Synthesis of novel antibacterial monomers (UDMQA) and their potential application in dental resin

To prepare antibacterial dental resin, a series of novel urethane dimethacrylates quaternary ammonium methacrylate monomers (UDMQAs) with different substituted alkyl chain length were synthesized, and their structures were confirmed by FTIR and ¹H‐NMR spectra. The obtained UDMQAs were used to replace 2,2‐Bis[4‐(2‐hydroxy‐3‐methacryloyloxypropyl)‐phenyl]propane (Bis‐GMA) totally as base monomers of dental resin and mixed with Tri‐ethyleneglycol dimethacrylate (TEGDMA) at the mass ratio of 50/50. The properties of these prepared resins like antibacterial activity, double bond conversion (DC), polymerization shrinkage, flexural strength (FS), and modulus (FM), water sorption and sol fraction were investigated. The most commonly used dental resin Bis‐GMA/TEGDMA (50wt/50wt) was chosen as a reference. The results showed that UDMQAs could endow dental resin with antibacterial activity. Compared with Bis‐GMA‐based dental resin, UDMQAs‐based resin had the same or higher DC, lower polymerization shrinkage, lower flexural strength and modulus, and higher water sorption and sol fraction. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of two PET waste derived bisacrylic and bisallylic monomers and their potential use as crosslinking agents and dental resin composites

Two novel bifunctional monomers obtained from PET waste glycolisis are reported. Bis(2‐(acryloyloxy)ethyl) terephthalate and bis(2‐(((allyloxy)carbonyl)oxy)ethyl) terephthalate (BACET) monomers were obtained from bis(hydroxyethyl) terephthalate derived from PET waste and acryloyl chloride and allyl chloroformate, respectively. The monomers were characterized by FTIR and ¹H‐NMR spectroscopies. They were evaluated as crossslinking agents for acrylic acid (AA) and methacrylic (MA) acids using thermally initiated polymerization. The obtained copolymers showed higher thermal stability than the acrylic homopolymers. They were also tested for dental formulations as Bis‐GMA substitutes in heat curing resin composites. In spite of its lower reactivity, only BACET was able to substitute Bis‐GMA, due to its high solubility in the TEGDMA comonomer. Resin formulations containing nanosized silica and the mixture Bis‐GMA/TEGDMA or BACET/TEGDMA were prepared in order to compare physical and chemical properties. Water sorption, solubility, and flexural strength were found statistically similar for both formulations. However, flexural modulus was lower and double bond conversion was higher for the BACET resin, which could make it appropriate for its potential use in dental resin composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41487.     

Synthesis and Photopolymerizations of New Crosslinkers for Dental Applications

Summary: Five new crosslinkers for use in dental composites were synthesized. Four are based on TBHMA: 1 via reaction of TBBr and Bisphenol A; 2 by hydrolysis of t‐butyl groups of the first monomer to give a diacid derivative; 3 by conversion of the first monomer to an amide derivative using benzyl amine; 4 by conversion of the first monomer to amide derivative using APTES. The AHM‐based monomer 5 was synthesized from the Michael addition of APTES to AHM. The photopolymerization behaviors of the synthesized monomers with Bis‐GMA, TEGDMA and HEMA were investigated using photodifferential scanning calorimetry at 40 °C using DMPA as photoinitiator. The polymerization rates and degrees of conversion for mixtures of any of the monomers 1 – 4 with Bis‐GMA:TEGDMA were found to be similar to Bis‐GMA:TEGDMA, higher than Bis‐GMA:HEMA, and also higher than mixtures with Bis‐GMA:HEMA. The incorporation of TBHMA‐based monomers into the conventional resin mixture (Bis‐GMA and TEGDMA) reduced the polymerization shrinkages. Monomer 5 and its mixtures polymerized much faster and to higher degrees of conversion than the other investigated systems, however, this system exhibited the largest volume shrinkage.

Structures of some of the new crosslinkers synthesized.     

