PURPOSE: The purpose of this study was to measure the color of low viscosity bulk-fill resin with a capping layer and to compare it with the color of microhybrid composite resin. MATERIALS AND METHODS: A low viscosity bulk-fill resin (SDR) and microhybrid composite resin of shade A2 (A2) or A3 (A3) were fabricated to 4 mm thickness and light cured for 20 seconds. CIE L*a*b* values of the resin specimens were measured with a colorimeter. Then shade A2 and A3 microhybrid composite resin was capped over low viscosity bulk-fill resins in 2 mm thickness (SA2, SA3). The resin specimens were light cured for 20 seconds and the color was measured and analyzed (n = 10). Color differences (DeltaE) between SA2 and A2, SA3 and A3 were also calculated. RESULTS: L* value was highest in SDR followed by SA2 and SA3. L* value of A2 and A3 was the lowest. a* value was lowest in SDR followed by SA2 and SA3, and A2 and A3 was the highest. b* value was lowest in SDR followed by A2 and SA2, and A3 and SA3 was the highest. DeltaE between A2 and SA2 (DeltaE = 3.4), and that between A3 and SA3 (DeltaE = 3.1) was lower than the perceptible color difference threshold of DeltaE = 3.7. CONCLUSION: DeltaE between low viscosity bulk-fill resin with a capping layer and microhybrid resin was lower than the perceptible color difference threshold.
Viscosity*

The evaluation of serum viscosity contributes to the diagnosis of some hematopathology, cardiopathology. A study on 303 healthy persons with ages of 18-81 in Hanoi was carried out to determine the Vietnamese serum viscosity. The results have shown that the serum viscosity found in the normal people was 9.180.47 (1.52-2.45). There is no significant different of the serum viscosity between men and women. The serum viscosity is gradually increased as increased age.
Viscosity ; serum

In order to compare the accuracy of impression technique using the addition silicone putty and improved heavy body material, impression were taken for the natural 6 maxillary anterior teeth, and for the metal mast model that has full arch shape with 4 cylindrical abutment teeth, Marginal gingiva was retracted by routine method using retraction cord, and two techniques were tried to compare the length of impression materials in the gingival sulcus. This was aimed to see the effect of viscosity and hydraulic pressure of impression materials for the subgingival impression. Impressions for the full arch-shaped metal master model were taken to compare the linear stability of the different impression materials and their related techniques. The conclusions were as belows : 1. The one-step impression technique showed longer extension of impression material in gingival sulcus than two-step impression technique. 2. High viscosity and hydraulic pressure of impression material were useful to take subgingival impression. 3. There was no statistically significant difference for the two-dimensional accuracy of impression technique, but two-step technique showed better trend than one-step technique.
Gingiva ; Silicones ; Tooth ; Viscosity

The purpose of the present study is to measure the viscosity of liquid in the capillary tube viscometer using the unsteady flow concept. The capillary tube viscometer is consisted of a small cylindrical reservoir, capillary tubes, and the mass flow rate measuring system interfaced with computer. Two capillary tubes with 1.152 and 3.002 mm (inner diameter) are used to determine the diameter effects on the viscosity measurements. The instantaneous shear rate and gravitational driving force in the capillary tube are determined by measuring the mass flow rate through the capillary tube instantaneously. The measured viscosities of water and aqueous Separan solution as the blood analogue fluid are in good agreement with the reported experimental data.
Capillaries* ; Viscosity* ; Water

The objectiveness of this study was to evaluate whether low-viscosity composite can bond effectively to dentin surface without bonding resin. The low-viscosity composites being 50wt% filler content were made by the inclusion of bonding resin of two self-etching systems(Clearfil SE Bond, Unifil Bond) varied with contents as 0, 10, 20, 30, 40, 50wt%. Exposed dentin surfaces of extracted 3rd molars are used. Dentin bond strengths were measured. The tests were carried out with a micro-shear device placed testing machine at a CHS of 1mm/min after a low-viscosity composite was filled into an iris cut from micro tygon tubing with internal diameter approximately 0.8mm and height of 1.0mm. 1. Flexural strength and modulus was increased with the addition of bonding resin. 2. Micro-shear bond strength to dentin was improved according to content of bonding resin irrespective of applying or not bonding resin in bonding procedure, and that of Clearfil SE Bond groups was higher than Unifil Bond. 3. There were no significant difference whether use of each bonding resin in bonding procedure for S-40, S-50, U-50(p>0.05). 4. In SEM examination, resin was well infiltrated into dentin after primed with self-etching primer only for S-50 and U-50 in spite of the formation of thinner hybrid layer. Low viscosity composite including some functional monomer may be used as dentin bonding resin without an intermediary bonding agent. It makes a simplified bonding procedure and foresees the possibility of self-adhesive restorative material.
Dentin* ; Iris ; Molar ; Viscosity

