No abstract available.
Acrylic Resins ; Breast ; Hydrogel

The purpose of this study was to investigate the physical effect of tissue conditioner on polymerized acrylic resins. Surface hardness and transverse strength were measured for evaluating physical effect of tissue conditioner on polymerized acrylic resins. 1) To measured surface hardness, the resin specimens(65x10x10mm size) of each resin material were made, applied tissue conditioner, stored in 37degrees C water for 1week, and changed tissue conditioner every week for 3 weeks. Surface hardness was measured every week with Shore hardness tester for 4 weeks. 2) To measured transverse strength, the resin specimens(65x10x3mm size & 65x10x1.5mm) of each resin material were made. The specimens were divided into four groups, and measured by universial testing machine. Group I (control group) : The resin specimens were stored in 37degrees C water for 5 weeks. Group II : The resin specimens were stored in 37degrees C water for 5 weeks, and relined in 1.5mm thickness with same resin. Group III : The resin specimens were stored in 37degrees C water for 1 week, applied tissue conditioner in 1.5mm thickness, stored in 37degrees C water for 1 week, changed tissue conditioner and water every week for 3 weeks, removed tissue conditioner, reduced 1.5mm thickness from resin surface which was applied tissue conditioner, and relined in 1.5mm thickness with same resin. The following conclusions were obtained : 1. Surface hardness changes of Vertex RS and Vertex SC were not different significantly (p>0.01). 2. Surface hardness of K-33, Tokuso rebase, and Kooliner were decreased (p<0.01). 3. With the exception of Kooliner, transverse strength of all resin materials between control group and groups which applied with tissue conditioner were not different significantly (p>0.01).
Acrylic Resins* ; Hardness ; Hardness Tests ; Polymers* ; Water

A variety of dermal fillers is available and has been used for soft tissue augmentation. Fillers used in rhinoplasty are minimally invasive and can help patients who are concerned with surgical procedures and recovery time. Nevertheless, there have been many reports about unsatisfactory results and complications using fillers for augmentation rhinoplasty. The unsatisfactory results include ill defined lateral aspect of nose, widening of injected filler, migration, and overcorrection. Therefore, the filler materials should be used according to its properties and nasal anatomical characteristics.
Acrylic Resins ; Humans ; Hyaluronic Acid ; Nose ; Rhinoplasty

This study aims to improve the solubility and bioavailability of daidzein by preparing the β-cyclodextrin-daidzein/PEG_(20000)/Carbomer_(940) nanocrystals. Specifically, the nanocrystals were prepared with daidzein as a model drug, PEG_(20000), Carbomer_(940), and NaOH as a plasticizer, a gelling agent, and a crosslinking agent, respectively. A two-step method was employed to prepare the β-cyclodextrin-daidzein/PEG_(20000)/Carbomer_(940) nanocystals. First, the insoluble drug daidzein was embedded in β-cyclodextrin to form inclusion complexes, which were then encapsulated in the PEG_(20000)/Carbomer_(940) nanocrystals. The optimal mass fraction of NaOH was determined as 0.8% by the drug release rate, redispersability, SEM morphology, encapsulation rate, and drug loading. The inclusion status of daidzein nanocrystals was determined by Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TGA), and X-ray diffraction(XRD) analysis to verify the feasibility of the preparation. The prepared nanocrystals showed the average Zeta potential of(-30.77±0.15)mV and(-37.47±0.64)mV and the particle sizes of(333.60±3.81)nm and(544.60±7.66)nm before and after daidzein loading, respectively. The irregular distribution of nanocrystals before and after daidzein loading was observed under SEM. The redispersability experiment showed high dispersion efficiency of the nanocrystals. The in vitro dissolution rate of nanocrystals in intestinal fluid was significantly faster than that of daidzein, and followed the first-order drug release kinetic model. XRD, FTIR, and TGA were employed to determine the polycrystalline properties, drug loading, and thermal stability of the nanocrystals before and after drug loading. The nanocrystals loaded with daidzein demonstrated obvious antibacterial effect. The nanocrystals had more significant inhibitory effects on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa than daidzein because of the improved solubility of daidzein. The prepared nanocrystals can significantly increase the dissolution rate and oral bioavailability of the insoluble drug daidzein.
Sodium Hydroxide ; Acrylic Resins ; Escherichia coli ; Nanoparticles