Properties of 2,2‐Bis[p‐(2′‐hydroxy‐3′‐methacryloxy propoxy)phenyl]propane/Isobornyl (Meth)acrylate copolymers

Isobornyl acrylate (IBOA) and isobornyl methacrylate (IBOMA) were used to replace triethylene glycol dimethacrylate (TEGDMA) as reactive diluents in dental restorative materials. Photopolymerization behaviors of mixtures of IBO(M)A and 2,2‐bis[p‐(2′‐hydroxy‐3′‐methacryloxy propoxy)phenyl]propane (Bis‐GMA) were investigated by Fourier transform infrared spectroscopy. The degree of conversion, volume shrinkage, contact angle, water sorption, water solubility, flexural strength, and modulus values of the Bis‐GMA/IBO(M)A formulations were measured and compared with those of a Bis‐GMA/TEGDMA formulation. The results illustrate that the degree of conversion, volume shrinkage, contact angle, water sorption, flexural strength, and modulus values of the Bis‐GMA/IBO(M)A systems were all lower than those of the Bis‐GMA/TEGDMA system; the water solubility values of the Bis‐GMA/IBO(M)A systems were higher than that of the Bis‐GMA/TEGDMA system. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Biobased isosorbide methacrylate monomer as an alternative to bisphenol A glycerolate dimethacrylate for dental restorative applications

In this study, a new biobased isosorbide urethane methacrylic monomer [isosorbide‐derived urethane dimethacrylate (Is‐UDMA)] was evaluated as a replacement for currently used bisphenol A glycerolate dimethacrylate (Bis‐GMA) based dental restorative materials. Dental composites were prepared at different Is‐UDMA and Bis‐GMA concentrations. For these composites, the photocuring kinetics, volumetric shrinkage, viscoelastic properties, water sorption, and solubility were evaluated. The photocuring kinetics, followed by real‐time IR spectroscopy, showed higher double‐bond conversion (DC) values for the formulations containing the Is‐UDMA monomer; the highest DC (82%) was achieved by the formulation prepared with only the Is‐UDMA monomer. The volumetric shrinkage was reduced to 23.7% as compared with the dental resin formulated with Bis‐GMA. The viscoelastic properties of the formulations containing both Is‐UDMA and Bis‐GMA monomers in a 50:50 composition were superior to the rest of the tested formulations, including those prepared with pure polymers. This behavior was explained in terms of a compromise between crosslinking and rigidity (or flexibility) of the resulting polymer network. A preliminary test on microleakage in a dental enamel demonstrated that the new Is‐UDMA monomer is a potential replacement for the Bis‐GMA monomer in dental restorative materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44591.     

Composite resins based on novel and highly reactive bisglycidyl methacrylate monomers

Three new bisglycidyl monomers; 1,4‐bis((2‐hydroxy‐3‐methacryloxypropoxy) methyl)benzene (MB‐Phe‐OH), 1,4‐bis(2‐hydroxy‐3‐methacryloxypropoxy)2‐cis‐butene (MB‐Cis‐OH), and 1,7‐bis(2‐hydroxy‐3‐methacryloxypropoxy)heptane (MB‐1,7‐OH); were synthesized and used as Bis‐GMA/TEGDMA (bisphenolglycidyl methacrylate/triethylene glycol dimethacrylate) composite resin additives. Flexural properties and double bond conversion of the dental resins composed of silanizated inorganic filler and organic matrices containing new monomers were evaluated. The composite resins formulated, using the monomers MB‐Cis‐OH and MB‐1,7‐OH, have mechanical properties and double bond conversion comparable with those of Bis‐GMA/TEGDMA composite resin used as control. The composite containing the new monomer MB‐Phe‐OH has better flexural properties (flexural strength 65.01 MPa and flexural modulus 5675.91 MPa) than the control composite resin (flexural strength 52.85 MPa and flexural modulus 4879.72 MPa); this could be attributed to the molecular structure of the monomer and its high double bond conversion level of 74.19%. The new bisglycidyl methacrylate monomer MB‐Phe‐OH could be potentially useful in the development of new organic matrices for dental composite resins with high double bond conversion and enhanced mechanical properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40971.     

