Changes in inflammatory mediators in gingival crevicular fluid following periodontal disease treatment in pregnancy: relationship to adverse pregnancy outcome

Effect of Treating Periodontal Disease in Pregnant Women to Reduce the Risk of Preterm Birth and Low Birth Weight: An Umbrella Review

Background: The aim of this review was to evaluate the effects of periodontal disease (PD) treatment in pregnant women to reduce the risk of preterm birth (PB) and low birth weight (LBW) by conducting an umbrella review. Methods: A comprehensive search for the literature up to April 2024 was conducted across multiple databases including PubMed, Cochrane Library, Scopus, EMBASE, Scielo, Web of Science, Google Scholar, Proquest Dissertations and Theses, and OpenGrey. We specifically targeted systematic reviews (SRs) with or without meta-analyses, irrespective of language or time constraints, focusing on primary studies examining the effect of PD treatment in pregnant women to reduce the risk of PB and LBW. Various types of non-systematic reviews, intervention studies, observational studies, preclinical and basic research, summaries, comments, case reports, protocols, personal opinions, letters, and posters were excluded from consideration. The quality and overall confidence of the included studies were assessed using the AMSTAR-2 tool. Results: After the initial search, 232 articles were identified, of which only 24 met the selection criteria after exclusion. The majority of these studies indicated that periodontal treatment reduces the risk of PB and LBW. Conclusions: According to the findings and conclusions drawn from the SRs with a high overall confidence level, PD treatment in pregnant women reduces the risk of PB and LBW.

Interleukin 1 beta and its association with the periodontal health of pregnant women

Objectives

In this study, we measured and compared serum and gingival crevicular fluid (GCF) levels of interleukin 1 beta (IL-1β) in pregnant women with periodontitis and pregnant women with a healthy periodontium. We also determined the prevalence of periodontitis among pregnant women attending Omdurman Midwifery Hospital.

Materials

This was a hospital-based clinical study and laboratory investigation using ELISA tests of 80 pregnant women in the third trimester conducted at the Omdurman Midwifery Hospital in Khartoum, Sudan. The study group consisted of 50 women while the control group consisted of 30 women.

Results

Independent samples t-tests were used to compare serum and GCF levels of IL-1β between the study and control groups. Pearson's correlation analysis was also used to compare gingival parameters and IL-1β levels in the GCF. For each comparison, the p-value was fixed at 0.05. The GCF in the research group showed a considerable increase in IL-1β levels. There was also a strong positive association between high IL-1β levels in the research group's GCF and probing pocket depth (PPD) and clinical attachment level (CAL) levels.

Conclusions

Our study provides further evidence that periodontitis, as measured by a PD ≥4 mm and a CAL ≥3 mm, is associated with an increased level of IL-1β in the GCF of pregnant women with active periodontal disease during pregnancy and may include the transient translocation of oral organisms to the utero-placental unit, inciting placental inflammation or oxidative stress early in pregnancy, ultimately resulting in placental damage and clinical manifestations.

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.

The bidirectional relationship between periodontal disease and pregnancy via the interaction of oral microorganisms, hormone and immune response

Periodontal disease has been suggested to be linked to adverse pregnancy outcomes such as preterm birth, low birth weight, and preeclampsia. Adverse pregnancy outcomes are a significant public health issue with important clinical and societal repercussions. This article systematically reviews the available epidemiological studies involving the relationship between periodontal disease and adverse pregnancy outcomes over the past 15 years, and finds a weak but independent association between adverse pregnancy outcomes and periodontal disease. The bidirectional association and the potential mechanisms are then explored, focusing on three possible mechanisms: inflammatory reaction, oral microorganisms and immune response. Specifically, elevated systemic inflammation and increased periodontal pathogens with their toxic products, along with a relatively suppressed immune system may lead to the disruption of homeostasis within fetal-placental unit and thus induce adverse pregnancy outcomes. This review also explains the possible mechanisms around why women are more susceptible to periodontal disease. In conclusion, pregnant women are more likely to develop periodontal disease due to hormonal changes, and periodontal disease has also been suspected to increase the incidence of adverse pregnancy outcomes. Therefore, in order to lessen the risk of adverse pregnancy outcomes, both obstetricians and dentists should pay attention to the development of periodontal diseases among women during pregnancy.