This study investigated the effect of intermittent polymerization on the rate of polymerization shrinkage and cuspal deflection in composite resins. The linear polymerization shrinkage of each composite was measured using the custom-made linometer along with the light shutter specially devised to block the light at the previously determined interval. Samples were divided into 4 groups by light curing method; Group 1) continuous light (60s with light on); Group 2) intermittent light (cycles of 3s with 2s light on & 1s with light off for 90s); Group 3) intermittent light (cycles of 2s with 1s light on & 1s with light off for 120s); Group 4) intermittent light (cycles of 3s with 1s light on & 2s with light off for 180s). The amount of linear polymerization shrinkage was measured and its maximum rate (Rmax) and peak time (PT) in the first 15 seconds were calculated. For the measurement of cuspal deflection of teeth, MOD cavities were prepared in 10 extracted maxillary premolars. Reduction in the intercuspal distance was measured by the custom-made cuspal deflection measuring machine. ANOVA analysis was used for the comparison of the light curing groups and t-test was used to determine significant difference between the composite resins. Pyramid showed the greater amount of polymerization shrinkage than Heliomolar (p < 0.05). There was no significant difference in the linear polymerization shrinkage among the groups. The Rmax was group 4 < 3, 2 < 1 in Heliomolar and group 3 < 4 < 2, 1 in Pyramid (p < 0.05). Pyramid demonstrated greater cuspal deflection than Heliomolar. The cuspal deflection in Heliomolar was group 4 < 3 < 2, 1 and group 4, 3 < 2, 1 in Pyramid (p < 0.05). It was concluded that the reduced rate of polymerization shrinkage by intermittent polymerization can help to decrease the cuspal deflection.
Acrylic Resins ; Bicuspid ; Composite Resins ; Light ; Polymerization ; Polymers ; Polyurethanes ; Tooth

The purpose of this study was to evaluate the effect of thickness, filling methods and curing methods on the polymerization of dual cured core materials by means of microhardness test. Two dual cured core materials, MultiCore Flow (Ivoclar Vivadent AG, Schaan, Liechtenstein) and Bis-Core (Bisco Inc., Schaumburg, IL, USA) were used in this study. 2 mm (bulky filled), 4 mm (bulky filled), 6 mm (bulky and incrementally filled) and 8 mm (bulky and incrementally filled)-thickness specimens were prepared with light cure or self cure mode. After storage at 37degrees C for 24 hours, the Knoop hardness values (KHN) of top and bottom surfaces were measured and the microhardness ratio of top and bottom surfaces was calculated. The data were analyzed using one-way ANOVA and Scheffe multiple comparison test, with alpha = 0.05. The effect of thickness on the polymerization of dual cured composites showed material specific results. In 2, 4 and 6 mm groups, the KHN of two materials were not affected by thickness. However, in 8 mm group of MultiCore Flow, the KHN of the bottom surface was lower than those of other groups (p < 0.05). The effect of filling methods on the polymerization of dual cured composites was different by their thickness or materials. In 6 mm thickness, there was no significant difference between bulk and incremental filling groups. In 8 mm thickness, Bis-Core showed no significant difference between groups. However, in MultiCore Flow, the microhardness ratio of bulk filling group was lower than that of incremental filling group (p < 0.05). The effect of curing methods on the polymerization of dual cured composites showed material specific results. In Bis-Core, the KHN of dual cured group were higher than those of self cured group at both surfaces (p < 0.05). However, in MultiCore Flow, the results were not similar at both surfaces. At the top surface, dual cured group showed higher KHN than that of self cured group (p < 0.05). However, in the bottom surface, dual cured group showed lower value than that of self cured group (p < 0.05).
Acrylic Resins ; Composite Resins ; Hardness ; Light ; Methacrylates ; Polymerization ; Polymers ; Polyurethanes

Dental composite resin is a kind of material which has been widely used in dental restoration. Research has found that the influence of residual monomer on the material mechanical, chemical and biological properties cannot be ignored. This paper elaborates these harms of residual monomers. The effects of resin matrix, inorganic filler and initiating system, illumination, secondarily treatment on the degree of conversion were also analyzed. The paper also discusses the effective measures to increase the conversion, and offers theoretical basis for the clinical application and development of composite resin.
Acrylic Resins ; Composite Resins ; Humans ; Light ; Polymers ; Polyurethanes

