[Gene polymorphisms of cytochrome B-245 alpha chain (CYBA) and cholesteryl ester transfer protein (CETP) and susceptibility to generalized aggressive periodontitis].

OBJECTIVE: To explore the correlation of cytochrome B-245 alpha chain (CYBA) rs4673 and cholesteryl ester transfer protein (CETP) rs12720922 polymorphisms with the susceptibility of gene-ralized aggressive periodontitis (GAgP). METHODS: The study was a case-control trial. A total of 372 GAgP patients and 133 periodontally healthy controls were recruited. The CYBA rs4673 and CETP rs12720922 polymorphisms were detected by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). Logistic regression models were used to analyze the correlation of CYBA rs4673 and CETP rs12720922 variants with the susceptibility of GAgP. The interaction between the two gene polymorphisms to the susceptibility of GAgP was analyzed by the likelihood ratio test. The interaction model adopted was the multiplication model. RESULTS: The mean age of GAgP group and control group was (27.5±5.2) years and (28.8±7.1) years respectively. There was significant difference in age between the two groups (P < 0.05). The gender distribution (male/female) was 152/220 and 53/80 respectively, and there was no significant difference between GAgP group and controls (P>0.05). For CYBA rs4673, the frequency of CT/TT genotype in the GAgP group was significantly higher than that in the controls [18.0% (66/366) vs. 10.6% (14/132), P < 0.05]. After adjusting age and gender, the individuals with CT/TT genotype had a higher risk of GAgP (OR=1.86, 95%CI: 1.01-3.45, P < 0.05), compared with CC genotype. There was no statistically significant difference in distributions of the CETP rs12720922 genotypes (GG, AA/AG) between GAgP patients and healthy controls (P>0.05). A significant interaction between CYBA rs4673 and CETP rs12720922 in the susceptibility to GAgP was observed. The GAgP risk of the individuals with CYBA rs4673 CT/TT and CETP rs12720922 GG genotypes was significantly increased (OR=3.25, 95%CI: 1.36-7.75, P < 0.01), compared with those carrying CC and AA/AG genotypes. CONCLUSION: CYBA rs4673 CT/TT genotype is associated with GAgP susceptibility. There is a significant interaction between CYBA rs4673 CT/TT genotype and CETP rs12720922 GG genotype in the susceptibility of GAgP.

Low-Dose Ozone Therapy Improves Sleep Quality in Patients with Insomnia and Coronary Heart Disease by Elevating Serum BDNF and GABA.

We studied the effects of low-dose ozone therapy on the sleep quality of patients with coronary heart disease (CHD) and insomnia by measuring the levels of brain-derived neurotrophic factor (BDNF) and GABA in blood serum. The 3-month course of low-dose ozone therapy significantly elevated serum BDNF and GABA in CHD patients with insomnia and improved parameters of anxiety, depression, and sleep quality according to Hospital Anxiety and Depression Scale (HADS), Pittsburgh Sleep Quality Index (PSQI), and Self-Rating Scale of Sleep (SRSS). Ozone therapy also significantly (p<0.05) improved the total antioxidant status of the body by elevating catalase activity and reducing malondialdehyde and 8-OHdeoxyguanosine in the saliva. The serum levels of BDNF and GABA negatively and closely correlated with PSQI and HADS scores. Low-dose ozone therapy improved sleep quality and reduced PSQI and HADS scores due to up-regulation of BDNF and GABA.

Associations of apolipoprotein E and low-density lipoprotein receptor-related protein 5 polymorphisms with dyslipidemia and generalized aggressive periodontitis in a Chinese population.

