This study helps to clarify conflicting reports by comparing the physical properties and accuracy of complete denture processed by the pack and press technique, continuous-pressure injection technique(SR-Ivocap system) and Mark press technique. The 6 different specimens have been evaluated using the SEM, Impact test, DSC (Differential Scanning Calorimetry) and DMTA(Dynamic Mechanical Thermal Analysis). Each sample was made of SR-Ivocap resin and QC-20 resin by different processing methods. The results were as follows ; 1. As the result of the observation on the fracture surface of resin by use of SEM, sample SR-Ivocap resin cured by continuous pressure injection method showed the most homogeneous structure. This is why molecules in SR-Ivocap resin have no orientation. 2. As the result of the Impact test in order to measure the deformity, fracture energy and impact resistance of resin, the samples with QC-20 acrylic resin and SR-Ivocap resin cured by continuous pressure injection method were exellent. 3. In consequence of measuring alpha-glass transition temperature by use of DSC on the basis of temperature change, the glass transition temperatures of sample QC-20 resin cured by pack and press method and sample SR-Ivocap resin cured by continuous pressure injection method were very similar. Thus volumetric stability could not be evaluated only by glass transition temperature. 4. In comparing volumetric stability data by DMTA, the glass transition temperature(Tg) showed 137.88degrees C at sample QC-20 resin cured by pack and press method and 139.78degrees C at sample SR-Ivocap resin cured by continuous pressure injection method. Therefore sample SR-Ivocap resin cured by continuous pressure injection method seems to be superior to sample QC-20 resin cured by pack and press method in the dimensional stability at high temperature. 5. In comparing storage modulus data by DMTA, the storage modulus of sample SR-Ivocap resin cured by continuous pressure injection method was higher than that of sample QC-20 resin cured by pack and press method. So, sample SR-Ivocap resin cured by continuous pressure injection method seems to be superior to sample QC-20 resin cured by pack and press method in impact strength.
Congenital Abnormalities ; Denture, Complete ; Glass ; Transition Temperature

Adaptation, Physiological ; physiology ; Humans ; Hypothermia ; Physical Examination ; Transition Temperature ; Water

OBJECTIVE: The aim of this research was to evaluate the mechanical properties (MP) and degree of the phase transformation (PT) of martensitic (M-NiTi), austenitic (A-NiTi) and thermodynamic nickel-titanium wire (T-NiTi). METHODS: The samples consisted of 0.016 x 0.022 inch M-NiTi (Nitinol Classic, NC), A-NiTi (Optimalloy, OPTI) and T-NiTi (Neo-Sentalloy, NEO). Differential scanning calorimetry (DSC), three-point bending test, X-ray diffraction (XRD), and microstructure examination were used. Statistical evaluation was undertaken using ANOVA test. RESULTS: In DSC analysis, OPTI and NEO showed two peaks in the heating curves and one peak in the cooling curves. However, NC revealed one single broad and weak peak in the heating and cooling curves. Austenite finishing (Af) temperatures were 19.7degrees C for OPTI, 24.6degrees C for NEO and 52.4degrees C for NC. In the three-point bending test, residual deflection was observed for NC, OPTI and NEO. The load ranges of NC and OPTI were broader and higher than NEO. XRD and microstructure analyses showed that OPTI and NEO had a mixture of martensite and austenite at temperatures below Martensite finishing (Mf). NEO and OPTI showed improved MP and PT behavior than NC. CONCLUSIONS: The mechanical and thermal behaviors of NiTi wire cannot be completely explained by the expected degree of PT because of complicated martensite variants and independent PT induced by heat and stress.
Calorimetry, Differential Scanning ; Dental Alloys ; Heating ; Hot Temperature ; Thermodynamics ; Transition Temperature ; X-Ray Diffraction

PURPOSE: We tried to find out an adequate sol-gel transition temperature of female urethra for the injection of thermosensitive polymer in incontinent patients. We measured the temperatures of three portions of female urethra and bladder. MATERIALS AND METHODS: Total of 53 female incontinent patients participated, excluding those with any kind of infection which could lead to an elevation of body temperature. The basal body temperatures were checked at the axilla, tympanic membrane and mouth. Temperatures of the proximal(U1), middle(U2), distal(U3) urethra and bladder(B) were measured by a digital thermometer under a lithotomy position. We divided our patients into 3 groups which were patients in follicular phase(F), luteal phase(L) and menopause(M). The temperature difference between the 4 portions of the urethra(D1; between U1 and U2, D2; between U2 and U3, D3: between U3 and B), was also analyzed. Statistics was done by the ANOVA of repeated measures, one-way ANOVA and Pearson correlation coefficient. RESULTS: The mean age of the patients was 48.1+/-10.7 years. The mean temperature of B, U1, U2, and U3 groups were 37.1+/-0.25 degreesC, 37.0+/-0.25 degreesC, 36.9+/-0.24 degreesC, and 36.7+/-0.25 degreesC. The mean temperature difference of D1, D2, and D3 were 0.2471+/-0.089 degreesC, 0.079+/-0.066 degreesC and 0.066+/-0.058 degreesC. The Pearson correlation coefficient of D1, D2 and D3 were 0.938, 0.965 and 0.970. This showed there was a constant temperature increase from distal urethra to bladder step by step. The number of patients in F, L and M groups were 25(47.2%), 10(18.9%) and 18(33.9%). There was no significant urethral temperature difference at each point(U1, U2, U3 and B) among these three groups. CONCLUSION: There was a constant temperature increase from distal urethra to bladder step by step. This is a baseline study for female urethra for future clinical study. We suggest that our data can be used as deciding the sol-gel transition temperature for thermosensitive polymer injection into incontinent female urethra.
Axilla ; Basal Bodies ; Body Temperature ; Female ; Humans ; Mouth ; Polymers ; Thermometers ; Transition Temperature ; Tympanic Membrane ; Urethra ; Urinary Bladder*

