Basic Study on the Application of Novel Functional Monomers to a Denture Base Resin

Abstract

To improve the mechanical properties and to reduce the water sorption amount of denture base resins, the polymerization characteristics of three novel fluoro-substituted monomers (MAF-TBN, MAF-MAE, MAF-TBN) and three styrene-type monomers (PTBS, PEES, PACS) were studied, as well as the copolymerization of these monomers with MMA. Subsequently, the mechanical properties and water sorption of the copolymers prepared from these monomers and MMA were evaluated. The polymerization reactivity of the monomers by BPO was lower than MMA, except for PACS. However, the copolymerization reactivity of the monomers with MMA was good, except for MAF-TBN. The copolymer of MAF-MAE and MMA in three fluoro-substituted monomers and PACS and MMA in three styrene-type monomers showed similar mechanical properties and extremely low water sorption compared with those of PMMA.Keywords: Functional monomer, Polymerization, Mechanical Property INTRODUCTION Poly(methyl methacrylate) (PMMA) is widely used in denture base resins. However, PMMA has posed several problems in clinical applications, such as poor water resistance, decrease in mechanical strength by water absorption, polymerization shrinkage, and monomer volatility. Against this background, novel resins with good mechanical properties and lower water sorption in the place of PMMA are required. To circumvent the abovementioned drawbacks, we have studied some monomers to date. For example, to improve the water resistance of PMMA, hydrophobic alkyl methacrylate and bis(methacryloyloxy) dimethylsiloxane oligomer were synthesized, and the mechanical properties of the copolymers of these monomers and MMA were evaluated 1,2) . The mechanical properties and water resistance of the copolymers were improved in comparison with PMMA, and the polymerization shrinkage was decreased. Increase in the monomer content for the copolymers was able to renders resin with the required hardness, but there was also increase in brittleness 1) . Decrease in the monomer content, on the other hand, did not improve water resistance and mechanical properties. In the case of the siloxane oligomer, the water resistance of the copolymer was improved, but the mechanical properties were poor compared with those of PMMA 2) . To improve the mechanical properties and to decrease the water sorption of resins, it has been proposed to introduce fluorine groups to the resins. Octafluoropentyl and 2,2,2-trifluoroethyl methacrylate have been investigated as resin binders of direct filling resins 3) and denture base resins 4) respectively. As for fluoroalkyl methacrylates, they were applied as visible light-cured soft resins 5) or as a modifier to the surface of denture base resins 6) to inhibit bacterial adherence. However, the mechanical properties of the resins were not improved. The poor strength might be due to decrease in interaction, such as van der Waals' force and the orientation of polar groups, among the polymer molecules by the substitution of the methyl group by long fluoroalkyl group at the ester position. Unfort...

Influence of monomer content on the viscoelasticity, water sorption and solubility of experimental fluorinated soft lining materials

“…Of the variety of polymer materials, attempts have been made to utilize fluorocarbon polymers and their monomers for dental materials such as denture base resins and soft lining materials [12][13][14][15][16] , composite resins 17) , dental acrylic resins 18) , and dental coating materials 19) . Fluorine compounds are known to exhibit certain specific properties, such as water repellency, chemical stability, and stain and discoloration resistance 20) .…”

Kinetic polymerization behavior of fluorinated monomers for dental use

“…On the other hand, it is reported that organic fluorine compounds exhibit certain specific properties, including but not limited to water repellency, chemical stability, and stain and discoloration resistance. Fluorinated monomers have been utilized for dental materials such as denture base resins and their related materials [2][3][4][5][6] , composite resins 7) , dental acrylic resins 8) and dental coating materials 9) with the aim of improving on the properties of non-fluorinated materials. Fluoroalkyl methacrylate has also been useful in the field of dental adhesives.…”

Flexural properties of ethyl or methyl methacrylate-UDMA blend polymers

“…There are several attempts [3][4][5][6][7][8][9][10][11][12][13][14][15][16] to increase the mechanical properties of denture base resins. One approach is to devise a reinforcement of denture base polymer with fibers, chips, or rods [12][13][14][15][16] .…”

“…Intraoral repeated masticatory forces lead to fatigue fracture, while extraorally impact fracture may occur as a result of dropping the denture onto the hard surface. Many attempts to improve the mechanical properties of polymethyl methacrylate (PMMA) have included using alternate polymers such as polycarbonate 3) , nylon 4,5) , copolymers 6,7) and urethane dimethacrylate (UDMA) 8,9) , and incorporating of butadiene-styrene rubber into PMMA matrix 10,11) . As another attempt, various fiber or chip materials [12][13][14][15][16] such as carbon, aramid and glass have been added into PMMA resin for reinforcing materials, and metal wires and meshes have ordinary been used for reinforcing materials to prevent the midline fracture of denture.…”