Effect of polyhedral oligomeric silsesquioxane on water sorption and surface property of Bis‐GMA/TEGDMa composites

2,2‐Bis[4‐(2‐hydroxy‐3‐methacryloxypropoxy)phenyl]propane (Bis‐GMA), one of the most important light‐curable dimethacrylate resins, is widely used as dental restorative material. However, one problem of Bis‐GMA is the high water sorption due to the hydrophilic hydroxyl (–OH) group, resulting in a short life in actual application. In this study, to overcome the drawback stated above, novel organic–inorganic dimethacrylate monomer containing polyhedral oligomeric silsesquioxanes (POSS), Bis‐GMA‐graft‐POSS, is synthesized via the nucleophilic addition reaction of isocyanate functionalized POSS (IPOSS) and pendent hydroxyl group of Bis‐GMA. Then the as‐synthesized Bis‐GMA‐graft‐POSS, of which hydroxyl group was substituted by hydrophobic POSS, is also introduced into the Bis‐GMA/TEGDMA matrix to prepare a series of methacrylate‐based hybrids for dental materials under visible light with camphorquinone and ethyl‐4N,N‐dimethy‐laminobenzoae (EDMAB) as initiator and coinitiator, respectively. Compared to Bis‐GMA/TEGDMA composites, water sorption of modified composites can be significantly reduced with the addition of Bis‐GMA‐graft‐POSS. Moreover, the Bis‐GMA/TEGDMA/POSS hybrids show hydrophobic surfaces, leading to much higher water contact angles than that of Bis‐GMA/TEGDMA composites. The morphology of hybrids containing POSS was furthermore studied by X‐ray diffraction (XRD) analysis and X‐ray photoelectron spectroscopy (XPS). The results show that POSS disperses in the matrix in noncrystalline form and tend to migrate to the surface of the modified composites that lead to the lower water sorption and higher water contact angles. These results are very useful for design of novel methacrylate monomers and clinical application. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Electrospun nano‐scaled glass fiber reinforcement of bis‐GMA/TEGDMA dental composites

The objective of this study was to investigate the electrospun nano‐scaled glass fiber reinforcement of 2,2′‐bis[4‐(methacryloxypropoxy)‐phenyl]‐propane/triethylene glycol dimethacrylate (Bis‐GMA/TEGDMA) dental composites. The hypothesis was that incorporation of the surface‐silanized electrospun nano‐scaled glass fibers into Bis‐GMA/TEGDMA dental composites would result in substantial improvement on mechanical properties. To test the hypothesis, photo‐cured Bis‐GMA/TEGDMA dental composites filled with various mass fractions of surface‐silanized electrospun nano‐scaled glass fibers were systematically fabricated; and their mechanical properties were then evaluated. The results indicated that small mass fraction substitutions (1, 2.5, 5, and 7.5%) of conventional dental filler with the surface‐silanized electrospun nano‐scaled glass fibers, significantly improved the flexural strength, elastic modulus, and work of fracture values of 70% (mass fraction) filled composites, by as much as 44%, 29%, and 66%, respectively. The mechanical properties of the composites could be further improved by optimizing the chemical compositions and the surface treatment methods of the fibers. We envision that the electrospun nano‐scaled glass fibers could be utilized to develop the next generation dental composites, which would be particularly useful for large posterior restorations. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Novel dental composite material reinforced with silane functionalized microsized gypsum filler particles