OBJECTIVEThe purposes of this study were to determine the spectral transmittance of GI-II glass/alumina composites and to explore the effects of different specimen thickness and fining arts of glass infiltration on the transmittance. Data were compared with those of Vita In-Ceram Alumina materials.

METHODSPlate-shaped specimens 12.5 mm in diameter, with 3 thickness (0.5, 1.0, 1.5 mm), 6 color groups for GI-II and 4 color groups for Vita In-Ceram Alumina were fabricated. Specimens of color AL2 for In-Ceram and IG2 for GI-II were selected in the study of relationship between different infiltration arts and transmittance. Five infiltration time duration and three temperatures were studied. A spectrophotometer with standard A light source paralleled light beam 5 mm in diameter and spectra range 380-780 nm was employed to measure the spectral transmittance.

RESULTSThe range of spectral transmittance were 2.7%-4.5% for GI-II and 2.4%-5.2% for Vita In-Ceram Alumina. Transmittance decreased with specimen thickness, but they were not linearly related. Transmittance of GI-II tended to increase and that of Vita In-Ceram Alumina decreased as the infiltration temperature elevated. The transmittance increased with infiltration time less than 4 hours and reduced with prolonged time over 6 hours for both materials.

CONCLUSIONGI-II glass/alumina composite has comparatively lower translucency. Influences of factors as color, thickness and infiltration arts on translucency of restorations should be considered in the clinical selection of the all-ceramic materials.

Aluminum Oxide ; chemistry ; Ceramics ; chemistry ; Dental Materials ; Dental Porcelain ; chemistry ; Glass ; chemistry ; Light ; Spectrophotometry ; Temperature ; Tensile Strength ; Transition Temperature

OBJECTIVES: The purpose of this study was to observe the change in the viscoelastic properties of thermoplasticized injectable root canal filling materials as a function of temperature and to compare the handling characteristics of these materials. MATERIALS AND METHODS: Three commercial gutta perchas and Resilon (Pentron Clinical Technologies) in a pellet form were heated in the Obtura-II system (Obtura Spartan) at 140degrees C and 200degrees C, and the extrusion temperature of the thermoplasticized materials was measured. The viscoelastic properties of the materials as a function of temperature were evaluated using a rheometer. The elastic modulus G', viscous modulus G", loss tangent tandelta, and complex viscosity eta* were determined. The phase transition temperature was determined by both the rheometer and a differential scanning calorimeter (DSC). The consistency of the materials was compared under compacting pressure at 60degrees C and 40degrees C by a squeeze test. RESULTS: The three gutta perchas had dissimilar profiles in viscoelastic properties with varying temperature. The phase transition of softened materials into solidification occurred at 40degrees C to 50degrees C, and the onset temperatures obtained by a rheometer and a DSC were similar to each other. The onset temperature of phase transition and the consistency upon compaction pressure were different among the materials (p < 0.05). Resilon had a rheologically similar pattern to the gutta perchas, and was featured between high and low-flow gutta perchas. CONCLUSIONS: The rheological characteristics of the thermoplasticized root canal filling materials changed under a cooling process. The dissimilar viscoelastic properties among the materials require different handling characteristics during an injecting and compacting procedure.
Elastic Modulus ; Gutta-Percha ; Handling (Psychology) ; Hot Temperature ; Phase Transition ; Root Canal Filling Materials ; Viscosity

OBJECTIVETo establish a rapid, accurate, noninvasive and low cost method for screening MT3243A>G mutation in mitochondrial diabetes.

METHODSBlood, saliva, and urine sediment samples were collected from 6 patients with confirmed mitochondrial diabetes and 50 healthy controls from Shanghai Children's Hospital and Shanghai Sixth People's Hospital. The heterozygosity levels of MT3243A>G mutation in above samples were detected with pyrosequencing, and the data were compared. MT3243A>G mutations were rapidly screened with high resolution melting curve analysis (HRM) in the urine sediment samples of 1070 diabetic patients from 4 communities in Shanghai. Furthermore, pyrosequencing was used to validate the suspected positive samples, and the heterozygosity levels were also quantified.

