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1.
J Nanosci Nanotechnol ; 16(2): 1450-3, 2016 Feb.
Article in English | MEDLINE | ID: mdl-27433603

ABSTRACT

A functional dental restorative system with antimicrobial properties was developed using zeolite (ZE) nanoparticles (NPs) as a drug delivery carrier. ZE NPs loaded with chlorhexidine (CHX) were prepared using the ionic immobilization method. The resulting CHX-loaded ZE NPs were then incorporated into commercial dental glass ionomer cement (GIC). The average size of the CHX-loaded ZE NPs was about 100 to 200 nm, and the NPs were dispersed homogeneously in the GIC. The in vitro release profile of encapsulated GIC containing CHX showed an early release burst of approximately 30% of the total CHX by day 7, whereas GIC containing CHX-loaded ZE NPs showed a sustained release of CHX without the early release burst in a 4-week immersion study. The agar diffusion test results showed that the GIC incorporated with CHX-loaded ZE NPs showed a larger growth inhibition zone of Streptococcus mutans than GIC alone, indicating that this innovative delivery platform potently imparted antimicrobial activity to the GIC. Moreover, these findings suggest that a range of antimicrobial drugs that inhibit the growth of oral bacteria can be incorporated efficiently into dental GIC using CHX-loaded ZE NPs.


Subject(s)
Anti-Infective Agents , Chlorhexidine , Glass Ionomer Cements , Nanoparticles/chemistry , Streptococcus mutans/growth & development , Zeolites , Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacokinetics , Anti-Infective Agents/pharmacology , Chlorhexidine/chemistry , Chlorhexidine/pharmacokinetics , Chlorhexidine/pharmacology , Delayed-Action Preparations/chemistry , Delayed-Action Preparations/pharmacokinetics , Delayed-Action Preparations/pharmacology , Glass Ionomer Cements/chemistry , Glass Ionomer Cements/pharmacokinetics , Glass Ionomer Cements/pharmacology , Zeolites/chemistry , Zeolites/pharmacokinetics , Zeolites/pharmacology
2.
J Nanosci Nanotechnol ; 16(2): 1883-6, 2016 Feb.
Article in English | MEDLINE | ID: mdl-27433692

ABSTRACT

A simple and scalable surface modification treatment is demonstrated, in which nano- and microscale features are introduced into the surface of titanium (Ti) substrates by means of a novel and eco-friendly oxidative aqueous solution composed of hydrogen peroxide (H202) and sodium bicarbonate (NaHCO3). By immersing mirror-polished Ti discs in an aqueous mixture of 30 wt% H2O2/5 wt% NaHCO3 at 23 +/- 3 degrees C for 4 h, it was confirmed that this mixture is capable of generating microscale topographies on Ti surfaces. It also simultaneously formed nanochannels that were regularly arranged in a comb-like pattern on the Ti surface, thus forming a hierarchical surface structure. Further, these nano/micro-textured Ti surfaces showed great surface roughness and excellent wettability when compared with control Ti surfaces. This study demonstrates that a H2O2/NaHCO3 mixture can be effectively utilized to create reproducible nano/microscale topographies on Ti implant surfaces, thus providing an economical new oxidative solution that may be used effectively and safely as a Ti surface modification treatment.

3.
Int J Oral Sci ; 8(1): 54-60, 2016 Mar 30.
Article in English | MEDLINE | ID: mdl-27025266

ABSTRACT

Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Deionized water (control) and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth (110) were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 °C. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers' microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ν1, ν3 phosphate contour: the ratio of the height amplitude of ν3 PO4 to that of ν1 PO4 (Method 1) and the shift of the ν3 PO4 peak to a higher wavenumber (Method 2). The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy (P<0.001). Method 1 was the most sensitive to these changes, followed by surface hardness change measurements and Method 2. This study suggests that ATR-FTIR spectroscopy is potentially advantageous over the microhardness test as a simple, non-destructive, sensitive technique for the quantification of enamel erosion.


