br Conclusions In conclusion EA irrigation and PUI

Conclusions In conclusion, EA irrigation and PUI were more effective than the CHX final rinse and Ca(OH)2 dressing in eliminating bacteria from infected root canals after SAF instrumentation. The presence of remnant bacteria after chemomechanical preparation using SAF and the supplementary effects of EA or PUI suggest that further modifications are required to enhance disinfection.
Conflicts of interest
Introduction New ceramic systems have been developed as attempts to eliminate metal infrastructures and allow optimal distribution of reflected light, providing high quality aesthetic restorations through the use of reinforced ceramic cores either by dispersion of leucite [1], glass infiltration into sintered alumina (Al2O3) [2,3], the use of high-purity alumina [4] or zirconium dioxide (zirconia, ZrO2) [5]. Zirconia has emerged as a versatile and promising ceramic material because of its biological, mechanical and optical properties. With a flexural strength of more than 900 MPa, fracture toughness of up to 10 MPa/m0.5, and an elastic modulus of 210 GPa, they exhibit better mechanical performance, superior strength and fracture resistance than do other ceramic materials [5,6]. Zirconium dioxide as a dental material has a wide range of applications [7], they were initially used for endodontic dowels and implant abutments [8,9]. Its use has been extended to single crowns [10,11] and posterior three-unit fixed partial dentures which can be fabricated with a manual copy-milling machine, or computer aided design/computer aided manufacturing (CAD/CAM) systems [12,13] of either pre-sintered [14] or fully sintered zirconia blocks [15]. Adhesion of resin cement to high-strength zirconia ceramics is not expected to be improved by gpr119 agonist etching and silanization because they are inert acid resistant ceramics [16–21]. For zirconia ceramics, airborne-particle abrasion is an alternative method for roughening the ceramic surface [20,22,23]. However, there are some possibilities for improving bonding to zirconia based ceramics that need to be tested, including modern techniques for surface treatments by plasma technology. Plasma is defined as a gas in which part of the particles that make up the matter are present in ionized form. This is achieved by heating the gas leading to dissociation of the molecular bonds and subsequently ionization of the free atoms. Thereby, plasma consists of positively and negatively charged ions and negatively charged electrons as well as radicals, neutral and excited atoms and molecules [24,25]. In material science, possible applications of plasma include the modification of surface properties like electrochemical charge or amount of oxidation, wettability, hardness, resistance to chemical corrosion, the water absorption capacity as well as the affinity toward specific molecules can be modulated [26], using the common plasma gas sources as oxygen, argon nitrogen or hydrogen.
Materials and methods
Results
Discussion Y-TZP ceramics have superior strength, toughness, fatigue resistance and potentially, enhanced long-term viability than other ceramics [28,29]. MAD/MAM systems bear the advantages of reduced cost, less sophistication, easy and fast technique compared to other types of milling machines [30,31]. Samples were milled from “green” pre-sintered zirconia blocks at a larger dimension to compensate for 20%–25% shrinkage during the sintering stage [14,32]. High crystalline content of zirconia ceramics renders them resistant to acid etching [33,34] therefore, alternative surface treatment techniques for long-term durable bonding are required [35–37]; such as sandblasting [38–43], plasma etching and silica ceramic coating [44] used in the present study. As the material and fabrication of test discs may have an influence on bond strength values to ceramic, composite resin discs were cemented in this study to zirconia samples as most investigations [45]. This will provide a uniform rather than heterogeneous structure of tooth enamel and dentin, allowing for more precise interpretation of bond strength values [40]. Also the present study aimed at evaluating the bond strength at cement/ceramic interface only after variable surface treatments of YZ-zirconia.