RESULTSComparative experiments found that heterozygosity of MT3243A>G mutation was 2 to 7 times higher in urine sediment than in saliva and blood samples from the 6 patients with confirmed mitochondrial diabetes. However, the heterozygosity was slightly higher in saliva than blood samples. MT3243A>G mutation was not detected in the 50 healthy controls. Two samples with suspected MT3243A>G mutation were identified in the 1070 urine sediment samples of diabetes patients with HRM screening, which were validated by pyrosequencing. The heterozygosity of MT3243A>G mutation were 33.32% and 14.67% in the urine sediment samples, respectively.

CONCLUSIONUrine sediment samples can be used for rapid screening of MT3243A>G mutation for its ease to collect, noninvasiveness and higher level of heterozygosity. HRM is suitable for rapid screening for mitochondrian mutations for its low cost, while such mutations could be detected with sensitivity and accuracy by pyrosequencing.

DNA, Mitochondrial ; genetics ; Diabetes Mellitus ; genetics ; Heterozygote ; Humans ; Mutation ; Sequence Analysis, DNA ; methods ; Transition Temperature

OBJECTIVETo characterize austenite, martensite and R phase temperatures as well as transition temperature ranges of the commonly used nickel-titanium (NiTi) orthodontic arch wires selected from several manufacturers.

METHODSDifferential scanning calorimetry (DSC) method was used to study the phase transformation temperatures and the phase transition processes of 9 commonly used NiTi alloys (types: 0.406 mm, 0.406 mm x 0.559 mm).

RESULTSThe austenite finish temperatures of A, B, D NiTi wires were 22.4 CT, 21.9 degrees C, 22.5 degrees C, respectively. No phase transformation was detected during oral temperature. It indicated that these types of NiTi wires did not possess shape memory property. For C and H NiTi wires, no phase transformation was detected during the scanning temperature range, suggesting that these two types of wires did not possess shape memory either. The austenite finish temperatures of E, G and I NiTi wires were 34.3 degrees C, 36.6 degrees C, 38.5 degrees C, respectively, which were close to the oral temperature and presented as martensitic-austenitic structures at room temperature, suggesting that the NiTi wires listed above had good shape memory effect. Although F NiTi wire also showed martensitic-austenitic structures at room temperature, its austenite finish temperature (61.5 degrees C) was much higher than oral temperature.

CONCLUSIONSThe transformation phase temperatures and transformation behavior were varied among different NiTi alloys, leading to variability in shape memory effect.

Calorimetry, Differential Scanning ; Dental Alloys ; chemistry ; Materials Testing ; Orthodontic Wires ; Phase Transition ; Temperature

OBJECTIVETo determine the rheological properties of shuanghuanglian in situ gel (SHL-gel) by using dynamic rheological experiments, in order to evaluate its gelling properties shuanghuanglian in situ gel and predict its gelling behavior in vivo.

METHODRheological parameters were determined by scanning of shear rate and frequency at different temperatures. The phase transition process from liquid to semisolid was described by testing of process heating/cooling and acute heating/cooling.

RESULTSHL-gel was Newtonian fluid under the conditions of a phase angle approaching 90 degrees at low temperature or room temperature, with its viscous characteristics dominated. It was shear-thinning pseudoplastic fluid under the conditions of a low phase angle at body temperature, with its elastic characteristics dominated. During the phase transition process, the phase angle delta was getting sharp, with exponential increase of the modulus. The gelling temperature (Tg) was at (35.38 +/- 0.05) degrees C, the phase transition temperature ranged from 33.71 to 37.01%, and phase transition time was 140 s.

CONCLUSIONThe dynamic rheological experiment characterizes the gelling properties of Shuanghuanglian in situ gel so precisely that it can be used as the basis of for in vitro evaluation and quality control of products.

Drugs, Chinese Herbal ; chemistry ; standards ; Phase Transition ; Quality Control ; Rheology ; Temperature ; Viscosity

In order to improve the interfacial bonding strength of hydroxyapatite/polyurethane implanted material and dispersion of hydroxyapatite in the polyurethane matrix, we in the present study synthesized nano-hydroxyapatite/polyurethane composites by in situ polymerization. We then characterized and analyzed the fracture morphology, thermal stability, glass transition temperature and mechanical properties. We seeded MG63 cells on composites to evaluate the cytocompatibility of the composites. In situ polymerization could improve the interfacial bonding strength, ameliorate dispersion of hydroxyapatite in the properties of the composites. After adding 20 wt% hydroxyapatite into the polyurethane, the thermal stability was improved and the glass transition temperatures were increased. The tensile strength and maximum elongation were 6.83 MPa and 861.17%, respectively. Compared with those of pure polyurethane the tensile strength and maximum elongation increased by 236.45% and 143.30%, respectively. The composites were helpful for cell adhesion and proliferation in cultivation.
Biocompatible Materials ; chemistry ; Cell Adhesion ; Cell Line ; Durapatite ; chemistry ; Humans ; Polymerization ; Polyurethanes ; Tensile Strength ; Transition Temperature