Assessment of the interaction of Portland cement-based materials with blood and tissue fluids using an animal model

Portland cement used in the construction industry improves its properties when wet. Since most dental materials are used in a moist environment, Portland cement has been developed for use in dentistry. The first generation material is mineral trioxide aggregate (MTA), used in surgical procedures, thus in contact with blood. The aim of this study was to compare the setting of MTA in vitro and in vivo in contact with blood by subcutaneous implantation in rats. The tissue reaction to the material was also investigated. ProRoot MTA (Dentsply) was implanted in the subcutaneous tissues of Sprague-Dawley rats in opposite flanks and left in situ for 3 months. Furthermore the material was also stored in physiological solution in vitro. At the end of the incubation time, tissue histology and material characterization were performed. Surface assessment showed the formation of calcium carbonate for both environments. The bismuth was evident in the tissues thus showing heavy element contamination of the animal specimen. The tissue histology showed a chronic inflammatory cell infiltrate associated with the MTA. MTA interacts with the host tissues and causes a chronic inflammatory reaction when implanted subcutaneously. Hydration in vivo proceeds similarly to the in vitro model with some differences particularly in the bismuth oxide leaching patterns.peer-reviewe

Residual monomer in denture base acrylic

published_or_final_versionDentistryDoctoralDoctor of Philosoph

Dental Resin-Zirconia Bonding Promotion Using High-Silica PVD Coating with High Ionization Sputtering Processing

Purpose: To evaluate the effect of high-silica coating deposited by high-silica physical vapor deposition (PVD) as a chemical bonding method on resin-zirconia bond strength under different aging conditions. Methods: Twelve Y-TZP blocks were used as the substrates. Four resin cement stubs were bonded on each Y-TZP block, with a total number of 48 resin cement stubs. Two test groups (n = 24) were evaluated: conventional Tribochemical silica-coating (TSC) and high-silica PVD with high ionization sputtering processing. Experimental silane primer (MPS) was brushed over the surface treated Y-TZP blocks, then a polyethylene mold was placed over the coated Y-TZP blocks and filled with the adhesive resin cement, then light-cured for 40 s. The shear bond strength (SBS) was then evaluated in dry condition and after thermo-cycling for 6000 cycles. Surface roughness, mode of failure, surface topography and elemental analysis were also evaluated. Results: In dry condition, PVD-coated zirconia specimens showed significantly higher mean SBS values (11.7 ± 1.3 MPa) compared to TSC (10.2 ± 1.1 MPa) (p = 0.027). The SBS values of TSC and PVD-coated samples after thermo-cycling were higher than in dry condition, but with no statistical significant difference (p > 0.05). Tetragonal-to-monoclinic phase transformation was detected in TSC, but not in PVD-coated zirconia. Significant decrease in surface roughness of PVD samples compared to TSC samples (p < 0.001). The silica content in PVD coating was 51% as detected by EDX. Conclusions: High-silica PVD coating on zirconia can give a reliable resin-zirconia chemical bond without any phase transformation and surface destruction by conventional grit-blasting

Application of Copper Nanoparticles in Dentistry

Nanoparticles based on metal and metallic oxides have become a novel trend for dental applications. Metal nanoparticles are commonly used in dentistry for their exclusive shape-dependent properties, including their variable nano-sizes and forms, unique distribution, and large surface-area-to-volume ratio. These properties enhance the bio-physio-chemical functionalization, antimicrobial activity, and biocompatibility of the nanoparticles. Copper is an earth-abundant inexpensive metal, and its nanoparticle synthesis is cost effective. Copper nanoparticles readily intermix and bind with other metals, ceramics, and polymers, and they exhibit physiochemical stability in the compounds. Hence, copper nanoparticles are among the commonly used metal nanoparticles in dentistry. Copper nanoparticles have been used to enhance the physical and chemical properties of various dental materials, such as dental amalgam, restorative cements, adhesives, resins, endodontic-irrigation solutions, obturation materials, dental implants, and orthodontic archwires and brackets. The objective of this review is to provide an overview of copper nanoparticles and their applications in dentistry

The Effect of Lithium Disilicate Ceramic Surface Neutralization on Wettability of Silane Coupling Agents and Adhesive Resin Cements

This in vitro study was aimed to evaluate the possible changes in wettability of an etched glass ceramic surface to silane primers, adhesive resin and resin cement when the surface had been neutralized by a special neutralizing agent after etching. Rectangular shaped specimens were cut from the CAD blocks of an e-max lithium disilicate glass ceramic, cut specimens were sequentially polished and ultrasonically cleaned. All the specimens were etched for 20 s with 5% hydrofluoric acid and ultrasonically cleaned. Specimens were randomly assigned to one control group (without neutralization) and one treatment group (with neutralization) having 20 specimens each. The specimens of each group were further divided into two subgroups having 10 specimens each and tested to determine the effect of neutralizing agent on wettability of experimental and commercial silanes. Each subgroup specimen was tested for wettability to adhesive resin and commercial resin cement. Data were analyzed using two-way ANOVA. Neutralizing the ceramic surface did not show a significant effect on wettability to the silanes and the resin based materials, but the experimental silane showed better wettability than the commercial silane. The adhesive resin had statistically significant lower contact angle (high wettability) values than the commercial resin cement. The results of the current study suggested that the neutralizing agent did not have an impact on the wettability of the etched ceramic. However, there were differences in wetting properties of the silane primers, and adhesive resin versus resin composite luting cements.</p