically lacking. Here we use next-generation sequencing to survey deeply the bacterial communities in the scent glands of wild spotted and striped hyenas. We show that these communities are dominated by fermentative bacteria and that the structures of these communities covary with the volatile fatty acid profiles of scent secretions in both hyena species. The bacterial and volatile fatty acid profiles of secretions differ between spotted and striped hyenas, and both profiles vary with sex and reproductive state among spotted hyenas within a single social group. Our results strongly support the fermentation hypothesis for chemical communication, suggesting that symbiotic bacteria underlie species-specific odors in both spotted and striped hyenas and further underlie sex and reproductive state-specific odors among spotted hyenas. We anticipate that the fermentation hypothesis for chemical communication will prove broadly applicable among scent-marking mammals as others use the technical and analytical approaches used here.