Diagnosis and treatment strategy of permanent tooth developmental disturbances caused by primary tooth trauma / 中华口腔医学杂志

The trauma to primary tooth may lead to developmental disturbances of permanent tooth. Because the traumatic events are often forgotten as accurred earlier, the timely diagnosis and intervention treatment are not conducted, resulting in aesthetic and functional disorders. This paper systematically elaborates the types of developmental disturbances in permanent tooth after traumatic injuries to the primary predecessor, and the etiology, mechanism, related factors as well as the treatment options, in order to provide references for the prevention of serious complications in inherited permanent tooth caused by primary tooth trauma.

Clinical application of direct composite resin in esthetic restoration / 中华口腔医学杂志

The direct composite resin bonding is widely used in the esthetic restorations of anterior teeth. Due to the technique sensitive procedure, the esthetic effect and long-term clinical performance of direct composite resin restoration have long been the focus of dental clinicians. This article will analyze the influencing factors of esthetic effect of composite resin from three aspects, including materials, teeth and technology. Also, it will summarize the clinical performance of direct composite resin from the perspective of esthetic evaluation. Eventually, this article will provide guidance for the clinical application of esthetic restoration of direct composite resin bonding.

Causes, diagnosis and treatment strategies for dental pulp calcification / 中华口腔医学杂志

Dental pulp calcification can lead to root canal stenosis or obliteration. It is usually difficult to negotiate the root canal if the affected tooth needs to be treated and intraoperative complications are easily brought about during the root canal treatment. The etiologies of dental pulp calcification are complicated and careful considerations should be given to the diagnosis and treatment. Only by weighing the advantages and disadvantages can appropriate treatment plan be chosen. Based on the literature and authors' clinical experiences, the present article summarizes the causes, pathogenesis, diagnosis and treatment strategies of dental pulp calcification, in order to provide some references in diagnosis and treatment for the dental clinicians.

An analysis on senior pupil's tobacco use and exposure in Shandong province in 2012 and 2019 / 中华流行病学杂志

Objective: To analyze the changes in tobacco use and exposure in primary school students in Shandong province in 2012 and 2019. Methods: A multi-stage stratified cluster random sampling method was used in the survey. In 2012 and 2019, 5 861 and 4 021 students from 3 different cities of Shandong province were selected as the study population. The questionnaire was filled anonymously by the subjects. χ2 test was conducted to compare the difference of groups. Results: In 2012 and 2019, the rate of attempting smoking among pupils under this study in Shandong province were 6.0％and 6.3%, respectively, while the current smoking rate were 1.2％and 2.3%, respectively. The sex ratio of male and female students attempting to smoke was 2.56∶1 in 2012 and 1.31∶1 in 2019. The sex ratio of current smoking rate was 2.43∶1 and 2.00∶1, respectively in 2012 and in 2019. The rate of tobacco exposure in the public places was 50.5％and 41.4%, respectively. The rate of tobacco exposure in family was 49.7% and 46.4%, respectively. Two rates of tobacco exposure decreased, but the reduction in family (3.3%) was far less than that in public places (9.1%). In 2019, the rate of tobacco exposure in family was higher than that in public places. Conclusions: The tobacco exposure rate declined in senior pupils in Shandong province. However, the situation is still grim for the current smoking rate, growth trend of girls tobacco use, and tobacco exposure in family.

Bioinformatics analysis on structure and function and expression vector construction of SARS-CoV-2 related protein TMPRSS2 / 中国药理学通报