Subject(s)
Spectroscopy, Fourier Transform Infrared/methods , Tooth Erosion/pathology , Animals , Beverages , Cattle , Hardness , Hydrogen-Ion Concentration , In Vitro Techniques , Sensitivity and Specificity , Surface Properties
4.
Materials (Basel) ; 9(7)2016 Jul 20.
Article in English | MEDLINE | ID: mdl-28773718

ABSTRACT

The microstructures and mechanical properties of cobalt-chromium (Co-Cr) alloys produced by three CAD/CAM-based processing techniques were investigated in comparison with those produced by the traditional casting technique. Four groups of disc- (microstructures) or dumbbell- (mechanical properties) specimens made of Co-Cr alloys were prepared using casting (CS), milling (ML), selective laser melting (SLM), and milling/post-sintering (ML/PS). For each technique, the corresponding commercial alloy material was used. The microstructures of the specimens were evaluated via X-ray diffractometry, optical and scanning electron microscopy with energy-dispersive X-ray spectroscopy, and electron backscattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test according to ISO 22674 (n = 6). The microstructure of the alloys was strongly influenced by the manufacturing processes. Overall, the SLM group showed superior mechanical properties, the ML/PS group being nearly comparable. The mechanical properties of the ML group were inferior to those of the CS group. The microstructures and mechanical properties of Co-Cr alloys were greatly dependent on the manufacturing technique as well as the chemical composition. The SLM and ML/PS techniques may be considered promising alternatives to the Co-Cr alloy casting process.

5.
Artif Cells Nanomed Biotechnol ; 44(1): 277-84, 2016.
Article in English | MEDLINE | ID: mdl-25111051

ABSTRACT

Hydroxyapatite (HA), the main mineral component of bones and teeth, was synthesized by using the reaction between calcium nitrate tetrahydrate Ca(NO3)2∙4H2O and diammonium hydrogen phosphate (NH4)2HPO4 (DAHP) with a chemical precipitation method. The objective of this study is to utilize novel inorganic-organic nanocomposites for biomedical applications. HA is an inorganic component (75% w) and chitosan, alginate and albumin (Egg white) are organic components of nanocomposites (25% w). Nanocomposites were prepared in deionized water solutions, at room temperature, using a mechanical and magnetic stirrer for 48 h. The microstructure and morphology of sintered n-HAP were tested at different preheating temperature and laser sintering speed with scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR).


Subject(s)
Biocompatible Materials/chemical synthesis , Dental Materials/chemical synthesis , Durapatite/chemical synthesis , Nanocomposites/chemistry , Albumins/chemistry , Albumins/pharmacology , Alginates/chemistry , Alginates/pharmacology , Biocompatible Materials/pharmacology , Calcium Compounds/chemistry , Cell Line, Tumor , Cell Survival/drug effects , Chemical Precipitation , Chitosan/chemistry , Chitosan/pharmacology , Dental Materials/pharmacology , Durapatite/pharmacology , Fibroblasts/cytology , Fibroblasts/drug effects , Glucuronic Acid/chemistry , Glucuronic Acid/pharmacology , Hexuronic Acids/chemistry , Hexuronic Acids/pharmacology , Humans , Materials Testing , Microscopy, Electron, Scanning , Nanocomposites/ultrastructure , Nitrates/chemistry , Phosphates/chemistry , Spectroscopy, Fourier Transform Infrared
6.
J Nanosci Nanotechnol ; 15(8): 5593-6, 2015 Aug.
Article in English | MEDLINE | ID: mdl-26369123

ABSTRACT

Plasma treatments are becoming a popular method for modifying the characteristics of a range of substrate surfaces. Atmospheric pressure plasma (APP) is cost-efficient, safe and simple compared to high-pressure plasma. This study examined the effects of a low-temperature APP treatment of a hydroxyapatite (HA)-coated Ti (HA-Ti) surface. The APP treatment made the HA-Ti surfaces more hydrophilic without changing surface morphologies. The APP-treated HA-Ti (APP-HA-Ti) surface showed enhanced cell spreading, cell proliferation, and alkaline phosphatase (ALP) levels with more developed cellular networks, and the formed extracellular matrix (ECM) was fused perfectly with the HA substrate than that on the HA-Ti surface. In conclusion, an APP treatment is a potential surface-modifying method that can enhance the cell affinity at the early stages in vitro.


