PURPOSE: The purpose of this study was to research the properties of some chemically cured methacrylate polymers such as MMA, HEMA, TEG-DMA, bis-GMA, GMA. MATERIAL AND METHOD: 5 kinds of methacrylates were selected and added 2% tertiary amine and benzoyl peroxide to make a chemically curable polymer. 25 micron crushed silicas which are treated with silane were selected as filler, they were added into methacrylate monomer until the consistency did not changed by the load of 500gram. All of the experimental resins were 5 kinds, and a serial test was done with 3 kinds of items including the filler contents, the tensile strength, and the bond strength. The number of specimen were 10 for each group. Filler contents were obtained by reducing the specimens to ashes at 600 degrees C for 1 hour. The specimens with the dimension of 6mm in diameter and 3mm thick were immersed in 37+/-1degrees C distilled water for 24 hours before test, and tensile strength were measured with cross-head speed 1mm/min. Shear bond strength were measured on the specimens attached to bovine enamel etched with 37% phosphoric acid for 1 minute. RESULTS: 1. Maximum filler incorporation was the highest as 75.5% on MMA, and the least as 53.4% on bis- GMA(p<0.0001). 2. The tensile stregth were MMA 141.3, GMA 154.3, TEG-DMA 157.4, bis-GMA 161.4 MPa, and HEMA showed the highest value, 226.9MPa(p=0.0004). 3. The bond strength were GMA 10.1, TEG-DMA 11.7, HEMA 12.2, bis-GMA 13.3 MPa, and MMA showed the highest value, 15.3MPa, however statistical significances were not (p=0.3838). 4. TEG-DMA and HEMA were not different on the aspect of maximum filler contents and shear bond strength(p>0.05). CONCLUSION: HEMA can be used as an another diluent substituting TEG-DMA with the increased strength and with the constant bond strength and the constant filler contents.
Benzoyl Peroxide ; Bisphenol A-Glycidyl Methacrylate ; Dental Enamel ; Methacrylates ; Polymers* ; Silicon Dioxide ; Tensile Strength ; Water

OBJECTIVES: This study investigated the effect of the strength and wetting characteristics of adhesives on the bond strength to dentin. The experimental adhesives containing various ratios of hydrophobic, low-viscosity Bis-M-GMA, with Bis-GMA and TEGDMA, were made and evaluated on the mechanical properties and bond strength to dentin. MATERIALS AND METHODS: Five experimental adhesives formulated with various Bis-GMA/Bis-M-GMA/TEGDMA ratios were evaluated on their viscosity, degree of conversion (DC), flexural strength (FS), and microtensile bond strength (MTBS). The bonded interfaces were evaluated with SEM and the solubility parameter was calculated to understand the wetting characteristics of the adhesives. RESULTS: Although there were no significant differences in the DC between the experimental adhesives at 48 hr after curing (p > 0.05), the experimental adhesives that did not contain Bis-GMA exhibited a lower FS than did those containing Bis-GMA (p < 0.05). The experimental adhesives that had very little to no TEGDMA showed significantly lower MTBS than did those containing a higher content of TEGDMA (p < 0.05). The formers exhibited gaps at the interface between the adhesive layer and the hybrid layer. The solubility parameter of TEGDMA approximated those of the components of the primed dentin, rather than Bis-GMA and Bis-M-GMA. CONCLUSIONS: To achieve a good dentin bond, a strong base monomer, such as Bis-GMA, cannot be completely replaced by Bis-M-GMA for maintaining mechanical strength. For compatible copolymerization between the adhesive and the primed dentin as well as dense cross-linking of the adhesive layer, at least 30% fraction of TEGDMA is also needed.
Adhesives ; Benzhydryl Compounds ; Bisphenol A-Glycidyl Methacrylate ; Chimera ; Dentin ; Methacrylates ; Polyethylene Glycols ; Polymethacrylic Acids ; Solubility ; Viscosity

