Synthesis of Novel Urethane-Dimethacrylate Monomer Containing Two Quaternary Ammonium Groups for Applications in Dentistry

The development of dental composites having antibacterial properties is one of the current trends in the restorative dentistry. It is justified by the need for the secondary caries reduction that is the main reason for dental restoration failure. In this field, the growing interest is associated with the development of quaternary ammonium monomers. In this study, we synthesized a novel urethane-dimethacrylate monomer containing two quaternary ammonium groups, via the three steps synthesis route. The synthesis procedure involved the transesterification of methyl methacrylate with the use of N-methyldiethanolamine, N-alkylation with the use of 1-bromohexadecane, and synthesis of urethane-dimethacrylate resin with the use of 2,4,4-trimethylhexamethylene diisocyanate. 1H NMR, 13C NMR, and ATR-FT IR analysis confirmed the chemical structure of the intermediate products and the structure of new urethane-dimethacrylate monomer.

Research Progress on All Ceramic Zirconia Core/Veneer Interface: A Review

The application of veneered zirconia system in clinical has last for few decades due to the excellent aesthetic performance. It was reported in many cases that porcelain delamination occurred in the interface between the zirconia infrastructure and veneer ceramics. There were many works have been carried out to improve the bond strength of interface. Most of the studies focused on the influence factors that affected the longevity of dental restoration. There existed different points of view both in vitro and in vivo. Hence, this review mainly focuses on veneered zirconia system and some interesting controversial findings that may lead to dental restoration failure. Furthermore, it was also found that the next generation of zirconia (such as monolithic zirconia, self-glazed zirconia) have brought the challenge to veneered zirconia system.

Calculation of Maximum Tensile and Shear Forces in Restorative Materials Using Finite Element Method

The purpose of this paper was to determine tensile loading that leads to dental restoration failure, i.e. the critical values of stress. In order to analyze stress distribution within the restoration and tooth, mechanical properties of materials and tissues, such as Young modulus and Poissons ratio were taken into account. An additional purpose of the paper was to determine whether tensile or shear stresses that occur in the restorative composite and the surrounding enamel cause this failure. Tensile stress is caused by forces acting in the direction perpendicular to the cross-section of a given element, whereas shear stresses are caused by forces parallel to said cross section. A 3D numerical model of a tooth including three different materials (dentine, enamel and composite) was made and used for these calculations. These results will be used as a base for the physical experiment.