Subject(s)
Durapatite/chemistry , Nanoparticles/chemistry , Osteoblasts/cytology , Plasma Gases/chemistry , Prostheses and Implants , Titanium/chemistry , Adsorption , Animals , Atmospheric Pressure , Bone Substitutes/chemical synthesis , Cell Adhesion/physiology , Cell Line , Cell Proliferation/physiology , Cell Survival/physiology , Coated Materials, Biocompatible/chemical synthesis , Materials Testing , Mice , Nanoparticles/ultrastructure , Osteoblasts/physiology , Particle Size , Surface Properties
7.
J Nanosci Nanotechnol ; 15(7): 4851-4, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26373046

ABSTRACT

Self-assembled monolayers of thiols (RSH), which are key elements in nanoscience and nanotechnology, have been used to link a range of materials to planar gold surfaces or gold nanoparticles. In this study, the adhesive performance of mercapto silane systems to dental noble metal alloys was evaluated in vitro and compared with that of commercial dental primers. Dental gold-palladium-platinum (Au-Pd-Pt), gold-palladium-silver (Au-Pd-Ag), and palladium-silver (Pd-Ag) alloys were used as the bonding substrates after air-abrasion (sandblasting). One of the following primers was applied to each alloy: (1) no primer treatment (control), (2) three commer- cial primers: V-Primer, Metal Primer II, and M.L. Primer, and (3) two experimental silane primer systems: 2-step application with 3-mercaptopropyltrimethoxysilane (SPS) (1.0 wt%) and then 3-methacryloxypropyltrimethoxysilane (MPS) (1.0 wt%), and a silane blend consisting of SPS and MPS (both 1.0 wt%). Composite resin cylinders with a diameter of 2.38 mm were bonded to the surfaces and irradiated for 40 sec using a curing light. After storage in water at 37 °C for 24 h, all the bonded specimens were thermocycled 5000 times before the shear bond strength test. Regardless of the alloy type, the mercapto silane systems (both the 2-step and blend systems) consistently showed superior bonding performance than the commercial primers. Contact angle analysis of the primed surfaces indicated that higher resin bond strengths were produced on more hydrophilic alloy surfaces. These novel mercapto silane systems are a promising alternative for improving resin bonding to dental noble metal alloys.


Subject(s)
Dental Alloys/chemistry , Resins, Synthetic/chemistry , Silanes/chemistry , Sulfhydryl Compounds/chemistry , Gold/chemistry , Palladium/chemistry , Platinum/chemistry
8.
J Nanosci Nanotechnol ; 15(1): 130-3, 2015 Jan.
Article in English | MEDLINE | ID: mdl-26328316

ABSTRACT

Novel porous biphasic calcium phosphate (BCP) granules incorporated with drug-releasing poly(lactic-co-glycolic acid) (PLGA) nanoparticles were developed as a drug delivery platform for bone regeneration. The charge interaction between the BCP and PLGA nanoparticle surfaces was manipulated to create this combination system. Spherical BCP granules with open micro-channels and PLGA nanoparticles loaded with dexamethasone (DEX) as a model drug were fabricated using a liquid nitrogen method and standard emulsion method, respectively. Polyethyleneimine was coated on the DEX-loaded PLGA nanoparticle surfaces, resulting in a net positively charged surface. Such modified nanoparticles were immobilized physically on the negatively charged BCP granule surfaces. An in vitro evaluation of MG 63 cells cultured for 1 and 2 weeks on the BCP granules containing DEX-loaded PLGA nanoparticles showed greater cell proliferation, differentiation, and a more extensively connected-tissue network than those cultured on the BCP granules alone. This innovative platform for bioactive molecule delivery more potently induced osteogenesis in vitro, which might be exploited in implantable bioceramic bone graft materials for stem cell therapy or improved in vivo performance.


