CLINICAL CONSIDERATIONS OF MICROLEAKAGE
CLINICAL CONSIDERATIONS OF MICROLEAKAGE
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DOI：
10.1016/s0099-2399(06)81567-0
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发表时间：
1990-02-01
影响因子：
4.2
通讯作者：
PASHLEY, DH
中科院分区：
文献类型：
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作者：
PASHLEY, DH
大多数牙科材料允许口腔液中的细菌和细菌产物微渗漏到达牙本质。因此，为了了解微渗漏的临床后果，我们需要分析牙本质的渗透性特征。牙齿预备过程中暴露的牙本质表面越多，微渗漏的可能性就越大。较厚的牙本质比薄牙本质的渗透性更差。髓角上的牙本质比中央牙本质更具渗透性。类似地，构成轴壁的牙本质比形成空腔牙髓底的牙本质更具渗透性。冠状牙本质的渗透性比根牙本质高得多。除了单位面积的小管数量、小管直径和牙本质在牙齿中的位置之外，另一个极其重要的变量是是否存在涂抹层。当形成涂抹层时，研磨碎屑被迫进入每个小管以形成涂抹塞。涂片塞通常长 1 至 2 μm，但也可能长 10 μm。它们比涂抹层的厚度长得多，并且比上面的涂抹层更能降低牙本质的渗透性。涂抹层构成了天然的蛀牙衬垫，其降低牙本质渗透性的作用远远超过任何蛀牙清漆。然而，它的存在限制了牙本质粘合剂的强度，因为将涂抹层固定在一起并保持在牙本质上的内聚力相对较低。如果将其去除，牙本质粘合树脂的粘合强度会增加，但如果粘合不均匀完美，去除也会增加牙髓炎症的潜在可能性。微渗漏渗透到牙本质的细菌产物的扩散速率与牙髓循环去除细菌产物的速率之间存在平衡。牙髓血流量的减少会使这些物质的浓度增加，从而引发牙髓炎症。
Most dental materials permit the microleakage of bacteria and bacterial products from oral fluids to reach dentin. Thus, an understanding of the clinical consequences of microleakage demands that we analyze the permeability characteristics of dentin. The more dentin surface that is exposed during tooth preparation, the greater the potential for microleakage. Thicker dentin is less permeable than thin dentin. Dentin over pulp horns is more permeable than central dentin. Similarly, the dentin making up axial walls is more permeable than dentin forming the pulpal floor of cavities. Coronal dentin is much more permeable than root dentin.In addition to the number of tubules per unit area, tubule diameter, and the location of the dentin in a tooth, another extremely important variable is the presence or absence of a smear layer. When smear layers are created, grinding debris are forced into each tubule to form a smear plug. Smear plugs are usually 1- to 2-μm long but may be 10-μm long. They are much longer than the smear layer thickness and they reduce dentin permeability more than the overlying smear layer. Smear layers constitute a natural cavity liner that reduces the permeability of dentin far more than any cavity varnish. However, its presence limits the strength of dentin bonding agents because of the relatively low cohesive forces holding the smear layer together and to dentin. If it is removed, the bond strengths of dentin adhesive resins increases, but removal also increases the potential liability for pulpal inflammation if the bond is not uniformly perfect.There is a balance between the rate of diffusion of bacterial products permeating dentin from microleakage and the rate at which they are removed by the pulpal circulation. Decreases in pulpal blood flow can permit the concentration of these products to increase, thereby triggering pulpal inflammation.