Periodontal disease in pregnancy and adverse pregnancy outcomes: Progress in related mechanisms and management strategies

Periodontal disease is an inflammatory and destructive disease of tissues supporting the tooth. A large number of studies have confirmed that periodontal pathogens and their metabolites can lead to adverse pregnancy outcomes in direct or indirect ways. Adverse pregnancy outcomes, such as preterm birth, low birth weight, and pre-eclampsia, have a serious impact on human reproductive health. In recent years, although the level of global medical technology has gradually improved, the incidence of adverse pregnancy outcomes has not declined and is still a global public health problem. The purpose of this review is to summarize the current data on periodontal disease in pregnancy and adverse pregnancy outcomes, including the association between periodontal disease and adverse pregnancy outcomes, the pathogenic mechanism related to this association, the efficacy of different nutrition supplements for both periodontal disease and adverse pregnancy outcomes and the effect of providing periodontal treatment on the occurrence of adverse pregnancy outcomes, to provide guidance for the prevention and treatment of adverse pregnancy outcomes in clinical practice.

Managing the Systemic Impact of Periodontitis

Periodontitis is a microbially driven host-mediated disease that leads to loss of periodontal attachment and bone. It is associated with elevation of systemic inflammatory markers and with the presence of systemic co-morbidities. Furthermore, periodontal treatment leads to a 24-48 h-long acute local and systemic inflammatory response. This systemic response might increase the burden of patients with compromised medical history and/or uncontrolled systemic diseases. The correlation between periodontitis and systemic diseases, the impact of periodontitis on the quality of life and public health, the effects of periodontal treatment on systemic health and disease, and the available methods to manage systemic inflammation after periodontal therapy are discussed. The main focus then shifts to a description of the existing evidence regarding the impact of periodontitis and periodontal treatment on systemic health and to the identification of approaches aiming to reduce the effect of periodontitis on systemic inflammation.

Association between Maternal Periodontitis and Development of Systematic Diseases in Offspring

Periodontal disease (PD) is one of the most common oral conditions affecting both youths and adults. There are some research works suggesting a high incidence of PD in pregnant women. As an inflammatory disease of bacterial origin, PD may result in the activation of the pathways affecting the course and the pregnancy outcome. The authors, based on the literature review, try to answer the PICO question: Does maternal periodontitis (exposure) influence the incidence of complications rates in pregnancy and the development of systemic diseases in childhood and adult offspring (outcome) in the humans of any race (population) compared to the offspring of mothers with healthy periodontium (comparison)? The authors try to describe the molecular pathways and mechanisms of these interdependencies. There is some evidence that maternal periodontitis may affect the pregnancy course and outcome, resulting in preeclampsia, preterm delivery, vulvovaginitis and low birth weight. It can be suggested that maternal periodontitis may affect offspring epigenome and result in some health consequences in their adult life.

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.

Oral Status in Pregnant Women from Post-Industrial Areas of Upper Silesia in Reference to Occurrence of: Preterm Labors, Low Birth Weight and Type of Labor

Increased levels of steroid hormones, action of local irritants and the lack of proper hygiene measures are of great importance in the development of dental caries, gingivitis and inflammation of the periodontal area in pregnant women. The aim of the study was to evaluate the state of oral hygiene and the periodontal area is such a population and assess the effectiveness of performed hygiene treatments and analyse changes in hygiene habits after oral hygiene instructions. The study was performed in two parts on a group of 50 pregnant women. The first part took place between the 14th and 17th week of pregnancy. The control study was conducted between the 27th and 30th week of pregnancy. Patients were subjected to a dental examination. Poor oral hygiene was observed among the examined patients. After the first examination, oral hygiene instruction was provided to 25 randomly selected pregnant patients. The effect of periodontal diseases on the time of labor was observed. Oral hygiene instructions significantly affected the state of the periodontal area of pregnant women for whom it was performed. It was confirmed that the advancement of pregnancy influences deterioration of the periodontium and also term of childbirth. Undoubtedly, pregnant women receive insufficient dental care. Priority should be given to dental care education of for pregnant women and alleviating the impact of oral diseases on the organism of a pregnant woman.