BACKGROUND AND OBJECTIVE: Dyslipidemia is associated with aggressive periodontitis, a condition characterized by the rapid destruction of the periodontium. Apolipoprotein E (APOE) and low-density lipoprotein receptor-related protein 5 (LRP5) are involved in immunomodulation and inflammatory activity. We evaluated the association of LRP5 and APOE polymorphisms with serum lipid concentrations and generalized aggressive periodontitis within a Chinese population. MATERIAL AND METHODS: Mean serum lipid concentrations were compared across LRP5 and APOE polymorphisms, among cases (n = 185) and controls (n = 138). Multivariable logistic regression was used to evaluate the independent and combined associations of LRP5 and APOE polymorphisms with generalized aggressive periodontitis. RESULTS: Compared with controls, individuals with generalized aggressive periodontitis exhibited significantly lower serum total cholesterol (TC) and lower high-density lipoprotein cholesterol (HDL-c). Individuals with LRP5 polymorphisms (rs682429-AA or rs312016-GG) exhibited higher TC, higher HDL-c and decreased odds for generalized aggressive periodontitis. Haplotype (A-G), determined by rs682429 and rs312016, was also associated with decreased odds for generalized aggressive periodontitis. Furthermore, individuals with the combined polymorphisms (LRP5-rs682429-AA and APOE-rs429358-CC/CT) had higher levels of low-density lipoprotein cholesterol, higher levels of TC and decreased odds for generalized aggressive periodontitis. CONCLUSION: Independently or combined with APOE, LRP5 polymorphisms may lead to dyslipidemia and are associated with generalized aggressive periodontitis. Dyslipidemia may be a risk indicator for generalized aggressive periodontitis in the Chinese population. Furthermore, two LRP5 polymorphisms (rs682429 and rs312016) might be useful for identifying subjects at higher risk of generalized aggressive periodontitis.

Effect of non-surgical periodontal treatment on short chain fatty acid levels in gingival crevicular fluid of patients with generalized aggressive periodontitis.

BACKGROUND AND OBJECTIVE: Short chain fatty acids (SCFAs) play important roles in periodontal diseases. However, the concentrations of SCFAs in gingival crevicular fluid of patients with aggressive periodontitis are not known. The aim of this intervention study was to investigate the influences of non-surgical periodontal therapy on levels of SCFAs in the gingival crevicular fluid of patients with generalized aggressive periodontitis (G-AgP), and analyze the concentrations of SCFAs in sites with or without the detected putative periodontal pathogens. MATERIAL AND METHODS: Eighty gingival crevicular fluid samples (four per subject) were collected on filter paper strips from patients with G-AgP (n = 20; mean age 24.5 years), before and at 2 wk, 2, 4 and 6 mo after non-surgical periodontal treatment. Eighty gingival crevicular fluid samples (four per subject) were collected from periodontally healthy controls (n = 20; mean age 26.2 years). Concentrations of formic acid, succinic acid, acetic acid, lactic acid, propionic acid, butyric acid and isovaleric acid from the supernatant of gingival crevicular fluid samples were measured by high performance capillary electrophoresis. Porphyromonas gingivalis, Treponema denticola, Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Fusobacterium nucleatum from the precipitate of the same pretreatment samples of gingival crevicular fluids were analyzed by polymerase chain reaction amplification. RESULTS: The clinical parameters of patients with G-AgP during the 6 mo after non-surgical periodontal treatment were improved remarkably. The formic acid concentration increased significantly after treatment; the level of formic acid was lower in the P. gingivalis-, T. denticola-, P. intermedia- or F. nucleatum-positive sites compared with the negative sites. The concentrations of acetic acid, propionic acid and butyric acid reduced significantly after treatment and reached the lowest level at 2 wk post-treatment, although showed a tendency to increase after 2 mo post-treatment, and the three SCFA levels were significantly higher in P. gingivalis-, T. denticola-, P. intermedia- or F. nucleatum-positive sites compared with those in the negative sites. CONCLUSION: Non-surgical periodontal treatment resulted in a significant decrease of acetic acid, propionic acid, butyric acid levels and increase of formic acid level in gingival crevicular fluids in patients with G-AgP, accompanied by improvement in clinical parameters. A marked lower level of formic acid, as well as higher levels of acetic acid, propionic acid and butyric acid in gingival crevicular fluid of patients with G-AgP was consistent with periodontal pathogen infection.

