The comparative study of microleakage which is a result of cementation in single rooted teeth restored with glass-fiber and zirconium ceramic posts using three different adhesive resin cements

Post-core restoration is a method frequently used in the restoration of endodontically treated teeth suffered from excessive material loss. In this type of restoration, posts are used for the core structure to provide retention and stability and core structure provides restoration retention by replacing the lost coronal tooth structure.Metal post systems are often used because of their superior physical properties. However, the most important disadvantages of these posts are their metallic and opaque colors and being exposed to corrosion and corrosion products that cause discoloration.In line with technological developments, new alternative materials are available on the dental markets. Non-metallic post systems can be aesthetically preferable. Prefabricated non-metallic posts have very high mechanical properties and bio-compatible. In addition these skins can be cemented by adhesive systems. For all these reasons, we used glass fiber and zirconium ceramic post systems in our study.Adhesive systems are very popular nowadays due to their good retention properties. But the most important disadvantage of this system is polymerization shrinkage. This problem can cause secondary dental caries, flexion of post, decementation between post surface and dentin surface, root fracture and even tooth loss. For this study we use three different adhesive resin cements in order to have little or no microleakage.The purpose of this study is the evaluation of microleakage resulted from the cementation of using glass fiber and zirconium ceramic posts with three different adhesive cements.In this study for the construction of samples, extracted and non-caries 60 mandibular human premolars, three different adhesive resin cements (PanaviaF 2.0, SmartCem2 and Variolink II) and two different post systems (glass fiber and zirconium post) were used. The teeth were divided into 6 different groups of 10 teeth each. All teeth crowns were cut at the root length of 13 mm. Canal preparations were made with ProTaper NiTi rotary instrument set. Root canals were filled with protaper guta-perka and AhPlus sealer. Then post spaces were prepared with their own drills at 9 mm depth. Post space preparation was performed immediately after filling the channel. Length of posts set at 13mm where 9mm piece of each post were used for cementation which die in root canal and 4mm piece of each post were used to provide support to core structure. Light-polymerized nano-composite was used for the restoration of core.Glass fiber and zirconium ceramic posts were adhesively luted using PanaviaF 2.0, SmarCem2 and Variolink II dual-polymerizing luting agents. All samples were subjected to thermal cycling 1000 times in between 5 ? C and 55 ? C water baths. Then samples were stored in 37 ? C distilled water for a week. At the end of this period, the samples removed from water and dried before being covered with clean nail polish. So that cement permeability of the tooth was prevented before the dye leakage method.All samples were stored in 2% methylene blue (solution) for a week. Then the samples scrubbed under running water with a brush and pumice. Cleaned samples were embedded in otopolimerized acrylic resin. The tooth were cut horizontally into three consecutive sections: apical, middle and coronal. Digital photographs were taken of each piece from their occlusal surface. Images were transferred to a PC and saved in JPEG format. For each sample, dye penetration was found as the ratio of methylene-blue-infiltrated area divided by total dentin area. The AutoCAD 2012 software used for the leak area detection and the ratio of each other. The data obtained were analyzed statistically by two-way ANOVA test (p>0,05). In addition, Tukey HSD was used to understand which group is better (p=0,146). PANZP group showed the least leakage which followed respectively by the groups PANFP, VPSFP, VPSZP, SCZP, SCFP.All samples were examined under SEM (scanning electron microscope). All of the samples in varying proportions were showed surface separations because of polymerization shrinkage between dentin and adhesive agent Apical sections showed the least microleakage and separation.Keywords: microleakage, glass fiber post, zirconium ceramic post, dental adhesives, resin cements.