Pregnancy, oral health and dental education: an overview on the northeast of Italy

Objectives To evaluate the level of knowledge of pregnant women and puerpers about oral health and prevention during and after gestation. Methods One hundred women aged 18-49 years (mean age 33±6 years) were included in this cross-sectional study. An anonymous questionnaire with 24 items related to oral health has been administered during or just after pregnancy. Firstly, answers have been analyzed on the full population and then subdividing the sample on the base of age ranges (G1: 18-25 years, G2: 26-35 years and G3: >35 years) and number of pregnancies (FP: first pregnancy; SP: second or more pregnancies). Parametric tests have been chosen for the statistical analysis; in particular, Anova test for independent samples was used to evaluate differences of baseline demographic characteristics among subgroups G1, G2, G3 while chi-square test was used for FP and SP subgroups. Anova test was also used to intercept differences on answers given to the questionnaire among G1, G2 and G3 group; for FP and SP group was used t-test. Results Level of information and knowledge of the full sample was medium-low and no significant differences have been observed between groups regarding awareness of the own level of the oral hygiene and knowledge of oral care. Conclusions Results of this survey underline the high necessity of educational programs regarding oral care in pregnant and puerpers women. A strict collaboration between medical figures (dentist, oral hygienist, gynecologist and obstetric) is strongly encouraged to spread the concept of prevention.

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.

Periodontal diseases and adverse pregnancy outcomes: Mechanisms

Adverse pregnancy outcomes (APOs) have been defined as (a) pre-term birth, when there is a delivery before 37 completed weeks (<259 days); (b) pre-eclampsia, which is a multisystem disorder of pregnancy characterized by maternal hypertension and proteinuria after the 20th gestational week; (c) low and very low birthweight, depending on whether the weight of the baby is less of 2500 g or <1500 g and (d) the spontaneous death of the fetus with <20 weeks (miscarriage) or between 20 and 36 weeks (stillbirth). In 2012, during the Consensus Report from the Joint EFP/AAP workshop on periodontitis and systematic diseases the role of periodontal diseases on APOs was reviewed. Some years later, this evidence has grown, and an update on the literature regarding the mechanisms related to this potential association (APOs and periodontal diseases) needs to be presented. The two major pathways (direct and indirect) already accepted in 2012 are still valid nowadays. Most evidence published in the last 5 years deals with a strong and solid evidence coming from the direct pathway while there is as scarce new evidence regarding indirect pathway. In this direct pathway, the haematological dissemination of oral microorganisms and their products, would later induce an inflammatory/Immune response in the foetal-placental unit. The most plausible route for this direct pathway is the hematogenous transmission through dental bacteremia, although not many new studies dealing with bacteremia has been performed lately.

The influence of nonsurgical periodontal therapy on the occurrence of adverse pregnancy outcomes: A systematic review of the current evidence

BACKGROUND AND OBJECTIVES

The poor maternal oral health in the pregnancy has an impact on the fetus through the oral-systemic link. Various studies have proven the relationship between poor maternal oral health and the occurrence of adverse pregnancy outcomes. Hence, periodontal therapy becomes indispensable during pregnancy. Previous systematic reviews and meta-analysis conducted to assess the influence of periodontal therapy on the occurrence of adverse pregnancy outcomes have shown inconsistent results. Hence, we conducted the present review to assess the influence of periodontal therapy on the occurrence of adverse pregnancy outcomes including the studies published till date.

MATERIALS AND METHODS

We searched for the relevant studies using the databases PUBMED, MEDLINE, CINAHL, and EMBASE on the randomized controlled trials evaluating the influence of periodontal treatment on adverse pregnancy outcomes from 2000 to 2018. Nineteen studies were considered for the present review based on the predetermined criteria. The risk of bias tool by Cochrane was used to evaluate the risk of bias among the studies.

