Mai Sui, Kim Young Kyung, Hiraishi Noriko, Ling Junqi, Pashley David H, Tay Franklin R
Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China.
J Endod. 2009 Jun;35(6):870-4. doi: 10.1016/j.joen.2009.01.025. Epub 2009 Apr 19.
The limited diffusion of self-adhesive resin cements into crown dentin raises doubts on whether self-adhesive root canal sealers are capable of creating micromechanical retention in instrumented canal walls in the absence of adjunctive use of calcium chelating irrigants. This study evaluated the true self-etching potential of MetaSEAL, a self-adhesive sealer.
Mixed MetaSEAL sealer was applied to (1) fractured radicular dentin that was devoid of smear layers, (2) instrumented canal wall radicular dentin that was irrigated with water as the final rinse to preserve the smear layer, and (3) instrumented canal wall radicular dentin that was irrigated with ethylenediaminetetraacetic acid (EDTA) as the final rinse to remove the smear layer. Cryofractured tooth halves without sealer application were examined by scanning electron microscopy to identify the characteristics of the bonding substrates. The other tooth-halves were filled with sealer and processed for transmission electron microscopy.
MetaSEAL did not demineralize fractured radicular dentin that was devoid of smear layer and smear plugs. The self-adhesive sealer was incapable of etching beyond the 1- to 2-mum-thick smear layer retained on water-irrigated instrumented dentin to demineralize the underlying radicular dentin. Smear layer and smear plugs were absent in EDTA-irrigated radicular dentin. The EDTA also partially demineralized the intact dentin, creating a thin bed of collagen for infiltration of the self-adhesive sealer.
The limited self-etching potential of MetaSEAL is a clinically legitimate concern. Incomplete smear layer removal from instrumented canal wall regions that are not reached by calcium chelating agents might jeopardize its bonding and sealing performance.
自粘树脂水门汀向冠部牙本质的扩散有限，这引发了人们对于在不辅助使用钙螯合剂冲洗剂的情况下，自粘根管封闭剂是否能够在预备后的根管壁上形成微机械固位的疑问。本研究评估了一种自粘封闭剂MetaSEAL的真正自酸蚀潜力。
将混合的MetaSEAL封闭剂应用于：（1）没有玷污层的根折牙本质；（2）以水作为最终冲洗液冲洗以保留玷污层的预备后的根管壁根段牙本质；（3）以乙二胺四乙酸（EDTA）作为最终冲洗液冲洗以去除玷污层的预备后的根管壁根段牙本质。通过扫描电子显微镜检查未应用封闭剂的冷冻断裂牙半体，以确定粘结底物的特征。将另一半牙体用封闭剂充填并进行透射电子显微镜检查。
MetaSEAL不能使没有玷污层和玷污栓的根折牙本质脱矿。这种自粘封闭剂无法蚀刻超过保留在用水冲洗的预备后的牙本质上的1至2微米厚的玷污层，从而使下方的根段牙本质脱矿。在经EDTA冲洗的根段牙本质中没有玷污层和玷污栓。EDTA还使完整的牙本质部分脱矿，形成一层薄的胶原床以供自粘封闭剂渗入。
MetaSEAL有限的自酸蚀潜力在临床上是一个合理的关注点。在钙螯合剂无法到达的预备后的根管壁区域，若玷污层未完全去除，可能会损害其粘结和封闭性能。
