Statistical Analysis of Current Oral Health Care and Dental Education Resources in China.

OBJECTIVE: To collect information and statistical data regarding the current oral health care and dental education resources in China. METHODS: Electronic databases were searched and a literature review conducted. The homepages of relevant universities and colleges were visited to collect dental education information. In addition, private conversations with related experts were conducted. RESULTS: Compared with the 3rd National Oral Health Survey (2005), the ratio of gingival bleeding in individuals aged 33 to 44 years has increased in the last 10 years. The average percentage of residents visiting departments of dentistry in public hospitals is less than 10%. The total number of dentists and assistant dentists increased to 167,227 in 2016, with a ratio of 1.21 per 10,000 people. There is a great imbalance in the distribution of dental practitioners among the provinces. There are 101 dental schools or departments of stomatology that provide 5-year dental training courses and offer bachelor's degrees in dentistry, with another 93 dental institutions offering shorter 3-year training courses for assistant dentists. CONCLUSION: The results of the present study show that there has been significant change during recent years in China. However, the ratio of dental practitioners to the population as well as the number of dental visits carried out is still much lower than in developed countries and does not satisfy the demand for dental care in China. The quality and quantity of dental education, including continuing dental education, calls for improvement in the future.

Prevalence and quantification of the uncommon Archaea phylotype Thermoplasmata in chronic periodontitis.

OBJECTIVE: Chronic periodontitis is a chronic inflammatory disease of the periodontal tissues and is caused by invasion of certain types of bacteria and Archaea, with Methanobrevibacter oralis as the predominant archaeon. In this study, we investigated the prevalence and quantity of the newly discovered Archaea phylotype Thermoplasmata in patients with chronic periodontitis. METHODS: Subgingival plaque samples were obtained from 49 patients with chronic periodontitis and 45 periodontally healthy subjects. Qualitative analyses of Archaea and class Thermoplasmata were carried out by amplification of 16S rRNA genes in DNA extracts from plaque samples, and all the samples were quantitatively analyzed by real-time polymerase chain reaction (PCR). RESULTS: The prevalence of Archaea in patients with chronic periodontitis was 69.4% according to the conventional PCR results, but was 87.8% according to real-time PCR. In the control group, three samples were detected as positive, but none of these were confirmed in qualitative analyses. The prevalence of class Thermoplasmata was 18.4% by nested PCR and 24.5% by quantitative PCR in the chronic periodontitis group. The prevalence of Thermoplasmata was significantly lower than that of total Archaea. The relative abundances of Archaea and Thermoplasmata varied among samples. Thermoplasmata were not the predominant archaeons in the subgingival dental plaque. Among the clinical parameters of patients with periodontitis, probing depth was positively associated with Archaea detection. CONCLUSIONS: The existence of Archaea was correlated closely with the presence of chronic periodontitis. Thermoplasmata represented a minor archaeon in periodontal infection.

[Analysis of virulence-related properties of P. gingivalis clinical isolates].

PURPOSE: To analyze the relation of virulence properties and pathogenicity of Porphyromonas gingivalis (P.gingivals) isolated from Chinese patients. METHODS: Based on the previous analysis of virulence properties, investigations of pathogenicity properties, including the adhesion to host cells, gingipain activities, and resistance to host immune reaction were performed to analyze the diversity of pathogenic properties of these strains. SAS 8.02 software package was used for statistical analyses. RESULTS: Less-virulent type strain showed higher adherence ability to host red blood cells and weaker resistance to serum killing, while virulent type strain showed the opposite reactions. However, the clinic isolates presented just the opposite relationship between virulence properties and pathogenicity. In addition, there was no obvious correlation between gingipain activities and virulence properties of P. gingivalis strains. CONCLUSIONS: The results suggested that there is no obvious linkage between the P. gingivalis virulence properties and pathogenicity diversity.

Neutrophil-lymphocyte ratio predicts the prognosis of patients with hepatocellular carcinoma after liver transplantation.

