应用植入控释系统进行一次法根管治疗术的动物实验研究

目的：利用自制含氯霉素、甲硝唑等药物的控释系统，对实验家兔的血药浓度、药物抗菌活性和家兔根管、尖周组织的病理观察，为今后临床应用提供理论和实验依据。方法：应用组织病理观察和液相色谱分析技术。结果：用ＨＰＬＣ法得出实验用家兔血药浓度和抗菌活性均为阴性，根管及尖周组织病理切片无特殊表现。结论：自制控释系统是一种无毒、无副作用、有效的根管治疗药物剂型，可进行临床应用。     

In vitro evaluation of bonding effectiveness to dentin of all-in-one adhesives

Objectives

The study was aimed at assessing the bonding potential of all-in-one adhesives to dentin.

Methods

The microtensile bond strength of the all-in-one adhesives Bond Force (Tokuyama), AdheSE One (Ivoclar-Vivadent), and Xeno V (Dentsply) was measured in comparison with the etch-and-rinse system XP Bond (Dentsply). The ultrastructural characteristics of dentin–adhesive interface were observed under scanning electron microscope (SEM). Twenty human extracted third molars had their mid-coronal dentin exposed and ground with wet 600-grit SiC paper in order to create a standardized smear layer. Bonding procedures were performed according to the manufacturers’ instructions and microtensile beams were obtained with the “non-trimming” technique. The bond strengths in MPa were statistically analyzed including pre-test failures as “zero” values (Kolmogorov–Smirnov test, Levene's test, One-Way ANOVA, Tukey's test p < 0.05).

Results

The following bond strengths were recorded in MPa (mean ± standard deviation): AdheSE One 31.7 ± 21.3; Xeno V 42.8 ± 26.4; Bond Force 43.3 ± 22.1; XP Bond 51.9 ± 18.6. The statistical analysis demonstrated that the bond strengths achieved by Bond Force and Xeno V were similar to that of the etch-and-rinse adhesive, whereas the bond strength of AdheSE One was significantly lower. A distinct hybrid layer with resin tags was seen only in XP Bond specimens. All-in-one adhesives demonstrated a rather superficial interaction with the dentin substrate.

Conclusions

Although the strongest bond to dentin was established by the etch-and-rinse system, however the all-in-one adhesives containing organic solvents reached bond strength levels that were comparable from a statistical point of view.     

In vitro comparison of root-canal measurements with conventional and digital radiology

AIM: The present study compared the efficacy of digital and conventional radiology for root-canal length measurement. METHODOLOGY: Seventy extracted teeth with pre-served roots were used. Root-canal length measurements were completed with K-Flexofiles (numbers 08, 10 and 15) with conventional and digital radiography using two systems (radiovisiography and photostimulate storage phosphor). All films and sensors were exposed at projections of 0 degrees and 20 degrees to the mesial. The images obtained were evaluated with and without magnification, and analysed using the Cohen's kappa test. The accuracy of the three systems to determine the root-canal length were evaluated by measuring the distance from the tip of the file to the apex. RESULTS: Most of the values corresponding with the apex occurred with conventional radiology. The digital systems yielded negative values that improved with a size 15 file. The agreement between the two digital systems was the best with size 15 file using 0 degrees projection (66.7%). CONCLUSIONS: Conventional radiology remains the technique of choice in determining the root-canal length; the digital techniques yielded good results for size 15 file.     

Assessment of in vitro interleukin-2-producing capacity of peripheral blood lymphocytes from patients with periodontitis.

Abstract In this cross-sectional study, we assessed the in vitro interleukin-2 (IL-2) producing capacity of peripheral blood mononuclear cells (PBMC) and lymphocytes from patients with different forms of periodontitis. 45 patients (12 with localised early onset periodontitis (LEOP), 20 with generalised early onset periodontitis (GEOP), and 13 with adult periodontitis (AP), and 20 periodontally healthy subjects (HS), participated in this study. PBMC and lymphocytes were isolated from the subjects and their cells were stimulated with an anti-CD3 monoclonal antibody (anti-CD3 MoAb) and the secreted IL-2 levels in the culture were bioassayed. No significant differences could be found in IL-2 producing activity of PBMC between the patients and HS group. There was wide interindividual variation and high and low “IL-2 producers” were noted. We found a LEOP patient who was a high producer of IL-2 (>mean+8 SD) and 2 LEOP patients and a HS who were low producers of IL-2 (相似文献   

Shear bond strengths of saliva contaminated 'one-bottle' adhesives

The aim of this study was to investigate the effect of saliva contamination on the bond strengths of three one-bottle bonding systems. The dentin of 90 recently extracted, non-carious human molar teeth was exposed and ground wet on 500 grit silicon carbide (SIC) paper to establish a bonding surface in superficial dentin. Specimens were randomly assigned to nine groups of 10 teeth each. Three testing conditions are: (i) contamination with fresh saliva (pH 5.5) after acid etching, (ii) contamination with fresh saliva after bonding application, and (iii) no contamination. Three adhesive systems are: syntac single component, prime & bond NT, and gluma one bond. Cylinders of composite were applied via PTFE (polytetrafluroethylene) split mould and light cured to the dentin surfaces. All specimens were thermocycled (5000 cycles) between baths of 5 and 55 degrees C. Shear bond strengths were measured using an Instron Universal testing machine at a crosshead speed of 1 mm min-1. Two-way ANOVA was used to analyse the data. The results of this study indicated that the saliva contamination of dentin has no adverse effect on the bonding efficiency of one-bottle adhesive systems (P > 0.05). No statistically significant differences were found between the shear bond strengths of tested adhesives.     

