Comparison of crown fit and operator preferences between tooth preparation with electric and air-turbine handpieces.

STATEMENT OF PROBLEM: Tooth preparations for ceramic crowns require precision and accuracy, which may be influenced by the choice of dental handpiece. However, comparisons of the accuracy of tooth preparations made with traditional air-turbine handpieces and electric handpieces are lacking. PURPOSE: The purpose of this in vitro study was to evaluate operator preferences and tooth preparation performance by using electric and air-turbine handpieces with self-reported preferences, sound levels, surface roughness, and the fit of the crown produced. MATERIAL AND METHODS: Twenty dentists were asked to use the air-turbine or the electric handpiece. Feedback on the noise, weight, feel of grip, flexibility, and tooth preparation in general was scored according to a visual analog scale (VAS). Additionally, the dentists were asked to complete a questionnaire on their handpiece preference. The noise of the 2 handpieces was measured by using a precision sound level meter. The surface roughness of 10 teeth was measured by using a profilometer. The other 18 teeth were prepared to measure the marginal and internal fit of ceramic crowns by the replica technique. The VAS scores of operator preferences were analyzed with the Wilcoxon signed ranks test. Decibel levels were analyzed with the Mann-Whitney U test. The McNemar test was used to compare the ratio of preferred handpiece. The surface roughness and marginal and internal fit were analyzed with the independent t test to determine significant differences (all α=.05). RESULTS: The electric handpiece was heavier, had a poorer grip feel, was less flexible (P<.001), produced lower noise and better feeling of the tooth preparation in general (P<.001), and was preferred in the finishing stage for its greater smoothness (P<.05). The noise produced by the electric handpiece was lower during both idling and tooth preparation at 15-cm, 30-cm, and 45-cm distances (P<.01). The electric handpiece produced surface roughness values (Sa) similar to those of the air-turbine handpiece (P>.05). No significant differences were noted for the marginal and internal crown fit between the air-turbine handpiece and electric handpiece groups (P>.05). CONCLUSIONS: Despite its heavier weight, poorer grip feel, and less flexibility, the electric handpiece emitted lower noise, produced better feeling of the tooth preparation in general, and was preferred in the finishing step of tooth preparation for its greater smoothness than the air-turbine handpiece. The surface roughness of the prepared teeth and the crown fit between the tooth and ceramic crown were not affected by the air-turbine or electric handpiece.

[Application research of entropy weight-based grey systematic theory in quality evaluation of Angelicae Sinensis Radix slices].

In order to discuss the "entropy weight method" for weighting various indicators in the comprehensive evaluation of Angelicae Sinensis Radix slices(ASR), the quality of ASR was comprehensively evaluated by entropy weight-based gray systematic theory and cluster analysis. In this study, the contents of ferulic acid, volatile oil, polysaccharide, alcohol extract, water extract, moisture, total ash and acid-insoluble ash in 44 batches of ASR from different sources were determined. The entropy weight method was used for objective weighting. With relative correlation(r_i) as a measure, a multi-index comprehensive evaluation model was constructed for the quality of ASR. The results showed that the relative correlation value of 44 batches of ASR ranged from 0.301 9 to 0.662 9. There were certain differences in the quality of ASR from different sources. The ASR S1-S8, traceable and standardized in processing techno-logy, showed a high relative correlation degree and high quality ranking, indicating that the implementation of systemic management of the production chain of Chinese herbal pieces was beneficial to the quality control of ASR. The quality evaluation results of 44 batches of ASR were consistent with those of traditional geo-authentic habitats for ASR and the mainstream varieties of ASR on market, and basically consistent with the results of cluster analysis. This study suggests that the gray systematic theory based on the entropy weighting method can be used for the quality evaluation of ASR. The objective weighting of the entropy weight method improves the reliability of the gray correlation method and the scientificity of ASR quality evaluation.

Knowledge of Infection Prevention and Attitudes Towards HIV/AIDS Among Chinese Dental Bachelor Interns: An Appeal for Educational Intervention.

