• 대한소아치과학회지
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• 제48권1호
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• pp.122-128
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• 2021

Short root anomaly는 비정상적으로 짧고 뭉툭한 치근 형태를 가진 드문 질환이다. 대부분 상악 중절치에 대칭적으로 나타나며 영구치에서만 관찰되어 왔다. 이 증례는 9세 여환으로 혼합치열기에 짧은 치근 발달을 주소로 개인병원에서 의뢰되었다. 방사선 사진 및 구강 내 검사에서 법랑질 저형성증과 치내치와 같은 다른 치아이상과 함께 상악 및 하악 전치부와 하악 제 1대구치에서 SRA가 관찰되었다. 5년동안의 장기추적 관찰을 통해 환아의 모든 치아들은 혼합치열기에서 영구치열기로 변화하였고 모든 영구치에서 전반적인 SRA가 관찰되었다. 교정적 진단을 위해 촬영된 측면 두부 방사선 사진에서 치아 이상과 밀접한 관련이 있는 것으로 보고된 전방과 후방 상돌기 사이의 석회화인 sella turcica bridge 또한 관찰되었다. 이러한 여러 요소들을 통하여 치근 흡수나 치아 상실의 예방과 성공적인 관리 위해 SRA를 조기 진단하는 것은 매우 중요하다. 이 증례 보고에서는 다른 치아이상과 sella turcica bridge와 함께 전악에 걸쳐 나타난 전반적인 SRA를 보이는 환아를 장기적으로 관찰하고 의미있는 결과를 나타내고 있기에 이를 보고하는 바이다.

• Restorative Dentistry and Endodontics
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• 제43권1호
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• pp.2.1-2.10
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• 2018

Objectives: To determine the effect of size and insertion depth of irrigation needle on the amount of apical extruded debris and the amount of penetration depth of sealer using a confocal laser scanning microscope (CLSM). Materials and Methods: Twenty maxillary premolars were assigned to 2 groups (n = 10), according to the size of needle tip, 28 G or 30 G. Buccal roots of samples were irrigated with respective needle type inserted 1 mm short of the working length (WL), while palatal roots were irrigated with respective needle type inserted 3 mm short of the WL. Prepared teeth were removed from the pre-weighed Eppendorf tubes. Canals were filled with F3 gutta-percha cone and rhodamine B dye-labeled AH 26 sealer. Teeth were transversally sectioned at 1 and 3 mm levels from the apex and observed under a CLSM. Eppendorf tubes were incubated to evaporate the irrigant and were weighed again. The difference between pre- and post-weights was calculated, and statistical evaluation was performed. Results: Inserting needles closer to the apex and using needles with wider diameters were associated with significantly more debris extrusion (p < 0.05). The position of needles and level of sections had statistically significant effects on sealer penetration depth (p < 0.05 for both). Conclusions: Following preparation, inserting narrower needles compatible with the final apical diameter of the prepared root canal at 3 mm short of WL during final irrigation might prevent debris extrusion and improve sealer penetration in the apical third.

• 대한치과교정학회지
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• 제34권2호
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• pp.131-142
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• 2004

본 연구는 골절단을 이용한 치아-치조골 분절의 급속 치아이동 후 치수, 치주인대 및 치조골의 변화를 유성견에서 평가하고자 하였다. 하악 제4소구치의 근심, 원심, 치근단 부위에서 피질골을 절단하여 치아-골 분절을 형성하고 하악 제3소구치를 발거하면서 협측, 설측 부위의 피질골을 삭제하였다. 1주 휴지기 부여에 따라 휴지기군과 비휴지기군으로 나누어 치아의존형 견인장치로 6일 동안 견인하고 강화기를 거친 후 0주, 1주, 2주, 4주, 6주, 8주에 희생시켜 치수 치주인대 및 치조골의 조직 변화를 임상적, 방사선적, 조직학적 및 면역화학적으로 평가하여 다음과 같은 결과를 얻었다. 1 치아이동 양과 강화기 동안의 조직 치유 양상에서 휴지기 유무에 따른 차이는 없었다. 2. 견인측에서 골형성은 강화기 8주까지 계속되었는데 강화기 1-2주에 가장 활발하였으며 6-8주간의 변화는 적었다. 3. 비휴지기군의 강화기 1주에서 치조골 흡수 및 파골세포 출현, 염증세포 침윤이 가장 많았으며, 특징적으로 파상아세포가 압박측의 치주인대와 치수 내에 나타났다. 4. $TGF-\beta$는 치조골의 골기질 및 골모세포, 파골세포, 치수 내 파상아세포에서 강양성 발현을 보인 반면 치수, 백악모세포, 무세포성 백악질에서 경미한 양성 발현을 나타내는 부위 특이성이 있었다. 5. $TGF-\beta$는 견인측 치주인대의 치조골에 인접한 혈관 및 치주인대세포, 골모세포에서 강화기 초기 1-2주에 주로 발현되었으며 6주 이후에는 발현이 크게 감소하였다.