Aim Human TMPRSS2 is a transmembrane serine protease.In this paper, the structure and func¬tion of the protein were systematically analyzed by bioinformatics, the codon was optimized and the pro- karvotie expression vector was constructed to explore the molecular mechanism of SARS-CoV-2 infecting host cells.Methods The recombinant expression vector pET-22b-TMPRSS2 was generated by molecular clo¬ning technology.The homology, functional sites, sub¬cellular localization, three-dimensional structure and evolutionary characteristics of TMPRSS2 protein were systematically analyzed by using analytical tools such as Protparam, NetPhos3.1, Blast, Clustal X2 and MEGA7.0.Results The prokarvotic expression plas- mid was constructed correctly; TMPRSS2 belongs to medium molecular weight protein, which is composed of 492 amino acid residues.The theoretical isoelectric point is 8.12, the molecular extinction coefficient is 118 145 L • mol~1 • cm"1 , and the half-life is 30 h; TMPRSS2 has 15 potential glycosylation sites and 49 possible phosphorylation sites.It is a transmembrane hydrophilie protein without signal sequenee.In addi¬tion, the protein has 13 potential B-cell epitopes and 7 T-eell epitopes.Seeondarv structure analysis showed that random coil accounted for the highest proportion of TMPRSS2 protein ( 0.453 3) , followed by extended strand (0.252 0).Sequence comparison and evolu¬tionary analysis showed that the highest sequence con¬sistency and closest genetic relationship with human TMPRSS2 was Pan troglodytes, followed by gorilla.Conclusions Human-derived TMPRSS2 protein is ev- olutionarilv conserved and functionally important.Hie results of this study can help to reveal the structure and mechanism of action of TMPRSS2 protein, provide ide¬as for the diagnosis and treatment of COYID-19, and accelerate the research and development process of new drugs targeting TMPRSS2 protein.

Correlation between physical activity and nutritional status among Chinese children and adolescents / 中国学校卫生

Objective@#To explore the correlation between physical activity and nutritional status of Chinese children and adolescents, and to provide references for the healthy development of Chinese adolescents.@*Methods@#According to the six administrative regions of China (East China, Northwest China, North China, Central China, Southwest China and South China), 4 269 children and adolescents aged 7 to 18 were selected by stratified random sampling method. "Physical Activity Level Evaluation Questionnaire" was used to conduct a physical activity survey. Chi square test and non parametric test were used to analyze the physical activity status.@*Results@#The overall detection rate of MVPA insufficiency in children and adolescents with normal BMI were 53.7%, 50.2%, 56.3%, and 52.5% in the wasting group, overweight and obese group, respectively. There was no significant difference in the detection rate of MVPA insufficiency between different nutritional status( χ 2=2.55, P >0.05); but in the 7-9 years old age group, the difference in the detection rate of MVPA insufficiency between different nutritional status were statistically significant( χ 2= 10.35, 8.86, 15.88, P <0.05). There were no significant differences in physical activity intensity and item types under different nutritional status ( P >0.05).@*Conclusion@#There are age differences in the correlation between physical activity and nutritional status of children and adolescents in my country.Therefore, the differences between different groups should be fully considered while formulating intervention policies.

Effect of autoclave on surface microstructure and cyclic fatigue resistance of R-phase rotary instruments / 北京大学学报(医学版)

OBJECTIVE@#To compare the effects of autoclave on surface microstructure and cyclic fatigue resistance of K3XF and K3.@*METHODS@#Forty-eight size 25, 0.06 taper 25 mm-long K3XF or K3 were randomly divided into 4 groups (n=12). The instruments from group 1 were not autoclaved, and the groups 2 to 4 underwent autoclave for 10 cycles, 20 cycles, and 30 cycles, respectively. The surface microstructure of two instruments randomly selected from each group was observed using scanning electron microscope (SEM). The remaining 10 instruments were submitted to the cyclic fatigue test by using a simulated metal root canal with curvature of 60° and radius 3.5 mm. The time till fracture was recorded, the number of cyclic fatigue (NCF) calculated, the fragment length evaluated, and the topographic features were analyzed using SEM. The data were analyzed using the two-way ANOVA analysis by SAS 9.3 software at a significance level of P<0.05.@*RESULTS@#SEM observation identified rough features on the surface of K3XF with micropores existing evenly. K3 was characterized by machining grooves, which located specifically in the flute, leaving a smooth cutting edge. After autoclave, SEM observation indicated that the micropores in the surface of K3XF became larger and more, whereas the machining grooves in the surface of K3 were squeezed, out of shape and flaking. As far as the NCF was concerned, new K3XF was 210±59, and no significant difference was found after 10, 20, and 30 cycles of autoclave for K3XF, values being 178±37, 208±48, and 227±43, respectively (P>0.05). For K3, the new one was 145±38, and no significant difference in NCF was demonstrated after 10 and 20 cycles of autoclave, with the values of 128±43 and 124±46, respectively (P>0.05). However, after 30 cycles of autoclave of K3, significant increase to 216±38 was identified (P<0.05). Topographic features demonstrated typical cyclic fatigue for all the groups.@*CONCLUSION@#The surface roughness of K3XF was increased after autoclave, while the cyclic resistance remained stable after up to 30 cycles.

