감염근관에서의 apical preparation size

금기연 大韓齒科保存學會 2010 Restorative Dentistry & Endodontics Vol.35 No.1

감염근관에서의 주치근단 파일의 크기는 학자들마다 많은 논란이 되고 있지만 최근 여러 연구 결과들은 감염근관의 효과적인 세정을 위해서는 근단부 확대 크기가 증가해야 함을 보여주고 있다. 따라서 임상가는 감염근관의 치료 시 새로운 개념에 맞는 치료 전략을 가지고 근관치료에 임해야 한다. The final preparation (MAF) size in infected root canals is still controversial. Nonetheless, recent studies demonstrated that larger apical preparation sizes produces a greater reduction in remaining bacteria and dentinal debris as compared to smaller apical preparation sizes. Therefore, clinicians should be practiced with treatment strategies guided by evidence-based information, especially in infected/failed root canals.

불소의 농도와 Seed Material이 Crystal Growth에 미치는 영향

오승연,정일영,금기연,이찬영 大韓齒科保存學會 1997 Restorative Dentistry & Endodontics Vol.22 No.2

The present study was undertaken to investigate the crystal growth onto human enamel mineral and synthetic hydroxyapatite(HA) seeds in media resembling the enamel fluid composition. Effects of fluoride at high concentrations on the precipitation were also examined in a bench-top crystal growth model adopting a miniaturized reaction column. The Ca, P and F concentrations and pH values of the inlet and outlet solutions were determined. The recovered solid samples were weighed to assess the amount of minerals precipitated during the experimental period, and finally viewed under a scanning electron microscope. Remarkable findings were that 1) both biological and synthetic seeds with the same total surface areas yielded similar amounts of crystal growth, 2) the amount of crystal growth was accelerated in a manner depending of fluoride concentrations in the media, 3) SEM observations disclosed that without the addition of fluoride, precipitation of thin, plate-like OCP crystals became prominent, but by increasing the fluoride concentration(beyond 1ppm F), rod-like crystals having a pointed edge were most frequently observed, without and evidence for precipitation of the plate-like crystals. Furthermore, the dimension of rod-like crystals was increased in proportion of fluoride concentrations, 4) there was no difference in the morphological feature of precipitated mineral phase upon seeding between human enamel seed and synthetic HA seed. The overall results support the view that the seeded crystal growth model is of value to gain insight into the mechanism of enamel crystal growth under fluoride regimens.

한국인의 하악 구치의 근관 형태에 관한 후향성 연구

정일영,금기연,이승종,이찬영 大韓齒科保存學會 1997 Restorative Dentistry & Endodontics Vol.22 No.2

A retrospective in vivo study of endodontically treated mandiblar molars was conducted. The radilographs and clinical records of mandibular molars that had been treated endodontically in the Dental hospital of Yonsei University from 1986 to July 1997 were reviewed and categorized. A total of 1751 cases were studied and following results were obtained. 1. The number of root canals in mandibular first permanent molar in d Korean population revealed three in 53.2%, four in 23.0%, two in 18.4%, C-shaped canal in 5.0%, and one in 0.4%. 2. In mandibular second molar, three canals was observed in 53.3%, four in 22.2%, two in 14.9%, C-shaped canal in 9.1%, and one in 0.6%. 3. In the results of the percentage of 4 canals of mandibular first molars at various age, before age 20, 37.7% was obtained whereas 19.3% after 30. 4. 7.94% of mandibular first molars examined were found to have three roots. 5. The mandibular second molar had C-shaped canals in 9.1%.