RESULTS

Among the studies included for the present review, the occurrence of preterm birth among the pregnant mothers who received periodontal therapy ranged from 0% to 53.5%, while in the control group, the range was 6.38%-72%. The rate of LBW among the mothers treated for periodontal disease ranged from 0% to 36%, and in the control group, it varied from 1.15% to 53.9%.

CONCLUSION

With best possible evidence, it can be inferred that nonsurgical periodontal therapy is safe during pregnancy. Even though it does not completely avert the occurrence of adverse pregnancy outcomes, it can be recommended as a part of antenatal care.

A review of the influence of periodontal treatment in systemic diseases

The effects and consequences of periodontal diseases might not be confined to the oral cavity. A great body of evidence has arisen supporting the claim demonstrating an association with several systemic conditions and diseases. With different levels of evidence, an association between periodontal disease and cardiovascular disease, diabetes, psoriasis, rheumatoid arthritis, pregnancy outcomes and respiratory diseases has been established. However, the true nature of this association, if it is causal, still remains elusive. For a better understanding of the complex relationships linking different conditions, interventional studies now begin to focus on the possible outcomes of periodontal treatment in relation to the events, symptoms and biomarkers of several systemic disorders, assessing if periodontal treatment has any impact on them, hopefully reducing their severity or prevalence. Therefore, we proceeded to review the recent literature on the subject, attempting to present a brief explanation of the systemic condition or disease, what proposed mechanisms might give biological plausibility to its association with periodontal disease, and finally and more importantly, what data are currently available pertaining to the effects periodontal treatment may have. Raising awareness and discussing the possible benefits of periodontal treatment on overall systemic health is important, in order to change the perception that periodontal diseases are only limited to the oral cavity, and ultimately providing better and comprehensive care to patients.

[Research progress on the relationship and mechanisms between periodontal disease and preterm birth and low-birth-weight infants]

Preterm birth (PB) is defined as the birth of a baby less than 37 weeks of gestational age. Low birth weight (LBW) is defined as a newborn baby's weight of less than 2 500 g. PB is often accompanied by LBW. Preterm low birth weight (PLBW) is the leading cause of newborn deaths. Periodontal disease (PD) is a chronic oral infectious disease, and it is closely related with general health. Epidemiological data show that PD is a risk factor for PLBW and other adverse pregnancy outcomes. The possible mechanisms include the direct effects of periodontal bacteria, inflammatory reactions, and immune response; however, the exact pathogenetic mechanism involved remains controversial. This article aims to review the research progress on the relationship between PD and PLBW and their underlying mechanisms, as well as the effects of periodontal treatment on PLBW incidence.

Tumor Necrosis Factor-alpha in Gingival Crevicular Fluid as a Diagnostic Marker for Periodontal Diseases: A Systematic Review

OBJECTIVES

The aim of this systematic review was to evaluate human gingival crevicular fluid (GCF) tumor necrosis factor-alpha (TNF-α) as a potential biomarker for diagnosis of periodontal disease (International prospective register of systematic reviews [PROSPERO] number: CRD42015020199).

METHODS

An electronic search for TNF-α in human GCF was conducted until May 17, 2018. Data from systemically healthy patients with healthy periodontium or periodontal disease were incorporated. Risk bias was assessed by Newcastle-Ottawa Scale for case-control studies and Jadad scale for clinical trials.

RESULTS

Twenty-six studies were included (12 case-control studies, 7 clinical trials, and 7 randomized controlled trials). Most case-control studies showed increased TNF-α concentration in GCF of patients with periodontal disease. The clinical trials and randomized controlled trials demonstrated no consistent modification of TNF-α level after periodontal intervention.

CONCLUSION

The present data support the use of TNF-α in GCF as a potential biomarker for diagnosis of periodontal disease but not to monitor the healing after therapy.