[Analysis of the correlation between peri-implant probing depth and radiographic bone level].

Objective: To evaluate the correlation between peri-implant probing depth (PPD) and radiographic bone level (rBL) in implants with peri-implantitis. Methods: From January 2019 to December 2022, 24 patients with 30 implants who suffered from peri-implantitis at the Department of Periodontology, Peking University School and Hospital of Stomatology were included in the present research. SPSS 26.0 software was used to simple random sampling select 30 healthy implants from which with electronic examination records in Department of Periodontology, Peking University School and Hospital of Stomatology from January 2007 to June 2023 as the control group. On the premise of retaining the implant prosthesis, PPD (distance between pocket bottom and peri-implant soft tissue margin) was examined using a Williams periodontal probe with a light force (about 0.2 N), and a total of 4 sites were recorded for each implant. Periapical radiography and cone beam CT were applied to measure the rBL (distance between the reference point at the neck of the implant and the apical point of the bone defect) and the width of the bone defect (DW), and the type of the bone defect was recorded. The correlation and consistency between the diagnosis of PPD and rBL were analyzed. Results: PPD was significantly correlated with rBL in a total of 60 implants in 180 sites (r=0.64, P<0.001). The chi-square test showed an 8.15-fold increase in the detection rate of PD≥6 mm at sites with rBL≥1 mm (P<0.001). Multivariate logistic regression analysis showed that rBL was still statistically associated with PPD after adjustment for jaw position and examination position of implants. Take rBL <1 mm as reference, the odds ratios (OR) of 1 mm≤rBL<2 mm, 2 mm≤rBL<3 mm and rBL≥3 mm group with PPD were 6.23 (P=0.014), 2.77 (P=0.183) and 10.87 (P=0.001), respectively. Conclusions: There is a positive correlation between PPD and rBL in implants with peri-implantitis. PPD can be used as a clinical examination index to assist in estimating the level of peri-implant bone under the premise of retaining the prosthesis.

Efficacy and safety of total glucosides of paeony in treating primary Sjögren's syndrome: a propensity-matched study.

OBJECTIVE: This study aimed to evaluate the efficacy and safety of total glucosides of paeony (TGP) in patients with primary Sjögren's syndrome (pSS). PATIENTS AND METHODS: This study included 236 patients with pSS, including 118 TGP users and 118 non-users. Propensity score matching and Binary logistic regression analyses were used to minimize confounding factors and determine the association between TGP treatment and clinical variables. RESULTS: The baseline indexes of TGP users and non-users were basically the same. The median time of follow-up in the two groups was also similar (p < 0.05). Compared with non-users, TGP users showed higher rates of improvement in dry mouth and eyes and musculoskeletal involvement, as well as more significant reductions in serum alanine aminotransferase (ALT) and direct bilirubin (DBIL) levels after treatment. Logistic regression confirmed that the use of TGP was negatively correlated with the increase of ALT and DBIL in pSS patients, and the reduction in these variables was more pronounced after 2 years of treatment. The incidence of adverse reactions in the TGP users was 11.9%, which was compatible with those in non-users. CONCLUSIONS: TGP is often a safe option for treating pSS patients with musculoskeletal features and abnormal ALT levels. Besides, it can help improve dry mouth and dry eyes and decrease DBIL levels.

Elevation of vitamin D-binding protein levels in the plasma of patients with generalized aggressive periodontitis.

