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GT rotary file을 이용한 만곡 근관형성시 작업 효율 및 file 변형 발생에 관한 연구
신주희,백승호,배광식,임성삼,윤수한,김병현 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.5
Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal. However, as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore, in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nitckel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature of root canal and reducing the deformation of root canal. However, it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150∼350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g, 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1.Analysis of the experiment results revealed that the tome spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range (β-weight test) . 2.Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease, In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of◎eater tier◎cal forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3.Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block. Key words : GT rotary file, Crown-down method, Working efficiency, Vertical force, Rpm, Deformation and breakage of file
비강 및 비인두에 발생한 도립유두종과 편평상피암종의 p53단백 및 세포증식능에 관한 연구
한주호,윤기중,이재규,신대균,박근호,조향정,문형배 圓光大學校 醫科學硏究所 1996 圓光醫科學 Vol.12 No.2
The inverted papilloma and squamous cell carcinoma are common neoplasia in the sinonasal cavity and nasopharynx, but the incidence of these tumors are very low and the study on the oncogenesis or biological activity of the tumor cells are not well known. This study was designed to evaluate the oncogenic roles of the p53 gene and the proliferative activity of the tumor cells in the inflammatory polyp, inverted papilloma and squamous cell carcinoma. The experiment was carried by the immunohistochemical stains about the p53 protein, PCNA and Ki-67, histochemical stain about the AgNORs. and flow cytometric analysis about the DNA ploidy using the formalin fixed paraffin embedded tissues. The frequency of the expression of p53 protein was 0%(0/16 cases) in the inflammatory polyps, 18.8% (3/16 cases) in the inverted papillomas, and 87.5%(14/16 cases) in the squamous cell carcinomas. The labelling index(%) of the PCNA and Ki-67 was 5.3% and 3.3% in the inflammatoy polyps, 29.6% and 25.2% in the inverted papillomas, and 51.9% and 36.8% in the squamous cell carcinoma. The expression of the PCNA and Ki-67 was distributed in the periphery of the tumor islands of the inverted papilloma and was distributed in the both of center and periphery of the tumor islands of the squamous cell carcinoma. The number of nuclear AgNORs was increased in the order of inflammatory polyps (0.96), inverted papillomas(1.34) and squamous cell carcinoma(2.09). The frequency of the DNA aneuploidy was 0%(0/16 cases) in the inflammatory polyps, 18.8%(3/16 cases) in the inverted papillomas. and 12.5%(2/16 cases) in the squamous cell carcinomas. Above results indicates that the changes of the p53 gene and proliferative activity of the tumor cells are involved on the oncogenesis and the biological activity of the inverted papilloma or squamous cell carcinoma in the nasopharynx and sinonasa cavity.
쥐 大腦 Muscarinic Receptor에 미치는 카드뮴의 影響
李正秀,朴令珠,裵基哲,李神雄 嶺南大學校 環境問題硏究所 1991 環境硏究 Vol.10 No.2
The effect of cadmium ?? on the [³H] quinuclidinyl benzilate (QNB) binding of the muscarinic receptors in the cerebrum was examined. ?? Inhibited [³H]QNB binding in both dose-dependent and time-dependent manners and this inhibitory action was irreversible. The ?? Value of ?? to inhibit [³H]QNB binding in the presence of 100 pM [³H]QNB in the cerebral microsome pretreated with ?? at 37℃ for 15 min was about 50㎛. The inhibition of [³H]QNB binding by 50㎛ ?? followed biphasic kinetics ; there is a rapid inhibition phase during first 10 min incubation periods and a slow inhibition phase after a rapid phase. ?? decreased the binding site concentration for [³H]QNB binding without affecting the affinity of QNB. These results suggest that sulphydryl group plays an important role to maintain the muscarinic receptor conformation for [³H]QNB binding.