Effect of intra-pregnancy nonsurgical periodontal therapy on inflammatory biomarkers and adverse pregnancy outcomes: a systematic review with meta-analysis

BACKGROUND

The aim of this systematic review with meta-analysis was to analyze the effects of intra-pregnancy nonsurgical periodontal therapy on periodontal inflammatory biomarkers and adverse pregnancy outcomes.

METHODS

On June 5, 2017, we searched PubMed, Cochrane, SCOPUS, Web of Science, LILACS, ProQuest, Open Grey, and Google Scholar databases. Randomized clinical trials in which pregnant women with chronic periodontitis underwent nonsurgical periodontal therapy, compared with an untreated group, tested for inflammatory biomarkers, and followed till delivery were included. Primary outcomes were preterm birth, low birth weight, and preeclampsia. Meta-analysis was performed with 5.3.5 version of Review Manager software.

RESULTS

We found 565 references in the databases, 326 after duplicates removal, 28 met criteria for full text reading, and 4 met eligibility criteria for quantitative and qualitative synthesis. Intra-pregnancy nonsurgical periodontal therapy improved periodontal clinical parameters (periodontal pocket depth, clinical attachment level, and bleeding on probing) and reduced biomarker level from gingival crevicular fluid (GCF), and some from blood serum; however, it did not influence biomarker level from umbilical cord blood. Meta-analysis showed tendency for reduction of the risk of preterm birth before 37 weeks for treated group (risk ratio (RR) = 0.54, 95% CI 0.38-0.77; p = 0.0007; inconsistency indexes (I2) 32%) but did not show any difference for low birth weight occurrence (RR = 0.78, 95%CI 0.50-1.21; p = 0.27; I2 41%). No included study considered preeclampsia as a gestational outcome.

CONCLUSIONS

These results demonstrated that the intra-pregnancy nonsurgical periodontal therapy decreased periodontal inflammatory biomarker levels from gingival crevicular fluid and some from serum blood, with no influence on inflammatory biomarker level from cord blood, and it did not consistently reduce adverse gestational adverse outcome occurrence.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015027750.

The oral microbiome and adverse pregnancy outcomes

Significant evidence supports an association between periodontal pathogenic bacteria and preterm birth and preeclampsia. The virulence properties assigned to specific oral pathogenic bacteria, for example, Fusobacterium nucleatum, Porphyromonas gingivalis, Filifactor alocis, Campylobacter rectus, and others, render them as potential collaborators in adverse outcomes of pregnancy. Several pathways have been suggested for this association: 1) hematogenous spread (bacteremia) of periodontal pathogens; 2) hematogenous spread of multiple mediators of inflammation that are generated by the host and/or fetal immune response to pathogenic bacteria; and 3) the possibility of oral microbial pathogen transmission, with subsequent colonization, in the vaginal microbiome resulting from sexual practices. As periodontal disease is, for the most part, preventable, the medical and dental public health communities can address intervention strategies to control oral inflammatory disease, lessen the systemic inflammatory burden, and ultimately reduce the potential for adverse pregnancy outcomes. This article reviews the oral, vaginal, and placental microbiomes, considers their potential impact on preterm labor, and the future research needed to confirm or refute this relationship.

Treating periodontal disease for preventing adverse birth outcomes in pregnant women

BACKGROUND

Periodontal disease has been linked with a number of conditions, such as cardiovascular disease, stroke, diabetes and adverse pregnancy outcomes, all likely through systemic inflammatory pathways. It is common in women of reproductive age and gum conditions tend to worsen during pregnancy. Some evidence from observational studies suggests that periodontal intervention may reduce adverse pregnancy outcomes. There is need for a comprehensive Cochrane review of randomised trials to assess the effect of periodontal treatment on perinatal and maternal health.