Fluoride Exposure, Follicle Stimulating Hormone Receptor Gene Polymorphism and Hypothalamus-pituitary-ovarian Axis Hormones in Chinese Women / 生物医学与环境科学（英文）

The effects of fluoride exposure on the functions of reproductive and endocrine systems have attracted widespread attention in academic circle nowadays. However, it is unclear whether the gene-environment interaction may modify the secretion and activity of hypothalamus-pituitary- ovarian (HPO) axis hormones. Thus, the aim of this study was to explore the influence of fluoride exposure and follicle stimulating hormone receptor (FSHR) gene polymorphism on reproductive hormones in Chinese women. A cross sectional study was conducted in seven villages of Henan Province, China during 2010-2011. A total of 679 women aged 18-48 years were recruited through cluster sampling and divided into three groups, i.e. endemic fluorosis group (EFG), defluoridation project group (DFPG), and control group (CG) based on the local fluoride concentration in drinking water. The serum levels of gonadotropin releasing hormone (GnRH), follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were determined respectively and the FSHR polymorphism was detected by real time PCR assay. The results provided the preliminary evidence indicating the gene-environment interaction on HPO axis hormones in women.

The influence of high fluoride exposure in drinking water on endocrine hormone in female / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the influence of water fluoride exposure on reproductive hormones in female.</p><p><b>METHODS</b>Cross-sectional study was conducted in seven villages of a county in Henan province by using simple random sampling including high fluoride area, defluoridation project area and control area on April, 2011 based on the preliminary study results of fluoride concentration in drinking water. Women who were born and growth or lived in the village at least 5 years and aged 18-48 years old were recruited using cluster sampling. They were divided into high fluoride group (HFG, 116 subjects), defluoridation project group (DFPG, 132 subjects) and control group (CG, 227 subjects) in accordance with the above areas. All subjects accepted questionnaire and physical checkup. Fasting blood and morning urine samples were collected. The concentration of fluoride in urine was determined by fluoride ion selective electrode method. The serum level of GnRH was detected using enzyme linked immunosorbent assay (ELISA). The serum level of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T), estradiol (E2) were determined by chemiluminesence immunoassay (CLIA).</p><p><b>RESULTS</b>The average age was (39.44 ± 7.34), (38.84 ± 8.03), (37.45 ± 7.70) years old in female from DFPG, HFG and CG respectively, there were no significant differences among the three groups (F = 3.02, P = 0.05). The urine fluoride levels were (1.34 ± 1.07), (2.59 ± 1.57), (0.92 ± 0.46) mg/ml in female from DFPG, HFG and CG respectively, there was a significant difference among three groups (F = 105.38, P < 0.01). No significant differences were observed of serum GnRH, LH, T, FSH and E2 among three groups in follicular phase (P > 0.05). The serum levels of E2 in Ovulatory period were 67.73, 58.09, 84.96 pg/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in CG (H = 4.00, P < 0.05). The serum levels of T in Ovulatory period were 0.55, 0.45, 0.55 ng/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in DFPG (H = 6.47, P < 0.05), but no significant difference was observed between HFG and CG (H = 2.41, P > 0.05). The serum levels of GnRH in Luteal phase were 24.09, 20.16, 23.50 ng/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in DFPG (H = 14.14, P < 0.05) and CG (H = 12.53, P < 0.05). The serum level of E2 in luteal phase were 81.47, 64.60, 74.55 pg/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in DFPG (H = 5.69, P < 0.05). As for LH, FSH and T, no significant differences were observed among the three groups (P > 0.05 respectively). The abnormal rates of E2 level were 22.73 (30/102), 37.93 (44/72), 20.26 (46/181) in female from DFPG, HFG and CG respectively. The E2 abnormal rate in female from HFG was higher that from DFPG (χ(2) = 6.82, P < 0.05) and CG (χ(2) = 12.38, P < 0.05).</p><p><b>CONCLUSION</b>Fluoride exposure may influence reproductive hormones in female, especially in ovulatory and luteal phase of menstrual cycle.</p>