Subject(s)
Biocompatible Materials/chemistry , Calcium Phosphates/chemistry , Drug Carriers/chemistry , Nanoparticles/chemistry , Biocompatible Materials/pharmacology , Calcium Phosphates/pharmacology , Cell Differentiation/drug effects , Cell Line, Tumor , Cell Survival/drug effects , Humans , Lactic Acid , Microscopy, Fluorescence , Osteogenesis , Particle Size , Polyglycolic Acid , Polylactic Acid-Polyglycolic Acid Copolymer , Porosity , Tissue Engineering
9.
J Nanosci Nanotechnol ; 15(1): 134-7, 2015 Jan.
Article in English | MEDLINE | ID: mdl-26328317

ABSTRACT

Plasma treatments are becoming a popular method for modifying the characteristics of a range of substrate surfaces. Atmospheric pressure plasma is cost-efficient, safe and simple compared to high-pressure plasma. This study examined the effects of atmospheric pressure plasma to a titanium (Ti) surface on osteoblast-like cell (osteoblast) spreading and cellular networks. The characteristics of the Ti surface before and after the atmospheric plasma treatment were analyzed by X-ray photoemission spectroscopy (XPS), scanning electron microscopy (SEM), contact angle measurements, and an optical 3D profiling system. The morphology of osteoblasts attached to the Ti surfaces was observed by SEM and confocal laser scanning microscopy. The atmospheric pressure plasma made the Ti surfaces more hydrophilic. The osteoblasts that adhered to the untreated surface were round and spherical, whereas the cells covered a larger surface area on the plasma-treated surface. The plasma-treated Ti surface showed enhanced cell spreading and migration with more developed cellular networks. In conclusion, an atmospheric plasma treatment is a potential surface modifying method that can enhance the initial the cell affinity at the early stages in vitro.


Subject(s)
Cell Proliferation/drug effects , Cell Shape/drug effects , Osteoblasts/drug effects , Plasma Gases/pharmacology , Titanium/chemistry , Animals , Atmospheric Pressure , Cell Line , Mice , Plasma Gases/chemistry , Surface Properties
10.
J Nanosci Nanotechnol ; 15(1): 587-90, 2015 Jan.
Article in English | MEDLINE | ID: mdl-26328408

ABSTRACT

Establishing a strong resin bond to dental zirconia ceramic remains difficult. Previous studies have shown that the conventional application of silane does not work well with zirconia. This paper reports that a silane pre-treatment of dental zirconia ceramic combined with subsequent heat treatment has potential as an adhesive cementation protocol for improving zirconia-resin bonding. Among the various concentrations (0.1 to 16 vol%) of experimental γ-methacryloxypropyltrimethoxysilane (γ-MPTS) primers assessed, the 1% solution was found to be the most effective in terms of the shear bond strength of the resin cement to dental zirconia ceramic. A high shear bond strength (approx. 30 MPa) was obtained when zirconia specimens were pre-treated with this primer and then heat-treated in a furnace for 60 min at 150 degrees C. Heat treatment appeared to remove the hydrophilic constituents from the silane film formed on the zirconia ceramic surface and accelerate the condensation reactions between the silanol groups of the hydrolyzed silane molecules at the zirconia/resin interface, finally making a more desirable surface for bonding with resin. This estimation was supported by Fourier transform infrared spectroscopy of the silanes prepared in this study.


