In one study of sealing effectiveness， Cavit  allowed penetration through the filling  material to a depth of up to 4.3mm and  marginal penetration of 4.4mm.
    在一项封闭有效性的研究中，Cavit暂封膏的微渗漏到暂封材料深度达4.3毫米，边缘微渗漏也有4.4毫米。
    Using IRM， a dye substance penetrated only  0.5mm marginally but along a length of  4.9mm.
   使用IRM暂封膏，染料物质在边缘仅仅有0.5毫米的渗入，但是在封闭界面，渗入深度却达到4.9毫米。
    Based on these results， a temporary restoration  thickness of 3.5mm is inadequate. Even  the application of a cotton pellet upon the medicinal  interim dressing beneath the temporary  filling must be avoided. A thickness of  over 4mm is the goal; this can only be  achieved by direct application onto the root canal orifices. Identically severe saliva penetration occurred three months after root canal fillings with a ca. 3mm thick IRM restoration as with teeth that were left open coronally. Such restorations must be replaced after one month in situ because sealing failure increases with time.
    基于这些研究结果，临时修复体厚度小于3.5毫米对于防止微渗漏是不够的。即便是在临时修复体下方使用药棉球也是必须避免的。大于4毫米的暂封材厚度应该是个基准；但是这个目标仅仅在暂封材直接封闭到根管口时才能实现。所以如果根管充填后，牙冠直接用3毫米厚的IRM暂封材暂封，那么三个月后，就可以发生比较严重的唾液微渗漏。因此，这种根管术后的暂封**在一个月内被换掉，否则随着时间推移，封闭失败率会******。
    With IRM cement， evidence of discoloration  of a cotton pellet placed directly beneath  a 5mm thick filling at the floor of the cavity  was observed twice as often compared with Cavit. If the canal orifices are directly sealed  by the temporary filling material， contamination  of the interim dressing by saliva that penetrates  through leaky crown or restoration  margins is less likely to occur.
    使用IRM暂封膏暂封时，染料试验证明，即便是5毫米的暂封厚度，暂封下方窝洞底部棉球的染色几率要比同等条件的CAVIT暂封膏高两倍。如果根管口直接用暂封膏封闭，唾液通过渗漏的冠边缘或者修复体边缘渗入内部的污染发生率会降低。
    The type of temporary filling material can  negatively influence the seal of the definitive  restoration. IRM cement， Cavit， Dycal， but  also Grossman cement lowers the bonding  strength of a composite material to dentin by  one-half of the control value.
    临时封闭材料的类型不会影响特定修复体的封闭性。但是，与对照组相比，IRM暂封膏，CAVIT，DYCAL，GROSSMAN等暂封剂降低了树脂材料对牙本质的粘接强度，粘接强度仅相当于对照组的一半。
    On the other hand， the type of temporary  dressing within the root canal does not significantly  influence the sealing properties of the  restorative materials. Neither eugenol nor formocresol  nor chlorphenol elicit any higher  penetration through or beyond the restoration.
    另一方面，在根管内的临时封闭材料不会明显影响修复材料的封闭性。临时封闭材料中的丁香油、formo甲酚、氯酚等都不会导致修复体有更多的微渗漏。
    It has long been known that recontamination  of an already treated root canal almost always  occurs from the coronal aspect， and that a poorly sealing restoration （or secondary caries） can lead over time to failure despite optimum  root canal instrumentation and filling. In a study of saliva contamination， canals were instrumented in vitro and filled， but not closed  coronally. A group of control teeth was sealed  coronally with wax. Following the set reaction  of the sealers， the apices of the teeth were placed into nutritive substrate solution and  the access cavities were filled with human saliva. In the teeth that were filled with gutta  percha and without any coronal closure， bacterial  growth at the apex was observed after only 48 hours. In the control group， not a single  case of bacteria penetrating apically was  observed. Following lateral or vertical condensation  using a sealer， the length of time for  complete penetration was maximally 48 days.
    很久以前，我们就知道，一个治疗后的根管的二次感染的发生总是来自冠方的封闭不良；而且，即便是理想的根管预备配以理想的根管充填结果，如果其上方修复体封闭效果不好或者是继发龋发生，随着时间的推移，可以导致根充失败。在一项唾液污染的体外研究中，根管预备后根管充填，但是没有冠方封闭。对照组的牙齿在冠方用蜡封闭。在根管封闭剂凝固后，牙齿的根尖被放入营养物质溶液，开髓孔充满人工唾液。在牙胶充填没有冠方封闭的牙齿组，细菌在仅48小时后就到达根尖。在对照组，没有观察到一例细菌渗漏到根尖的情况。使用侧方加压或者垂直加压根充后，试验组细菌完全渗漏到根尖的时间延长到最多48天。
    If the tooth was not closed coronally， after a maximum of three months less than half of  the teeth still exhibited an impervious filling.Over the long term， best results were achieved  with adhesive composite resins， followed by  glass ionomer cement. With only a onemonth  interim dressing， two-thirds remained  coronally impermeable， i.e.， no penetration  could be observed along the restoration margin.  As a result of these studies， the temporary dressing should not be left in place longer  than four weeks， also because of possible  coronal leakage of the temporary restoration.
    如果牙齿没有冠方封闭，最多三个月，将会有仅仅一半的牙齿还能保持良好的根尖封闭。长时间的情况下，**的封闭结果是玻璃离子垫底，辅以粘接性树脂充填。仅仅一个月的暂封，冠方已经仅有三分之二是没有微渗漏的。换句话说，沿着修复体边缘没有渗漏。这些研究的结果显示，由于可能的冠方临时修复体的微渗漏，暂封材料最长不要超过4周