[A survey on human resources of dentists who deal with periodontal disease in Beijing].

Objective: To investigate the status quo of human resources of dentists who deal with periodontal disease in Beijing area through an online survey, which may hopefully provide a preliminary basis for the decision-making of administrative departments and the formulation of periodontal professional development plan. Methods: The dentists who deal with periodontal disease at least half a day per week in Beijing area were investigated. A questionnaire was designed by the chairman of the Periodontology Committee of Beijing Stomatological Association. The questionnaire was sent to and finished by the dentists via "WenJuanXing" online survey software. The contents of the survey included general condition, the property of practice unit, title and position of the dentist, membership of professional society, time and content of periodontal treatment, adoption of new technology and new method of periodontal therapy during the past one year, status of periodontal treatment in the local population and reasons, understanding and influencing factors of periodontal professional development. Results: A total of 1 255 dentists completed the survey, who came from all 16 districts in Beijing, mainly Haidian, Chaoyang, Dongcheng and Xicheng Districts [The total percentage of these four main districts was 70.3% (882/1 255)]. The mean age of the dentists was (36.1±8.3) years. Among the dentists, 71.1% (892/1 255) were females, 88.1% (1 106/1 255) got a Bachelor's degree or above. It was estimated that 35.4% (444/1 255) of the dentists had received standardized periodontal training ever. The percentage of dentists carrying out new technology in the past one year was as high as 68.1% (855/1 255). There were only 163 periodontal specialists (13.0%) out of the dentists in the survey. Only 15.9% (200/1 255) of the dentists routinely performed periodontal surgery. The majority of the dentists [82.8% (1 039/1 255)] were from the state-owned hospitals. Fifty-four point seven percemt (686/1 255) of the dentists thought that lack of knowledge was the main reason why the general public failed to receive periodontal treatment. As for the biggest bottleneck affecting periodontal professional development, fifty-one point zero percent (640/1 255) of the dentists attributed it to the public neglect. Conclusions: The periodontal practitioners in Beijing are young, highly educated, unevenly distributed in 16 districts and mostly females. State-owned oral health institutions are an important force in periodontal diagnosis and treatment services in Beijing. The number of periodontal specialists need to be improved. Promotion of standardized periodontal surgery and the popularization of healthcare knowledge on periodontal disease should also be the focus in the future.

[Relationship between periodontitis and glomerular filtration rate in non-diabetic Chinese elderly patients in Beijing community].

Objective: To investigate the correlation between clinical periodontal indexes of periodontitis and glomerular filtration rate (GFR) in a non-diabetic elderly population in four communities of Shijingshan, Beijing. Methods: This was a cross-sectional study. Questionnaires, blood biochemical examinations, and periodontal indexes were conducted in elderly people (35 to 84 years old) in four communities of Shijingshan, Beijing between May and July 2005. Non-diabetic patients with fasting blood glucose<6.1 mmol/L, postprandial blood glucose<7.8 mmol/L, and ≥ 10 remaining teeth were included. Patients with diabetes, fasting blood glucose ≥6.1 mmol/L or postprandial blood glucose ≥7.8 mmol/L, and total residual teeth less than 10 were excluded. A total of 362 study subjects met the inclusion criteria. The survey subjects were selected by convenient sampling method. The mean full-mouth probing depth (PD), bleeding index (BI), attachment loss (AL), and plaque index (PLI), as well as PD≥4 mm% (the number of sites with PD≥4 mm as a percentage of the total number of sites in full mouth), PD≥5 mm%, PD≥6 mm%, AL≥3 mm%, AL≥4 mm%, AL≥5 mm% and AL≥6 mm% were used for the analysis. Serum creatinine values was used to calculate GFR. GFR≥90 ml/(min·1.73 m2) was defined as normal group and GFR<90 ml/(min·1.73 m2) was defined as reduced group. Univariate analysis was conducted between two groups. Multivariate regression analysis was performed with GFR as dependent variable and adjusted for risk factors such as age, sex, smoking, waist-hip ratio and physical activity. Results: There were 164 subjects in the normal GFR group (45.3%) and 198 in the reduced GFR group (54.7%). Percentage of males in the reduced GFR group, 118 in total, accounting for 59.6%, were significantly higher than in the normal GFR group (73, 44.5%)(P=0.004). The median of age, uric acid, triglyceride, and waist-to-hip ratio (65 years, 323 mmol/L, 1.73 mmol/L, 0.90) were significantly higher in the reduced GFR group than in the normal GFR group (54 years, 277 mmol/L, 1.45 mmol/L, 0.88) (P<0.05). The median of PD mean, AL mean, BI mean, PD≥4 mm%, AL≥3 mm%, and AL≥4 mm% in the reduced GFR group were 2.80 mm, 2.52 mm, 2.06, 20.4%, 46.5%, and 30.4%, respectively, which were significantly higher than those in the GFR normal group (2.60 mm, 2.37 mm, 1.93, 16.6%, 42.9%, 28.9%) (P<0.05). After adjusting for confounding factors such as age, gender, smoking, waist-to-hip ratio and physical activity, the results of logistic regression analysis showed that PD mean, AL mean, PD≥4 mm%, PD≥5 mm%, PD≥6 mm%, AL≥3 mm% and AL≥4 mm% of clinical periodontal indexes were significantly correlated with reduced GFR in this population (OR values were 1.765, 1.879, 1.430, 1.713, 1.771, 1.428, 1.445, respectively, P<0.05). Conclusions: In the non-diabetic elderly population in communities of Shijingshan, Beijing, clinical periodontal indexes reflecting the degree of periodontal tissue destruction were associated with a decreased level of GFR.

