Department of Restorative Dentistry, School of Dentistry, Diego de Robles Y Av. Interoceánica, Universidad San Francisco de Quito USFQ, Quito, Ecuador, 170901.
Department of Restorative Dentistry. School of Dentistry, State University of Ponta Grossa. Ponta Grossa, Paraná, Brazil.
Clin Oral Investig. 2022 Jun;26(6):4447-4456. doi: 10.1007/s00784-022-04408-x. Epub 2022 Feb 15.
To evaluate the influence of the composite resin translucency used in direct anatomic fiber posts on the bond strength (BS) and microhardness (VHN) of a luting agent into flared roots.
The root canals of 70 single-rooted premolars were endodontically treated and prepared to simulate an oversized root canal. Prior to post cementation, composite resins with varying translucency (high translucent, HT; medium translucent, MT; high opacity, HO) were placed around the fiber posts to create anatomic fiber posts. The attenuation profile (%) of light passing either through the post or through the anatomic posts (n = 8) was obtained prior to the cementing procedures. A positive control group (PC) in which a prefabricated fiber post (PFP) with the diameter compatible with the root canal was cemented and a poorly adapted fiber post (negative control group, NC) were also evaluated. For both tests, the data were subjected to 2-way ANOVA and Bonferroni tests (α = 0.05).
A more severe light attenuation through the post at the cervical (P < .001) and medium (P < 0.001) thirds was noted when less translucent composite resin surrounded the anatomic post. HO groups showed lower BS (P = .009) and VHN (P < .001) values than the other groups, regardless of root third. No significant difference in BS values was noted between PC and HT groups.
The use of a more translucent composite resin in anatomic fiber posts increased the microhardness and bond strength of a dual polymerization self-adhesive RLA compared to the use of MT and HO composite. A well-adapted PFP showed the highest adhesive and mechanical behavior.
Clinicians should choose more translucent composite resins to create direct anatomic fiber posts to be cemented in flared root canals. That choice may allow improved mechanical properties of self-adhesive RLA and higher bond strength to the root canal as a consequence.
评估直接解剖纤维桩中使用的复合树脂的半透明度对成喇叭口状根管内黏结剂的黏结强度（BS）和显微硬度（VHN）的影响。
对 70 颗单根前磨牙的根管进行根管治疗和预备，模拟超大根管。在纤维桩黏固之前，将具有不同半透明度（高半透明度，HT；中半透明度，MT；高不透明度，HO）的复合树脂放置在纤维桩周围以形成解剖纤维桩。在黏固程序之前，通过穿过桩或穿过解剖桩的光的衰减曲线（%）（n=8）。还评估了一个预制纤维桩（PFP）与根管直径匹配的阳性对照组（PC）和一个适配不良的纤维桩（阴性对照组，NC）。对于这两种测试，数据均采用双因素方差分析和 Bonferroni 检验（α=0.05）。
当解剖纤维桩周围的复合树脂半透明度较低时，在颈部（P<0.001）和中部（P<0.001）三分之一处观察到更严重的光通过桩衰减。HO 组的 BS（P=0.009）和 VHN（P<0.001）值均低于其他组，与根三分之一无关。PC 组和 HT 组之间的 BS 值无显著差异。
与 MT 和 HO 复合树脂相比，在解剖纤维桩中使用半透明度更高的复合树脂可提高双固化自黏结 RLA 的显微硬度和黏结强度。适配良好的 PFP 表现出最高的黏附性和机械性能。
临床医生应选择半透明度更高的复合树脂来制作直接解剖纤维桩，以黏固在喇叭口状根管中。这样的选择可能会使自黏结 RLA 的机械性能得到改善，并提高与根管的黏结强度。