PURPOSE: The present study aimed to assess the current situation of Chinese dental bachelor interns on HIV/AIDS-related knowledge and their attitudes towards HIV/AIDS patients. MATERIALS AND METHODS: A cross-sectional, paper-based survey involving 147 dental students from three Chinese dental schools was conducted. Students were recruited to complete the questionnaire regarding their knowledge, awareness and attitudes concerning HIV/AIDS anonymously and voluntarily. RESULTS: A total of 144 students responded to the study, generating a response rate of 98.0%. Although 97.0% of the dental students believed dentists were at high risk of HIV infection, 97.2% of students expressed no prejudice towards HIV/AIDS patients and stated their willingness to provide oral healthcare service for such patients. No statistically significant differences in the responses on attitudes and some basic knowledge were found between students who had received the relevant education about infection control and the students who had not. However, regarding most questions about oral manifestations in adult and paediatric patients living with AIDS, the students who received relevant education showed more knowledge than the students who did not (p <0.05). The cognitive level about respecting HIV/AIDS patients' autonomy and privacy was generally low in all the students. CONCLUSIONS: Most of the dental students in this survey held positive attitudes towards HIV/AIDS patients and good grasp of some basic knowledge about HIV/AIDS. On the other hand, the questionnaire results reflected gaps in education, such as respecting HIV/AIDS patients' privacy.

[Influence of preparation height and cement space on the fit and retention of computer aided design/computer aided manufacturing zirconia crown].

OBJECTIVE: To investigate the effects of preparation height and cement space on the fit and retention of computer aided design (CAD)/computer aided manufacturing (CAM) zirconia crown, and to provide reference for the clinical design and fabrication of CAD/CAM crowns. METHODS: 3D printing system was used to fabricate resin abutment teeth with convergence angle of 2° and height of 1-3 mm. The models' optical impressions were collected by the three-shape scanner. Then, the cement spaces were set by Cradle CAD/CAM system at 10-50 µm to create an all-ceramic zirconia crown. The fit of the crowns was measured by using silicone rubber interstitial impression method. The retention of the crowns was measured by pull-off test with uniaxial tensile force after the crown was bonded. The data were analyzed by SPSS 22.0 soft-ware. RESULTS: When the preparation height was fixed, the fitness values of different cement space groups have statistical difference (P<0.05), whereas the retention values of different cement space groups have no statistical difference (P>0.05). The fitness values of different preparation height groups have no statistical difference (P>0.05), and the retention values of different preparation height groups have statistical difference (P<0.05) when the cement space was fixed. No interaction was observed between the cement space and the preparation height (P>0.05). CONCLUSIONS: When cradle CAD/CAM system is used to create a full crown in the clinic, the preparation height should be set to more than 3 mm, and the cement space should be set at 30 µm.

Role of the autophagy-related marker LC3 expression in hepatocellular carcinoma: a meta-analysis.

BACKGROUND: Microtubule-associated protein 1 light chain 3 (LC3), an autophagic gene, has been reported as a vital marker for many diseases and cancers. However, the role of LC3 in hepatocellular carcinoma (HCC) was not still investigated. Therefore, we conducted a meta-analysis to examine the association of LC3 with its clinicopathological and prognostic in HCC. METHODS: We consulted the PubMed, Cochrane Library, Web of Science, EMBASE, China National Knowledge Infrastructure and Wan Fang databases for published studies on LC3 in HCC. Newcastle-Ottawa scale was used to screen the quality of the literature. The statistical analysis was calculated by STATA 14.2. RESULTS: Of the 1329 titles identified, 10 articles involving 949 patients in HCC were included in this meta-analysis. The results of our study show that increased LC3 expression is related to size of tumor, but not to gender, age, number of tumor, liver cirrhosis, HBsAg, TNM stage, alpha fetoprotein, vascular invasion and histological grade. Positive LC3 expression was associated with overall survival by pooled hazard ratio. CONCLUSIONS: This meta-analysis indicated that positive LC3 expression was related to size of tumor, and could predict prognosis in human hepatocellular carcinoma.

Vibrio gangliei sp. nov., a novel member of Vibrionaceae isolated from sawdust in a pigpen.