Gypsum has been recognized as acceptable for human consumption as a dietary source of calcium. During contact with teeth, it releases Ca²⁺ ions needed for remineralization of tooth tissue, and therefore based on the concept of remineralization, gypsum may be a strategic additive for dental restorative materials. Hence, the objective of this study was to develop and characterize a novel dental material reinforced with different weight fraction of micro sized gypsum filler particle. A novel composite material was fabricated using conventional resin matrix consisting of Bisphenol‐A glycidyl methacrylate (Bis‐GMA), tri‐ethylene glycol dimethacrylate (TEGDMA), camphorquinone (CQ) and ethyl 4 dimethyl amino benzoate (EDMAB). Four different compositions were prepared by reinforcing different weight percentage (0–3 wt%) of silane functionalized micro sized gypsum particle. Fourier Transformed Infrared spectroscopy (FT‐IR), Transmission Electron Microscope (TEM) and Thermogravimetric Analysis (TGA) of silane treated filler were used to study the coupling phenomena between filler and resin. Polymerization shrinkage of composites was evaluated using specific gravity method. The Dynamic Mechanical Analysis (DMA) result revealed that the Glass transition temperature was found to be decreased by 15°C compared to unfilled composite. It was also found that the 2 wt% gypsum content recorded the highest value of storage modulus. Simultaneous Thermal Analysis (STA) result revealed that 2 wt% gypsum filled dental composite exhibited maximum thermal stability. The novel dental material exhibited better physical, optical, mechanical, thermal properties and lowest polymerization shrinkage with maximum conversion. POLYM. COMPOS., 38:404–415, 2017. © 2015 Society of Plastics Engineers     

Photopolymerizable bisallylcarbonate and bisacrylic monomers useful in the formulation of dental composite resins and in the crosslinking of methyl methacrylate

Two new bisallylic monomers [allyl p‐allyl carbonate benzoate (ApACBz) and 1,4‐phenylenbis(methylene)diallyl carbonate (1,4‐FMDAC)] and one bisacrylic monomer [1,4‐bis(acryloyloxymethyl)benzene (1,4‐BAMB)] were synthesized and used as crosslinking agents of methyl methacrylate (MMA) at different mass ratios (10, 20, 40, and 50%). All of the obtained copolymers showed improved thermal stability in comparison with that of the MMA homopolymer. Also, ApACBz and 1,4‐FMDAC were used as bisphenol A glycidyl methacrylate (Bis‐GMA) eluents to prepare dental resin composites. When compared to the control, the Bis‐GMA–new eluent composites had a higher double‐bond conversion, a higher solubility (p < 0.05) and a lower flexural strength (p < 0.05), whereas the elastic modulus and water sorption values were not statistically different (p > 0.05). The 1,4‐FMDAC and ApACBz monomers are promising eluents of Bis‐GMA for the preparation of dental composites with high degrees of conversion. In addition, the ApACBz, 1,4‐FMDAC, and 1,4‐BAMB monomers are potentially useful crosslinking agents when polymer networks of poly(methyl methacrylate) with a high thermal stability are desired. The application‐oriented tests of the monomers in dental composite formulations showed a sufficient storage stability, high photocuring activity, excellent crosslinking of MMA, and good thermal and mechanical properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42920.     

Synthesis and photopolymerization of ethylene glycol 3‐morpholine‐propionate methacrylate for potential dental composite application

2,2‐Bis[4‐(2‐hydroxy‐3‐methacryloxypropoxy) phenyl]‐propane (bis‐GMA), triethylene glycol dimethylacrylate (TEGDMA), camphorquinone (CQ), ethyl‐4‐dimethylaminobenzoate (EDMAB), or 2‐(dimethylamine)ethyl methacrylate (DMEM) were composed of the modern dental composite system and acted as resin, diluent, photoinitiator, and coinitiator, respectively. In this study, ethylene glycol 3‐morpholine‐propionate methacrylate (EGMPM) was synthesized via Michael addition reaction to replace both the TEGDMA as a diluent and the nonpolymerizable amine EDMAB as a coinitiator. Mixtures of bis‐GMA/TEGDMA/CQ/EGMPM and bis‐GMA/TEGDMA/CQ/DMEM were found to have almost the same rate of polymerization and reach final double bond conversion at 58%, slightly lower than that of the bis‐GMA/TEGDMA/CQ/EDMAB (63%) and bis‐GMA/EGMPM/CQ (60%) under comparable visible light irradiation conditions. In addition, the results of dynamic mechanical analysis showed that all of the four samples had approximately the same modulus and the glass transition temperature. The water sorption and solubility of bis‐GMA/TEGDMA/CQ with different amines (EDMAB, DMEM, and EGMPM) had almost the same value except that the water sorption of bis‐GMA/EGMPM/CQ was out of the range of the ISO 4049 (2000) standards. The results indicated that EGMPM was potentially a coinitiator for dental composite, because there are no significant differences in photopolymerization characteristic and physical properties when compared with traditional system (bis‐GMA/TEGDMA/CQ/EDMAB). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4589–4594, 2006     