The acrylic resin was first introduced as denture base materials in 1937 and it is commonly used for denture base fabrication nowadays. Three different curing cycles (Conventional curing cycle, short curing cycle and long curing cycle) and three commercially available heat-activated acrylic resins (Vertex RS, Lucitone 199 and ProBase Hot) were investigated to find the curing cycle and ma-terial that showed the minimum shrinkage of the resin during polymerization process. A brass master mold was fabricated and duplicated by additional silicone impression material. Stone molds were made by pouring of type III dental stone (SILKY-ROCK YELLOW, Whip-Mix, Louisville, Kentucky). It was embedded in the flask. Strain gauge and thermocouple were embedded in the specimen. Strain gauge and thermocouple were connected to signal conditioning amplifier and data was recorded by pre-programmed software. The parameters ESmax (Maximum ex-pansion strain), Sb (Strain measured just before deflasking procedure), Sa (Strain measured just af-ter deflasking procedure) and Sf (Strain measured at the end of the experiment) were measured delta S was calculated from Sb and Sa (delta S=Sb-Sa). In the experiment concerned about materials, the pa-rameters 90-ESmax (Maximum expansion strain measured during early 90 minutes of curing procedure), 180-ESmax (Maximum expansion strain measured from 90 minutes to 180 minutes), Sb, Sa, delta S and Sf were measured and the following conclusions were made. 1. The ESmax value of conventional curing cycle showed the largest value and the 180-ESmax val-ue of Lucitone 199 showed the smallest value. 90-ESmax values showed no significant difference (p<0.05). 2. delta S values of conventional curing cycle showed the positive values. delta S values of short curing cycle and long curing cycle showed the negative values. All three materials cured by conventional curing cycle showed the positive values. 3. The Sf values of long curing cycle and ProBase Hot (cured by conventional curing cycle)showed the smallest values.
Acrylic Resins ; Denture Bases ; Fungi ; Polymerization ; Polymers ; Silicones

The bond failure of resin teeth to denture base resin is one of the failure in prosthodontic treatment. The purpose of this study was to evaluate the bond strength of artificial resin teeth to the denture base resins. Specimens were made with heat curing acrylic resins (Vertex Rs, Lucitone 199) and artificial resin teeth (Tiger, Trubyte biotone, Endura, Orthosit, Trubyte bioform IPN) and the bond strength were measured with testing machine (Zwick, Germany) and the mode of bond failure were observed. The results were as follows; 1. The bond strength of Vertex Rs to artificial resin teeth was the highest in Trubyte biotone, and It was the lowest in Tiger and Trubyte bioform IPN 2. The bond strength of Lucitone 199 to artificial resin teeth were higher in Orthosit and Trubyte bioform IPN than in Tiger and Trubyte biotone. 3. The bond strength of Trubyte biotone to Vertex Rs was higher than to Lucitone 199 and that of the Trubyte bioform IPN to Lucitone 199 was higher than to Vertex Rs. 4. Nearly all bond failures of specimens occured cohesively within the resin teeth.
Acrylic Resins ; Denture Bases* ; Dentures* ; Hot Temperature ; Prosthodontics ; Tigers ; Tooth*

Poly (N-isopropylacrylamide) (PNIPAAm), a temperature-responsive polymer, can be potentially applied to replace enzymes or cell scrapers to recover attached cells. Taking full advantage of this unique function of PNIPAAm, cells can be protected from enzymatic hydrolysis and mechanical treatment, thereby to provide ideal seed cells with high quality for biomedical fields. In this review we describe the method to facilitate cell effective adhesion and rapid detachment on thermoresponsive two dimensional surfaces, including selecting special substrate, introducing hydrophilic group, adjusting reactant ratio, controlling polymer thickness/density, providing appropriate external force, so as to effectively improve adherent cell adaptability to thermoresponsive surfaces, depress the risk of bacterial contamination and reduce the effect of low-temperature treatment on the cells. The three dimensional cell culture systems involved in temperature-sensitive microcarriers, scaffolds and gels were briefly discussed. The application based on the platforms for cell culture was also presented.
Acrylic Resins ; Cell Adhesion ; Cell Culture Techniques ; Temperature