Subject(s)
Ceramics/chemistry , Methacrylates/chemistry , Nanoparticles/chemistry , Silanes/chemistry , Zirconium/chemistry , Dental Bonding , Hot Temperature , Resins, Synthetic , Shear Strength , Surface Properties
11.
Int J Prosthodont ; 28(4): 396-8, 2015.
Article in English | MEDLINE | ID: mdl-26218024

ABSTRACT

A preliminary tensile test was performed to evaluate the mechanical properties of cobalt-chromium (Co-Cr) alloys fabricated by three new manufacturing processes: metal milling, milling for soft metal, and rapid prototyping (n=6). For comparison, the three alloy materials were also used to fabricate specimens by a casting procedure. In all groups tested, the proof strength and elongation were over 500 MPa and 2%, respectively. The milled soft alloy in particular showed a substantially greater elongation, whereas the alloy fabricated by rapid prototyping exhibited a higher proof strength.


Subject(s)
Chromium Alloys/chemistry , Cobalt/chemistry , Materials Testing , Humans , Microscopy, Electron, Scanning
12.
J Adv Prosthodont ; 7(2): 85-92, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25932305

ABSTRACT

PURPOSE: This study aimed to investigate the efficacy of cleaning solutions on saliva-contaminated zirconia in comparison to air-abrasion in terms of resin bonding. MATERIALS AND METHODS: For saliva-contaminated airabraded zirconia, seven cleaning methods)-no contamination (NC), water-spray rinsing (WS), additional airabrasion (AA), and cleaning with four solutions (Ivoclean [IC]; 1.0 wt% sodium dodecyl sulfate [SDS], 1.0 wt% hydrogen peroxide [HP], and 1.0 wt% sodium hypochlorite [SHC])-were tested. The zirconia surfaces for each group were characterized using various analytical techniques. Three bonded resin (Panavia F 2.0) cylinders (bonding area: 4.5 mm(2)) were made on one zirconia disk specimen using the Ultradent jig method [four disks (12 cylinders)/group; a total of 28 disks]. After 5,000 thermocycling, all specimens were subjected to a shear bond strength test with a crosshead speed of 1.0 mm/minute. The fractured surfaces were observed using an optical and scanning electron microscope (SEM). RESULTS: Contact angle measurements showed that groups NC, AA, IC, and SHC had hydrophilic surfaces. The X-ray photoelectron spectroscopy (XPS) analysis showed similar elemental distributions between group AA and groups IC and SHC. Groups IC and SHC showed statistically similar bond strengths to groups NC and AA (P>.05), but not groups SDS and HP (P<.05). For groups WS, SDS, and HP, blister-like bubble formations were observed on the surfaces under SEM. CONCLUSION: Within the limitations of this in vitro study, some of the cleaning solutions (IC or SHC) were effective in removing saliva contamination and enhancing the resin bond strength.

13.
Eur J Orthod ; 37(5): 550-5, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25548147

ABSTRACT

OBJECTIVE: To test the null hypothesis that neither the flexural properties of orthodontic adhesive resins nor the enamel pre-treatment methods would affect metal bracket debonding behaviours, including enamel fracture. MATERIALS AND METHODS: A dimethacrylate-based resin (Transbond XT, TX) and two methyl methacrylate (MMA)-based resins (Super-Bond C&B, SB; an experimental light-cured resin, EXP) were tested. Flexural strength and flexural modulus for each resin were measured by a three-point-bending test. Metal brackets were bonded to human enamel pretreated with total-etch (TE) or self-etch adhesive using one of the three resins (a total of six groups, n = 15). After 24 hours of storage in water at 37°C, a shear bond strength (SBS) test was performed using the wire loop method. After debonding, remaining resin on the enamel surfaces and occurrence of enamel fracture were assessed. Statistical significance was set at P < 0.05. RESULTS: The two MMA resins exhibited substantially lower flexural strength and modulus values than the TX resin. The mean SBS values of all groups (10.15-11.09MPa) were statistically equivalent to one another (P > 0.05), except for the TE-TX group (13.51MPa, P < 0.05). The two EXP groups showed less resin remnant. Only in the two TX groups were enamel fractures observed (three cases for each group). LIMITATIONS: The results were drawn only from ex vivo experiments. CONCLUSIONS: The hypothesis is rejected. This study suggests that a more flexible MMA resin is favourable for avoiding enamel fracture during metal bracket debonding.