Effects of water on the long‐term properties of Bis‐GMA and silylated‐(Bis‐GMA) polymers

Bis‐GMA (2,2‐bis‐[4‐(2‐hydroxy‐3‐methacryloxypropoxy)phenyl]propane) is a viscous hygroscopic monomer which is used with triethyleneglycol‐dimethacrylate (TEGDMA) for dental restorations. Bis‐GMA was silylated with dimethyl‐isopropyl‐siloxane and further polymerized in order to increase water resistance and viscosity. The viscosity of the silylated monomer, Sil·Bis‐GMA, was 50 times lower than that of the parent monomer. After 1 month in water, poly(Bis‐GMA/TEGDMA) absorbed 2.6% water and the silylated polymer, poly(Sil·Bis‐GMA), only 0.56%. During this process water extracted residual monomer from each polymer. The behavior of water sorption and desorption as a function of time in poly(Sil·Bis‐GMA) was completely different from that shown by poly(Bis‐GMA/TEGDMA). The difference is discussed in terms of diffusion coefficients. Initially, water advancing contact angles (θ_ADV) were 75° and 95°, respectively. After 1 month in water both polymers showed a reduction of about 20° in θ_ADV. In poly(Bis‐GMA/TEGDMA), the reduction in θ_ADV obey to water absorption and bulk plasticization; it showed a reduction of 15°C in glass transition temperature, T_g. In contrast, the reduction in θ_ADV in poly (Sil·Bis‐GMA) obeyed to water adsorption and reorientation of the molecules at the surface in contact with the water phase; it only showed a change of 2°C in T_g. Contact angle hysteresis provided further evidence about plasticization. According to our results poly(Sil·Bis‐GMA) is more stable in water than poly(Bis‐GMA/TEGDMA). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and photopolymerizations of new phosphonated methacrylates from alkyl α‐hydroxymethacrylates and glycidyl methacrylate

Novel aromatic mono‐ and di(phosphonate) or phosphonic acid monomers for use in dental composites were synthesized. Synthesis of monomer 1a involved three steps: (i) reaction of t‐butyl α‐bromomethacrylate (t‐BuBMA) and Bisphenol A, (ii) conversion to diacid chloride derivative using thionyl chloride, (iii) reaction of diacid chloride with diethyl (2‐hydroxyphenyl) phosphonate. Monomer 2a was synthesized from the reaction of 2‐chloromethacryloyl chloride and diethyl (2‐hydroxyphenyl) phosphonate. Synthesis of monomer 3a involved reaction of glycidyl methacrylate (GMA) with diethyl (2‐hydroxyphenyl) phosphonate. Hydrolysis of the phosphonate groups of monomers 1a and 2a with trimethylsilyl bromide (TMSBr) gave monomers 1b and 2b with phosphonic acid functionality, which is intended to improve binding ability of dental composites. The homopolymerization and copolymerization behaviors of the synthesized monomers with (Bis‐GMA) were investigated using photodifferential scanning calorimetry at 40°C with 2,2′‐dimethoxy‐2‐phenyl acetophenone as photoinitiator. The interaction of the monomer 1b with hydroxyapatite (HAP) was investigated using Fourier transform infrared technique. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Dental restorative composites containing methacrylic spiroorthocarbonate monomers as antishrinking matrixes

In this work, the synthesis of two new antishrinking methacrylic monomers of spiroorthocarbonate type, SOC-IP-UDMA and SOC-UDMA, is discussed, along with studies of their performance as polymeric matrix in dental composites. The monomers were photoactive with components of a conventional resin composite. In order to study the photocuring kinetics of these SOC monomers, a real-time test was performed using FTIR spectroscopy. It was found that SOCs promoted higher double bond conversions (DC) than conventional methacrylic monomer bis-GMA (48%), reaching a DC value of 68% for SOC-UDMA and 75% for SOC-IP-UDMA. The shrinkage stress that accompanies curing of dental composites was measured by a universal testing machine. These new monomer SOCs are capable of reducing the shrinkage up to 51.1% and 27.7% for both methacrylic monomers when they were compared with bis-GMA as control. Also, a dynamical mechanical analysis was conducted on the dental composites, obtaining a higher modulus and a range of T _g values from 80 to 100 °C. Others parameters like flexural properties, solubility, and sorption water were determined, obtaining values better than or equal to the parameters established by the standard ISO 4049. These monomers can be considered as alternative matrixes to replace bis - GMA in dental composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47114.     

