• 대한소아치과학회지
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• 제47권4호
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• pp.389-396
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• 2020

Pyramidal molar는 완전히 융합된 하나의 치근과 근관을 갖는 대구치를 의미한다. 이번 연구의 목적은 청소년들에서 Pyramidal molar의 유병률과 특성을 파악하는 것이다. 이 연구에서는 연세대학교 치과대학병원 소아치과에 내원한 만 13세에서 16세 사이의 1,612명의 파노라마가 분석되었고 총 12,896개의 대구치(제1,2대구치)가 평가되었다. Pyramidal molar의 발생 위치와 성별에 대한 상대적인 유병률을 계산하였고 카이제곱 검정을 사용하여 상관관계를 분석하였다. Pyramidal molar의 유병률은 1.49%였으며 Pyramidal molar가 발견된 24명의 환자 중 남성이 6명, 여성이 18명으로 여성에서 호발하였다. 전체 대구치(제3대구치 제외)에서 Pyramidal molar는 0.31%를 차지하였다. Pyramidal molar 중 88%가 상악에서 발견되었고 모든 Pyramidal molar는 제2대구치에서 나타났다. Pyramidal molar는 일반적인 다근치에 비해 치주적인 예후가 좋지 못하며 치수치료시 구조적 특성에 대한 이해가 중요하다. 임상가들은 pyramidal molar의 해부학적 특성을 이해하고 치료 및 예후 평가에 적용할 수 있어야 한다.

• Restorative Dentistry and Endodontics
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• 제27권1호
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• pp.24-33
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• 2002

Leakage studies have been performed frequently, since a fluid-tight seal provided by various dental fill-ing materials has been considered clinically important. The leakage of the various root-end filling materials has been widely investigated mostly dye penetration method. These dye studies cannot offer any information about the quality of the seal of a test material over a long period of time The purpose of this study was to evaluate the microleakage of root end cavities in blood contamination filed amalgam, intermediate restorative material(IRM), light cured glass ionomer cement(GI) and mineral trioxide aggregate(MTA) by means of a modified fluid transport model. Fifty standard human root sections, each 5mm high and with a central pulp lumen of 3mm in diameter, were and filled with our commonly used or potential root end fill ing materials after they were contaminated with blood. At 24h. 72h, 1, 2, 4, 8, and 12 weeks after filling, leakage along these filling materials was determined under a low pressure of 10KPa(0.1atm) using a fluid transport model. The results were as follows : 1 MTA group showed a tendency of decreasing percent of gross leakage (20m1/day) in process of time, whereas the other materials showed a tendency of increasing in the process time. 2. At the all time interval, GI group leaked significantly less than amalgam group and IRM group (p＜0.05). 3. At the 4 weeks, the percentage of gross leakage in MTA group decreased to 0% thereafter, the low per-centage of gross leakage was maintained in MTA group until the end of the experiment, whereas the percentage in IRM group increased to 100% 4. At the 12 weeks, percentage of gross leakage was significantly low in MTA group(0%), comparison with GI group(40%), amalgam group(90%) and IRM group(100%), but there was no significant difference between latter two materials.

• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.54.1-54.16
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• 2020

Objectives: This study aimed to synthesize nanocrystals (NCs) of zinc oxide (ZnO) and calcium ion (Ca²⁺)-doped ZnO with different percentages of calcium oxide (CaO), to evaluate cytotoxicity and to assess the effects of the most promising NCs on cytotoxicity depending on lipopolysaccharide (LPS) stimulation. Materials and Methods: Nanomaterials were synthesized (ZnO and ZnO:xCa, x = 0.7; 1.0; 5.0; 9.0) and characterized using X-ray diffractometry, scanning electron microscopy, and methylene blue degradation. SAOS-2 and RAW 264.7 were treated with NCs, and evaluated for viability using the MTT assay. NCs with lower cytotoxicity were maintained in contact with LPS-stimulated (+LPS) and nonstimulated (-LPS) human dental pulp cells (hDPCs). Cell viability, nitric oxide (NO), and reactive oxygen species (ROS) production were evaluated. Cells kept in culture medium or LPS served as negative and positive controls, respectively. One-way analysis of variance and the Dunnett test (α = 0.05) were used for statistical testing. Results: ZnO:0.7Ca and ZnO:1.0Ca at 10 ㎍/mL were not cytotoxic to SAOS-2 and RAW 264.7. +LPS and -LPS hDPCs treated with ZnO, ZnO:0.7Ca, and ZnO:1.0Ca presented similar NO production to negative control (p > 0.05) and lower production compared to positive control (p < 0.05). All NCs showed reduced ROS production compared with the positive control group both in +LPS and -LPS cells (p < 0.05). Conclusions: NCs were successfully synthesized. ZnO, ZnO:0.7Ca and ZnO:1.0Ca presented the highest percentages of cell viability, decreased ROS and NO production in +LPS cells, and maintenance of NO production at basal levels.