Structure of experimental in vitro and in vivo lesions around composite (Addent XV®) fillings

abstract — In the in vitro experiments of the present study Class V Addent XV® fillings were inserted on buccal surfaces of 32 permanent human teeth. Lesions were produced by placing acidified gelatin around the fillings. In the corresponding in vivo experiments, caries was produced around similar fillings in 17 permanent teeth. In both series, sections of the teeth with the fillings in situ were studied by polarized light microscopy and microradiography. All teeth showed "outer lesions", but the tendency to development of "cavity wall lesions" was negligible. A comparison with lesions produced previously in corresponding experiments with silver amalgam and silicate fillings has been done.     

Determinantion and evaluation of antisperm antibodies and seminal immunosuppressive material in recurrent aborting couples

Circulating antisperm antibodies (AsAb) and immunosuppressive material in seminal plasma (SPIM)were determined by solid-phase enzyme staining assay and anticomplement test respectively in 686 patients with abortion (including 285 couples) . 241 fertile couple served as control. It's found that the positive rate of AsAb in infertile patients was significantly higher than that in fertile control,being 36.6% vs 3.3% (P<0.001). AsAb was even more offen detected in recurrent aborting patients. Male patients whose spouses aborted 2-6 fetuses had significantly less SPIM than control, sperm count and sperm motility were also significantly decreased. But the incidence of pyospermia was significantly greater than that in control. It is concluded that AsAb and SPIM have played an important role in the development of recurrent abortions.     

复合树脂充填物与酸蚀牙齿间密合度的扫描电镜观察

用SEM观察6种复合树脂充填物与酸蚀牙齿间密合度。结果表明6种复合树脂充填物与牙齿间均有微缝隙,其宽度多数在5μm内,最宽为10～15μm。1月后再观察,清晰见到从酸蚀牙本质小管曳出的树脂突,其曳出方向与缝隙形成可能有关。     

蝇类对环境中动物废弃物的净化作用初探

本文报告了常见蝇类对环境中动物废弃物的分解、净化作用的初步研究结果,从动物废弃物中共采到蝇类幼虫24种,甲虫6种,螨2种,其中主要为丽蝇、绿蝇与麻蝇。这些幼虫在孳生期间可以消耗动物废弃物,减少气味与污染,起到一定的生物净化作用。试验结果表明这些幼虫在高峰季节20天左右就可以消除2.5公斤的动物废弃物,并且表明在动物废弃物分解、净化过程中,蝇类及其它节肢动物之间相互交替,有利于环境中动物废弃物的清理。此外,文中对该问题的利弊还予以分析与讨论。     

牙髓对垫底材料的反应

本试验用狗４只，分ＡＢ两组．所有试验牙制备Ｖ类洞，分别在洞底衬垫氧化锌等四种材料．Ａ组在试验后所定时间内给动物饲料中加四环素５天，第１２８天拔除试验牙，制作牙磨片．Ｂ组在试验后相应时间拔除试验牙制作组织切片．通过本试验，来观察在试验时间内所形成修复性牙本质的量，以及牙髓炎性反应与此量之间的关系．     

Dye penetration in dry and water-filled gaps along root fillings

AIM: The aim of this study was to investigate the influence of hydration in voids along root fillings on methylene blue penetration. METHODOLOGY: A total of 80 human root canals were prepared using a step-back technique and filled with a zinc oxide based sealer and gutta-percha. Leakage along the fillings was measured by a transport fluid model and classified into three categories: gross leakage (GL), slight leakage (SL) and no leakage (NL). Specimens with NL and SL were immersed into methylene blue (MB) 2% for 24 h (group I). Specimens with GL which had wide gaps filled with water were randomly divided into two groups (II, III). Transport air was applied to remove water from gaps only in specimens of group III. All tested specimens from groups II and III were also immersed into MB 2% for 24 h. Each specimen was then split longitudinally and linear measurements of dye penetration were recorded. RESULTS: Group III (with dry gaps) showed significantly more dye penetration than group II. No significant difference was found between group I and group II. CONCLUSIONS: Methylene blue penetrates along root fillings more easily in dry gaps than in water-filled gaps.     

Failure of medullary tubes. A materials analysis

The objective of this study is to determine the effects of autoclaving on the stress, strain, ultimate tensile strength (UTS), fracture strain, modulus, and yield stress of nylon medullary tubes. There are three reports describing nylon medullary tube failure in the literature. All cases involved the use of nylon medullary tubes during open reduction internal fixation of fractured long bones. We demonstrated increased brittleness and decreased strength with increased exposure of medullary tubes to autoclaving, most dramatically after 100 autoclave cycles. Visual inspection of tubes is a clear indication of material degradation after repeated autoclaving. Furthermore, there is a significant difference in ultimate tensile strength (P < 0.0001) between tubes exposed to less than 100 sterilization cycles compared to tubes exposed to greater than 100 cycles. Likewise, there is a significant decrease in yield stress (P < 0.0004) between the same groups. We recommend disposal and replacement of nylon medullary tubes before they are exposed to 100 autoclaving cycles in order to avoid failure of the device.     

中药复方物质基础研究新思路和方法

复杂的化学成分是中药复方发挥预防、治疗、诊断疾病的物质基础。基于对传统中药复方物质基础和现代中药复方创新物质基础的认识,提出了"功能组分"新观点,中药复方成分可以划分为有效组分、功能组分和无用成分。中药复方物质基础由"有效组分 功能组分"共同构成有序的整体结构,具有"三个层次多维结构";提出了由"微观到宏观"和"宏观到微观"的二个不同的物质基础整体性结构研究解决方案。