Effect of increasing application time of single bottle adhesives to microtensile bond strength of dried dentin / 대한치과보존학회지

The purpose of this study was to evaluate the effect of increasing application time of single bottle adhesives (SBA) to microtensile bond strength (MTBS) of dried dentin. To expose the superficial dentin surfaces, human molars were sectioned perpendicular to the long axis of tooth. 32% phosphoric acid gels were applied for 15s and rinsed. The teeth were randomly assigned to 3 groups ; S group (Single Bond), O group (One-Step), P group (Prime & Bond NT). Each group was divided to 3 subgroups (W: dentin wipe with wet gauge and light cured immediately, D: dentin dried for 30s and light cured immediately, 30: dentin dried for 30s and light cured after applying SBA for 30s). Composite resin was built up on the dentin surface and sectioned to obtain 20 specimens with 1 mm2 cross sectional area and the MTBS was measured. For Single Bond, the mean MTBS of S-W and S-30 group were higher than that of S-D group statistically (P < 0.05). For One-Step, the mean MTBS of O-D group was statistically lower than that of O-W group (P < 0.05). For Prime & Bond NT, the mean MTBS of P-30 group was statistically lower than that of P-D group (P < 0.05).

The influence of the vital bleaching agents on translucency of the bovine enamel / 대한치과보존학회지

This study was done to evaluate whether vital bleaching agents could influence on the translucency of the bovine enamel. The anterior bovine teeth that were extracted one day before and without any gross discoloration were obtained and then were preserved in physiologic saline. 6 mm cylindrical tooth specimens were fabricated with diamond puncher perpendicularly on labial surface of bovine tooth. After embedded in transparent acrylic resin with labial surface being exposed, they were cut to a thickness of 1.2 mm with low speed diamond saw (Isomat, Buehler Co., Lake Bluff, IL, USA). They were smoothly ground to 1 mm thickness of enamel with sandpaper. 24 specimens were randomly divided into 3 groups and control group respectively. Opalescence (10% carbamide peroxide, Ultradent, South Jordan, USA), Rembrandt (10% carbamide peroxide, DenMat, USA) and Opalescence F (15% carbamide peroxide with fluoride, Ultradent, USA) were applied on labial sides of the bovine enamel for 7 days (bleaching agents were reapplied every 24 hours) and the opposite surface was contacted to cotton that soaked in distilled water. The control group was soaked in distilled water. Three stimulus value X, Y and Z were evaluated with colorimeter (Color & Color Differencemeter, Model TC-6FX, Tokyo Denshoku Co., Japan) on the labial surface of all specimen three times on white and black background plate before the bleaching agents were applied and on 3rd, 5th and 7th day after applied. The degree of translucency was normally assessed by measuring the inverse property, opacity (contrast ratio). 10% Opalescence, 15% Opalescence-F, and control group showed no significant variation in the translucency of bovine enamel, However Rembrandt decreased the translucency of it (p < 0.01).

Two cases of upper airway obstruction masquerading as asthma: One tracheal adenoid cystic carcinoma, the other foreign body aspiration / 천식및알레르기

Reversible airway obstruction and wheezing are typical features of bronchial asthma, but these features may also be observed in other conditions. However, the inclusion of these conditions in the differential diagnosis of asthma-like symptoms in adults is often neglected, resulting in a correct diagnosis being made after months of unsuccessful treatment for asthma. We report two cases of an upper airway obstruction masquerading as asthma. In case one, adenoid cystic carcinoma was identified in the trachea of a patient showing asthma-like symptoms, positive response to allergic skin test and methacholine inhalation challenge. In the other case, aspirated foreign body was misdiagnosed and treated as asthma for more than one year. A high degree of suspicion and a thorough medical evaluation censisting of history, physical examination and pulmonary function test including shapes of spirogram are essential to the differential diagnosis of asthma-like symptoms

Respiratory Compensation Thresholds in Healthy Korean Adults / 대한내과학회지

OBJECTIVES: The respiratory compensation threshold(RCT) is thought to be one of parameters by some for the evaluation of physical performance despite its controversial status. The purpose of this investigation is to establish the reference values of the RCT in healthy Korean adults, and to examine the usefulness of this parameter in evaluating physical performance. METHODS: Symptom-limited maximal exercise test by Bruce protocol was carried out, and RCT and AT were determined by the aid of the computerized V-slope method, along with the VO2 max, in 441 healthy Korean adults consisting of 284 men and 157 women aged from 20`s to 60`s. In addition, correlation between RCT and AT was observed, and regression equations of the RCT were also derived. RESULTS: The RCT VO2 was tended to decrease with age in men, but not in women and the RCT VO2 of women was 26-30% less than that of men. The ratio of RCT VO2 to VO2 max (RCT VO2/VO2 max) was tended to increase with age and the RCT V was significantly correlated with AT VC4 and VO2 max in both sexes. CONCLUSION: Our study reveals that the RCT is another useful submaximal index along with the AT in evaluating physical performance. The regression equation of the RCT was RCT VO2(L/min)=1.4232-0.0102 A(age in year)+0.0204 W(weight in kg)-0.4889 S (sex, coded O for males and 1 for females).