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.

Objective To investigate the mechanism of epidermal growth factor receptor-forkhead transcription factor A2 (EGFR-FOXA2) pathway-involved high secretion of mucus in human bronchial epitheli-um (HBE) cells after respiratory syncytial virus (RSV) infection and to evaluate the effects of intervention using agonist ( rosiglitazone ) and antagonist ( GW9662 ) of peroxidase proliferation activated receptor γ( PPARγ) and EGFR inhibitor ( AG1478 ) . Methods HBE cells were randomly divided into six groups: A group ( AG1478+RSV) , B group ( rosiglitazone+RSV) , C group ( GW9662+RSV) , D group ( RSV) , E group (0. 1％ dimethyl sulfoxide DMSO) and F group (HBE cell control group). Two hours before RSV infection, A, B and C groups were respectively treated with 10 μmol/L of AG1478, rosiglitazone and GW9662. Expression of EGFR, PPARγ and FOXA2 at mRNA level in each group was detected by real-time fluorescence quantitative RT-PCR 12 h, 24 h and 48 h after HBE cells were infected with or without RSV. Expression of phosphorylated-EGFR ( p-EGFR) and EGFR at protein level was detected by Western blot. ELISA was performed to measure the expression of mucin-5AC (MUC5AC). Results Compared with F group, EGFR expression at mRNA lev-el, p-EGFR/EGFR protein ratio and MUC5AC expression at protein level were increased in a time-dependent manner in A, B, C and D groups at 12 h, 24 h and 48 h. Compared with group F, the expression of PPARγat mRNA level in A, B, and D groups increased at each time point. Moreover, PPARγ expression gradually in-creased over time in A and B groups, reaching the peaks at 48 h, but was in decline in D group. Expression of FOXA2 at mRNA level in RSV-infected HBE cells was declined at each time point compared with that in group F, especially in D group. Compared with group D, A and B groups showed significantly decreased EGFR ex-pression at mRNA level, p-EGFR/EGFR protein ratio and MUC5AC expression at protein level, but markedly increased FOXA2 expression at mRNA level. Conclusions RSV infection increased the expression of MUC5AC at protein level in HBE cells. PPARγand EGFR-FOXA2 signaling pathways were involved in the hypersecretion of airway mucus during RSV infection.

Objective : The purpose of this study was to investigate the relevant social and environmental factors affecting the occurrence of periodontal diseases during pregnancy in pregnant women and to analyze the influence of the periodontal status of women in the second trimester of pregnancy on small for gestational age (SGA) delivery. Methods: A total of 215 pregnant women were enrolled in this study in the Department of Periodontology of the West China Hospital of Stomatology of Sichuan University from May 2015 to May 2018. Periodontal parameters, such as bleeding on probing (BOP), probing depth (PD) and clinical attachment loss (CAL), were recorded at 16-24 weeks of gestational age. Subjects were divided into the periodontitis (n=32) group, gingivitis (n=171) group and periodontally healthy (n=12) group according to their periodontal conditions. With the patient′s informed consent, the patient decided whether to receive periodontal treatment. Basic and socioeconomic information was collected through questionnaires. After delivery, subjects were divided into the SGA group and non-SGA group according to their birth results. The periodontal clinical indicators, questionnaire results and delivery results were compared among the groups. Results : The mean PD (P=0.005, r=-0.192) and BOP% (P=0.003, r=-0.199) were negatively correlated with economic income. The family income in the periodontitis group was significantly lower than that in the healthy group and the gingivitis group (P < 0.05). The flossing use rate was significantly higher in the healthy group than that in the gingivitis group (P < 0.05). A total of 106 pregnant women received scaling and root planing, while 109 patients only received oral hygiene instruction. After delivery, SGA occurred in 23 cases (10.7%), and there were no significant difference in SGA incidence among the three groups (P > 0.05). PD ≥ 5 mm% and PD ≥ 4 mm% (P < 0.05) were significantly higher in the SGA group than in the non-SGA group. There was no significant difference in SGA incidence between the treated group and the untreated group (P > 0.05). Conclusion Family income and dental flossing use have an impact on the incidence of periodontal diseases during pregnancy. The severity of periodontitis in pregnant women is correlated with the incidence of SGA.