Fokkinga Wietske A, Kreulen Cees M, Le Bell-Rönnlöf Anna-Maria, Lassila Lippo V J, Vallittu Pekka K, Creugers Nico H J
College of Dental Science, Department of Oral Function and Prosthetic Dentistry, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
Am J Dent. 2006 Dec;19(6):326-32.
To study the fracture behavior of direct resin composite crowns with or without experimental fiber reinforcement.
Clinical crowns of single-rooted maxillary premolars were cut off at the cemento-enamel junction. Canals were prepared with Gates Glidden drills up to size 4. No additional post-space preparations were made. Roots were embedded in acrylic and canal entrances were standardized (depth 2 mm, diameter 1.75 mm). Three groups of 14 samples were treated as follows: (1) custom-made glass FRC post (EverStick Post); fibers 5 mm deep in the canal, (2) similar post-system as (1) with incorporation of a new type of glass fiber fabric, (3) no fiber reinforcement (control). Posts were cemented with resin cement (Panavia F). Resin composite crowns (Filtek Z250) were made using an anatomically formed mold. Static load until fracture was applied using a universal loading device with a cylindrical bar (diameter 2 mm) with a crosshead speed of 5 mm/minute (loading angle: 30 degrees to the tooth long-axis). Failure modes were categorized as favorable and unfavorable failures.
There was no significant difference in mean failure loads among the four groups (P > 0.05). Favorable failures occurred significantly more often in Group 2 than in the other groups (P < 0.05). The results suggest that an incorporated glass fiber fabric does not affect the load-bearing capacity of resin composite complete crowns on structurally compromised and non-vital premolars. Incorporation of a glass fiber fabric, however, has a beneficial effect on the failure mode.
研究有或没有实验性纤维增强的直接树脂复合冠的断裂行为。
将单根上颌前磨牙的临床冠在牙骨质-釉质界处截断。用盖茨·格利登钻制备根管直至4号尺寸。未进行额外的桩道预备。将牙根嵌入丙烯酸树脂中，根管入口标准化（深度2毫米，直径1.75毫米）。14个样本分为三组，处理如下：（1）定制玻璃纤维增强复合树脂桩（EverStick桩）；纤维在根管内深5毫米，（2）与（1）类似的桩系统，但加入一种新型玻璃纤维织物，（3）无纤维增强（对照组）。用树脂水门汀（Panavia F）粘结桩。使用解剖形态的模具制作树脂复合冠（Filtek Z250）。使用带有圆柱形杆（直径2毫米）的通用加载装置施加直至断裂的静载，十字头速度为5毫米/分钟（加载角度：与牙长轴成30度）。将失败模式分为有利和不利失败。
四组之间的平均失败载荷无显著差异（P>0.05）。第2组中有利失败的发生率显著高于其他组（P<0.05）。结果表明，加入玻璃纤维织物不影响树脂复合全冠在结构受损和无活力前磨牙上的承载能力。然而，加入玻璃纤维织物对失败模式有有益影响。
