EDTA对年轻恒牙釉质粘接强度的影响

目的 研究乙二胺四乙酸二钠（EDTA）对年轻恒牙釉质粘接强度的影响。方法 收集手术拔除的牙根未发育完全的上下颌第三磨牙，共180颗，选取全部离体牙牙冠颊面与牙长轴相对平行的釉质面（倾斜角度小于5°）作为实验粘接面，按实验方法不同随机均分为5组，每组36颗，分别进行以下处理：G0（对照组）：37%磷酸常规酸蚀；G1：37%磷酸+17% EDTA；G2：37%磷酸+10% EDTA；G3：17% EDTA+37%磷酸，G4：10% EDTA+37%磷酸。以上样本均采用GLUMA通用型粘接剂粘接后，行流动树脂堆砌。使用万能材料试验机进行树脂剪切粘接强度的测试。剔除剪切测试中由于树脂块断裂而未形成树脂-釉质面分离的试件，针对剪切粘接强度采用SPSS21.0统计软件进行统计学分析。结果 G0的平均剪切粘接强度（9.80±2.78 MPa）要明显低于G1（11.56±3.30 MPa）、G2（12.01±3.28 MPa）和G4（12.19±3.04 MPa）的剪切粘接强度，其差异都具有统计学意义（P<0.05）。尽管G3的平均剪切粘接强度（10.75±2.85 MPa）要高于G0，但两组之间的强度差异无统计学意义（P=0.261）。此外，G1、G2、G3和G4各组之间的平均剪切粘接强度差异无统计学意义（P>0.05）。结论：酸蚀前、后EDTA去蛋白化处理较单纯酸蚀处理更能增强树脂的剪切粘接强度，但其作用可能会受到EDTA浓度的影响。

Effects of EDTA on bond strength of immature permanent teeth enamel

Objective This study aimed to investigate the effect of EDTA on the bond strength of immature permanent teeth enamel. Methods 180 maxillary and mandibular immature third molars were collected. The buccal surface parallel to the axis of the tooth (tilt angle <5°) was selected as an experimental adhesive surface. According to different treatments, the teeth were randomly divided into five groups on average (resulting in 36 teeth each):G0(the control group):conventional acid-etching bonding group(37% phosphoric acid); G1:37% phosphoric acid and then 17% EDTA solution treatment group; G2:37% phosphoric acid and then 10% EDTA solution treatment group; G3:17% EDTA solution treatment and then 37% phosphoric acid group; G4:10% EDTA solution treatment and then 37% phosphoric acid group. GLUMA Comfort Bond was used for all the samples followed by the application of a flowable composite resin. Shear bond strength was measured by a universal testing machine. Samples without resin-enamel surface separation caused by resin fractures in the shear test were excluded from the experiment. SPSS21.0 statistical software was used for all the data analysis. Results The average shear bond strength in G0 (9.80±2.78 MPa) was significantly lower than that in G1(11.56±3.30 MPa, P=0.034), G2(12.01±3.28 MPa, P=0.006), and G4(12.19±3.04 MPa, P=0.003). Although G3 exhibited a little higher average shear bond strength (10.75±2.85 MPa) than G0, there was no significant differences between the two groups (P=0.261). In addition, there was also no significant difference among the groups including G1, G2, G3 and G4 (P>0.05). Conclusions The deproteinization before and after acid-etching are more likely to improve the shear bond strength than the conventional acid-etching, but the effect might be affected by the concentration of EDTA solution.