BACKGROUND AND OBJECTIVE: Vitamin D-binding protein (DBP) is a multifunctional and highly expressed plasma protein. Among its diverse roles, including those in the immune and inflammatory responses, it is the primary carrier of vitamin D, which has been implicated in periodontitis. We hypothesized that there is a correlation between systemic DBP levels and generalized aggressive periodontitis (GAgP). MATERIAL AND METHODS: Forty-four patients with GAgP and 32 healthy controls were recruited. Clinical parameters were examined, including the mean bleeding index, probing depth, attachment loss and percentage of severely affected sites. Blood chemistry analyses were performed for each subject. Plasma levels of DBP, interleukin-6 (IL-6) and procalcitonin (PCT) were measured using ELISAs, and plasma levels of 25-hydroxy-vitamin D(3) (25(OH)D(3)) were detected using a radioimmunoassay. RESULTS: Significantly higher levels of plasma DBP, IL-6, PCT and 25(OH)D(3), as well as leukocyte counts, neutrophil counts and neutrophil percentages were found in patients with GAgP compared with healthy controls (p < 0.05 for all). Multiple linear regression analysis showed that the plasma DBP levels were significantly correlated with GAgP, plasma PCT levels and smoking status (p < 0.05 for all). In the GAgP group, the plasma DBP levels in smokers were significantly higher than those in nonsmokers (p < 0.001). CONCLUSION: Elevated plasma vitamin DBP levels are associated with GAgP.

[The histopathological characteristics of peri-implantitis].

Peri-implantitis (PI) has been defined as an inflammatory lesion of the mucosa surrounding an endosseous implant and with progressive loss of supporting peri-implant bones. In recent years, histopathological differences between PI and periodontitis of natural teeth had been described in animal experiments and a certain number of human experiments. In this paper, we review the histopathological differences between PI and periodontitis reported in the existing literature and try to find the differences in the occurrence and progression of these two diseases. Overall, inflammatory cell infiltrate (ICT) is more extensive in PI than in periodontitis, extending to the alveolar ridge, with dense infiltration of plasma cells, lymphocytes, macrophages, polymorphonuclear leukocytes and a greater number of osteoclasts in the connective tissue, but with less vascular density within ICT than in periodontitis. In addition, foreign bodies are found in PI lesions. The histopathological differences between the two diseases in terms of inflammatory infiltration, vascularity, bone loss, and foreign bodies could partially explain the more rapid progression of PI than periodontitis, suggesting that PI should be taken seriously by physicians. Early diagnosis and treatment are essential to control the progression of PI. In addition, targeted therapy against specific inflammatory cells may become a new direction for PI treatment; reducing titanium particles released into peri-implant tissue by friction or electrochemical corrosion may help to prevent PI.

[Interpretation of the European Federation of Periodontology S3 level clinical practice guideline for prevention and treatment of peri-implant diseases].

The S3 level clinical practice guideline for the prevention and treatment of peri-implant diseases, developed by the European Federation of Periodontology, was published in June, 2023 (DOI: 10.1111/jcpe.13823), which culminated in the recommendations for implementation of various different interventions before, during and after implant placement/loading. Aim of the present article is to summarize and interpret the key points of this guideline and help clinicians understand this guideline better, in order to standardize the prevention and treatment of peri-implant diseases.

FoxO1/NLRP3 Inflammasome Promotes Age-Related Alveolar Bone Resorption.

Periodontitis is the utmost common chronic oral disease that exhibits intense susceptibility to aging. Aging is characterized by persistent sterile low-grade inflammation, leading to age-related periodontal complications represented by alveolar bone loss. Currently, forkhead transcription factor O1 (FoxO1) is generally believed to have a significant role in body development, senescence, cell viability, and oxidative stress in numerous organs and cells. However, the role of this transcription factor in mediating age-related alveolar bone resorption has not been examined. In this study, FoxO1 deficiency was discovered to have a beneficial correlation with halting the progression of alveolar bone resorption in aged mice. To further investigate the function of FoxO1 in age-related alveolar bone resorption, osteoblastic-specific FoxO1 knockout mice were generated, leading to an amelioration in alveolar bone loss compared to aged-matched wild-type mice, manifested as enhanced osteogenic potential. Mechanistically, we identified enhancement of the NLRP3 inflammasome signaling in FoxO1-deficient osteoblasts in the high dose of reactive oxygen species. Concordant with our study, MCC950, a specific inhibitor of NLRP3 inflammasome, greatly rescued osteoblast differentiation under oxidative stress. Our data shed light on the manifestations of FoxO1 depletion in osteoblasts and propose a possible mechanism for the therapy of age-related alveolar bone loss.