생활치 표백술 후 수종의 자유 산소기 제거제 처리가 복합 레진-법랑질 전단 접착 강도 및 파절 양상에 미치는 영향

임경한,금기연,김애리,장수미 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.5

Tooth bleaching has been prevailing recently for its ability to recover the color and shape of natural teeth without reduction of tooth material. However, it has been reported that bleaching procedure adversely affects the adhesive bond strength of composite resin to tooth. At the same time the bond strength was reported to be regained by application of some chemical agents. The purpose of this in vitro study was to investigate the effect of the removal of residual peroxide on the composite- enamel adhesion and also evaluated fracture mode between resin and enamel after bleaching. Sixty extracted human anterior and premolar teeth were divided into 5 groups and bleached by combined technique using office bleaching with 35 % hydrogen peroxide and matrix bleaching with 10% carbamide peroxide for 4 weeks. After bleaching, the labial surfaces of each tooth were treated with catalase, 70% ethyl alcohol, distilled water and filled with composite resin. Shear bond strength was tested and the fractured surfaces were also examined with SEM. Analysis revealed significantly higher bond strength values. (p<0.05) for catalase-treated specimens, but water-treated specimens showed reduction of bond strength, alcohol- treated specimens had medium value between the two groups(p<0.05). The fracture mode was shown that the catalase group and the alchohol group had cohesive failure but the water sprayed group had adhesive failure. It was concluded that the per-oxide residues in tooth after bleaching seems to be removed by gradual diffusion and the free radical oxygen from peroxide prevents polymerization by combining catalyst in the resin monomer. Therefore it may be possible to eliminate the adverse effect on the adhesion of composite resin to enamel after bleaching by using water displacement solution or dentin bonding agent including it for effective removal of residual per-oxide Key words : Vital tooth bleaching, Shear bond strength, Composite resin, Fracture mode catalase, Ethylalcohol, Free oxygen radical, Adhesive failure, Cohesive failure

수종의 NiTi 전동 파일 단면 형태 비교 및 pecking motion의 사용방법이 피로 파절에 미치는 영향

김재관,금기연,김의성 大韓齒科保存學會 2006 Restorative Dentistry & Endodontics Vol.31 No.2

본 연구는 현재 시판중인 Profile^(®), ProTaper^(®), K3^(®), Hero 642^(®), Hero Shaper^(®)를 단면을 비교하고 이들 5가지 NiTi 파일과 사용방법에 따른 피로 파절 소요 시간을 비교하고자 시행되었다. 각 NiTi 전동파일의 치근단 1/3을 temporary resin에 매몰시키고 다이아몬드 표면처리된 버로 잘라내어, 초음파를 이용하여 세척 후, 주사전자현미경으로 단면을 관찰하였다. 주기적인 피로 실험을 수행하기 위해, 회전속도, pecking 거리를 자동적으로 조절할 수 있는 장치를 제작하고 파일을 만곡된 상태를 재현하기 위하여 15도 경사진 금속 토막에 위치시키고 분당 300회전의 속도로 회전시켜 파일이 파절될 때까지의 시간을 측정하였다. 사용방법에 따른 실험군은 동적군과 정적군으로 나누고 pecking 거리는 3㎜, 6㎜로 하였다. 실험결과 동적군 보다는 정적군의 피로파절 소요시간이 통계학적으로 유의차 있게 짧았으며 3㎜, 6㎜의 pecking distance에 따른 영향은 나타나지 않았다. 결론적으로 NiTi전동파일은 pecking motion으로 사용하는 것이 피로파절을 줄이는데 도움이 될 것으로 사료된다. There are various factors affecting the fracture of NiTi rotary files. This study was performed to evaluate the effect of cross sectional area, pecking motion and pecking distance on the cyclic fatigue fracture of different NiTi files. Five different NiTi files-Profile^(®) (Maillefer, Ballaigue, Switzerland), ProTaper™ (Maillefer, Ballaigue, Switzerland), K3 ^(®) (SybronEndo, Orange, CA), Hero 642^(®) (Micro-mega, Besancon, France). Hero Shaper^(®) (Micro-mega, Besancon, France)-were used. Each file was embedded in temporary resin, sectioned horizontally and observed with scanning electron microscope. The ratio of cross-sectional area to the circumscribed circle was calculated. Special device was favricated to simulate the cyclic fatigue fracture of NiTi file in the curved canal,. On this device, NiTi files were rotated (300rpm) with different pecking distances (3㎜ or 6㎜) and with different motions (static motion or dynamic pecking motion). Time until fracture occurs was measured. The results demonstrated that cross-sectional area didn't have any effect on the time of file fracture. Among the files, Profile^(®) took the longest time to be fractured. Between the pecking motions, dynamic motion took the longer time to be fractured than static motion. There was no significant difference between the pecking distances with dynamic motion, however with static motion, the longer time was taken at 3㎜ distance. In this study, we could suggest that dynamic pecking motion would lengthen the time for NiTi file to be fractured from cyclic fatigue.

