Dimethacrylate network formation and polymer property evolution as determined by the selection of monomers and curing conditions

Abstract

Objectives This overview is intended to highlight connections between monomer structure and the development of highly crosslinked photopolymer networks including the conversion dependent properties of shrinkage, modulus and stress. Methods A review is provided that combines the polymer science and dental materials literature along with examples of relevant experimental results, which include measurements of reaction kinetics, photorheology as well as polymerization shrinkage and stress. Results While new monomers are continually under development for dental materials applications, mixtures of dimethacrylate monomers persist as the most common form of dental resins used on composite restorative materials. Monomer viscosity and reaction potential is derived from molecular structure and by employing real-time near-infrared spectroscopic techniques, the development of macromolecular networks is linked to the evolution of polymerization shrinkage (measured by linometer), modulus (measured by photorheometer), and stress (measured by tensometer). Relationships between the respective polymer properties are examined. Significance Through a better understanding of the polymer network formation and property development processes using conventional dimethacrylate monomer formulations, the rational design of improved materials is facilitated with the ultimate goal of achieving dental polymers that deliver enhanced clinical outcomes.

Influence of irradiation time on subsurface degree of conversion and microhardness of high-viscosity bulk-fill resin composites

“…Taking these parameters that influence the final DC, in the present study, all measurements were conducted after 24-h-darkstorage at 37°C. Dental polymers based on Bis-EMA and lower viscosity (higher molecular mobility) urethane derivates usually exhibit higher DC than the typical Bis-GMA/TEGDMA resins [55,56]. Consequently, the high DC of QF through depth might not only be attributed to the high translucency of the material, but also to its favorable resin composition containing Bis-EMA, UDMA and TEGDMA, but no Bis-GMA (Table 1).…”

Rheological Investigation of the Gel Time and Shrinkage in Hybrid Organic/inorganic UV Curable Films

“…Another creative approach for reducing film shrinkage is the addition of another component which is miscible with the UV curable resin prior to radiation but undergoes photopolymerization induced phase separation (PIPS) at higher conversions. When phase separation occurs, film volume expands and compensates a portion of the shrinkage that arises from photopolymerization [25,37]. Herein, all the samples were completely transparent and homogenous before irradiation but formulations that contained inorganic oligomers became turbid after photopolymerization.…”

“…All these concerns are of prime importance in the coating area. Therefore, there is an increasing interest for monitoring the shrinkage during photopolymerization and proposing methods to reduce it [25][26][27]. Recently, Schmidt and coworkers proposed a new method for real time investigation of shrinkage during photopolymerization by implementing photorheometry [23].…”

Effect of the functionalization of silica nanoparticles as a reinforcing agent on dental composite materials

“…This situation was improved partly by using filling materials such as quartz, Nevertheless, these composite materials did not have much success due to the lack of adherence between the polymer and filler particles. [2][3][4]. The materials commonly used for fillings are silicon dioxide [2,5], barium or strontiumcontaining silicate glass powder [2,6], quartz [1,2], and titanium and zirconium oxides [2,7,8].…”