• 대한심미치과학회지
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• 제13권2호
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• pp.7-11
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• 2004

The Schwachman-Diamond syndrome is an autosomal recessive syndrome(1/20,000 births), consisting of pancreatic insufficiency, neutopenia, which may be intermittent, neutrophil chemotaxis defects, metaphyseal dysostosis, failure to thrive and short stature. Patients present in infancy with poor growth and grease, foul-smelling stools that are characteristic of malabsorption. These children can be readily differentiated from those with cystic fibrosis by their normal sweat chloride levels, lack of the cystic fibrosis gene, and characteristic metaphyseal lesions. Pathologically, the pancreatic acini are replaced by fat with little fibrosis. The neutropenia may be cyclic. Recurrent pyogenic infections otitis media, pneumonia, dermatitis(fig 1), sepsis are common and a frequent cause of death. In dental examination, these patients had a poor oral hygine and moderate generalized marginal gingivitis, also show delayed primary tooth exfoliation and oral development. This report illustrates a case that pancreatic agenesis 6 yeas-old boy with various esthetic dental problems has been served the esthetic dental restoration of 6 years.

• 환경생물
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• 제33권2호
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• pp.170-176
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• 2015

Oncholaimid nematode, Oncholaimus secundicollis Shimada, Kajihara and Mawatari, 2009, is firstly reported based on a comparative morphological study. The present specimens of O. secundicollis are collected from rocky intertidal seagrass on the eastern coast of Korea. Oncholaimus secundicollis is distinguished from all of its congeners by the following combination of morphological characteristics: buccal cavity large with thick cuticular wall and three teeth, left subventral tooth larger than right subventral or dorsal teeth, and the presence of two remarkable precloacal papillae with nine pairs of cloacal setae and single ventral tail papilla with two pairs of short setae. In this study, we provide taxonomic description and illustration of unrecorded species of the genus Oncholaimus.

• 대한치과교정학회지
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• 제19권2호
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• pp.155-163
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• 1989

Indirect bonding is done by placing the brackets on a model in the laboratory and using a template or tray to transfer the laboratory positioning to the teeth. The advantages of this technique are 1. decreased chair time 2. less patient discomfort 3. accuracy of a attachment placement 4. good adaptation of attachment to tooth contour 5. occlusal relationship of brackets and opposing teeth can be checked The disadvantages of the technique are 1. complex laboratory procedure 2. sometimes difficult on very short clinical crowns 3. teeth with crowns, large buccal restoration will not bond 4. may not be fitted close, if poor adaptation 5. likely to be disturbed setting Several indirect bonding techniques have proved reliable in clinical practice. However, they differ in the way the brackets are attached temporarily to the model, the type of transfer tray or other mechanism used, the adhesive or sealant employed, whether segmented or full bonding used, and the way the transfer is removed so as not to exert excessive force on a still maturing bond.

• Journal of Photoscience
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• 제5권1호
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• pp.33-37
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• 1998

One macroscopic effect in the free-running Er:YAG laser is an accumulation of microscopic effects. Understanding of the exogenous water induced mechanical effect on the dental hard tissue by the Qswitched Er:YAG laser has an important impact on the further understanding of the free-running Er:YAG laser ablation on the dental hard tissue. The Q-switched Er:YAG laser (1-$\mu$s-long pulse width) was used in the recoil pressure measurement with an aid of water-jet system and a pressure transducer. The amplitude of the recoil pressure depends on the tooth surface conditions (dry and wet) and the volume of the water upon it. Wet surfaces yielded higher recoil pressure than that of dry, surface, and as the volume of the exogenous water drop increased, the amplitude of the recoil pressure increased also.

• 한국치위생학회지
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• 제8권4호
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• pp.11-18
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• 2008

The purposes of this study were to examine the effect of 35% Carbamide Peroxide(CP) bleaching agent on the changes in physical and chemical characteristics of tooth. The effect of bleaching agent on enamel was analyzed using Hardness test, SEM and EDS. The microhardness between bleached groups after bleaching showed statistically significant difference according to the paired t-test. The bleached enamel surface showed apparent morphological changes compared to the enamel, which was stored in distilled water only. The difference of the total mineral contents for the distilled water and Carbamide Peroxide did not show statistical significance. These results demonstrated that bleaching using 35% Carbamide Peroxide were adversely affects application time of experimental group and may the safety of using these agents for a short time in dentist-monitored bleaching.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 춘계학술대회
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• pp.257-257
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• 2001

Failures occur in dentistry as a result of manny factors some of which can be controlled by the operator whilst others are unavoidable. The long-term success rate of endodontic treatment has often been thought to be very high although studies reported in the literature do not support this perception. The number of failure can be reduced by adhereing to accepted treatment procedures and by avoiding 'short cut'. Endodontic disaters are usually related to operator errors and they mat have detrimental effects on the outcome of treatment in the long term, eventually becoming catastrophes. Endodontic disasters will require special techniques to salvage them whereas catastrophes usually result in loss of the tooth and every effort should be made to prevent such problems from occurring. This presentation will cover common errors in endodontic procedures especially access opening, canal negotiation, canal irrigation, canal preparation, canal filling, post preparation.ration.

• 한국해양공학회지
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• 제7권1호
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• pp.33-55
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• 1993

선수충격파의 문제를 푸는데 있어서 Boundary Integral Method(BIM)의 여러가지 수치 해석방법이 검토되었으며, 특히 여러가지 Time stepping scheme, Green function, far-field 조건등에 따른 수치해석안정성과 정확성의 상관관계가 연구되었다. von Neumann 안정성해석과 matrix 안정성해석 등을 이용한 선형 안정성해석을 기초로하여, 수치해석방법의 안정성 여부를 체계적으로 조사할 수 있는 parameter(Free Surface Stability number)를 설정하고, 이 parameter의 변화에 따른 비선형 운동해석을 연구하였다. 그 결과 비선형성이 심하지 않은 기진파의 경우에서는 비선형 운동해석의 수치해석 안정성의 선형 수치해석 안정성과 큰 차이가 없음을 알 수 있게 된다.