Subject(s)
Dental Debonding/adverse effects , Dental Enamel/injuries , Orthodontic Brackets , Resin Cements/chemistry , Tooth Fractures/etiology , Acid Etching, Dental/methods , Boron Compounds/chemistry , Composite Resins/chemistry , Dental Alloys/chemistry , Dental Stress Analysis , Elastic Modulus , Humans , Materials Testing , Methacrylates/chemistry , Methylmethacrylates/chemistry , Pliability , Polymethyl Methacrylate/chemistry , Random Allocation , Shear Strength , Stress, Mechanical , Surface Properties , Temperature , Time Factors , Water/chemistry
14.
Materials (Basel) ; 8(3): 850-866, 2015 Mar 02.
Article in English | MEDLINE | ID: mdl-28787975

ABSTRACT

This in vitro study was conducted to evaluate the shear bond strength of "non-self-adhesive" resin to dental zirconia etched with hydrofluoric acid (HF) at room temperature and to compare it to that of air-abraded zirconia. Sintered zirconia plates were air-abraded (control) or etched with 10%, 20%, or 30% HF for either 5 or 30 min. After cleaning, the surfaces were characterized using various analytical techniques. Three resin cylinders (Duo-Link) were bonded to each treated plate. All bonded specimens were stored in water at 37 °C for 24 h, and then half of them were additionally thermocycled 5000 times prior to the shear bond-strength tests (n = 12). The formation of micro- and nano-porosities on the etched surfaces increased with increasing concentration and application time of the HF solution. The surface wettability of zirconia also increased with increasing surface roughness. Higher concentrations and longer application times of the HF solution produced higher bond-strength values. Infiltration of the resin into the micro- and nano-porosities was observed by scanning electron microscopy. This in vitro study suggests that HF slowly etches zirconia ceramic surfaces at room temperature, thereby improving the resin-zirconia bond strength by the formation of retentive sites.

15.
Materials (Basel) ; 8(3): 1150-1161, 2015 Mar 16.
Article in English | MEDLINE | ID: mdl-28787993

ABSTRACT

In this study, type I collagen was coated onto unmodified and modified microporous biphasic calcium phosphate (BCP) scaffolds. Surface characterization using a scanning electron microscope (SEM) and a surface goniometer confirmed the modification of the BCP coating. The quantity of the collagen coating was investigated using Sirius Red staining, and quantitative assessment of the collagen coating showed no significant differences between the two groups. MG63 cells were used to evaluate cell proliferation and ALP activity on the modified BCP scaffolds. The modified microporous surfaces showed low contact angles and large surface areas, which enhanced cell spreading and proliferation. Coating of the BCP scaffolds with type I collagen led to enhanced cell-material interactions and improved MG63 functions, such as spreading, proliferation, and differentiation. The micropore/collagen-coated scaffold showed the highest rate of cell response. These results indicate that a combination of micropores and collagen enhances cellular function on bioengineered bone allograft tissue.

16.
Acta Odontol Scand ; 72(8): 954-62, 2014 Nov.
Article in English | MEDLINE | ID: mdl-24922092

ABSTRACT

OBJECTIVE: This study investigated the effect of different drying methods of dentin surface on the bonding efficacy of self-adhesive resin cements (SRCs). MATERIALS AND METHODS: Three SRCs (RelyX U200, RU; Maxcem Elite, ME; and BisCem, BC) and one resin-modified glass ionomer cement (RelyX Luting 2, RL) were used. The characteristics of the materials were evaluated using thermogravimetric analysis and surface roughness and contact angle measurements. Human dentin surfaces were finished with 600-grit silicon carbide paper and assigned to three groups according to these drying methods: ethanol dehydration, drying by waiting for 10 s after blot-drying and blot-drying. The four cements were used for luting composite overlays to the dried dentin. After 24 h storage at 37°C and 100% relative humidity, stick-shaped specimens with a cross-sectional area of 0.8 mm(2) were prepared and stressed to failure in tension at a crosshead speed of 0.5 mm/min (n = 27). Failure modes of fractured specimens were assessed by optical and scanning electron microscopy. RESULTS: RL was the most hydrophilic, followed by BC and ME and then RU. All the luting cements luted to ethanol-dehydrated dentin showed zero bond strengths. For the three SRCs, drying by waiting produced higher microtensile bond strengths than blot-drying. RU showed the best bonding performance in the above two dentin conditions. RL showed significantly higher bond strength in blot-drying condition than in drying-by-waiting (p < 0.001). CONCLUSIONS: This study suggests that dentin surface moisture has a crucial effect on the bond strength of SRCs.


