• 대한소아치과학회지
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• 제39권4호
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• pp.397-403
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• 2012

미성숙 영구치는 치아우식증, 외상, 비정상적인 치아 형태로 인한 파절 등에 의하여 치수 생활력을 상실할 수 있다. 이때 이용되는 치료법이 치근단 형성술로서 실활치의 치근단 치수 부위에 광화된 조직의 형성을 통하여 치근단 폐쇄를 유도한다. 현재 수산화칼슘 치근단 형성술이 가장 많이 이용되는데 근관 내에 수산화칼슘을 장기간 적용할 경우 치근단 경조직 형성을 유도할 수 있지만, 강한 알칼리성으로 인하여 치근 약화를 야기하여 치아 파절 위험성이 높아진다. 그러므로 근관 충전 시 치아보강을 위한 수복이 고려되어야 한다. 본 증례는 생활력을 상실한 미성숙 영구치에서 장기간의 수산화칼슘 치근단 형성술 후 치아 보강을 위하여 MTA plug, 섬유강화형 포스트 그리고 복합 레진을 이용한 근관 충전을 시도하였기에 보고하는 바이다.

• 대한치과보철학회지
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• 제42권5호
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• pp.535-543
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• 2004

Purpose: The purpose of this study is to compare the effect of two fiber post systems and one metal cast post system on the fracture strength and fracture pattern of crowned, endodontically treated teeth with 2 mm-height of the reamining tooth structure. Materials and methods: A total of 36 recently extracted sound human mandibular premolars were selected Each tooth structure of the crown portion except 2mm-height of the one above the cementoenamel junction was removed. After being endodontically treated, they were randomly distributed into 3 groups: group 1, restored with quarts fiber post(D.T. Light-Post), group 2, with glass fiber post(FRC Postec), and group 3, metal cast post and core. All teeth were fully covered with nonprecious metal crowns. Each specimen was embedded in an acrylic resin block and then secured in a universal load-testing machine. A compressive load was applied at a 130 degree angle to the long axis of the tooth until fractured, at a crosshead speed 20mm/min. The highest fracture loads were measured and recorded as the fracture strength of each specimen. Fracture areas were measured on the mid-buccal and mid-lingual point from the crown margins. One-way analysis of variance and Turkey test were used to determine the statistic significance of the different fracture loads and areas among the groups (p<0.05). Results: The mean fracture loads were $1391{\pm}$425N(group 1), $1458{\pm}476N$(group 2) and $1301{\pm}319N$(group 3). The fracture loads among the three groups had no statistically signifiant difference (p>.05). The mean fracture area of the fiber post was closer to the crown margin than that of the metal cast post and core(p<.05). The metal cast post showed unrestorable and catastrophic fracture patterns. Conclusion: Within the limitations of this study, fracture loads with any statistically significant difference were not recorded for endodontically treated teeth restored with two fiber posts and the metal cast post. But teeth restored with the fiber posts typically showed the fracture pattern close to the crown margin, which was almost restorable.

• 영어영문학
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• 제58권4호
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• pp.723-752
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• 2012

Although his mythic poetry deals with the fall and resurrection of Albion as the origin of humankind, William Blake (1757-1827) simultaneously links it to the professionalization and unification of disciplinary knowledge itself. He particularly takes a great interest in the cross-referential relation of poetry to science. He argues for the communication of poetry and science on equal footing with each other without the former's prioritization over the latter, or vice versa. In his works Vala, or The Four Zoas (1797-1807) and Jerusalem: The Emanation of the Giant Albion (1804-1820), on which I focus in this essay, Blake's primary problematic is to display strong conflicts among different systems of knowledge. I approach this issue in light of the ideological clash of Newtonian thought, Romantic thought, and postmodern thought. In his poetry, Blake thematizes the very clashes of these different thought patterns. From the standpoint of Romantic thought, first of all, Blake problematizes Newtonian Enlightenment. He criticizes abstract universalization both in poetry and science, which Urizen, one of four Zoas, propagates. Protesting against Urizen's Newtonism, Los values "living form." Thus, Blake demonstrates, through this figure, that poetic imagination and scientific organicism are discursively communicative. Blake, however, also questions the network of Romantic science and Romantic poetry so as to suggest what current critics would call postmodern thought. Blakean postmodernism pursues the self-similarity of organic structure in science and poetry. Precisely, Blake sees polypus as a proliferation of organic body; he arranges four Zoas' self-repetitive stories in a non-linear way. Blake aspires for the conflicting coexistence of different thought patterns.

• 구강회복응용과학지
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• 제32권3호
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• pp.149-157
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• 2016

성공적인 라미네이트 치료를 위해서는 치아형성 방법이 매우 중요하다. 법랑질에 국한된 보존적인 치아형성, 치태조절이 용이한 치은연선상(equigingival) 변연, 가능한 존재하는 접촉점의 유지 등의 조건이 일반적으로 알려져 있으나 구체적인 치아형성 디자인에 관하여는 논쟁의 여지가 존재한다. 생역학적으로 고려해볼 때, 다음과 같은 사항들이 추천된다. 절단면 피개는 심미적 요구와 전방유도의 재설정 필요 여부 측면에서 결정해야 하며, 법랑질 두께가 충분한 경우에는 구개측 연장을 하는 것이 좋으나 응력 집중이 큰 구개오목(palatal concavity)에 변연이 위치하는 것은 부적절하다. 인접면 연장은 증례에 따라 선택적으로 시행하며, 인접면에 레진수복물이 존재하는 경우에는 표면처리 후 레진 수복물을 절반 이상 피개하는 형태의 라미네이트로 수복한다. 변색이 심하지 않은 근관치료가 시행된 치아의 경우 라미네이트 수복을 고려해 볼 수 있으며, 이 때 섬유강화레진 포스트를 사용하는 것을 추천한다.

• 대한치과보철학회지
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• 제41권2호
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• pp.232-242
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• 2003

Statement of problem : Fiber-reinforced posts have lower modulus of elasticity than titanium post or cast post-core. With this similar elasticity to that of dentin, fiber-reinforced posts have been known to have a tendency to reduce the risk of root fracture. However, there were few studies on the teeth restored with fiber-reinforced posts under the condition of reduced periodontal support. Purpose : The purpose of this study was to evaluate the fracture strength and failure mode of endodontically treated teeth restored with fiber-reinforced posts and titanium posts under the condition of reduced periodontal support. Material and method : Extracted human maxillary incisor roots were divided into 3 groups (group 1 carbon fiber post, group 2 : glass fiber post, and group 3 : titanium alloy post). After coronectomy and endodontic treatment, teeth were restored with each post systems and resin core according to the manufacturer's recommendation. Then, teeth with simulated periodontal ligament were embedded in the acrylic resin blocks at the level of 4 mm below the cemento-enamel junction. Each specimen was exposed to $10^5$ load cycles with average 30 N force in $36.5^{\circ}C$ water using a computer-controlled chewing simulator. Loads were applied at $45^{\circ}$ angle to the long axis of the teeth. After cyclic loading, teeth were subjected a compressive load until failure at a crosshead speed of 0.5 mm/min. Fracture strength (N) and failure mode were examined. The fracture strength was analyzed with one-way ANOVA and the Scheffe adjustment at the 95% significance level. Results and conclusion : The results were as follows. 1. There was no statistically significant difference in the mean fracture strength among the groups (P<.05). 2. Carbon fiber post and glass fiber post group showed less root fracture tendency than control group. 3. All specimens with root fractures showed fracture lines above the level of acrylic resin block, except for only one specimen in group 3.