AIM: To determine whether an elevated neutrophil-lymphocyte ratio (NLR) is negatively associated with tumor recurrence in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) after liver transplantation (LT), and to determine the optimal predictive NLR cut-off value. METHODS: The data of HCC patients who had undergone LT came from the China Liver Transplant Registry database. We collected data from 326 liver cancer patients who had undergone LT at our medical center. We divided the patients into groups based on their NLRs (3, 4 or 5). We then compared the clinicopathological data and long-time survival between these groups. Meanwhile, we used receiver operating characteristic analysis to determine the optimal NLR cut-off. RESULTS: Of 280 HCC patients included in this study, 263 were HBV positive. Patients with an NLR < 3 and patients with an NLR ≥ 3 but < 4 showed no significant differences in overall survival (OS) (P = 0.212) or disease-free survival (DFS) (P = 0.601). Patients with an NLR ≥ 4 but < 5 and patients with an NLR ≥ 5 also showed no significant differences in OS (P = 0.208) or DFS (P = 0.618). The 1-, 3- and 5-year OS rates of patients with an NLR < 4 vs an NLR ≥ 4 were 87.8%, 63.8% and 61.5% vs 73.9%, 36.7% and 30.3%, respectively (P < 0.001). The 1-, 3- and 5-year DFS rates of patients with an NLR < 4 vs NLR ≥ 4 were 83.9%, 62.9% and 60.7% vs 64.9%, 30.1% and 30.1%, respectively (P < 0.001). Univariate and multivariate analyses demonstrated that three factors, including NLR ≥ 4 (P = 0.002), were significant predictors of tumor recurrence in HCC patients after LT. CONCLUSION: A preoperative elevated NLR significantly increased the risk for tumor recurrence in HCC patients after LT.

MicroRNA-146 inhibits pro-inflammatory cytokine secretion through IL-1 receptor-associated kinase 1 in human gingival fibroblasts.

BACKGROUND: Although various microRNAs (miRNAs) regulate immune and inflammatory responses, the function of miRNAs in periodontitis has not been clearly illuminated. In this study, we measured miRNA-146 (miRNA-146a and miRNA-146b-5p) expression and explored its regulatory function in the inflammatory response in human gingival fibroblasts (HGFs). METHODS: miRNA-146a and miRNA-146b-5p expression was measured by performing real-time polymerase chain reaction in HGFs after Porphyromonas gingivalis (p.g) lipopolysaccharide (LPS) stimulation. After the HGFs were transfected with miRNA-146a and miRNA-146b-5p inhibitor, the expression levels of interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). Meanwhile, IL-1 receptor-associated kinase 1 (IRAK1) and TNF receptor-associated factor 6 (TRAF6) were detected by western blot and quantitative PCR. A luciferase assay was used to detect whether miRNA-146 could directly bind to the 3'-UTR of IRAK1. RESULTS: The expression levels of miRNA-146a and miRNA-146b-5p significantly increased in the P.g LPS-stimulated HGFs compared to the non-stimulated HGFs. The inhibition of miRNA-146a and miRNA-146b-5p resulted in increased IL-1ß, IL-6 and TNF-α secretion. The mRNA and protein levels of IRAK1, but not TRAF6, also increased. We further found that miRNA-146a and miRNA-146b-5p directly bound to the IRAK1 3'-UTR. CONCLUSION: Our data suggest that miRNA-146 inhibits pro-inflammatory cytokine secretion through IRAK1 in HGFs, which indicates that miRNA-146 functions as a negative regulator of periodontal inflammation.

[A clinical study of osteotome sinus floor elevation and simultaneous implant placement in the periodontally compromised patients].

PURPOSE: To study the clinical effect of osteotome sinus floor elevation (OSFE) combined with simultaneous implant placement in the treatment of edentulous posterior maxilla subject to insufficient bone height in the periodontally compromised patients. METHODS: Forty-seven Straumanns implants were placed in the posterior maxilla in 35 patients with the procedure of OSFE. The final prostheses were restored after 3 to 6 months. The follow-up period was 6 to 30 months. Radiographs were taken and PD, PLI, BOP were measured and analyzed. RESULTS: The overall survival rate was 95.74% during the study period. Forty-five out of the 47 implants were clinically stable and loaded without pain or any subjective sensation. The perforation ratio of the membrane was 4.26%. The average of PD around the implants was (3.22±1.07) mm. The average of the marginal bone loss was (1.38±0.59) mm. CONCLUSIONS: OSFE without bone graft proves to be an effective and predictable treatment for atrophic edentulous posterior maxillary region in patients with periodontitis, but the long-term effect needs further observation.

[Using DGGE to analyze bacteria community structure changes in subgingival plaque after periodontal initial therapy].

