Dental composites have improved significantly in physical properties over the past few decades. However, polymerization shrinkage and stress is still the major drawback of composites, limiting its use to selected cases. Much effort has been made to make low shrinking composites to overcome this issue and silorane-based composites have recently been introduced into the market. The aim of this study was to measure the volumetric polymerization shrinkage kinetics of a silorane-based composite and compare it with conventional methacrylate-based composites in order to evaluate its effectiveness in reducing polymerization shrinkage. Five commercial methacrylate-based (Beautifil, Z100, Z250, Z350 and Gradia X) and a silorane-based (P90) composites were investigated. The volumetric change of the composites during light polymerization was detected continuously as buoyancy change in distilled water by means of Archemedes'principle, using a newly made volume shrinkage measurement instrument. The null hypothesis was that there were no differences in polymerization shrinkage, peak polymerization shrinkage rate and peak shrinkage time between the silorane-based composite and methacrylate-based composites. The results were as follows: 1. The shrinkage of silorane-based (P90) composites was the lowest (1.48%), and that of Beautifil composite was the highest (2.80%). There were also significant differences between brands among the methacrylate-based composites. 2. Peak polymerization shrinkage rate was the lowest in P90 (0.13%/s) and the highest in Z100 (0.34%/s). 3. The time to reach peak shrinkage rate of the silorane-based composite (P90) was longer (6.7 s) than those of the methacrylate-based composites (2.4-3.1 s). 4. Peak shrinkage rate showed a strong positive correlation with the product of polymerization shrinkage and the inverse of peak shrinkage time (R = 0.95).
Composite Resins ; Kinetics ; Light ; Polymerization ; Polymers ; Silorane Resins ; Water

Since the introduction of restorative dental composites, their physical properties have been significantly improved. However, polymerization shrinkage is still a major drawback. Many efforts have been made to develop a low shrinking composite, and silorane-based composites have recently been introduced into the market. In addition, many different methods have been developed to measure the polymerization shrinkage. In this study, we developed a new method to measure the linear polymerization shrinkage of composites without direct contact to a specimen using a particle tracking method with computer vision. The shrinkage kinetics of a commercial silorane-based composite (P90) and two conventional methacrylate-based composites (Z250 and Z350) were investigated and compared. The results were as follows: 1. The linear shrinkage of composites was 0.33-1.41%. Shrinkage was lowest for the silorane-based (P90) composite, and highest for the flowable Z350 composite. 2. The new instrument was able to measure the true linear shrinkage of composites in real time without sensitivity to the specimen preparation and geometry.
Kinetics ; Polymerization ; Polymers ; Silorane Resins ; Track and Field ; Vision, Ocular

BACKGROUND: The i-Smart 30 point-of-care (POC) analyzer (i-SENS, Korea) is a compact and portable system used for the analysis of electrolytes (sodium, potassium, chloride) and hematocrit in whole blood samples. In this study, we evaluated the analytical performance of the i-Smart 30 analyzer. METHODS: Precision and sample-related percent carry-over were determined using the quality control materials. Comparison study was performed with the Stat Profile Critical Care Xpress (STP CCX; Nova Biomedical, USA) analyzer using venous whole blood samples. RESULTS: In the precision study, imprecision studies demonstrated within-run and total-run coefficients of variation within 0.5-3.9% and 0.7-4.4%, respectively, for all analytes. A good correlation was found between the i-Smart 30 analyzer and the STP CCX analyzer, except for chloride that showed high intercept. In the study of carry-over, sample-related carry-over for Na+, K+, Cl- and Hct were demonstrated as 0.84%, 0%, 0.86% and 1.56%, respectively. CONCLUSIONS: We conclude that the i-Smart 30 analyzer is suitable for routine use in clinical laboratories, especially where rapid test results are required such as emergency departments, intensive care units, and dialysis units. However, for Cl-, it is necessary that a significant correlation between this analyzer and a reference method should be demonstrated.
Critical Care ; Dialysis ; Electrolytes ; Emergencies ; Hematocrit ; Intensive Care Units ; Point-of-Care Systems ; Potassium ; Quality Control

No abstract available.
Amyloid Neuropathies* ; Amyloid*

BACKGROUND AND OBJECTIVES: This study examined the expressions of p16 and the programmed cell death 1 ligand (PD-L1) in patients with oropharyngeal cancer (OPC) treated with radiotherapy (RT) to identify the correlation between p16 and PD-L1 expression, and to examine the prognostic significance of these markers for OPC patients receiving RT.SUBJECTS AND METHOD: Forty-eight OPC patients diagnosed and treated at a tertiary referral hospital were enrolled in this retrospective analysis. Patients were initially treated with RT or chemoradiotherapy (CRT) with curative intent and completed the planned schedule. Expression of p16 and PD-L1 by primary tumors was evaluated by immunohistochemistry, and results were interpreted separately and dichotomized according to outcome analyses. RESULTS: Of the 48 patients, 25 (52.1%) expressed p16 and 15 (31.3%) expressed PD-L1. Expression of these markers showed a mutual positive correlation (p=0.046). Positive PD-L1 expression was associated with poor complete remission (CR) rates after RT (p=0.040). Positive p16 expression was associated with better recurrence-free survival (RFS) (p=0.004) but not overall survival (OS) (p=0.192). PD-L1 expression showed no independent association with survival (p>0.05); however, PD-L1 expression tended toward poorer RFS, even in p16-positive individuals. CONCLUSION There was a positive correlation between the expression of p16 and PD-L1 in OPCs. PD-L1 expression was associated with poorer CR rates after RT or CRT. PD-L1 alone did not show an association with RFS or OS, but when combined with p16, it tended toward poorer RFS, even in p16-positive cases.

The objective of this study was to compare dentin shear bond strength (DSBS) of dentin bonding agents (DBAs) cured with a plasma arc (PAC) light curing unit (LCU) and those cured with a light emitting diode (LED) LCU. Optical properties were also analyzed for Elipar freelight 2 (3M ESPE); LED LCU, Apollo 95E (DMT Systems); PAC LCU and VIP Junior (Bisco); Halogen LCU. The DBAs used for DSBS test were Scotchbond Multipurpose (3M ESPE), Singlebond 2 (3M ESPE) and Clearfil SE Bond (Kuraray). After DSBS testing, fractured specimens were analyzed for failure modes with SEM. The total irradiance and irradiance between 450 nm and 490 nm of the LCUs were different. LED LCU showed narrow spectral distribution around its peak at 462 nm whereas PAC and Halogen LCU showed a broad spectrum. There were no significant differences in mean shear bond strength among different LCUs (P > 0.05) but were significant differences among different DBAs (P < 0.001).
Dentin ; Dentin-Bonding Agents ; Enzyme Multiplied Immunoassay Technique ; Light ; Plasma ; Resin Cements