Current-pulse-induced enhancement of transient photodetective effect in tilted manganite film.

A current-pulse-induced enhancement effect of transient photovoltage has been discovered in tilted manganite La(2/3)Ca(1/3)MnO(3) film at room temperature. Here, by applying a pulsed current stimulus before pulse laser irradiation, we observed a significant enhancement of more than 50% in photovoltaic sensitivity. The current-pulse-induced photovoltaic enhancement can be tuned not only by the stimulating current value but also by the stimulating time. Such enhancement is time-sensitive and reproducible. This electrically induced effect, observed at room temperature, has both the benefit of a discovery in materials properties and the promise of applications for thin film manganites in photodetectors.

Association analysis between the -2518MCP-1(A/G) polymorphism and generalized aggressive periodontitis in a Chinese population.

BACKGROUND AND OBJECTIVE: It has been suggested that aggressive periodontitis has a genetic basis. Monocyte chemoattractant protein 1 (MCP-1) plays a critical role in the recruitment of monocytes and the development of periodontitis. The -2518MCP-1(A/G) polymorphism has been implicated as a risk or susceptibility factor for a variety of autoimmune conditions and inflammatory diseases. The intent of this investigation was to study whether the -2518MCP-1(A/G) polymorphism is associated with generalized aggressive periodontitis in the Chinese population. MATERIAL AND METHODS: One hundred and twenty-four patients with generalized aggressive periodontitis and 94 healthy subjects were included in this case-control study. Genomic DNA was isolated from a peripheral blood sample obtained from each subject. Gene polymorphisms of -2518MCP-1(A/G) were analyzed by a standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. A logistic regression analysis was performed to test the association between the -2518MCP-1(A/G) genotype (alleles) and generalized aggressive periodontitis with adjustment of the major covariates (gender, age and smoking status). RESULTS: There was no significant association of the -2518MCP-1(A/G) polymorphism with generalized aggressive periodontitis in the unstratified subjects. However, when patients were stratified by gender, the frequency of the G(+) genotype was significantly lower in female patients with generalized aggressive periodontitis compared with female controls (p = 0.036, adjusted odds ratio = 0.3, 95% CI: 0.1-0.9). In female patients with generalized aggressive periodontitis, the probing pocket depth was larger in subjects with the AA genotype than in subjects with the G(+) genotype (5.07 mm vs. 4.30 mm; Z = -2.470, p = 0.014). CONCLUSION: The polymorphisms of -2518MCP-1 may play an important role in determining generalized aggressive periodontitis susceptibility in this cohort of Chinese women.

The prevalence of dentine hypersensitivity in Chinese adults.

Dentine hypersensitivity is a common oral problem. This study investigated the prevalence of dentine hypersensitivity in the adult population of Shanghai, China. A multi-stage, stratified, random sampling method was used to investigate the study population. A total of 2120 subjects were examined at 10 investigation points in Shanghai City. Subjects were divided into age groups (10 years per age group) and included the same number of male and female subjects in each group. Participants completed a dentine hypersensitivity questionnaire and underwent clinical examination. The diagnosis of dentine hypersensitivity was confirmed clinically as a sharp well-localised pain in response to administration of a blast of cold air from a triple syringe. Gingival recession of sensitive teeth was measured by a Williams periodontal probe. Among 2120 participants, 723 were diagnosed as having dentine hypersensitivity, indicating a prevalence of 34·1%. The male to female ratio of dentine hypersensitivity was 1:1·5. The prevalence of dentine hypersensitivity was highest in the 40- to 49-year age group at 43·9%. The number of teeth with dentine hypersensitivity was 3·2 per patient. Dentine hypersensitivity occurred predominantly in the premolars (49·6%), followed by the anterior teeth (30·5%). A total of 84·3% of dentine hypersensitive patients had gingival recession. The prevalence of dentine hypersensitivity in Shanghai adults was 34·1%, indicating that it is a common condition. Therefore, public education about the condition and effective treatment of dentine hypersensitivity are required.