Microbial diversity in failed endodontic root-filled teeth / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Persistent/secondary infections of human root canals play an important role in the failure of endodontic treatment. This study used 16S rRNA sequencing to assess microbial diversity in root-filled teeth associated with failed endodontic treatment.</p><p><b>METHODS</b>DNA was extracted from 15 teeth with persistent intraradicular infections, and the 16S rRNA of all present bacteria were amplified by PCR, followed by cloning and sequencing of the 16S rRNA amplicons.</p><p><b>RESULTS</b>All sample extracts were positive for PCR amplification using the universal 16S rRNA gene primers. Negative control reactions yielded no amplicons. Sixty-five phylotypes belonging to seven phyla were identified from 760 clones; a mean of 9.4 phylotypes were detected in each sample (range 3 - 15). Twenty-eight phylotypes were detected in more than one sample, revealing a high inter-sample variability. Parvimonas micra (60%, 9/15), Solobacterium moore (47%, 7/15), Dialister invisus (33%, 5/15), Enterococcus faecalis (33%, 5/15), Filifactor alocis (27%, 4/15), and Fusobacterium nucleatum (27%, 4/15) were the prevalent species. Nineteen as-yet-uncultivated phylotypes were identified, comprising a substantial proportion of the bacteria in many cases.</p><p><b>CONCLUSIONS</b>Persistent intraradicular infections were present in all root-filled teeth associated with failed endodontic treatment. The current observations reveal new candidate endodontic pathogens, including as-yet-uncultivated bacteria and phylotypes that may participate in the mixed infections associated with post-treatment apical periodontitis.</p>

Treatment outcome of iatrogenic perforation repair by mineral trioxide aggregate / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe the clinical effect of iatrogenic perforation repaired by mineral trioxide aggregate (MTA).</p><p><b>METHODS</b>Twenty-one iatrogenic perforation cases were included. The root canals were shaped and cleaned and then obturated after MTA was used to repair the perforation with microscopes. Preoperative, immediate postoperative, and follow-up radiographs were evaluated to determine the pathologic changes adjacent to the perforation site.</p><p><b>RESULTS</b>Nineteen cases healed and two cases were healing. No cases failed.</p><p><b>CONCLUSIONS</b>MTA is effective in the treatment of iatrogenic perforation.</p>

Evaluation of homogeneity and density of root canal filling with four obturation techniques / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the homogeneity and density of root canal filling with four obturation techniques.</p><p><b>METHODS</b>Forty extracted single root teeth were randomly divided into four groups with 10 teeth each. Under simulated clinical conditions, the root canals were shaped with Nickle titanium rotary files (Protaper) using crown-down technique and were filled with warm vertically condensed gutta-percha (group A), core carrier technique-thermafil (group B), guttaflow (group C) and conventional cold laterally condensed gutta-percha (group D). Roots were sectioned at four levels. The cross-sections were photographed through a microscope, the photos were analysed, and the percentage of gutta-percha filled area (PGFA) was measured.</p><p><b>RESULTS</b>The overall PGFA values were (96.5 ± 3.6)%, (95.6 ± 3.9)%, (86.5 ± 5.7)% and (81.5 ± 4.2)% for groups A, B, C and D, respectively. The differences between these groups were statistically significant (P < 0.01). Group A and B were significantly higher than group C and D (P < 0.01). The PGFA in group D was significantly lower than that in other groups (P < 0.01). The average PGFA in both group A and B was higher than that of group C and D at apical and middle level (P < 0.01).</p><p><b>CONCLUSIONS</b>Warm vertical condensation and thermafil produce significantly higher PGFA than guttaflow and cold lateral condensation technique.</p>

Torque resistance of three different types of nickel-titanium rotary instruments / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare torsional fracture of three different types of nickel-titanium rotary instruments ProTaper, Hero642 and Mtwo by making a stimulate models in vitro.</p><p><b>METHODS</b>Through the establishment of model in vitro, compared the different time with 3 kinds of nickel titanium file in cutting-edge bound occurs, and to observe the section of fractured instruments by scanning electron microscope.</p><p><b>RESULTS</b>The resistence to torque was different from three types of nickel titanium instruments. The time to fracture of Mtwo was significantly longer than ProTaper's and Hero642's, but ProTaper's and Hero642's had no significant difference. Three kinds cross-sectional design were different, a lot of toughness nests were seen in broken surface. Most of them were ductile fracture. Time to fracture was influenced by the quality disfigurement.</p><p><b>CONCLUSION</b>The resistance to torque of Mtwo was better than ProTaper and Hero642. The lifespan was influenced by the design of cross-section. The quality disfigurement of the files reduced the resistance to flexual fatigue.</p>