OBJECTIVE: The aim of this study was to evaluate and compare the shear bond strength (SBS) and failure-mode of orthodontic buttons bonded to erupted and unerupted teeth with conventional and self-etching adhesive systems. METHODS: Eighty-four erupted and 84 unerupted, human third-molar teeth were used. For both groups, the buccal surfaces of each tooth were assigned one of the following type of adhesive systems (n = 12). A, Conventional systems: 1, Transbond XT (3M Unitek, Monrovia, CA, USA); 2, Prime & Bond NT (Dentsply/Caulk, Milford, USA); 3, Single Bond (3M ESPE, Minnesota, USA); and B, Self-etching adhesives; 4, Clearfil SE Bond (Kuraray, Okayama, Japan); 5, Transbond Plus (3M Unitek, Monrovia, CA, USA); 6, Clearfil S3 (Kuraray, Tokyo, Japan); 7, G Bond (GC, Tokyo, Japan). The SBSs of the attachments and the adhesive remnant index (ARI) scores were recorded. Data were analyzed with analysis of variance (ANOVA), independent-sample t-test and chi-square tests. RESULTS: When the SBSs of erupted and unerupted teeth were compared, only the Clearfil-SE Bond and G-Bond were significantly different. Bond strengths of all adhesive systems were higher in unerupted teeth than erupted teeth, except the Single-Bond system. CONCLUSIONS: When using conventional adhesives, bonding to erupted and unerupted teeth may not be significantly different. However, clinicians need to take into consideration the types of self-etching systems before usage.
Adhesives ; Bisphenol A-Glycidyl Methacrylate ; Humans ; Methacrylates ; Minnesota ; Polymethacrylic Acids ; Resin Cements ; Tokyo ; Tooth ; Tooth, Unerupted

PURPOSE: The purpose of this study was to investigate the diametral tensile strength of polymer-based temporary crown and fixed partial denture (FPD) materials, and the change of the diametral tensile strength with time. MATERIAL AND METHODS: One monomethacrylate-based temporary crown and FPD material (Trim) and three dimethacrylate-based ones (Protemp 3 Garant, Temphase, Luxtemp) were investigated. 20 specimens (the empty set 4 mm x 6 mm) were fabricated and randomly divided into two groups (Group I: Immediately, Group II: 1 hour) according to the measurement time after completion of mixing. Universal Testing Machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed using one-way ANOVA, the multiple comparison Scheffe test and independent sample t test (alpha = 0.05). RESULTS: Trim showed severe permanent deformation without an obvious fracture during loading at both times. There were statistically significant differences among the dimethacrylate-based materials. The dimethacrylate-based materials presented an increase in strength from 5 minutes to 1 hour and were as follows: Protemp 3 Garant (23.16 - 37.6 MPa), Temphase (22.27 - 28.08 MPa), Luxatemp (14.46 - 20.59 MPa). Protemp 3 Garant showed the highest value. CONCLUSION: The dimethacrylate-based temporary materials tested were stronger in diametral tensile strength than the monomethacrylate-based one. The diametral tensile strength of the materials investigated increased with time.
Acrylic Resins ; Bisphenol A-Glycidyl Methacrylate ; Collodion ; Composite Resins ; Crowns ; Denture, Partial, Fixed ; Methacrylates ; Polymethacrylic Acids ; Tensile Strength

STATEMENT OF PROBLEM: The degree of conversion may influence the ultimate mechanical and physical properties of provisional crown and fixed partial denture materials. The high levels of the unreacted residual monomer may cause deleterious effect on the properties. PURPOSE: The purpose of this study was to measure the degree of conversion of bis-acrylic based provisional crown and fixed partial denture materials by using an infrared spectroscopic method. MATERIAL AND METHODS: Chemically activated three bis-acrylic based provisional crown and fixed partial denture materials, LuxaTemp [DMG, Hamburg, Germany], fast set TemPhase [Kerr, Orange, CA, USA] and Protemp 3 Garant [3M-ESPE, St Paul, MN, USA], were investigated by Fourier transform infrared spectrometry (FTIR). The FTIR spectra of the materials tested were immediately obtained after mixing. The specimens were stored under dry conditions and at 23 degrees C for 24 hours, and then the spectra of the materials were also obtained. The degree of conversion (percent) was calculated from the spectrum of the absorbance between the aliphatic double bond at 1637 cm-1 and the aromatic double bond at 1608 cm-1 using the baseline method. The data were statistically analyzed using one-way ANOVA and the multiple comparison Scheffe test at the significance level of 0.05. RESULTS: The mean value and standard deviation of the degree of conversion were 52.5 percent +/- 1.1 percent, 50.3 percent +/- 0.8 percent, and 42.3 percent +/- 4.9 percent for LuxaTemp, Protemp 3 Garant and fast set TemPhase, respectively. There was no significant difference between LuxaTemp and Protemp 3 Garant, whereas there was a statistically difference between Protemp 3 Garant and fast set TemPhase, and LuxaTemp and fast set TemPhase (P < .05). CONCLUSION: The degree of conversion of fast set TemPhase was significantly lower than those of the others. The degree of conversion may be correlated with the rate of polymerization.
Acrylic Resins ; Bisphenol A-Glycidyl Methacrylate ; Citrus sinensis ; Composite Resins ; Crowns ; Denture, Partial, Fixed ; Fourier Analysis ; Methacrylates ; Polymerization ; Polymers ; Spectroscopy, Fourier Transform Infrared ; Spectrum Analysis

