The aim of this in vitro study was to evaluate the effect of two fibers (polyethylene or glass) and a flowable resin liner on microleakage in Class II adhesive restorations.
Class II adhesive cavities were prepared on mesial and distal surfaces of 40 extracted sound human molars. The cavity margins were below or above the CEJ. The teeth were randomly divided into four groups according to the restoration technique: group 1: restored with a resin composite (AP-X, Kuraray) in bulk after SE Bond (Kuraray) treatment; group 2: flowable resin liner (Protect Liner F, Kuraray) was used before composite restoration; in group 3, a polyethylene fiber (Ribbond) and in group 4, a glass fiber (everStick NET, StickTech) was placed into the bed of flowable resin before composite restoration. Samples were finished, stored in distilled water for 7 days at room temperature, and then thermocycled for 300 cycles between 5 degrees C and 55 degrees C. After sealing the apices, the teeth were varnished within 1 mm of the margins and placed in 0.5% basic fuchsin dye for 24 h at 37 degrees C. After rinsing, the teeth were sectioned longitudinally through the restorations and microleakage was evaluated with a stereomicroscope. Marginal penetration was scored on a 0 to 4 scale, and the data were statistically analyzed using Kruskal-Wallis and the Mann-Whitney U-test.
Flowable resin, everStick NET, and Ribbond THM used in combination with flowable resin significantly reduced leakage at occlusal margins in cavities with enamel margins (p < 0.05). When the leakage values on cervical dentin margins were evaluated, there was no statistically significant difference among the tested groups (p > 0.05).
Use of flowable composite alone or in combination with polyethylene or glass fibers reduces occlusal leakage in Class II adhesive cavities with enamel margins.
"An elastic liner between the tooth structure and composite resin may compensate for contraction stresses and prevent gap formation . The performance of dentin adhesives or a low-viscosity, low-modulus intermediate resin as an elastic barrier between the dentin adhesive and resin-based restorative material has been investigated previously  . "
"Woven fiber is placed in the restoration or used for cusp splinting. Some studies have evaluated the effect of woven fiber on the fracture resistance of endodontically treated teeth [13, 15, 19, 30]. However, its effect on stress creation has not been evaluated. "
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to analyze the stresses that develop by oblique and vertical forces in endodontically treated maxillary second premolars that were restored with resin composite. Additionally, in our study the effects of the different restorative approaches and use of different base materials on stress formation were analyzed using three-dimensional finite element stress analysis. For restoration, the models representing both cusp capping, palatinal cusp capping, standard MOD restoration, and use of woven fiber in occlusal part were prepared. In all models, oblique forces caused more stress than did vertical forces. Materials with low elastic moduli cause high amounts of stress, whereas materials with elastic moduli similar to that of dental tissues cause low amounts of stress. Additional approaches such as cusp capping, functional cusp capping, and woven fiber use do not affect stress formation on the tooth after endodontic treatment.
The Scientific World Journal 07/2013; 2013:426134. DOI:10.1155/2013/426134 · 1.73 Impact Factor
"This may also act as a flexible intermediate layer that helps relieve stresses during the polymerization shrinkage of the restorative resin. There is a great deal of stress at the resin dentin layer and the modifications that would reduce or eliminate the interfacial stress concentrations may reduce gap formation and microleakage. Over the last few years new dental materials containing glass, polyethylene, Quartz, carbon or other fibers have been made available which would improve the mechanical properties of the composites and provide wide extended applications for resin composites. "
[Show abstract][Hide abstract] ABSTRACT: To evaluate the effect of glass and polyethylene fiber inserts and flowable composite as a liner on the microleakage of Class II composite restorations with gingival margins on root surfaces.
Class II slots were prepared on both the proximal sides of thirty freshly extracted mandibular molars and were divided into six groups, according to the type of fiber insert and use of flowable composite (Filtek Z350) as a liner. Filtek P-60 (3M/ESPE) posterior composite was used to restore all cavities. The specimens were thermocycled and stained with 2% Basic Fuchsin dye, and sectioned to evaluate the dye penetration under Stereomicroscope. Statistical analysis was done using Kruskalwallis test and Mann whitney U test.
This study showed that, fiber insert groups, with or without flowable liner, had reduced microleakage scores as compared to the control groups. However, statistically no significant difference was found between the groups with fiber inserts. Less microleakage was seen in Group IV (With flowable liner and without Fiber inserts) as compared to Group I (Without flowable liner and Fiber inserts).
Journal of Conservative Dentistry 04/2012; 15(2):166-9. DOI:10.4103/0972-0707.94590
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