Slumping tendency and rheological property of flowable composites / 대한치과보존학회지

The aim of this study was to develop a method for measuring the slumping resistance of flowable resin composites and to evaluate the efficacy using rheological methodology. Five commercial flowable composites (Aelitefil flow:AF, Filtek flow:FF, DenFil flow:DF, Tetric flow:TF and Revolution:RV) were used. Same volume of composites in a syringe was extruded on a glass slide using a custom-made loading device. The resin composites were allowed to slump for 10 seconds at 25degrees C and light cured. The aspect ratio (height/diameter) of cone or dome shaped specimen was measured for estimating the slumping tendency of composites. The complex viscosity of each composite was measured by a dynamic oscillatory shear test as a function of angular frequency using a rheometer. To compare the slumping tendency of composites, one way-ANOVA and Turkey's post hoc test was performed for the aspect ratio at 95% confidence level. Regression analysis was performed to investigate the relationship between the complex viscosity and the aspect ratio. The results were as follows. 1. Slumping tendency based on the aspect ratio varied among the five materials (AF < FF < DF < TF < RV). 2. Flowable composites exhibited pseudoplasticity in which the complex viscosity decreased with increasing frequency (shear rate). AF was the most significant, RV the least. 3. The slumping tendency was strongly related with the complex viscosity. Slumping resistance increased with increasing the complex viscosity. The slumping tendency could be quantified by measuring the aspect ratio of slumped flowable composites. This method may be applicable to evaluate the clinical handling characteristics of flowable composites.

Anterior esthetic improvement through orthodontic extrusive remodeling and single-unit implantation in a fractured upper lateral incisor with alveolar bone loss: A case report / 대한치과보존학회지

The treatment of esthetic areas with single-tooth implants represents a new challenge for the clinician. In 1993, a modification of the forced eruption technique, called "orthodontic extrusive remodelling," was proposed as a way to augment both soft- and hard-tissue profiles at potential implant sites. This case report describes augmentation of the coronal soft and hard tissues around a fractured maxillary lateral incisor associated with alveolar bone loss, which was achieved by forced orthodontic extrusion before implant placement. Through these procedures we could reconstruct esthetics and function in a hopeless tooth diagnosed with subgingival root fracture by trauma.

Development of nano-fluid movement measuring device and its application to hydrodynamic analysis of dentinal fluid / 대한치과보존학회지

This study was aimed to develop an instrument for real-time measurement of fluid conductance and to investigate the hydrodynamics of dentinal fluid. The instrument consisted of three parts; (1) a glass capillary and a photo sensor for detection of fluid movement, (2) a servo-motor, a lead screw and a ball nut for tracking of fluid movement, (3) a rotary encoder and software for data processing. To observe the blocking effect of dentinal fluid movement, oxalate gel and self-etch adhesive agent were used. BisBlock (Bisco) and Clearfil SE Bond (Kuraray) were applied to the occlusal dentin surface of extracted human teeth. Using this new device, the fluid movement was measured and compared between before and after each agent was applied. The instrument was able to measure dentinal fluid movement with a high resolution (0.196 nL) and the flow occurred with a rate of 0.84 to 15.2 nL/s before treatment. After BisBlock or Clearfil SE Bond was used, the fluid movement was decreased by 39.8 to 89.6%.

The Effect on Age, Body Weight, Height, Body Mass Index and Smoking to Coagulation Factor VII, VIII and Fibrinogen in Pilots

BACKGROUND: The pilots with cardiovascular events have a possibility for a risk of suffering from sudden incapacitation which is closely related to flying safety. The coagulation factors such as fibrinogen, factor VII, and factor VIII are possibly related to cardiovascular events. Several studies for general population have shown that an increase of those coagulation factors with age, a correlation of Factor VII and fibrinogen with BMI, and of fibrinogen with smoking. However, this study is to find out whether pilots' age, body weight, body mass index (BMI) and smoking are related to the baseline measurement of coagulation factor VII, factor VIII and fibrinogen. METHOD: Samples were taken from 21 pilots from Asiana Airlines: 11 smokers and 10 non-smokers. In order to measure the relationship between age, body weight, BMI, and the coagulation factors, Pearson correlation was used in this analysis. Independent two sampled t-test was used to analyze the correlation between smoking and the coagulation factors. RESULTS: Mean age, mean height, mean body weight and mean BMI of pilots were examined: 38 years, 171.81 cm, 70.67 Kg and 23.94 Kg/m(2). Mean fibrinogen, mean factor VII, and mean factor VIII were also obtained: 236.0 mg/dl, 92.93%, and 60.16%. The coagulation factor VII, factor VIII and fibrinogen were not significant related to age, body weight, BMI, smoking of pilots. CONCLUSION: This study has no correlation between age, body weight, BMI, smoking and the coagulation factors because the age of this study does not have pilots with over 60 years old and healthy behaviors (e.g., exercise, smoking, drinking, etc.) of most pilots are relatively well.

Prognosis and Complications of Depressed Skull Fracture

Complications such as infection, seizure, or intracranial hemorrhage are relatively common after depressed skull fractures. However, indications, methods, and efficacy of the surgical treatment are controversial. This study includes 113 patients with depressed skull fractures who were treated at Soonchunhyang University Chonan Hospital between 1989 and 1992. Methods of treatment, complications, and the prognosis were retrospectively collected and the prognostic factors were analysed. Depressed skull fracture was common below the age of 20 years(38%). Male to female ration was 5.3:1. Traffic injury was the most common of depressed skull fracture(68.1%). Glasgow coma score(GCS) on admission was 13-15 in 52%, 9-12 in 18.6%, and closed in 32%. Intracranial injury was accompanied in 43%. The frontal area was the most common site of depression(53%), and the parietal region was the next(28%). In 65% of open fractures and 28% of closed ones, the lesions were surgically corrected. Cranitomy with primary reconstruction was the most common operative procedure. The mean hospital stay was 26 days in surgically treated patients, and it was 17 days in conservatively managed patients. Prophylactic anticonvulsants were administered in 43%. Seizures occured in 6.2%, and infections were encountered in 3.5%. The outcome was favorable(good recovery and moderate disability) in 80% and the mortality rate was 16%. The outcome was better when the GCS on admission was high(P<0.005), the pupillary response was normal(P<0.005), and the lesion was treated by surgery(P<0.005). Seizures were more common when the GCS was low(P<0.005). Although infections were developed in surgically treated patients only, this difference lacked a statistical significance.