Subject(s)
Dental Bonding , Dentin/ultrastructure , Resin Cements/chemistry , Composite Resins/chemistry , Dental Materials/chemistry , Dental Stress Analysis/instrumentation , Dentin-Bonding Agents/chemistry , Desiccation , Ethanol/chemistry , Glass Ionomer Cements/chemistry , Humans , Humidity , Materials Testing , Microscopy, Electron, Scanning , Solvents/chemistry , Spectroscopy, Fourier Transform Infrared/methods , Stress, Mechanical , Surface Properties , Temperature , Tensile Strength , Time Factors , Wettability
17.
Biomed Res Int ; 2014: 914739, 2014.
Article in English | MEDLINE | ID: mdl-24779020

ABSTRACT

Dental modeling resins have been developed for use in areas where highly precise resin structures are needed. The manufacturers claim that these polymethyl methacrylate/methyl methacrylate (PMMA/MMA) resins show little or no shrinkage after polymerization. This study examined the polymerization shrinkage of five dental modeling resins as well as one temporary PMMA/MMA resin (control). The morphology and the particle size of the prepolymerized PMMA powders were investigated by scanning electron microscopy and laser diffraction particle size analysis, respectively. Linear polymerization shrinkage strains of the resins were monitored for 20 minutes using a custom-made linometer, and the final values (at 20 minutes) were converted into volumetric shrinkages. The final volumetric shrinkage values for the modeling resins were statistically similar (P > 0.05) or significantly larger (P < 0.05) than that of the control resin and were related to the polymerization kinetics (P < 0.05) rather than the PMMA bead size (P = 0.335). Therefore, the optimal control of the polymerization kinetics seems to be more important for producing high-precision resin structures rather than the use of dental modeling resins.


Subject(s)
Acrylic Resins/chemistry , Models, Dental , Polymethyl Methacrylate/chemistry , Elasticity , Humans , Kinetics , Microscopy, Electron, Scanning , Polymerization , Surface Properties
18.
J Med Food ; 17(1): 135-41, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24456364

ABSTRACT

Soybean is an essential food ingredient that contains a class of organic compounds known as isoflavones. It is also well known that several plant agglutinins interfere with bacterial adherence to smooth surfaces. However, little is known about the effects of soybean extracts or genistein (a purified isoflavone from soybean) on bacterial biofilm formation. We evaluated the effects of soybean (Glycine max) extracts, including fermented soybean and genistein, on streptococcal agglutination and attachment onto stainless steel orthodontic wire. After cultivating streptococci in biofilm medium containing soybean extracts and orthodontic wire, the viable bacteria attached to the wire were counted. Phase-contrast microscopy and scanning electron microscopy (SEM) analyses were conducted to evaluate bacterial agglutination and attachment. Our study showed that soybean extracts induce agglutination between streptococci, which results in bacterial precipitation. Conversely, viable bacterial counting and SEM image analysis of Streptococcus mutans attached to the orthodontic wire show that bacterial attachment decreases significantly when soybean extracts were added. However, there was no significant change in pre-attached S. mutans biofilm in response to soybean. A possible explanation for these results is that increased agglutination of planktonic streptococci by soybean extracts results in inhibition of bacterial attachment onto the orthodontic wire.