Analysis of plasma calprotectin and polymorphisms of S100A8 in patients with aggressive periodontitis.

BACKGROUND AND OBJECTIVE: Calprotectin is an important proinflammatory mediator in various inflammatory diseases and is composed of two subunits (S100A8 and S100A9). However, the level of calprotectin in plasma of patients with aggressive periodontitis and its relationship with gene polymorphisms of S100A8 are unclear. MATERIAL AND METHODS: The plasma concentrations of calprotectin were measured, using an enzyme immunoassay, in 139 patients with aggressive periodontitis and in 88 periodontally healthy control subjects. These patients were genotyped for the rs3795391 and rs3806232 polymorphisms of S100A8. RESULTS: The plasma concentration of calprotectin in patients with aggressive periodontitis was significantly higher than in controls (2.17 mg/L vs. 1.72 mg/L, respectively, p = 0.001). The percentage of the AA genotype of S100A8 rs3795391 was significantly higher in patients than in controls (82% vs. 69.3%, respectively, p = 0.027), while the frequency of the allele G was decreased among patients compared with controls (9.6% vs. 16.1%, respectively, p = 0.036), which was especially apparent in men (rs3795391 genotype, p = 0.005; rs3795391 allele, p = 0.015). The mean probing depth in patients carrying the AA genotype was significantly higher than that of patients carrying the GA + GG genotype of two polymorphisms of S100A8 (rs3795391, p = 0.035; rs3806232, p = 0.040), whereas the levels of calprotectin between different genotypes were not significantly different (rs3795391, p = 0.11; rs3806232, p = 0.15). CONCLUSION: These findings indicate that aggressive periodontitis is associated with elevated levels of plasma calprotectin and that gene polymorphisms of S100A8 may influence the susceptibility and severity of aggressive periodontitis.

[Exploration and practice of periodontal specialist training system].

The standardized training of specialist doctors is an important part of medical education after graduation and it is the only way to train clinicians to diagnose and treat the specialist diseases independently by using a standardized and high-quality way. The prevalence of periodontal disease and the proportion of patienets with severe and advanced periodontitis in our country are high and the diagnosis and treatment process for the periodontal disease are complicated. There is an urgent need to expand the team of periodontal specialists capable of the specialized treatment. The training of periodontal specialists in our country has just started. The present article summarizes the exploration and practice of periodontal specialist training in Peking University School and Hospital of Stomatology in the past five years, including the establishment of training bases, formulation of clear training goals, strict implementation of training rules, strengthening of process quality control to ensure the trainees could reach the expected standard of periodontal specialist after training. Through the summary of the previous stage practice, the authors hope to explore and establish a periodontal specialist training system in line with our country's national conditions and further to promote and accelerate the pace of nationwide periodontal specialist training system.

[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.

Ethnic Disparities in Dental Caries among Adolescents in China.