The effect of curvature of simulated root canal and location of fragment on removal of broken file from simulated root canal / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate effect of root canal curvature and location of the fragment on the removal of broken file from root canal.</p><p><b>METHODS</b>Sixty extracted mandibular premolars were divided equally into six groups according to location of fragment (2 mm or 8 mm below root canal orifice) and root canal curvature (20 degrees, 30 degrees or 40 degrees). Broken files were removed using ultrasonic tips combined with dental operating microscope. Number of successfully removed case and operating time were recorded. Pre- and post-operative digital radiographs were input into image analyzing software to calculate diameter variance of root canal at the level of tip of broken file.</p><p><b>RESULTS</b>All the 6 groups of broken files were successfully removed with out perforation. Among same fragment location groups, diameter variance was increased in greater curvature groups and the difference was significant (P < 0.05), while operation time was not significantly different (P > 0.05). Among same root canal curvature groups, the deeper the fragment, the longer operation time, difference being significant (P < 0.05), while difference of diameter variance was not significant (P > 0.05).</p><p><b>CONCLUSION</b>The more curvature of root canal, the more dentine removal amount at the level of broken file tip. Location of fragment has no effect on dentine removal amount. Safe straight-line access and adequate thickness of dentine are essential to removal of broken file from root canal.</p>

Theoretical research and clinical practices of contemporary root canal therapy / 中国医学科学院学报

Root canal therapy is currently the most effective treatment for pulpal and periapical diseases. With the innovation of endodontic theory and techniques, the concept of contemporary root canal therapy has been established and promoted gradually. Advances in endodontic technology, instruments, and materials have increased the safety and clinical success rate of root canal therapy. This article reviews the recent theoretical research and clinical practices of contemporary root canal therapy.

Bond strength of different adhesives to normal and caries-affected dentins / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Currently, several systems of dentin substrate-reacting adhesives are available for use in the restorative treatment against caries. However, the bond effectiveness and property of different adhesive systems to caries-affected dentin are not fully understood. The objective of this study was to evaluate the bond strength of different adhesives to both normal dentin (ND) and caries-affected dentin (CAD) and to analyze the dentin/adhesive interfacial characteristics.</p><p><b>METHODS</b>Twenty eight extracted human molars with coronal medium carious lesions were randomly assigned to four groups according to adhesives used. ND and CAD were bonded with etch-and-rinse adhesive Adper Single Bond 2 (SB2) or self-etching adhesives Clearfil SE Bond (CSE), Clearfil S(3) Bond (CS3), iBond GI (IB). Rectangular sticks of resin-dentin bonded interfaces 0.9 mm(2) were obtained. The specimens were subjected to microtensile bond strength (microTBS) testing at a crosshead speed of 1 mm/min. Mean microTBS was statistically analyzed with analysis of variance (ANOVA) and Student-Newman-Keuls tests. Interfacial morphologies were analyzed by Scanning Electron Microscopy (SEM).</p><p><b>RESULTS</b>Etch-and-rinse adhesive Adper(TM) Single Bond 2 yielded high bond strength when applied to both normal and caries-affected dentin. The two-step self-etching adhesive Clearfil SE Bond generated the highest bond strength to ND among all adhesives tested but a significantly reduced strength when applied to CAD. For the one-step self-etching adhesives, Clearfil S(3) Bond and iBond GI, the bond strength was relatively low regardless of the dentin type. SEM interfacial analysis revealed that hybrid layers were thicker with poorer resin tag formation and less resin-filled lateral branches in the CAD than in the ND for all the adhesives tested.</p><p><b>CONCLUSION</b>The etch-and-rinse adhesive performed more effectively to caries-affected dentin than the self-etching adhesives.</p>