OBJECTIVES

To assess the effects of treating periodontal disease in pregnant women in order to prevent or reduce perinatal and maternal morbidity and mortality.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 6 October 2016), Cochrane Pregnancy and Childbirth's Trials Register (to 7 October 2016), the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 9) in the Cochrane Library, MEDLINE Ovid (1946 to 6 October 2016), Embase Ovid (1980 to 6 October 2016), and LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; 1982 to 6 October 2016). ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials on 6 October 2016. We placed no restrictions on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) investigating the effects of periodontal treatment in preventing or reducing perinatal and maternal morbidity and mortality. We excluded studies where obstetric outcomes were not reported.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts and extracted data using a prepiloted data extraction form. Missing data were obtained by contacting authors and risk of bias was assessed using Cochrane's 'Risk of bias' tool. Where appropriate, results of comparable trials were pooled and expressed as risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CI) . The random-effects model was used for pooling except where there was an insufficient number of studies. We assessed the quality of the evidence using GRADE.

MAIN RESULTS

There were 15 RCTs (n = 7161 participants) meeting our inclusion criteria. All the included studies were at high risk of bias mostly due to lack of blinding and imbalance in baseline characteristics of participants. The studies recruited pregnant women from prenatal care facilities who had periodontitis (14 studies) or gingivitis (1 study).The two main comparisons were: periodontal treatment versus no treatment during pregnancy and periodontal treatment versus alternative periodontal treatment. The head-to-head comparison between periodontal treatments assessed a more intensive treatment versus a less intensive one.Eleven studies compared periodontal treatment with no treatment during pregnancy. The meta-analysis shows no clear difference in preterm birth < 37 weeks (RR 0.87, 95% CI 0.70 to 1.10; 5671 participants; 11 studies; low-quality evidence) between periodontal treatment and no treatment. There is low-quality evidence that periodontal treatment may reduce low birth weight < 2500 g (9.70% with periodontal treatment versus 12.60% without treatment; RR 0.67, 95% CI 0.48 to 0.95; 3470 participants; 7 studies).It is unclear whether periodontal treatment leads to a difference in preterm birth < 35 weeks (RR 1.19, 95% CI 0.81 to 1.76; 2557 participants; 2 studies; ) and < 32 weeks (RR 1.35, 95% CI 0.78 to 2.32; 2755 participants; 3 studies), low birth weight < 1500 g (RR 0.80, 95% CI 0.38 to 1.70; 2550 participants; 2 studies), perinatal mortality (including fetal and neonatal deaths up to the first 28 days after birth) (RR 0.85, 95% CI 0.51 to 1.43; 5320 participants; 7 studies; very low-quality evidence), and pre-eclampsia (RR 1.10, 95% CI 0.74 to 1.62; 2946 participants; 3 studies; very low-quality evidence). There is no evidence of a difference in small for gestational age (RR 0.97, 95% CI 0.81 to 1.16; 3610 participants; 3 studies; low-quality evidence) when periodontal treatment is compared with no treatment.Four studies compared periodontal treatment with alternative periodontal treatment. Data pooling was not possible due to clinical heterogeneity. The outcomes reported were preterm birth < 37 weeks, preterm birth < 35 weeks, birth weight < 2500 g, birth weight < 1500 g and perinatal mortality (very low-quality evidence). It is unclear whether there is a difference in < 37 weeks, preterm birth < 35 weeks, birth weight < 2500 g, birth weight < 1500 g and perinatal mortality when different periodontal treatments are compared because the quality of evidence is very low.Maternal mortality and adverse effects of the intervention did not occur in any of the studies that reported on either of the outcomes.

AUTHORS' CONCLUSIONS

It is not clear if periodontal treatment during pregnancy has an impact on preterm birth (low-quality evidence). There is low-quality evidence that periodontal treatment may reduce low birth weight (< 2500 g), however, our confidence in the effect estimate is limited. There is insufficient evidence to determine which periodontal treatment is better in preventing adverse obstetric outcomes. Future research should aim to report periodontal outcomes alongside obstetric outcomes.