[Effect of Porphyromonas gingivalis infection on atherosclerosis in apolipoprotein-E knockout mice].

OBJECTIVE: Studies have indicated that periodontal pathogen Porphyromonas gingivalis (P. gingivalis) infection may contributed to accelerate the development of atherosclerosis. The aim of this study was to investigate the effect of inflammation, oxidative stress and the mechanism on atherosclerosis in apolipoprotein-E knockout (ApoE-/-) mice with P. gingivalis infection. METHODS: Eight-week-old male ApoE-/- mice (C57BL/6) were maintained under specific pathogen-free conditions and fed regular chow and sterile water after 1 weeks of housing. The animals were randomly divided into two groups: (a) ApoE-/- + PBS (n=8); (b) ApoE-/- + P.gingivalis strain FDC381 (n=8). Both of the groups received intravenous injections 3 times per week for 4 weeks since 8 weeks of age. The sham control group received injections with phosphate buffered saline only, while the P. gingivalis-challenged group with P.gingivalis strain FDC381at the same time. After 4 weeks, oxidative stress mediators and inflammation cytokines were analyzed by oil red O in heart, Enzyme linked immunosorbent assay (ELISA) in serum, quantitative real-time PCR and Western blot in aorta. RESULTS: In our study, we found accelerated development of atherosclerosis and plaque formation in aorta with oil red O staining, increased oxidative stress markers [8-hydroxy-2-deoxyguanosine (8-OHdG), NADPH oxidase (NOX)-2 and NOX-4], as well as increased inflammation cytokines [interleukin (IL)-1ß, IL-6 and tumor necrosis factor-α (TNF-α)] in the serum and aorta of the P. gingivalis-infected ApoE-/- mice. Compared with the control group, there was a significant increase protein level of nuclear factor-kappa B (NF-κB) in aorta after P. gingivalis infection. CONCLUSIONS: Our results suggest that chronic intravenous infection of P. gingivalis in ApoE-/- mice could accelerate the development of atherosclerosis by disturbing the lipid profile and inducing oxidative stress and inflammation. The NF-κB signaling pathway might play a potential role in the P. gingivalis-accelerated atherogenesis.

[Correlation between cigarette smoking and periodontal status: A survey on the population of a community above 35-year-old in Beijing].

