Objective:To observe the elimination of smear layer on the dentin exposed to Er,Cr:YSGG laser with different energy and irradiating distance. Methods:The in vitro first premolar was selected and slices with 1.5 mm thickness were obtained by horizontal sectioning through the middle third of the teeth crown using a high-speed bur. Each dentinal slice was irradiated under the laser with different irradiating distance(

Using registration information on candidates for the written examination in medical synthesis, a part of the doctor qualification examination, from 1999 to 2001 as processing data, the authors made a comparative study on the composition of the candidates in the eastern, middle and western regions of the country from 7 aspects, viz. total number, category of registration for the examination, educational background, time of graduation, age, organization and rank of organization. It was found that the educational background of the candidates was on the whole very low and the number and quality of health personnel in the western region and at the grass roots level was in dire need of enhancement.

Objective:To evaluate the effects of Er,Cr:YSGG laser combined with NaF treatment on the acid resistance of human dental hard tissue.Methods:The enamel or dentin samples were randomly divided into four groups and prepared by different methods as follows: ①without treatment(control group),②laser irradiation(Laser group),③ treated with 20 g/L NaF solution(NaF group),④laser irradiation+ NaF solution treatment(Laser and NaF group).The samples of each group were respectively demineralized in 0.1 mol/L of lactic acid for 24 h and the calcium ion in the demineralization solution in each group was measured by atomic absorption spectrophotometry.The fluoride on the surface of the samples was examined by SED-X and the ultrastructure was investigated by SEM.Results:The concentrations of Ca~(2+) dissolved from the enamel or dentin samples in NaF,laser and NaF and laser groups were significantly lower than that in the control group(P(0.05)).Only in the NaF group,the F peak appeared.SEM observation showed the lased surface showed various patterns of microirregulation with a scaly appearance,the openings of dentinal tubules were visible,but no melting or carbonization;there were lot of particles attached to the surface of NaF treated samples;the ultrastructure of the NaF and laser-treated sample surfaces was similar to that of the laser treated.Conclusion:The combined use of laser and NaF dose not have synergetic effects on acid resistance of human dental hard tissue.

0.05).SEM revealed that the lased enamel surface appeared various patterns of microirregularity, and there was no smear layer.Conclusion:Laser irradiation can be used to prepare the enamel before placing pit and fissure sealant.

We defined the prerequisite managing capacity of hospital directors through a comprehensive set of methods including literature review, interview of specialists and questionnaires. There were altogether 7 assessment items with 36 assessment indexes. The acquired assessment items and indexes were edited as Likert Scales and as signed to extprts concerned. The weight ofthe assessment indexes was obtained through a statistical analysis of the results. Hence the pre iluninary establishment of the system of standards for assessing the managing capacity of hospital directors.

Objective To observe the surface morphology of dentin irradiated by Er,Cr∶YSGG laser under anhydrous conditions and discuss the possible clinical applications of the laser.Methods 11 freshly extracted specimens (approximately 1.5 mm thick) taken from the first premolars were selected.One was regarded as the control group without any treatment and the remaining ten were divided into 5 groups whose dentin surface was irradiated by Er,Cr∶ YSGG laser with different energy (1,2,3,4,6 W) under anhydrous condition.The specimens were routinely prepared for electron microscopic scanning observation.Results As the output power increased with Er,Cr∶YSGG laser irradiation,the dentin surface was observed of the constriction of tubular lumen,and part of the tubules closed.The dentin surfaces with 3 ～6 W laser irradiation were observed thermal injury alters such as micro crack and carbonization.Conclusion 1 ～2 W anhydrous Er,Cr:YSGG laser irradiation play a more ideal and safe constriction and sealing role to dentinal tubules,and the laser is expected to be used for the treatment of dentin hypersensitivity.

Objective To establish a simple and rapid detection technique for Oncomelania infected with Schistosoma japonicum(SJ), with high sensitivity and good specificity .Methods The gene fragment of SJ was amplified by PCR , and cloned into the T-vector to construct positive-reference.An isothermal nucleic acid amplification reaction system for detecting Oncomelania infected with SJ was set up , and its sensitivity was analyzed by detecting positive-reference diluted according to geometric proportion , and its specificity by detecting the genomic DNA of relative samples .Then, a corresponding means of purifying nucleic acid was designed to assemble a reagent detecting Oncomelania infected with SJ . This reagent was validated by detecting Oncomelania samples.Results The 213 bp amplified products were obtained and used to construct recombination T-vector for positive reference .An isothermal nucleic acid amplification reaction system was set up for detecting Oncomelania infected with SJ , and the amplification results could be simply determined by color change, with better sensitivity and specificity .The reagents for detecting Oncomelania infected with SJ were assembled , which could detect samples containing only 1% infected Oncomelania.Conclusion A visible detection method for Oncomelania infected with SJ is successfully established and validated .

