17％EDTA不同处理时间对根面超微结构的影响

Effect of treatment with 17% EDTA for different periods of time on the microstructure of root surfaces

目的探讨17%乙二胺四乙酸(EDTA)凝胶及溶液处理不同时间对根面超微结构的影响,并与24%EDTA溶液的根面处理效果进行比较。方法 30颗牙周炎患牙经刮治和根面平整后,制备成牙骨质和牙本质根片,2组根片分别按下列分组行根面处理:A组,生理盐水处理3 min;B组,24%EDTA溶液处理3 min;C组,17%EDTA凝胶处理3 min;D组,17%EDTA凝胶处理5 min;E组17%EDTA溶液处理3 min;F组,17%EDTA溶液处理5 min。扫描电镜下观察各样本根面的超微结构。结果 1根面牙本质:A组牙本质表面几乎没有牙本质小管暴露;B组牙本质小管开放数目最多,暴露最为清楚;D组与F组次之;C组与E组牙本质小管开放数目最少,尚存许多堵塞的牙本质小管。2根面牙骨质:除A组外,B^F组根面干净,均去除玷污层。其中B组牙骨质脱矿明显,较好地显露出胶原纤维结构;D组与F组牙骨质部分脱矿,牙骨质表浅纤维呈块状,无明显空间构象;C组与E组牙骨质脱矿不明显,未见胶原纤维显露。结论 17%EDTA溶液与凝胶的根面处理效果无明显差异;将时间从3 min延长至5 min,17%EDTA根面处理效果变优,但仍不如24%EDTA溶液的根面处理效果理想。

Objective To explore the effect of treatment with 17% EDTA gel and solution for different periods of time on the microstructure of root surfaces and compare the effect between 17% EDTA gel and solution and 24% EDTA solution. Methods Thirty freshly extracted teeth from patients with periodontitis were treated with scaling and root planing （SRP）, and dentin fragments and cementum fragments were prepared. These fragments were randomly assigned to the A group treated with saline solution for 3 min, the B group treated with 24% EDTA solution for 3 min, the C group treated with 17% EDTA gel for 3 min, the D group treated with 17% EDTA gel for 5 min, the E group treated with 17% EDTA solution for 3 min, and the F group treated with 17% EDTA solution for 5 min. Scanning electron microscopy was used to observe the microstructure of root surfaces. Results @The dentin on root surfaces： There were no exposed dentin tubules on the surface of dentin in the A group. The number of open dentin tubules in the B group was the largest and the exposure was the clearest, followed by the D group and F group. The C group and E group had the fewest open dentin tubules, where many blocked tubules existed. @The cementum on root surfaces： Root surfaces in all groups were clean and the smear layer was removed except the A group. The cementum demineralization in group B was presented significantly and collagen fibers were exposed clearly. The D and F groups showed partial cementum demineralization and collagen fibers on the surface of cementum were lumpish with no significant spatial conformation. The cementum demineralization in the C and E groups was not significant with noexposure of collagen fibers. Conclusion There is no significant difference in the treatment of root surfaces with 17% EDTA gel and solution. When extending the treatment time from 3 min to 5 min, the effect of 17% EDTA becomes better, but is still inferior to 24% EDTA solution.