The effect of simulated intrapulpal pressure on bond strength to enamel and dentine

The purpose of this study was to evaluate the effect of simulated intrapulpal pressure on the shear bond strength (SBS) of a self-etching bonding system (Clearfil Liner Bond II) to both enamel and dentine surfaces. Forty-two caries-free human molar teeth were randomly assigned to two equal groups (n=21). One group of 21 teeth was connected to a special pulpal pressure machine, which is developed to simulate in vivo conditions. The buccal and lingual surfaces of the teeth were prepared with a diamond wheel to create flat dentine and enamel surfaces. A self-etching bonding system was then applied under pulpal pressure and 2.5 mm diameter composite cylinders were bonded to the prepared surfaces. The samples were then stored in distilled water at room temperature for 24 h under pulpal pressure before SBS was tested. The second restored group was used as a control and the teeth were not connected to the pulpal pressure apparatus during material application and test procedures. They were stored for 24 h in distilled water at room temperature before the SBS test. Fracture analysis of the enamel and dentinal surfaces was performed using a stereomicroscope. Shear bond strength values to dentine was significantly reduced with pulpal pressure (P < 0.001). However, in the enamel, SBS was increased (P < 0.001). In the control group, the SBS values to dentine and enamel did not show any significant difference (P > 0.05). Based on these results, it can be concluded that further analysis of enamel histology and bonding mechanisms are needed.     

Effects of adhesive temperature on the early and 6-month dentin bonding

Objectives

The aim of this study was to test the effect of adhesive temperature on the bond strength to dentin (μTBS) and silver nitrate uptake (SNU) of an ethanol/water (Adper Single Bond 2 [SB]) and an acetone-based (Prime&;Bond 2.1 [PB]) etch-and-rinse adhesive system.

Methods

The bottles of each adhesive were kept in various temperatures (5 °C, 20 °C, 37 °C and 50 °C) for 1 h previously to its application in the occlusal demineralized dentin of 40 molars. Bonded sticks (0.8 mm²) were tested in tension (0.5 mm/min) immediately (IM) or after 6 months (6 M) of water storage. Two bonded sticks from each hemi-tooth were immersed in silver nitrate and analyzed by SEM. Data were analyzed by two-way repeated measures ANOVA and Tukey's test (α = 0.05).

Results

No significant difference in μTBS was detected for both adhesives at 5 °C and 20 °C. The highest bond strength for PB was observed in the 37 °C group while for SB it was in the 50 °C. Significant reductions of bond strengths were observed for PB at 37 °C and SB at 50 °C after 6 M of water storage. Silver nitrate deposition was seen in all hybrid layers, irrespective of the group. Lower silver nitrate deposition (water trees) in the adhesive layer was seen for PB and SB at higher temperatures.

Conclusions

The heating or refrigeration of the adhesives did not improve their resin–dentin bond resistance to water degradation over time.     

Anthogyr种植系统固定修复的近期临床疗效评估

目的：评价Anthogyr种植系统修复牙缺失的近期临床效果.方法：采用Anthogyr种植系统的常规操作方法Ⅰ期植入398枚种植体,3～6个月后进行Ⅱ期手术,完成烤瓷修复体修复.结果：Anthogyr种植体修复后随访1～4年,累计成功率为96.7%.结论：Anthogyr种植系统固定修复牙列缺损具有良好的临床效果.     

系统观在龋病病因研究中的体现

龋病病因是口腔医学爱们多年来的探索重点之一,20世纪．60,70年代提出的“四联因素”学说已被逐步证实,并逐渐得到公认,因为它是在系统观点的指导下形成的,本文就龋病病因学理论中的系统观点进行了较为详细的分析与阐释。     

不同处理方式对热压铸造增强陶瓷的双轴弯曲强度影响的研究

目的研究不同处理方式对白榴石增强陶瓷的双轴弯曲强度的影响。方法试件的蜡型制作采用将融化的铸造蜡灌注于机械加工模具内,制成厚度和直径一致的蜡型。厚度为2.0 mm、直径为18 mm圆片,共40个。实验分组按照不同处理方式即:打磨和抛光、上釉和离子交换组。以不做打磨、上釉和离子交换的为对照组。根据ASTM标准F394-78.1991(美国材料实验协会)测试试件的双轴弯曲强度。经one-way ANOVA统计分析各实验组。同时辅以扫描电镜、X线衍射仪和能谱分析观察其结构的变化。结果不同处理方法与对照组比较双轴弯曲强度,差异有显著性(P<0.01)。不同处理方法组内的比较双轴弯曲强度,差异有显著(P<0.01)。结论热压铸陶瓷的不同处理均可以增加陶瓷的双轴弯曲强度,而以离子交换处理的影响最大。