Clinical significance of PHPT1 protein expression in lung cancer / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>In our previous studies, we found the expression of 14-kD phosphohistidine phosphatase (PHPT1) was associated with lung cancer cells migration and invasion, and PHPT1 mRNA expression level in lung cancer tissues clinically correlated with lymph node metastasis. In the present study, we aimed to further investigate the expression of PHPT1 protein in lung cancer.</p><p><b>METHODS</b>Expression of PHPT1 protein in tissue samples from 146 lung cancers and 30 normal tissues adjacent to lung cancers was assessed using immunohistochemical method. Fisher's exact test was used to analyze expression patterns of PHPT1 protein in these tissue types. Meanwhile, we studied the correlation between expression of PHPT1 protein and clinicopathological features in lung cancer.</p><p><b>RESULTS</b>Significantly higher expression levels of PHPT1 protein were found in lung cancer samples (53.42%) than in normal tissues adjacent to lung cancer (23.33%) (P = 0.003). Fisher's exact test showed that lung cancer stage positively correlated with expression of PHPT1 protein (P = 0.02), and lung cancer samples with lymph node metastasis showed higher PHPT1 protein expression (P = 0.016) than the samples without lymph node metastasis.</p><p><b>CONCLUSIONS</b>The results of this study agree with findings from our previous study of PHPT1 mRNA expression in lung cancer tissues, and strongly suggest that PHPT1 protein is closely associated with the carcinogenesis and metastasis of lung cancer. Thus, therapy targeting PHPT1 (inhibition or silencing) could be potentially benefited for lung cancer patients.</p>

Investigation into the serum uric acid level of the residents in Henglan town of Zhongshan city / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relationship between cardiac Cerebrovascular disease and serum uric acid(SUA) in the coastal inhabitant, and try to provide base for prevention of the local metabolic disease and cardiac Cerebrovascular disease.</p><p><b>METHOD</b>We got 3111 local people who had participated in the annual physical examination in the perch hospital for the research on the level of SUA and the relative risk factor. According to SUA level we divided the cases into two groups. One is hyperuricemia group and the other is control group.</p><p><b>RESULTS</b>(1)The average SUA level was (380.2-/+62.58) micromol/L in the males, while (290.82-/+60.32) micromlo/L in the female. The sick rate of hyperuricaemia rate, was 21.8% for male, and the 17.6% of female. This disease affected more men than women. It has significant difference (P<0.01); (2)The SUA level of the showed a positive correlation with the indexes of the total cholesterol, the triglyceride, the blood pressure and the body weight index. The SUA level in overweight/obesity people was obviously higher than that of the normal weight people.</p><p><b>CONCLUSIONS</b>(1)The sick rate of hyperuricaemia is high in Zhongshan coastal area, which due to many related factors. As far as, few people know it, so we should adopt the synthesis measure to prevent and control it to reduce the sick rate; (2)the rise of The SUA level possibly becomes one of the independent dangerous and predictive factor for the heart cerebral von disease.</p>

Clinical effect of the use of dental operating microscope and ultrasonic instruments in the management of blocked canals / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of using dental operating microscope and ultrasonic instruments in treating blocked canals.</p><p><b>METHODS</b>The etiology of canal blockage included calcification, broken instruments, posts, resinifying, etc. 236 blocked canals were treated with ultrasonic tips under dental operating microscope. The success rate was calculated.</p><p><b>RESULTS</b>178 blocked canals were successfully managed with a success rate of 75.4%. The success rate of each category of the blocked canals were: 71.7% for calcified canals, 81.1% for broken instruments, 100% for canals blocked by posts, 62.5% for canals blocked by resinifying therapy, and 84.1% for canals blocked by filling materials.</p><p><b>CONCLUSION</b>The use of dental operating microscope and ultrasonic instruments is proved to be an effective method in the management of blocked canals.</p>

Application of a Simple Method for Detection of Rubella Virus Genome by Loop-mediated Isothermal Amplification (LAMP) / 中国疫苗和免疫

Objective To use a new simple Reverse Transcription Loop-mediated isothermal amplification(RTLAMP) method was applied to detect rubella virus nucleic acid and compared with Reverse TranscriptionPolymerase Chain Reaction (RT-PCR).Method Comparing the detection rate of the RT-LAMP method with that of RT-PCR for detecting rubella virus nucleic acid from rubella virus.Results The nucleic acid positive rates of all 11 strains of rubella virus were 100% by the two methods,the positive rate was 55%.Conclusion RT-LAMP is more simple and convenient than RT-PCR.