Objective To explore the reliability and validity of poly ether ether ketone (PEEK) rods and pedicle screw system for lumbar degenerative diseases.Methods Sixty-three patients,including 23 men and 40 women with the mean age of 56.2±5.1 years (range,35-75 years),treated by PEEK rods pedicle screw system from September 2012 to March 2013 were retrospectively recruited.Fusion procedure were performed in 10 patients,with 2 cases at L3,4,5 cases at L4,5,3 cases at L5S1; nonfusion procedure were performed in 17 patients,with 4 cases at L3,4,10 cases at L4,5,3 cases at L5S1; hybrid procedure were performed in 36 patients,with 22 case fusion at L4,5 and nonfusion at L3,4,with 2 cases fusion at L3,4 and nonfusion at L4,5,with 12 cases fusion at L5S1 and nonfusion at L4,5.Clinical effects were evaluated via Japanese Orthopedics Association (JOA) score and Oswestry disfunction index (ODI) at 3 months,6 months and 24 months postoperatively.Disc heights were measured by disc height index on lateral lumbar radiograph.Range of motion (ROM) was measured by extension-flexion lumbar X-ray.Three-dimensional CT reconstruction was achieved to observe the integrity of PEEK rods at the final follow-up.Results The mean follow-up were 23.4±3.3 months.The mean operation time were 110±17 min in the fusion group,98±22 min in the non-fusion group and 121±25 min in the hybrid group.The mean blood loss were 270±85 ml in the fusion group,255±72 ml in the non-fusion group and 316±80 ml in the hybrid group.The JOA score improved from 10.5±2.6 preoperatively to 24.0±3.1 at the final follow-up in the fusion group,from 10.3±2.2 to 24.3±3.4 in the non-fusion group and from 11.1±2.3 to 23.9±3.3 in the hybrid group (P＜0.05).The ODI decreased from 51.8％±10.3％ preoperatively to 14.1％±3.7％ at the final follow-up in the fusion group,from 52.2％±11.1％ to 13.2％±3.2％ in the non-fusion group and from 53.4％±9.2％ to 13.8％±2.5％ in the hybrid group.There was no significantly statistical difference in the disc height index at 3 months,6 months and 24 months postoperatively compared with that at preoperative.The ROM decreased from 8.8°±1.8° preoperatively to 2.2°±0.3° at the final follow-up (P＜0.05).One case demonstrated cage migration at one month follow-up,bony fusion in situ at 3 months follow-up,and the patient had no related symptoms during the follow-up.No screw loosening or breakage and rods breakage was observed during the follow-up.Conclusion PEEK rods and pedicle screw system for lumbar degenerative diseases by fusion,non-fusion and hybrid procedure can achieve considerable clinical outcome with low complication rate.

Objective To evaluate the efficacy of self?made breathing circuit joint for intermittent positive pressure ventilation ( IPPV) in patients with central airway obstruction undergoing interventional fi?beroptic bronchoscopy ( FOB) . Methods Sixty?two patients of both sexes with central airway obstruction requiring tracheal intubation, aged 60-80 yr, with body mass index of 20-26 kg∕m2 , of American Society of Anesthesiologists physical status Ⅲ or Ⅳ and Medical Research Council dyspnea scale grade Ⅲ or Ⅳ, undergoing interventional FOB under general anesthesia, were divided into 2 groups ( n=31 each) using a random number table:high frequency jet ventilation ( HFJV) group and IPPV group. The patients were tra?cheally intubated after induction of general anesthesia. The self?made breathing circuit joint was connected, then the anesthesia machine was connected to perform IPPV, and the ventilator settings were adjusted to maintain the end?tidal pressure of carbon dioxide 35-45 mmHg in group IPPV, and HFJV was used in group HFJV. Before induction ( baseline) , at 10, 20, 30 and 40 min after start of operation, and at the end of operation, arterial blood samples were collected for blood gas analysis, the pH value, arterial oxy?gen partial pressure, and arterial carbon dioxide partial pressure were recorded. The development of hyper?capnia was recorded. Results Hyoxemia was not found in the two groups. The incidence of hypercapnia was 74%, and in addition the incidence of severe hypercapnia was 10% in group HFJV. The incidence of hypercapnia was 16%, and all the patients presented with permissive hypercapnia in group IPPV. Com?pared with group HFJV, the incidence of hypercapnia was significantly decreased, and the pH value and arterial oxygen partial pressure were increased, and arterial carbon dioxide partial pressure was decreased from 10 min after start of operation to the end of operation in group IPPV (P<0.05). Conclusion The self?made breathing circuit joint provides better efficacy than HFJV when used for IPPV in the patients with central airway obstruction undergoing interventional FOB.

OBJECTIVEThe purpose of this study was to evaluate the morphological changes of Er, Cr: YSGG laser irradiated dental hard tissues by scanning electron microscopy (SEM).

METHODS12 freshly extracted premolars were treated with fissure bur, Er, Cr: YSGG laser at 4 watt, Er, Cr: YSGG laser at 6 watt, respectively, and then bisected transversally and longitudinally. The tooth slice were prepared with conventional methods and observed by SEM.

RESULTSCompared with fissure bur, laser treatment resulted in a rather scaly and rough surface. The sections were free of smear layer, with open dentinal tubules. No carbonization and thermal damages were observed. The laser at 6 watt appeared rougher than at 4 watt, occasionally caused micro-cracks.

CONCLUSIONThe utilizing of Er, Cr: YSGG laser can contribute to enhance the bond strength between restorative materials and dental hard tissues. It suggests that higher energy could be applied in cutting enamel, whereas the lower energy in dentin.

Dental Cavity Preparation ; instrumentation ; methods ; Dental Enamel ; radiation effects ; ultrastructure ; Dental High-Speed Equipment ; Dentin ; radiation effects ; ultrastructure ; Hardness ; Humans ; In Vitro Techniques ; Lasers ; Microscopy, Electron, Scanning ; Tooth ; radiation effects ; ultrastructure