OBJECTIVE: To survey the cigarette smoking status and periodontal status, and to study the correlation between cigarette smoking and periodontal status. METHODS: Questionnaires were distributed (including self-assessed periodontal status, such as bleeding while brushing teeth, oral odor, tooth loosening, gum swelling, etc.) and clinical periodontal examinations performed for parameters including probing depth (PD), bleeding index (BI), attachment loss (AL), plaque index (PLI) and amount of teeth loss, which was recorded in the population above 35 years of a community in Beijing. A total of 974 subjects were recruited in the study. The population was divided into current smokers and non-smokers, and the differences of self-assessed periodontal status and periodontal parameters between the groups analyzed. RESULTS: The smokers had significantly less bleeding during toothbrushing, and in the meantime, had significantly more self-reported tooth loosening compared with the non-smokers. The smokers brushed their teeth less than the non-smokers (P<0.05). The self-reported gum swelling and oral odor had no significant difference between the smokers and non-smokers. The smokers had 0.565 times and 1.572 times the risk of bleeding during toothbrushing, self-reported tooth loosening and from Logistic regression analyses, respectively (P<0.05). The mean PD, AL, PLI and the amount of tooth loss of the smokers were significant higher than the non-smokers (P<0.05). However, the mean BI of the smokers was slightly less than the non-smokers' (1.93±0.540 vs. 1.94±0.512, P=0.707). The smokers had 2.129 times, 1.698 times and 1.933 times the risk of the mean PD>3 mm, the mean AL>3 mm, and the amount of tooth loss above 8, respectively compared with the non-smokers (P<0.05) from Logistic regression analyses. CONCLUSION: The self-assessed periodontal status is different between smokers and non-smokers in the population of a community in Beijing. Smokers have less bleeding during toothbrushing but no significant difference with BI. Smokers also have more self-reported tooth loosening. Compared with non-smokers, smokers have more severe periodontal destruction.

[Tooth loss and multivariable analysis after 5-year non-surgical periodontal treatment on molars with furcation involvement].

OBJECTIVE: To evaluate the tooth loss status of mandibular molars with furcation involvements after 5-year non-surgical periodontal treatment, and to analyze the factors that affected the tooth loss. METHODS: A retrospective analysis was conducted in 79 patients with chronic periodontitis, who had received non-surgical periodontal treatment and 5 years of periodontal maintenance treatment in Department of Periodontology, Peking University School and Hospital of Stomatology from 1988 to 2012. Their clinical indexes, including probing depth (PD), bleeding index (BI), furcation index (FI) and tooth mobility were both evaluated before treatment and at the last time of the maintenance treatment. Bone resorption at furcation area was measured at the first visit by periapical radiographs taken by professional doctors of medical imaging. The status of tooth loss after 5-year non-surgical periodontal treatment on mandibular molars with furcation involvement, and the factors that affected the tooth loss were analyzed. RESULTS: (1) Non-surgical treatment was significantly effective on the changes of PD in the patients of chronic periodontitis with furcation involvement, while the presence of furcation involvement could affect the improvement of PD here. (2) PD at the furcation area, tooth mobility, vertical bone resorption, and bone resorption area were all significant risk factors of mandibular molar missing (P<0.001), and the same with FI=3 and FI=4 (P=0.017, P=0.007), while age (P=0.703), gender (P=0.243) and smoking history (P=0.895) were not related to the tooth loss in this study. (3) The risk of tooth loss in mandibular molars with FI≥3 were significantly higher than those with FI≤2, and the survival rate of the former was less than 50%. CONCLUSION: The loss of mandibular molars with furcation involvement was related to the furcation involvement, meanwhile the degree of furcation involvement and bone resorption can significantly increase the risk of tooth loss.

[Association between chronic periodontitis and carotid intima-media thickness of middle-aged and older adults in Shijingshan community of Beijing].

OBJECTIVE: To investigate the relationship between periodontal disease and subclinical atherosclerosis in middle-aged and older adults in Shijingshan community of Beijing. METHODS: In 2005-2010, a total of 830 middle-aged and older adults were recruited from Shijingshan community of Beijing, who were divided into two groups by severity of periodontitis. A questionnaire, periodontal examination, blood biochemical examination, carotid intima-media thickness (CIMT), including common carotid artery (CCA-IMT), internal carotid artery (ICA-IMT) and carotid bifurcation (CB-IMT), were measured of each subject. The associations of periodontitis with CIMT was evaluated by multivariable Logistic regression analysis and analysis of covariance, adjusted for age, gender, education level, hypertension, hyperlipidemia, obesity, smoking, drinking, and diabetes. And then anther definition of periodontitis (mild periodontitis: percentage of AL≥3 mm <10%; moderate periodontitis: percentage of AL≥3 mm 10%-30%; severe periodontitis: percentage of AL≥3 mm ≥30%) was used to investigate the hypotheses that different classification of periodontitis would affect results. RESULTS: The subjects with moderate-severe periodontitis were characterized by significantly higher levels of CCA-IMT, ICA-IMT, CB-IMT and mean CIMT than the mild group. In the univariate analysis, moderate-severe periodontitis was associated with an increased risk of ICA-IMT>0.9 mm (adjusted OR=1.230, 95% CI: 1.058-1.452, P=0.031). Furthermore, moderate periodontitis was associated with an increased risk of CB-IMT>0.9 mm (adjusted OR: 1.297, 95%CI: 1.117-1.753, P=0.011) and severe periodontitis was associated with an increased risk of CB-IMT>0.9 mm (adjusted OR=1.771, 95%CI: 1.176-3.503, P=0.042) according to another classification of periodontitis. CONCLUSION: Our data provided evidence that periodontitis was associated with CIMT among middle-aged and older adults in Shijingshan community of Beijing and different periodontitis classification would affect the results.