By studying the blood viscosity from 313 healthy people, 90 patients with hypertension, 20 patients with cerebral vascular accident (CVA) and 9 patients with polycythemia Vera (PV). The authors found that: The blood viscosity of the health people is from 3.21-5.19. The blood viscosity of the patients with hypertension is from 3.38-5.82. There was no difference from the viscosity of the health people (p>0.01). The blood viscosity of the patients with CVA is from 4.43-7.13; and of the patients with PV is from 6.31-7.87; Both of them are significantly difference from the viscosity of the healthy people (p<0.05 and p<0.01 respectively).
Blood Viscosity ; epidemiology ; blood

The objective of the current study is to investigate the effect of physical vibration on blood viscosity. The "capillary tube viscometer concept" is applied to measure blood viscosity. Blood viscosity can be measured at the minimum shear rate of 12 s(-1) by the capillary tube viscometer. To examine the effect of physical vibration on blood viscosity, the vibrations are produced by contact with an electronic speaker. The frequencies of vibration are varied from 0 to 1000 Hz. The experimental results show that blood viscosity can be effectively reduced by applying vibration. Blood viscosity decreases as much as 10~12 % by applying vibration.
Blood Viscosity ; Capillaries ; Vibration

Malignant tumor have hypoxic cell fraction, which makes radio-resistant and hypoxia in tumor is a result from the blood flow decrease caused by increase in blood flow resistance. Blood viscosity increase is major factor of increased blood flow resistance and it could be attributed to the decrease in blood deformability index. For the evaluation of the change of blood viscosity and blood deformability in oral squamous cell carcinoma, we perform the test of the change of those factors between the normal control group and oral squamous cell carcinoma cell patient group. Relative viscosity measured against distilled water was 5.25+/-0.14 for normal control group, and 5.78+/-0.26 for the SCC patient group and there was statistical significance between the groups. However, there was no significant difference between the groups in blood viscosity between the groups by tumor size (T1+T2 vs T3+T4). Also, there was no significant difference between the normal control group and SCC patient group in blood deformability index and between the groups by tumor size (T1+T2 vs T3+T4). Increase in blood viscosity was confirmed with this study and it can be postulated that modification blood viscosity might contribute to decrease of hypoxia fraction in oral squamous cell carcinoma, thus improve the effect of radiotherapy and it can be assumed that the main factor of blood viscosity increase is not decrease of blood deformability in oral squamous cell carcinoma.
Anoxia ; Blood Viscosity* ; Carcinoma, Squamous Cell* ; Humans ; Radiotherapy ; Viscosity ; Water

As an optimal quality of the restorations, there should be a least amount of seating discrepancy between the casting and abutment teeth. However, high viscosity of the cementing medium and its resulting thickness ay prevent complete seating of the restoration. The use of die spacing material provides adequate internal relief for the cementing medium. The purpose of this study is to compare the thickness of three commonly used die spacing materials. Materials and Methods : Stone plates were fabricated and divided into 12 sections to be painted with die spacers. Tru-Fit, Whip-Mix and Belle de St. Claire die spacer which are commonly used in dental practice were tested in this study. Each die spacers were painted layer by layer according to the manufacturer's recommendation. The average thickness of each die spacers were measured with light microscope(x100) and compared between them. Results and Conclusions: A silver-colored Tru-Fit die spacer has the lowest value of thickness without statistical significance comparing with a gold-colored Tru-Fit die spacer and a gray layer of Whip-Mix die spacer has the highest value of thickness without any statistical significance comparing with Belle de St. Claire die spacer. Three and four layers of Tru-Fit die spacer and two layers of Whip-Mix and Belle de St. Claire die spacers seem to be in the acceptable range of thickness of 25 to 45micrometer for optimal seating of the restorations. The standard experimental design and method should be further evaluated for more consistent and objective results.
Paint ; Research Design ; Tooth ; Viscosity

Although percutaneous abscess drainage has become and accepted alternative from of therapy for selected patients with abscess, it is well known that there are several factors in the failure of adequate drainage such as pre-and post- procedural management, technique itself, various features of abscess, and selection and application of catheters. Among these factors, we made an experiment about drain efficacy of commonly used various catheters with different viscosities of water-glycerin solution under the two different pressure gradients. The experimental values of flow rate were lower than than the calculated values. An efficacy of experimental value was 4-14%. Because the inner diameter of fittings and stopcocks was usually smaller than the inner diameter of catheters, these factors also affected the drain efficacy. Finally, we though that it will be very helpful to the treatment of patients as well as to study about the catheter drainage, if the drain efficacy of individual catheters has been notified.
Abscess ; Catheters* ; Drainage ; Humans ; Viscosity