Subject(s)
Bacterial Adhesion/drug effects , Biofilms/drug effects , Glycine max/chemistry , Orthodontic Wires/microbiology , Plant Extracts/pharmacology , Streptococcus mutans/physiology , Streptococcus mutans/drug effects , Streptococcus mutans/growth & development
19.
Angle Orthod ; 84(4): 680-6, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24308530

ABSTRACT

OBJECTIVE: To test the hypothesis that there are no differences in mutans streptococci (MS) adhesion between esthetic and metallic orthodontic arch wires based on their surface characteristics. MATERIALS AND METHODS: Surface roughness (Ra) and apparent surface free energy (SFE) were measured for six wires-four esthetic, one nickel-titanium (NiTi), and one stainless-steel (SS)-using profilometry and dynamic contact angle analysis, respectively. The amount of MS (Streptococcus mutans and Streptococcus sobrinus) adhering to the wires was quantified using the colony-counting method. The surfaces, coating layers, and MS adhesion were also observed by scanning electron microscopy. Statistical significance was set at P < .05. RESULTS: The Ra values of the esthetic wires were significantly different from one another depending on the coating method (P < .05). The NiTi wire showed the highest SFE, followed by the SS wire and then the four esthetic wires. The NiTi wires produced a significantly higher MS adhesion than did the SS wires (P < .05). The esthetic wires showed significantly lower MS adhesions than did the NiTi wire (P < .05). Pearson correlation analyses found moderate significant positive correlations between the SFE and the S mutans and S sobrinus adhesions (r  =  .636/.427, P < .001/P  =  .001, respectively). CONCLUSIONS: The hypothesis is rejected. This study indicates that some esthetic coatings on NiTi alloy might reduce MS adhesion in vitro in the short term.


Subject(s)
Bacterial Adhesion/physiology , Coated Materials, Biocompatible/chemistry , Dental Alloys/chemistry , Nickel/chemistry , Orthodontic Wires/microbiology , Stainless Steel/chemistry , Streptococcus mutans/physiology , Streptococcus sobrinus/physiology , Titanium/chemistry , Bacterial Load , Biopolymers/chemistry , Epoxy Resins/chemistry , Gold Alloys/chemistry , Humans , Materials Testing , Microscopy, Electron, Scanning , Rhodium/chemistry , Silver/chemistry , Surface Properties , Surface Tension , Time Factors , Wettability
20.
J Nanosci Nanotechnol ; 14(11): 8422-6, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25958539

ABSTRACT

We developed a simple and highly efficient method for delivery from titanium (Ti) surfaces using albumin nanoparticle carriers. A Ti disc with a resorbable blasting media surface was used as a metal implant with a localized drug delivery structure. Human serum albumin (HSA) nanoparticles loaded with chlorhexidine (CHX) diacetate salt hydrate as the model drug were fabricated using a desolvation technique. The CHX-loaded HSA nanoparticles produced were cross linked with glutaraldehyde (GA). The nanoparticles were pre-coated with positively-charged polyethylenimine (PEI) molecules and then immobilized via electrical interactions on the negatively charged Ti disc surface. Our results suggested that the PEI-coated HSA nanoparticles loaded with CHX (PEI-CHX-HSA) were incorporated successfully and well-dispersed on the Ti disc surfaces. The agar diffusion test on the Ti surface treated with PEI-CHX-HSA nanoparticles showed a larger growth inhibition zone of Streptococcus mutans versus the control Ti surface, suggesting that this innovative delivery platform imparts potent antibacterial activity to the Ti surface. Thus, CHX, which inhibits the growth of oral bacteria, can be efficiently incorporated onto Ti surfaces by using HSA nanoparticles.


Subject(s)
Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/chemistry , Nanoparticles/chemistry , Serum Albumin/chemistry , Titanium/chemistry , Anti-Bacterial Agents/pharmacokinetics , Chlorhexidine/administration & dosage , Chlorhexidine/chemistry , Chlorhexidine/pharmacokinetics , Drug Delivery Systems/methods , Humans , Nanoparticles/administration & dosage , Serum Albumin/administration & dosage , Streptococcus mutans/drug effects , Surface Properties
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