Development of gestational diabetes mellitus in women with periodontitis in early pregnancy: A population-based clinical study.

AIM: This study aimed to determine whether periodontitis in early pregnancy and periodontal therapy during gestation affect the incidence of gestational diabetes mellitus (GDM) through a population-based clinical study. MATERIALS AND METHODS: Subjects without periodontitis at 1-4 weeks of gestation who met our inclusion criteria were enrolled in the non-periodontitis group. Periodontitis patients who agreed or refused to receive periodontal therapy during pregnancy were separately enrolled in the periodontitis treated or untreated group. At 12-16 weeks of gestation, gingival crevicular fluid (GCF) and venous blood were collected for analyses of bacterial species and serum inflammatory mediators, respectively. At 24-28 weeks of gestation, GDM patients were identified by oral glucose tolerance tests. The association tests were performed using Chi-squared statistics and regression analyses. RESULTS: The complete data of 3523 pregnant women were recorded during the study period. GDM incidence among the untreated periodontitis participants (84/749, 11.21%) was significantly higher than that among the non-periodontitis participants (108/2255, 4.79%) (p < .05), and periodontal treatment during gestation reduced the incidence from 11.21% (untreated group) to 7.32% (38/519, treated group) (p < .05). Based on multiple logistic regression analyses, it was found that periodontitis in early pregnancy was associated with GDM, and three-step regression analyses showed that Porphyromonas gingivalis (P. gingivalis) and the serum TNF-α and IL-8 levels played a role in the association between untreated periodontitis and GDM. Furthermore, Pearson's correlation test indicated that the existence of P. gingivalis in GCF was positively correlated with high serum levels of these two inflammatory mediators. CONCLUSIONS: This study establishes a connection between periodontitis in early pregnancy and GDM and demonstrates that the presence of P. gingivalis is associated with high levels of inflammatory mediators in serum, and thereby may contribute to the development of GDM. In-depth mechanistic studies are needed to further support these findings.

Effects of Er:YAG laser pre-treatment on dentin structure and bonding strength of primary teeth: an in vitro study.

BACKGROUND: To investigate the effects of Er:YAG laser pre-treatment on the dentin structure and shear bond strength of primary teeth. METHODS: Dentin specimens were prepared using freshly extracted intact primary molars and divided randomly into four groups based on the surface treatment applied. The control and etchant groups received no treatment and conventional acid etching treatment, respectively, while the energy and frequency groups received laser surface treatment with variable energy (50-300 mJ) and frequency (5-30 Hz) parameters. The morphology was observed using scanning electron microscopy. The surface-treated dentin slices were bonded to resin tablets, followed by thermocycle treatment. The shear strength was determined using a universal testing machine and de-bonded surfaces were observed using a stereomicroscope. RESULTS: SEM observation showed that the surface morphology of the dentin slices changed after etching as well as after Er:YAG laser pre-treatment with different energy and frequency values. The dentin tubules opened within a specific energy (50-200 mJ) and frequency (5-20 Hz) range. Beyond this range, the intertubular dentin showed cracks and structural disintegration. Shear strength tests showed no significant changes after acid etching. The shear strength increased significantly (P < 0.05) after Er:YAG laser pre-treatment compared with that of the control group. The shear strength increased within the same energy (50-200 mJ) and frequency (5-20 Hz) range as the tubule opening, but not significantly (P > 0.05). The most common mode of interface failure was adhesive (interface) failure, followed by mixed and resin cohesive failure. CONCLUSIONS: Pre-treatment using Er:YAG laser opens the dentinal tubules without the formation of a smear layer and improves the bonding strength between the primary teeth dentin and the resin composites.

[Mechano-growth factor regulated cyclic stretch-induced osteogenic differentiation and MMP-1, MMP-2 expression in human periodontal ligament cells by activating the MEK/ERK1/2 pathway].

PURPOSE: To explore the role and mechanism of mechano-growth factor (MGF) in cyclic stretch (CS)-induced osteogenic differentiation and MMP-1, MMP-2 expression in human periodontal ligament cells (hPDLCs). METHODS: HPDLCs were isolated and transfected with si-MGF, or stimulated with MGF or MEK/ERK pathway inhibitor U0126. Cells were cultured in Flexercell system with 10% elongation at 0.1 Hz. An alkaline phosphatase (ALP) kit was used to detect ALP activity. QRT-PCR assay was performed to determine the transcript levels of MGF and osteogenic genes, including ALP, runt-related transcription factor 2 (Runx2) and osteopontin (OPN). Western bot was used to evaluate the effect on MEK/EKR1/2 signaling. Statistical analysis was performed using SPSS 19.0 software package. RESULTS: CS induced the expression of MGF in hPDLCs in a time-dependent manner (P＜0.05). In contrast to the control group, transfection with si-MGF inhibited the expression of MGF in hPDLCs (P＜0.05). Moreover, cessation of MGF dramatically suppressed ALP activity (P＜0.05) and the expression of osteogenic gene ALP, Runx2 and OPN (P＜0.05) in hPDLCs. Furthermore, down-regulation of MGF restrained the expression of MMP-1 and MMP-2, in contrast to CS group (P＜0.05). Conversely, stimulation with MGF further enhanced the effects of CS on osteogenic differentiation of hPDLCs and MMP-1, MMP-2 expression (P＜0.05). Additionally, MGC silencing abrogated CS-induced expression of p-ERK (P＜0.05), which was further enhanced following MGF treatment (P＜0.05). Simultaneously, precondition with U0126 antagonized MGF-enhanced effects on CS-triggered osteogenic differentiation and MMP-1, MMP-2 expression (P＜0.05). CONCLUSIONS: Mechano-growth factor regulates cyclic stretch-induced osteogenic differentiation and MMP-1, MMP-2 expression in human periodontal ligament cells by activating MEK/ERK1/2 signaling pathway.