PURPOSE: To analyze bacteria community structure changes in subgingival plaque after initial therapy, and to provide experimental evidences for clinical decision. METHODS: Six patients with chronic periodontitis were chosen. Subgingival plaque samples, as well as clinical indexes, were collected at baseline and six weeks after initial therapy. The generated two different 16S rDNA fragments of subgingival plaque samples were separated by denaturing gel, creating bands patterns representative of community structure. Subsequent cluster analysis was made. RESULTS: The clinical indexes were improved significantly. The diversity of population of clinical subgingival samples was not significantly different between baseline and 6 weeks after initial therapy. Through cluster analysis, it was confirmed that same patient got similar subgingival plaque between baseline and 6 weeks after treatment. CONCLUSIONS: Same patient tend to get similar subgingival plaque between baseline and after initial therapy. DGGE can detect the microbial composition of subgingival plaque.

[Virulent properties of Porphyromonas gingivalis clinical strains].

PURPOSE: To investigate the virulent properties of P. gingivalis clinical strains. METHODS: By using mouse abscess model (MAM), six P. gingivalis clinical strains, L2, L3, L4, L5, L11 and L12 were subcutaneously inoculated into the central back of BALB/C mice. The clinical signs of the mice were observed and the virulent properties of the clinical strains were analyzed by comparison with type strains of W83 and ATCC 33277. SPSS11.5 software package was used for statistical analysis. RESULTS: According to the criteria established in previous reports, L3, ATCC33277, and W83 produced a localized abscess at the site of injection and were categorized as noninvasive. L2, L5, L11, and L12-induced lesions spread to distant organs and may produce severe systemic reactions and these strains were classified as invasive. CONCLUSIONS: Clinical strains from Chinese patients showed similarities to type strains in MAM. The virulent properties of P. gingivalis clinical strains are quite different from each other.

Comparison of microRNA profiles of human periodontal diseased and healthy gingival tissues.

MicroRNAs (miRNAs) have been demonstrated to play an important role in regulation of the immunoinflammatory response; however, the function of miRNAs in periodontal inflammation has not been investigated. The objective of this study was to explore the properties of miRNAs in periodontal inflammation by comparing miRNA profiles of inflamed and healthy gingival tissues. Gingival tissues were obtained from 10 periodontitis patients and 10 healthy subjects. After RNA extraction, miRNA profiles were analyzed by microarray, and expression levels of selected miRNAs were confirmed by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). Analyses using two computational methods, Targetscan and MicroRNA.org, were combined to identify common targets of these miRNAs. Finally, the individual miRNA expression levels of three toll-like receptor (TLR)-related miRNAs from inflamed and healthy gingival tissues were evaluated by RT-PCR. Ninety-one miRNAs were found to be upregulated and thirty-four downregulated over two-fold in inflamed gingival tissue compared with those in healthy gingival tissue. Twelve selected inflammatory-related miRNAs, hsa-miR-126*, hsa-miR-20a, hsa-miR-142-3p, hsa-miR-19a, hsa-let-7f, hsa-miR-203, hsa-miR-17, hsa-miR-223, hsa-miR-146b, hsa-miR-146a, hsa-miR-155, and hsa-miR-205 showed comparable expression levels by microarray and real-time quantitative RT-PCR analyses. In addition, the putative inflammation targets of these miRNAs were predicted, and three that were tested (hsa-miRNA-146a, hsa-miRNA-146b, and hsa-miRNA-155), showed significant differences between inflamed and healthy gingiva. This remarkable difference in miRNA profiles between periodontal diseased and healthy gingiva implicates a probable close relationship between miRNAs and periodontal inflammation. The data also suggest that the regulation of TLRs in periodontal inflammation may involve miRNA pathways.

[The effect of periodontal initial therapy on chronic periodontitis and subgingival periodontal pathogen].

PURPOSE: To evaluate the effect of periodontal initial therapy on clinical parameters and subgingival periodontal pathogen in patients with chronic periodontitis. METHODS: One hundred and twenty patients with chronic periodontitis were included. Probing depth (PD), attachment loss (AL), plaque index (PLI) and gingival index (GI) were evaluated at baseline and after-initial therapy. P.g and A.a in subgingival plaque were investigated by real-time PCR. Data was statistically analyzed by SAS6.12 software for Student's t test. RESULTS: The PD, AL, PLI and GI were significantly decreased after periodontal initial therapy (P<0.01), and meanwhile the ratio of P.g versus total bacteria was significantly decreased after-initial therapy (P<0.05). However, the change of ratio of A.a versus total bacteria was not significant (P>0.05). CONCLUSION: Periodontal initial therapy could effectively control the inflammation of chronic periodontitis, and decrease the ratio of P.g in subgingival plaque.