Role of Maternal Periodontitis in Preterm Birth

In the last two decades, many studies have focused on whether periodontitis is a risk factor for preterm birth (PTB). However, both epidemiological investigation and intervention trials have reached contradictory results from different studies. What explains the different findings, and how should future studies be conducted to better assess this risk factor? This article reviews recent epidemiological, animal, and in vitro studies as well as intervention trials that evaluate the link between periodontitis and PTB. Periodontitis may act as a distant reservoir of microbes and inflammatory mediators and contribute to the induction of PTB. Animal studies revealed that maternal infections with periodontal pathogens increase levels of circulating IL-1β, IL-6, IL-8, IL-17, and TNF-α and induce PTB. In vitro models showed that periodontal pathogens/byproducts induce COX-2, IL-8, IFN-γ, and TNF-α secretion and/or apoptosis in placental tissues/cells. The effectiveness of periodontal treatment to prevent PTB is influenced by the diagnostic criteria of periodontitis, microbial community composition, severity of periodontitis, treatment strategy, treatment efficiency, and the period of treatment during pregnancy. Although intervention trials reported contradictory results, oral health maintenance is an important part of preventive care that is both effective and safe throughout pregnancy and should be supported before and during pregnancy. As contradictory epidemiological and intervention studies continue to be published, two new ideas are proposed here: (1) severe and/or generalized periodontitis promotes PTB and (2) periodontitis only promotes PTB for pregnant women who are young or HIV-infected or have preeclampsia, pre-pregnancy obesity, or susceptible genotypes.

Biomarker levels in gingival crevicular fluid of subjects with different periodontal conditions: A cross-sectional study

OBJECTIVE

To compare five biomarker levels in gingival crevicular fluid (GCF) in different tooth-sites of subjects with healthy periodontium, aggressive periodontitis and severe chronic periodontitis, and to evaluate the value of these biomarker levels for diagnosis of the type and activity of periodontitis.

MATERIALS AND METHODS

Prior to therapy, GCF samples were collected using filter paper strip at different tooth-sites of 10 subjects with healthy periodontium (H), 15 with severe chronic periodontitis (CP) and 15 with aggressive periodontitis (AgP). The strips were weighed and the periodontal clinical parameters were recorded. Levels of interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), and alkaline phosphatase (ALP) in GCF were assessed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The volumes of the GCF samples obtained in CP and AgP subjects were significantly higher than those from subjects with healthy periodontium (P<0.05). Levels of IL-6, TNF-α, CRP and ALP were significantly higher in the untreated disease sites in the CP and AgP groups compared to those in control sites in the H group, while IL-10 levels were lower in the CP and AgP groups than those in the control sites in the H group. However, the levels of all five biomarker levels showed significant correlation with the clinical parameters.

CONCLUSION

The measurement of five biomarker levels in GCF may facilitate overall screening of periodontitis patients in epidemiological studies and allow estimation of periodontitis activity.

Putative periodontopathic bacteria and herpesviruses in pregnant women: a case-control study

Little is known about herpesvirus and putative periodontopathic bacteria in maternal chronic periodontitis. The present case-control study aimed to explore the potential relationship between putative periodontopathic bacteria and herpesviruses in maternal chronic periodontitis.Saliva samples were collected from 36 pregnant women with chronic periodontitis (cases) and 36 pregnant women with healthy periodontal status (controls). Six putative periodontopathic bacteria (Porphyromonas gingivalis [Pg], Aggregatibacer actinomycetemcomitans [Aa], Fusobacterium nucleatum [Fn], Prevotella intermedia [Pi], Tannerella forsythia [Tf], and Treponema denticola [Td]) and three herpesviruses (Epstein-Barr virus [EBV], human cytomegalovirus [HCMV], and herpes simplex virus [HSV]) were detected. Socio-demographic data and oral health related behaviors, and salivary estradiol and progesterone levels were also collected. The results showed no significant differences in socio-demographic background, oral health related behaviors, and salivary estradiol and progesterone levels between the two groups (all P > 0.05). The detection rates of included periodontopathic microorganisms were not significantly different between the two groups (all P > 0.05), but the coinfection rate of EBV and Pg was significantly higher in the case group than in the control group (P = 0.028). EBV and Pg coinfection may promote the development of chronic periodontitis among pregnant women.