[Periodontology from the perspective of holistic integrative medicine].

Medical diciplines have been gradually differentiated and specialized during its developement, and problems due to deep specialization have been increasingly apparent. Its performance is as follows: dental specialists tends to focus on a certain narrow area and ignore neither the patients as a whole existence nor the role of the environmental factors. In this article, the author tries to show the holistic integrative medicine (HIM) from the point of view of periodontal specialty. In fact, the pathogenesis, the differential diagnosis and the treatment of periodontal diseases along with the role of preventive dentistry and basic medicine for periodontology must be considered as a whole using the philosophy of HIM. The future development of periodontal specialty should absorb the achievements of other medical and dental diciplines. Periodontist should pay more attention to HIM. The author also gives some thoughts and suggestions on how to practice HIM in the field of periodontics.

[Comparative study of proliferative and periodontal differentiation propensity of induced pluripotent stem cells at different passages].

OBJECTIVE: To compare the proliferative and periodontal specific differentiation abilities of induced pluripotent stem cells (iPSCs) at different passages, and to investigate whether long term culturing would have a negative influence on their proliferation and specific differentiation capacity, thus providing a theoretical basis for further in-depth research on periodontal regeneration and the possible clinical applications of iPSCs. METHODS: IPSCs derived from human gingival fibroblasts at passages 5, 10, 15 and 20 were recovered and cultured in vitro. Their morphology and proliferation rates were observed respectively. We further induced the iPSCs at different passages toward periodontal tissue under the treatment of growth/differentiation factor-5 (GDF-5) for 14 days through the EB routine, then compared the periodontal differentiation propensities between the different passages of iPSCs by detecting their calcified nodules formation by Alizarin red staining and assaying their relative periodontal tissue related marker expressions by qRT-PCR and immunofluorescence staining, including bone related markers: osteocalcin (OCN), bone sialoprotein (BSP); periodontal ligament related markers: periostin, vimentin; and cementum related markers: cementum attachment protein (CAP), cementum protein 1 (CEMP1). The untreated spontaneous differentiation groups were set as negative controls respectively. RESULTS: iPSCs at different passages all showed a high proliferative capacity when cultured in vitro and turned into a spindle-like shape similar to fibroblasts upon periodontal specific differentiation. All iPSCs formed typical calcified nodules upon GDF-5 induction by Alizarin red staining in comparison to their untreated controls. The relative calcium deposition at all passages had been significantly upgraded under the treatment of GDF-5 (P5: t=2.125, P=0.003; P10: t=2.246, P=0.021; P15: t=3.754, P=0.004; P20: t=3.933, P=0.002), but no significant difference in their calcium deposition were detected within passages 5, 10, 15 and 20 (periodontal differentiation: F=2.365, P=0.109; spontaneously differentiation: F=2.901, P=0.067). Periodontal tissue related marker expressions of iPSCs at all passages had also been significantly upgraded under the treatment of GDF-5 (P<0.05), but still, no significant difference in their expression levels of periodontal tissue related proteins were detected within passages (BSP: F=0.926 7, P=0.450; vimentin: F=0.917 1, P=0.455; CEMP1: F=2.129, P=0.1367). CONCLUSION: Our results preliminarily confirmed that long term culturing won't influence the proliferation capacity and periodontal specific differentiation propensity of iPSCs, as they can still proliferate and differentiate toward periodontal cells with high efficiency upon growth factor induction after continuous passaging. Therefore, iPSCs could be recognized as a promising cell source for future possible application in periodontal tissue regeneration.

MiR-129-5p is downregulated in breast cancer cells partly due to promoter H3K27m3 modification and regulates epithelial-mesenchymal transition and multi-drug resistance.