Comprehensive research on ethnic disparities in dental caries in China is limited. The aims of this cross-sectional study were to compare the levels of dental caries in adolescents between the Han ethnic group and ethnic minority groups in China and to explore the risk indicators for dental caries within ethnic subgroups. Data from the Fourth National Oral Health Survey in 2015, which covered all 31 province-level administrative divisions in mainland China, were used. The dental caries status in the permanent dentition of adolescents aged 12, 13, 14, and 15 y was measured using the decayed, missing, and filled teeth (DFMT) score, and sociodemographic characteristics and oral health-related behaviors were also collected. A total of 118,601 adolescents were included, with ethnic minority groups accounting for 13.15%. Of the Han and minority groups, the standardized prevalence of dental caries experience was 40.58% and 47.67%, and the mean DMFT scores were 0.97 and 1.28, respectively. According to the multivariate zero-inflated negative binomial regression analysis, the caries status of minorities was more severe than Han adolescents (adjusted prevalence rate ratio [PRR], 1.14; 95% confidence interval [CI], 1.10-1.18). This disparity was greater among adolescents who lived in rural areas, had mid-level economic status, and frequently consumed sugary beverages. After propensity score matchings, Uygur (PRR, 1.44; 95% CI, 1.25-1.67), Tibetan (PRR, 1.39; 95% CI, 1.3-1.48), and Yi (PRR, 1.24; 95% CI, 1.04-1.48) adolescents were significantly more likely to have caries than Han adolescents. Subgroup analyses revealed that gender, age, location of residence, economic status, region, consumption of sweet snacks and sugary beverages, and dental visit pattern were significantly associated with dental caries within ethnic minorities.

Parametric nanomechanical amplification at very high frequency.

Parametric resonance and amplification are important in both fundamental physics and technological applications. Here we report very high frequency (VHF) parametric resonators and mechanical-domain amplifiers based on nanoelectromechanical systems (NEMS). Compound mechanical nanostructures patterned by multilayer, top-down nanofabrication are read out by a novel scheme that parametrically modulates longitudinal stress in doubly clamped beam NEMS resonators. Parametric pumping and signal amplification are demonstrated for VHF resonators up to approximately 130 MHz and provide useful enhancement of both resonance signal amplitude and quality factor. We find that Joule heating and reduced thermal conductance in these nanostructures ultimately impose an upper limit to device performance. We develop a theoretical model to account for both the parametric response and nonequilibrium thermal transport in these composite nanostructures. The results closely conform to our experimental observations, elucidate the frequency and threshold-voltage scaling in parametric VHF NEMS resonators and sensors, and establish the ultimate sensitivity limits of this approach.

[Effect of systemic use of amoxicillin and metronidazole during mechanical therapy on the periodontal microorganisms in subgingival plaque and saliva of patients with aggressive periodontitis].

Objective: To explore the effect of systemic use of amoxicillin and metronidazole during mechanical therapy on the clinical parameters of the first molars and periodontal microorganisms in subgingival plaque and saliva in patients with generalized aggressive periodontitis (GAgP). Methods: A total of 23 GAgP patients were recruited from Peking University School and Hospital of Stomatology from January 2006 to December 2009 and then randomly divided into two groups according to random number table: 12 patients received scaling and root planning (SRP) only and 11 patients received SRP combined with systemic administration of antibiotics (amoxicillin and metronidazole for a week after supragingival scaling). Clinical examination of periodontal parameters and collection of saliva and pooled subgingival plaque samples from mesial-buccal sites of 4 first molars were performed before initial therapy and 2, 4 and 6 months respectively after mechanical therapy, and saliva samples were also collected 2 weeks after therapy. Eight different periodontal microorganisms were detected in these samples by PCR. In addition, semiquantitative analysis of red complex microorganisms [Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td)] was performed. Results: Both therapies led to significant decrease of the plaque index (PLI), probing depth (PD) and bleeding index (BI) from mesial-buccal sites of first molars. Meanwhile the PD of antibiotics group [(4.21±1.50), (4.00±1.54), (3.84±1.89) mm of 2, 4 and 6 months respectively after therapy] was significantly lower than the SRP group [(5.29±1.27), (5.30±1.34), (4.98±1.36) mm of 2, 4 and 6 months respectively after therapy] at 3 different time points after mechanical therapy (P<0.05). In the antibiotics group, the quantities of Pg, Tf and Td in subgingival plaque samples (the median quantity decreased to 0.0 ng at 2, 4 and 6 months after therapy) and saliva samples (the median quantity of Tf and Td decreased to 0.0 ng at 2, 4 and 6 months after therapy (P<0.05), and the median quantity of Pg decreased to 16.3, 59.6 and 22.4 ng at 2, 4 and 6 months respectively after therapy) significantly decreased at 3 different time points after mechanical therapy compared with before therapy (P<0.05). While in the SRP group, there were no significant changes in the quantities of Tf and Td in saliva at 2, 4 and 6 months after mechanical therapy (P>0.05) , and the quantities of Tf and Td in subgingival plaque significantly decreased only at 2 months after therapy (P<0.05). Conclusions: SRP combined with systemic administration of amoxicillin and metronidazole could achieve greater improvement in PD of first molars and better control of the amounts of red complex microorganisms in the saliva and subgingival plaque of GAgP patients over a 6-month period.