A Gram-stain-negative, rod-shaped, catalase- and oxidase-positive, facultatively anaerobic, and motile bacterium, designated strain SZDIS-1T, was isolated from pigpen sawdust bedding in Xiamen, Fujian Province, China. Cells grew at 10-50 °C, pH 6.0-9.0, up to 12 % (w/v) NaCl, resisted vibriostatic agent O/129 and were negative for gelatin and alginate hydrolysis. No growth on thiosulfate citrate bile salts sucrose agar medium. Based on 16S rRNA gene sequences and multilocus sequence analysis, this strain should be assigned to the genus Vibrio, with the closest relatives being Vibrio aphrogenes CA-1004T (97.7 % 16S rRNA gene sequence pairwise similarity), Vibrio algivorus SA2T (96.6 %), Vibrio casei WS 4539T (96.3 %), Vibrio rumoiensis S-1T (96.1 %) and Vibrio litoralis MANO22DT (95.5 %), but separate from them by large distances in different phylogenetic trees. Based on whole genome analysis, the orthologous average nucleotide identity and in silico DNA-DNA hybridization values against the five relatives were 76.1-78.7 and 20.1-28.7 %. The major fatty acids were summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), C16 : 0, summed feature 2 (one or more of C12 : 0 aldehyde, C14 : 0 3OH and/or iso-C16 : 1) and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). The DNA G+C content was 43.0 mol% from whole genomic sequence analysis. Therefore, phylogenetic, genotypic, phenotypic and chemotaxonomic characteristics showed that the isolate represented a novel species of the genus Vibrio, for which the name Vibrio gangliei sp. nov. is proposed. The type strain is SZDIS-1T (=DSM 104291T=CGMCC 1.15236T).

Blastomonas marina sp. nov., a bacteriochlorophyll-containing bacterium isolated from seawater.

A Gram-stain-negative, facultatively anaerobic, dark-yellow-pigmented bacterium, named SSR2A-4-2T, was isolated from coastal water in the East China Sea. Cells were ovoid or short rods with peritrichous flagella and contained carotenoid in addition to bacteriochlorophyll a pigment. A phylogenetic dendrogram based on 16S rRNA gene sequences showed that strain SSR2A-4-2T formed a distinct clade with members of the genus Blastomonas, with Blastomonasnatatoria EY 4220T (=DSM 3183T) (similarity 95.6 %), Blastomonasursincola KR-99T (=DSM 9006T) (95.5 %) and Blastomonasaquatica PE4-5T (=JCM 30179T) (94.8 %) as its closest phylogenetic relatives. Q-10 was the predominant respiratory quinone. The major fatty acids were summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c), summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C17 : 1ω6c and C18 : 1ω7c 11-methyl. The polar lipids contained diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, sphingoglycolipid, four unknown glycolipids and one unknown lipid. The DNA G+C content was 65.1 mol%. On the basis of the evidence presented in this study, strain SSR2A-4-2T represents a novel species of the genus Blastomonas, for which the name Blastomonas marina sp. nov. is proposed, with strain SSR2A-4-2T (=CGMCC 1.15297T=DSM 103453T) as the type strain.

Microbacterium sorbitolivorans sp. nov., a novel member of Microbacteriaceae isolated from fermentation bed in pigpen.

Two bacterial strains SZDIS-1-1T and GZDIS-1-1 were isolated from fermentation bed of a pigpen in Fujian Province, China. Cells were Gram-stain-positive, facultatively anaerobic, short rods without flagellum. Their nearest phylogenetic neighbours were Microbacterium amylolyticum N5T (16S rRNA gene sequence similarity 98.2 %), Microbacterium indicum BBH6T (97.9 %) and Microbacterium gubbeenense DPC 5286T (97.8 %) with the DNA-DNA hybridization values to strain SZDIS-1-1T as 20.0±1.2, 14.3±5.8 and 19.1±1.6 %, respectively. The DNA G+C content of the new isolates was 67.6-71.1 mol% and anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0 were their predominant cellular fatty acids. These results were consistent with classification into the genus Microbacterium. However, cell-wall sugars and characteristic amino acid were rhamnose, glucose, galactose and ornithine. Major menaquinones were MK-11 and MK-10. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, glycolipids, unknown phospholipid and unknown lipids. These characteristics constructed a distinct profile of the two isolates. Therefore, based on polyphasic taxonomic characteristics, strains SZDIS-1-1T and GZDIS-1-1 represented a novel species of genus Microbacterium, for which the name Microbacterium sorbitolivorans sp. nov. is proposed, with strain SZDIS-1-1T (=CGMCC 1.15228T=DSM 103422T) as the type strain.