[Application of objective structured clinical examination system in pediatric dental education for 8-year-program and 5-year-program students].

PURPOSE: To explore a more comprehensive and objective method for dental students examination, and improve the quality of pediatric dental education. METHODS: Fifteen 8-year-program students and 30 5-year-program dental students from School of Stomatology, the Fourth Military Medical University were enrolled in this study. Objective structured clinical examination (OSCE), traditional diadactic test and questionnaires were carried out in all students. The scores of the two testing methods between students in 2 groups were compared using SPSS 11.5 software package. RESULTS: The average score of OSCE for 8-year-program students was significantly higher than that of 5-year-program students. In contrast, the traditional test score of 8-year-program students was significantly lower than that of 5-year-program students. Most students accepted OSCE and approved the evaluation system combining OSCE with traditional test. CONCLUSIONS: As a comprehensive, objective and effective evaluation system, OSCE is helpful for students to master knowledge and improve clinical ability.

Effects of cathepsin K on Emdogain-induced hard tissue formation by human periodontal ligament stem cells.

Recent studies have shown that patients with pycnodysostosis caused by cathepsin K (CTSK) genetic mutations exhibit significantly abnormal periodontal hard tissue structure. This finding suggests that CTSK may play a role in regulating the development of alveolar bone and cementum. However, the source of CTSK in the periodontal environment and the role of CTSK in periodontal regeneration, particularly hard tissue regeneration and development, remain unclear. After the isolation, cultivation, identification, and multi-lineage induction of human periodontal ligament stem cells (hPDLSCs), the present study used light and scanning electron microscopy, reverse-transcription quantitative polymerase chain reaction, western blotting, micro-computed tomography, immunohistochemical assays and ectopic hard tissue formation experiments to examine CTSK expression in hPDLSCs. The results indicated that CTSK expression was significantly upregulated in hPDLSCs during Emdogain induction but underwent minimal change during osteogenic or adipogenic induction. The present study also showed that the downregulation of CTSK expression inhibited osteogenic/cementogenic differentiation and ectopic hard tissue formation of hPDLSCs. It is therefore concluded that hPDLSCs expressed CTSK and that CTSK levels were significantly upregulated during Emdogain induction. Furthermore, CTSK promoted not only the osteogenic/cementogenic differentiation of hPDLSCs but also their ability to form ectopic hard tissue. These new findings may enhance the understanding of periodontal hard tissue development and functional regeneration. However, the specific underlying mechanisms require further investigation. Copyright © 2016 John Wiley & Sons, Ltd.

Nicotine favors osteoclastogenesis in human periodontal ligament cells co-cultured with CD4(+) T cells by upregulating IL-1ß.

Periodontitis, which is the main cause of tooth loss, is one of the most common chronic oral diseases in adults. Tooth loss is mainly a result of alveolar bone resorption, which reflects an increased osteoclast formation and activation. Osteoclast formation in periodontal tissue is a multistep process driven by osteoclastogenesis supporting cells such as human periodontal ligament (PDL) cells and CD4(+) T cells. Inflammatory cytokines, such as interleukin-1ß (IL-1ß), can induce osteoclastogenesis by affecting the expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in human PDL cells. Nicotine, the major component in tobacco smoking and a specific agonist of the α7 nicotinic acetylcholine receptor (α7 nAChR), has been proven to regulate the expression of inflammatory cytokines in smoking-associated periodontitis. In this study, we investigated the mechanism(s) through which nicotine affects osteoclastogenesis in human PDL cells co-cultured/non-co-cultured with CD4(+) T cells. Human PDL cells were stimulated with nicotine (10-5 M) and/or α-bungarotoxin (α-BTX, specific antagonist of α7 nAChR, 10-8 M) before being co-cultured with CD4(+) T cells. Compared with mono-culture systems, stimulation with nicotine caused an increased secretion of IL-1ß in serum of human PDL cell-CD4(+) T cell co-culture, and the expression of RANKL in human PDL cells was further upregulated co-cultured with CD4(+) T cells, while no differences were observed in the expression of OPG between the co-culture and mono-culture systems. Our data suggested that nicotine upregulated IL-1ß secretion, further upregulated RANKL expression in smoking-associated periodontitis, which may aid in the better understanding of the relationship between nicotine and alveolar bone resorption.

[Effect of dexmedetomidine on patient-controlled intravenous analgesia with fentanyl in elderly patients after total hip replacement].

OBJECTIVE: To investigate the effect of a continuous infusion of low-dose dexmedetomidine on patient-controlled analgesia (PCA) with fentanyl in elderly patients after total hip replacement. METHODS: Forty patients (ASA I-II) aged 66-81 years after total hip replacement were randomized equally into the control and test groups. The patients in the test group received continuous infusion of dexmedetomidine at the rate of 0.2 µg·kg(-1)·h(-1) from the beginning to the end of PCA with fentanyl after the surgery, while those in the control group received normal saline. The cumulative fentanyl dose, VAS pain scores and Ramsay sedation score were recorded at 0, 4, 8, 12 and 24 h after the surgery. RESULTS: All the patients in the two groups reported good pain relief and none needed additional fentanyl. The VAS pain score was significantly lower (P<0.05 or 0.01), while the Ramsay sedation scores higher (P<0.05) in the test group than in the control group. The cumulative fentanyl dose was significantly lower in the test group (P<0.05 or 0.01). The incidence of such adverse effects as nausea and vomiting was significantly lower in the test group (P<0.05). CONCLUSION: PCA with fentanyl combined with low-dose dexmedetomidine infusion is safe for elderly patients, and can decrease fentanyl consumption and improve the effect of PCA with fentanyl.