OBJECTIVE: In this study, we firstly studied whether H3K27me3 modification is a mechanism of miR-129-5p downregulation in breast cancer and further investigated the functional role of miR-129-5p in epithelial-to-mesenchymal transition (EMT) and in multi-drug resistance (MDR) of the cancer cells. MATERIALS AND METHODS: Immunoprecipitation (IP) and Chromatin Immunoprecipitation (ChIP) assay were performed to detect the association among SOX4, EZH2 and H3K27me3 and their enrichment in the promoter region of miR-129-2. Western blot and immunofluorescent staining were performed to detect the expression of epithelial and mesenchymal markers. MTT assay was applied to test drug sensitivity. RESULTS: Enforced EZH2 and SOX4 expression resulted in suppressed miR-129-5p level in MCF-7 cells. There was an interaction among SOX4, EZH2 and H3K27me3 modification and they were significantly enriched in the region upstream of transcription start of miR-129-2. MCF-7 cells transfected with miR-129-5p mimics had significantly suppressed SOX4 expression. MCF-7 cells with miR-129-5p overexpression had significantly restored E-cadherin expression and suppressed N-cadherin and Vimentin expression. The drug sensitivity assay showed that miR-129-5p substantially reduced IC50 of ADM, VCR and PTX in MCF-7/ADM cells CONCLUSIONS: There is a reciprocal regulation between miR-129-5p and SOX4 via the SOX4/EZH2 complex mediated H3K27me3 modification in breast cancer cells. MiR-129-5p is an important miRNA modulating EMT and MDR in breast cancer cells.

[Evaluation of dental plaque by quantitative digital image analysis system].

OBJECTIVE: To analyze the plaque staining image by using image analysis software, to verify the maneuverability, practicability and repeatability of this technique, and to evaluate the influence of different plaque stains. METHODS: In the study, 30 volunteers were enrolled from the new dental students of Peking University Health Science Center in accordance with the inclusion criteria. The digital images of the anterior teeth were acquired after plaque stained according to filming standardization.The image analysis was performed using Image Pro Plus 7.0, and the Quigley-Hein plaque indexes of the anterior teeth were evaluated. RESULTS: The plaque stain area percentage and the corresponding dental plaque index were highly correlated,and the Spearman correlation coefficient was 0.776 (P<0.01). Intraclass correlation coefficients of the tooth area and plaque area which two researchers used the software to calculate were 0.956 and 0.930 (P<0.01).The Bland-Altman analysis chart showed only a few spots outside the 95% consistency boundaries. The different plaque stains image analysis results showed that the difference of the tooth area measurements was not significant, while the difference of the plaque area measurements significant (P<0.01). CONCLUSION: This method is easy in operation and control,highly related to the calculated percentage of plaque area and traditional plaque index, and has good reproducibility.The different plaque staining method has little effect on image segmentation results.The sensitive plaque stain for image analysis is suggested.

Association of Carotid Intima-media Thickness and Atherosclerotic Plaque with Periodontal Status.

Studies have suggested an association between clinical/subclinical atherosclerosis and periodontal status. The purpose of this study was to investigate the association among maximal carotid intima-media thickness (cIMT), atherosclerotic plaque, and periodontal status in Chinese elderly patients. A cross-sectional study was conducted of 847 participants (age, 70.64 ± 9.03 yr) with ≥10 teeth. A questionnaire survey, routine biochemical tests, a periodontal examination, and maximal cIMT measurement were performed for each. Traditional risk factors for atherogenesis were considered in the statistical analysis. Mean plaque index, which reflects oral hygiene, was correlated with maximal cIMT and atherosclerotic plaque in the study sample overall (ß = 0.068, p < .001; OR = 2.051, p < .001) and in euglycemic participants (ß = 0.066, p = .008; odds ratio = 2.122, p = .009). In hyperglycemic participants, multiple linear regression analysis (p = .006) and multivariate logistic regression analysis (p = .025) revealed a linear and dose-dependent association between mean clinical attachment loss and maximal cIMT after adjustment for traditional risk factors. Each 1-mm increase in mean clinical attachment loss corresponded to a 0.018-mm increase in maximal cIMT. The risk of atherosclerotic plaque increased by 18.3% with each 1-mm increase in mean clinical attachment loss. Other indicators of periodontal exposure, including percentage of sites with attachment loss ≥ 3 to 5 mm (3%-5%), were also correlated with cIMT and atherosclerotic plaque in hyperglycemic patients. In this elderly population, a linear and dose-dependent association among mean clinical attachment loss, attachment loss 3% to 5%, maximal cIMT, and atherosclerotic plaque was verified in those with hyperglycemia. Poor oral hygiene was correlated with maximal cIMT and atherosclerotic plaque in all participants, including those with normal blood glucose.