OBJECTIVETo observe the bonding interface of sclerotic dentin after treated with total-etching system and self-etching system by confocal laser scanning microscope (CLSM).

METHODSA total of 12 maxillary bicuspids with non-caries, natural cervical sclerotic lesions were divided into three groups. The sclerotic dentin was bonded with Single Bond (SB, total-etching adhesive), Clearfil SE Bond (CB, two-step self-etching) and Xeno III (XB, one-step self-etching) according to the manufacturer's instruction. Artificially prepared wedge-shaped lesions made in sound maxillary bicuspids and bonded with same adhesive were used as control. The primer component was labeled with Rhodamine B Isothiocyanate. Hybrid layer and resin tag of dentin bonding interface were observed by CLSM.

RESULTSTwo-way ANVOA revealed significant influence of both the type of dentin and the bonding adhesive systems tested on resin tag and hybrid layer (P<0.05). Resin tag and hybrid layer in total-etching adhesive (SB) were longer and thicker than in self-etching adhesive (CB, XB) whatever in normal dentin or sclerotic dentin, while the resin tag and hybrid layer thickness were similar in two kind self-etching adhesive (P<0.05).

CONCLUSIONThe resin rags were fewer and shorter and the hybrid layers were thinner in sclerotic dentin than in normal dentin. When bonding the same type dentin substrate, the resin rags were shorter and the hybrid layer thinner in used self-etching adhesive than total-etching.

Acid Etching, Dental ; Bisphenol A-Glycidyl Methacrylate ; Dental Bonding ; Dentin ; Dentin, Secondary ; Dentin-Bonding Agents ; Humans ; Methacrylates ; Microscopy, Electron, Scanning ; Resin Cements

OBJECTIVETo evaluate the effects of a zirconia primer and a self-adhesive resin cement on the resin bonding zirconia.

METHODSEighty zirconia blocks were manufactured, alumina-sandblasted, and randomly divided into five groups that received surface-treatments using different resin cements: group C, treated with a conventional bisphenol-A diglycidyl dimethacrylate (Bis-GMA)-based resin cement; group R, treated with a self-adhesive resin cement; group S, silica-coated via a Sol-gel process, conditioned with silane, and then treated with the Bis-GMA-based resin cement; group ZC, conditioned with a zirconia primer (Z-Prime Plus) and subsequently treated with the Bis-GMA-based resin cement; group ZR, conditioned with the zirconia primer and treated with the self-adhesive resin cement. Light-cured composite resin cylinders were prepared and bonded on the prepared zirconia blocks. Half of the specimens in each group were water-stored for 24 hours, whereas the remaining specimens were aged by thermocycling. All specimens were then subjected to shear bond strength (SBS) testing. Fourier transmission infrared (FT-IR) spectroscopy and gas chromatography-mass spectrometry (MS) were performed to characterize the zirconia primer.

RESULTSGroup C presented the lowest SBS, whereas groups R, ZC, and ZR presented the highest values. Thermocycling had no effect on SBS. FT-IR results showed that Z-Prime Plus contained a benzene ring and a carbonyl group. MS analysis showed that Z-Prime Plus contained 2-hydroxyethyl methacrylate, triethylamine.

CONCLUSIONZirconia primer and self-adhesive resin cement increase the resin bonding of zirconia.