Fabrication and properties of surface‐modified β‐Si3N4 whiskers reinforced dental resin composites

In this article, three kinds of surface‐modified methods were used to treat β‐Si₃N₄ whiskers before being incorporated into Bis‐GMA/TEGDMA dental resin matrix in order to improve the whiskers' reinforcing effect. The experimental results showed that composites with directly heat‐treated and then silanized β‐Si₃N₄ whiskers had the best reinforcing effect. They had flexural strength of 160 ± 7.0 MPa (mean ± SD; n = 6), compressive strength of 371 ± 1.4 MPa (mean ± SD; n = 5) and HRA of 48.4 ± 0.5(mean ± SD; n = 5), respectively. In addition, water sorption and solubility test demonstrated that the composites were reliable to use as the dental restoration materials. Therefore, the directly heat‐treated and then silanized β‐Si₃N₄ whiskers (better than β‐Si₃N₄ whiskers mixed with SiO₂ nanoparticles or SiO₂ sols) were most suitable fillers to reinforce dental resin composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The mechanical properties of β‐Si3N4 whiskers‐reinforced dental resin composites

The surface‐modified β‐Si₃N₄ whiskers were used as inorganic fillers to reinforce dental resin (Bis‐GMA/TEGDMA) matrix with filler level ranging from 0 to 60 wt %. The experimental results indicated that the fracture strength of the composites increased from 79.85 to 139.8 MPa with increasing the whiskers loading. The compressive strength, elastic modulus, and rockwell hardness all increased monotonously with increasing filler level. Furthermore, thermal cycling did not decrease the fracture strength of the composites. Moreover, the composites showed good biocompatibility to support MG63 cells adhesion and proliferation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40692.     

Study of physicochemical properties of two current commercial dental self‐curing resin composites

The aim of the present work is the study of some physicochemical properties of two current commercial dental self‐curing two component composites, i.e., of Concise? (3M?, Dental Products, St. Paul, USA), and Alfacomp (VOCO GmbH, Germany). Based on their filler type Concise is characterized as “conventional” or “macrofilled” composite and Alfacomp as “hybrid.” The resin matrix of Concise is a copolymer of 2‐bis[4‐2‐hydroxy‐3‐(methacryloxy)‐propyl]phenyl propane (Bis‐GMA)/triethyleneglycol dimethacrylate, while that of Alfacomp a homopolymer of Bis‐GMA. The composites were prepared in accordance with the manufacturers' instructions by mixing equal amounts of the two components at room temperature. The degree of conversion of double bonds of resin matrix during curing was determined in thin film of composites using FTIR transmission spectroscopy. The degree of conversion of Concise and Aflacomp was found to be correspondingly (73.63 ± 4.33)% and (47.75 ± 1.80)% after a day‐polymerization. Sorption, solubility, and volumetric change were determined after storage of composites in water or ethanol/water solution 75 vol % at 37°C (a good food/oral simulating fluid) for 30 days. These properties for both composites were higher in ethanol/water solution than in water. Also these properties for Concise were lower than those for Alfacomp in both liquids. Thermal stability of composites was studied by thermogravimetric analysis which performed in air atmosphere from 50 to 800°C. This analysis of composites showed the degradation of their resin matrix in three steps. The organic resin content of Concise was found to be 18.0% w/w and that of Alfacomp 20.1% w/w. Concise showed generally better properties than Alfacomp. This behavior must due to the differences in the chemical structure of the organic resin matrix and the type of inorganic filler. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of a dimethacrylates monomer with low shrinkage and water sorption for dental application

