电离辐射对初生牙两种不同粘接系统剪切粘接强度的影响——体外研究

放射治疗是头颈部癌症患者的常用治疗方式，但其对粘接剂粘接强度具有负面影响。目前关于放疗对初生牙粘接强度影响的资料有限。因此，本体外研究旨在检测在放射后，哪种粘接系统在初生牙中的粘接强度更优，以及最佳修复时间。将来自初生牙的牙本质样本根据修复时间和辐射暴露情况随机分为4组（G1：对照组，G2：放疗前，G3：放疗后24小时，G4：放疗后6个月），每组20个样本。每组根据所用粘接系统再分为两个亚组（1）3M™ Single Bond Universal粘接剂（SB），（2）3M AdperSingle Bond 2（AS）。样本用钴-60机进行伽马辐射，剂量为60 Gy。然后进行剪切粘接强度测试，施加载荷直至失败，记录最大载荷。数据以均值和标准差表示，并根据Shapiro-Wilk或Levene检验进行分布检验，采用双因素方差分析分析，显著性水平设定为p < 0.05。使用R软件（版本4.4.1）进行统计分析。结果显示，SB组的粘接强度显著高于AS组（p < 0.001）。SB组中，G1与G4组之间无显著差异（p > 0.001），但G1、G2和G3之间存在显著差异（p < 0.001，p = 0.025，p = 0.265不显著），G3值最低。对于AS组，G1与G4之间无显著差异（p < 0.001），G3组的粘接强度显著低于其他组（p = 0.265不显著），表现最差。放射后24小时进行的修复粘接强度低于放射6个月后修复的结果。无论使用何种粘接系统，SB表现均优于AS，且在剪切粘接强度方面效果更佳。

Radiotherapy is a treatment modality used for head and neck cancer patients. It has a negative influence on bonding strength of adhesives. Little information is available about the effect of radiotherapy on bonding strength of adhesives in primary teeth. Therefore, this in vitro study aimed to detect the best adhesive system and ideal time to apply restorations in primary irradiated teeth regarding adhesive shear bond strength.Dentin samples from primary teeth were randomly assigned to four groups based on restoration application time and radiation exposure, (G1: control, G2: preradiation, G3: 24 h postradiation, and G4: 6 months postradiation) with 20 samples per group. These groups were further divided into 2 subgroups according to the adhesive system used, with 10 samples per subgroup. (1) 3M™ Single Bond Universal Adhesive (SB), (2) 3M AdperSingle Bond 2 (AS). Samples were exposed to gamma radiation from a cobalt-60 machine. One shot of 60 Gy of radiation was delivered. Then samples were subjected to a shear bond strength test. The load was applied until failure and the maximum load was recorded. Numerical data are presented as mean and standard deviation values, then distributed according to Shapiro-Wilk test or Levene's test and analyzed via two-way ANOVA. The significance level was set at p < 0.05 for all tests. Statistical analysis was performed with R statistical analysis software version 4.4.1 for Windows (Team RC, R: A language and environment for statistical computing. R foundation for statistical computing, 2023).Compared with the AS subgroup, the SB subgroup presented significantly greater values (p < 0.001). For SB, there was no significant difference among the G1 and G4 groups (p > 0.001). However, there was a significant difference between G1, G2, and G3 (p < 0.001, P = 0.025, P = 0.265 ns respectively), and G3 presented the lowest values. For AS, there was no significant difference between groups G1 and G4 (p =  < 0.001). Compared with the other groups, G3 presented a significant difference (p = 0.265 ns) and the lowest results.Restorations performed 24 h after radiation had lower bond strength than those performed six months after radiation. Regardless of the adhesive system used, SB performed better than AS in terms of the shear bond strength.