Adhesives ; Aluminum Oxide ; Benzhydryl Compounds ; Bisphenol A-Glycidyl Methacrylate ; Composite Resins ; Dental Bonding ; Dental Cements ; Humans ; Methacrylates ; Resin Cements ; Shear Strength ; Silanes ; Spectroscopy, Fourier Transform Infrared ; Zirconium

OBJECTIVES: This study investigated the optimal combination of 3-component photoinitiation system, consisting of CQ, p-octyloxy-phenyl-phenyl iodonium hexafluoroantimonate (OPPI), and 2-dimethylaminoethyl methacrylate (DMAEMA) to increase the degree of conversion of resin monomers, and analyze the effect of the ratio of the photoinitiator to the co-initiator. MATERIALS AND METHODS: Each photoinitiators (CQ and OPP) and co-initiator (DMAEMA) were mixed in three levels with 0.2 wt.% (low concentration, L), 1.0 wt.% (medium concentration, M), and 2.0 wt.% (high concentration, H). A total of nine groups using the Taguchi method were tested according to the following proportion of components in the photoinitiator system: LLL, LMM, LHH, MLM, MMH, MHL, HLH, HML, HHM. Each monomer was polymerized using a quartz-tungsten-halogen curing unit (Demetron 400, USA) for 5, 20, 40, 60, 300 sec and the degree of conversion (DC) was determined at each exposure time using FTIR. RESULTS: Significant differences were found for DC values in groups. MMH group and HHM group exhibited greater initial DC than the others. No significant difference was found with the ratio of the photoinitiators (CQ, OPPI) to the co-initiator (DMAEMA). The concentrations of CQ didn't affect the DC values, but those of OPPI did strongly. CONCLUSIONS: MMH and HHM groups seem to be best ones to get increased DC. MMH group is indicated for bright, translucent color and HHM group is good for dark, opaque colored-resin.
Ethylamines ; Methacrylates ; Polymers ; Terpenes

AIMTo evaluate the interactive effects of different self-adhesive resin cements and tribochemical treatment on bond strength to zirconia.

METHODOLOGYThe following self-adhesive resin cements for bonding two zirconia blocks were evaluated: Maxcem (MA), Smartcem (SM), Rely X Unicem Aplicap (UN), Breeze (BR), Biscem (BI), Set (SE), and Clearfil SA luting (CL). The specimens were grouped according to conditioning as follows: Group 1, polishing with 600 grit polishing paper; Group 2, silica coating with 110 microm Al2O3 particles which modified with silica; and, Group 3, tribochemical treatment--silica coating + silanization. Specimens were stored in distilled water at 37 degrees C for 24 hours before testing shear bond strength.

RESULTSSilica coating and tribochemical treatment significantly increased the bond strength of the MA, UN, BR, BI, SE and CL to zirconia compared to #600 polishing. For both #600 polished and silica coating treatments, MDP-containing self-adhesive resin cement CL had the highest bond strengths to zirconia.

CONCLUSIONApplying silica coating and tribochemical treatment improved the bond strength of self-adhesive resin cement to zirconia, especially for CL.

Aluminum Compounds ; chemistry ; Aluminum Oxide ; chemistry ; Bisphenol A-Glycidyl Methacrylate ; chemistry ; Composite Resins ; chemistry ; Dental Bonding ; methods ; Dental Etching ; methods ; Dental Materials ; chemistry ; Fluorides ; chemistry ; Humans ; Materials Testing ; Methacrylates ; chemistry ; Microscopy, Electron, Scanning ; Polyethylene Glycols ; chemistry ; Polymethacrylic Acids ; chemistry ; Polyurethanes ; chemistry ; Resin Cements ; chemistry ; Shear Strength ; Silanes ; chemistry ; Silicon Compounds ; chemistry ; Silicon Dioxide ; chemistry ; Stress, Mechanical ; Surface Properties ; Tricarboxylic Acids ; chemistry ; Zirconium ; chemistry

OBJECTIVETo analyze chemical mechanism of bonding improvement of zirconia via 10-methacryloyloxydecyl dihydrogen phosphate (MDP) conditioning.

METHODSVarious models were created for tetragonal zirconia crystals, molecular MDP, and MDP complex, and tetragonal zirconia crystal. Thermodynamic methods were used to analyze configuration between MDP and tetragonal zirconia crystal through calculation of their Gibbs free energy values and equilibrium constants.

RESULTSTwo potential configurations (double- and single-coordinate) may occur between MDP and ZrO2 crystal clusters. Thermodynamic calculations showed that -147.761 and -158.073 kJ·mol⁻¹ Gibbs free energy were required to form single- and double-coordinate configurations; their negative signs indicate that reactions for both configurations can occur. Equilibrium constant for single-coordinate configuration was 7.72×10²⁵, which was less than that of double-coordinate configuration (4.95×10²⁷), suggesting that the latter was more stable.

CONCLUSIONSMDP can spontaneously establish a double-coordinate configuration with zirconia.
.

Materials Testing ; Methacrylates ; Phosphates ; Zirconium