[Interaction analysis between epidermal growth factor and peroxidase proliferators activate receptor-α gene polymorphism and susceptibility to generalized aggressive periodontitis].

Objective: To explore the correlation and interaction between epidermal growth factor (EGF) rs2237051 and peroxidase proliferators activate receptor-α (PPAR-α) rs4253623 polymorphisms and the susceptibility of generalized aggressive periodontitis (GAgP). Methods: Two hundred and nineteen Chinese patients with GAgP were enrolled from the patients of the Department of Periodontology, Peking University School and Hospital of Stomatology from January 2001 to December 2015. The control group comprised 138 periodontally healthy volunteers recruited from the staff and students of the Peking University School and Hospital of Stomatology. The EGF rs2237051 and PPAR-α rs4253623 polymorphisms were genotyped using time-of-flight mass spectrometry. Logistic regression models were conducted to analyze the correlation between the EGF rs2237051 and PPAR-α rs4253623 variants with GAgP. The likelihood ratio test was used to analyze whether there was an interaction between the two polymorphisms in the susceptibility of GAgP. The interaction model adopted was the multiplication model. Results: The mean ages of GAgP group (male:87; female:132) and control group (male: 53; female: 85) were (27.3±4.5) years and (27.1±4.2) years respectively and there was no significant difference in age and gender distribution between the two groups. For EGF rs2237051, the frequency of AA genotype in the GAgP group [49.5% (107/216)] was significantly higher than that in the control group [37.7% (52/138)], and the frequency of AG/GG genotype in the GAgP group [50.5% (109/216)] was significantly lower than that in the control group [62.3% (86/138)](P<0.05). Compared with AA genotype, individuals with AG/GG genotype had a 39% lower risk of GAgP after adjustment of age and gender (OR: 0.61, 95%CI: 0.40-0.95, P<0.05). For PPAR-α rs4253623, the frequency of AA genotype in the GAgP group [76.2% (160/210)] was significantly higher than that in the control group [65.9%(81/123)], and the frequency of AG/GG genotype in the GAgP group [23.8% (50/210)] was significantly lower than that in the control group [34.1%(42/123)] (P<0.05). Compared with AA genotype, individuals with AG/GG genotype had a 40% lower risk of GAgP after adjustment of age and gender (OR: 0.60, 95%CI: 0.36-0.98, P<0.05). EGF rs2237051 and PPAR-α rs4253623 showed a significant interaction in the susceptibility to GAgP. Compared with AA genotype, the risk of GAgP in individuals with both AG/GG genotypes of EGF rs2237051 and PPAR-α rs4253623 was reduced by 66% (OR: 0.34, 95%CI: 0.17-0.66, P<0.01). Conclusions: EGF rs2237051 and PPAR-α rs4253623 are correlated with GAgP susceptibility, and there is a significant interaction between them in the susceptibility of GAgP. The G allele of the two loci has a protective effect on the disease of GAgP.