Department of Restorative Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia.
Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia.
Photodiagnosis Photodyn Ther. 2019 Sep;27:415-418. doi: 10.1016/j.pdpdt.2019.06.022. Epub 2019 Jun 25.
To evaluate the push out bond strength and modes of failure of fiber post by using photodynamic therapy (PDT), Er,Cr:YSGG laser and conventional cleaning and shaping (CCS).
Sixty maxillary anterior teeth were sectioned horizontaly 2 mm incisal to the cemento-enamel junction, and root canal were prepared for post space. Tapered fiber posts were placed inside the root canal after post space was made. The fiber posts were subjected to PDT, Er,Cr:YSGG laser and CSS with 20 specimens in each group. The specimens obtained were sectioned in cervical and apical sections. A universal testing machine was used to perform the push out test and the push out bond strength was formulated by σ = C/A, expressed in mega-pascals (MPa).
The highest mean push out bond strength was achieved by PDT group (8.08 ± 2.73 MPa) and the lowest was shown by specimens in CCS group (7.45 ± 1.04 MPa). ANOVA showed no statistical difference among the experimental groups (p = 0.481). In the cervical segments, the mean push-out bond strength was found to be slightly higher for all three groups compared to apical segments (P < 0.05). The independent t-tests results showed that the mean push-out bond strength values of the cervical segments were slightly higher than the apical segments in PDT, Er,Cr:YSGG and CSS groups (P < 0.05). Significant differences were observed when mean push-out bond strengths were compared for both cervical (p = 0.037) and apical (p = 0.019) segments between all the groups. Twenty-one failures were found at the interface between the adhesive and the dentin surface, 6 failures were observed at the interface between the adhesive and post, whereas 5 failures were mixed.
Push-out bond strength to root canal dentin were not affected by Er,Cr:YSGG compared with conventional cleaning and shaping. However, PDT produced the smallest number of failure modes and slightly higher push-out bond strength to root dentin.
评估光动力疗法（PDT）、Er，Cr：YSGG 激光和常规清洗成型（CCS）对纤维桩推出粘结强度和失效模式的影响。
将 60 颗上颌前牙在距釉牙骨质界 2mm 处横断，根管预备后放置锥形纤维桩。每组 20 个试件分别接受 PDT、Er，Cr：YSGG 激光和 CCS 处理。获得的标本在颈段和根尖段进行切割。使用万能试验机进行推出试验，根据 σ=C/A 计算推出粘结强度，以兆帕（MPa）表示。
PDT 组的平均推出粘结强度最高（8.08±2.73 MPa），CCS 组最低（7.45±1.04 MPa）。方差分析显示各组间无统计学差异（p=0.481）。在颈段，三组的平均推出粘结强度均略高于根尖段（P<0.05）。独立样本 t 检验结果显示，PDT、Er，Cr：YSGG 和 CCS 组颈段的平均推出粘结强度均略高于根尖段（P<0.05）。颈段（p=0.037）和根尖段（p=0.019）的平均推出粘结强度在各组间均有显著差异。21 个失效发生在粘结剂和牙本质表面之间的界面处，6 个失效发生在粘结剂和纤维桩之间的界面处，5 个失效为混合模式。
与常规清洗成型相比，Er，Cr：YSGG 对根管牙本质的推出粘结强度没有影响。然而，PDT 产生的失效模式最少，对根管牙本质的推出粘结强度略高。