In this study, a dimethacrylates monomer 1,3-bis[2-(4-(2′-hydroxy-3′-methacryloyloxy-propoxy)phenyl)-2propyl]benzene (BMPB) was synthesized to replace 2,2-bis[4-(2′-hydroxy-3′-methacryloyloxy-propoxy)phenyl]propane (Bis-GMA) as one component of dental restorative material with the aim of reducing polymerization shrinkage and water sorption. The structure of BMPB was confirmed by FTIR, ¹H-NMR, and elemental analysis. Double bond conversion, polymerization shrinkage, contact angle, water sorption, solubility, flexural strength, and flexural modulus of BMPB/tri(ethylene glycol) dimethacrylate (TEGDMA) based resin were measured. Bis-GMA/TEGDMA based resin was used as reference. The results illustrated that double bond conversion, polymerization shrinkage, water sorption, and solubility of BMPB/TEGDMA were lower than that of Bis-GMA/TEGDMA (P < 0.05). BMPB/TEGDMA had the same flexural strength with Bis-GMA/TEGDMA (P > 0.05), but higher flexural modulus (P < 0.05). Therefore, BMPB could possibly replace Bis-GMA as one component of dental restorative materials with the advantages of similar mechanical properties, being slightly more hydrophobic but presenting less shrinkage. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effects of composition and extrusion parameters on the morphological development and rheological properties of PP/PC blends. Co-continuity investigation

In this work, a new dimethacrylate monomer named ??,????-Bis(4-(2??-hydroxy- 3??methacryloyloxy-propoxy)-3,5-dimethylphenyl)-1,4-diisopropyl-benzene (??,????-BHMPDDB) was synthesized to replace 2,2-bis[4-(2??-hydroxy-3??-methacryloyloxy-propoxy)-phenyl]propane (Bis-GMA) as one component of dental composite materials. The structures of ??,????-BHMPDDB and its intermediate product ??,????-Bis(4-oxiranylmethoxy-3,5-dimethylphenyl)-1,4-diisopropylbenzene (??,????-BODDB) were confirmed by FT-IR, ¹H-NMR, and elemental analysis. ??,????-BHMPDDB was mixed with TEGDMA to form a new dental resin, and double bond conversion, polymerization shrinkage, contact angle, water sorption and solubility, flexural strength and modulus before and after water immersion of this new dental resin were studied. Compared with the commonly used Bis-GMA/TEGDMA dental resin, ??,????-BHMPDDB/TEGDMA had higher double bond conversion (60.5?±?0.3?%), lower polymerization shrinkage (5.6?%), and comparable flexural strength before water immersion (94.1?±?3.9?MPa), which made ??,????-BHMPDDB/TEGDMA having potential to replace Bis-GMA/TEGDMA as matrix phase of dental composites materials. However, ??,????-BHMPDDB/TEGDMA also had drawbacks, such as higher water sorption (5.06?±?0.17?%), water solubility (2.37?±?0.1?%), and lower flexural strength after water immersion (71.4?±?14.6?MPa).     

New Diluents for Dental Composites

Five new urethane groups containing monomers 1 – 5 , acetylated glycerol dimethacrylate (AGDMA), and glycerol trimethacrylate (GTMA) are synthesized as alternative diluents to triethylene glycol dimethacrylate (TEGDMA) for dental resins or composites. The synthesized monomers are characterized by means of ¹H NMR, ¹³C NMR, and IR spectroscopy. The secondary acrylamide group containing hybrid monomers 1 and 2 are solids. However, the monomers 3 – 5 , AGDMA and GTMA are colorless and relatively low‐viscosity liquids. They are not mutagenic in the Ames test and show a lower cytotoxicity and a lower polymerization shrinkage compared to TEGDMA. The tertiary amide group containing crosslinker 3 shows a significantly higher photopolymerization rate compared to that of TEGDMA in the presence of the monomolecular Ge‐based photoinitiator Ivocerin. The synthesized diluents are evaluated in experimental dental formulations for resins, cements, and direct filling composites using a conventional binary camphorquinone/amine photoinitiator.