인공치아우식의 재광화에 미치는 불소의 영향

한원섭,금기섭,이찬영 大韓齒科保存學會 1996 Restorative Dentistry & Endodontics Vol.21 No.1

4종 전자근관장측정기의 정확성과 일관성에 관한 in vitro 연구

조재현,금기연,이승종 대한치과보존학회 2006 Restorative Dentistry & Endodontics Vol.31 No.5

이번 연구는 서로 다른 4개의 전자근관장측정기의 정확성을 측정하고 각각 0.5지점과 Apex지점에서의 일관성을 비교하고자 하였다. 40개의 발치된 상하악 소구치를 대상으로 치수강 개방 후 alginate model에 고정시키고 근관장을 측정하였다. 사용된 전자근관장측정기는 Root ZX (Morita, Tokyo, Japan), SmarPex (META, Seoul, Korea), Elements Diagnostic Unit (SybronEndo, CA, USA), E-Magic Finder Deluxe (S-Denti, Seoul, Korea)이다. 먼저 모든 치아에서 4개의 전자근관장측정기를 사용하여 0.5지점과 Apex지점에서 근관장을 측정하여 한 치아당 8개의 측정값을 얻었다. 다음으로 치아를 각 전자근관장측정기당 10개씩 4개의 그룹으로 나누어, 각각 제조사의 지시대로 Root ZX, Elements Diagnostic Unit 및 E-Magic Finder Deluxe는 "0.5"지점에서, SmarPex는 ''Apex" 지점에서 file을 치아에 cement로 고정시켰다. 이후 치근단부 4 mm를 삭제하여 100배율의 Image ProPlus로 관찰하여 file 끝에서 주근단공의 외연까지의 실제거리를 측정한 후, 4개의 전자근관장측정기의 0.5지점 및 Apex지점에서 file 끝과 주근단공 사이의 거리를 계산하여 비교하였다. 그 결과 Root ZX와 E-Magic Finder는 실험군 100%, SmarPex는 90%, Elements Diagnostic Unit는 70%에서 주근단공과의 거리가 임상적 허용범위인 土0.5 mm 이내에 있었다. 또한 각 전자근관장측정기마다 0.5지점과 Apex지점에서의 근관장의 표준편차와 사분위 범위를 구하여 두 지점간의 일관성을 비교한 결과, Root ZX, E-Magic Finder는 0.5지점과 Apex지점에서 비슷한 일관성을 보였으며 SmarPex와 Elements Diagnostic unit는 Apex지점에서 0.5지점보다 더 높은 일관성을 보였다. 전자근관장측정기는 근관 내의 조건에 관계없이 근첨협착부에서 항상 일정한 거리를 재현해 낼 수 있는 일관성이 중요하므로, 이렇게 0.5지점 또는 Apex지점에서의 일관성이 증명된다면 실제 임상에서 사용할 때 전자근관장에서 일정한 거리를 가감하여 사용할 수 있다. The purpose of this study was to evaluate the accuracy and the consistency of four different electronic apex locators in an in vitro model. Fourty extracted premolars were used for the study. Four electronic apex locators (EAL) were Root ZX, SmarPex, Elements Diagnostic Unit (EDU), and E-Magic Finder Deluxe (EMF). After access preparation, the teeth were embedded in an alginate model and the length measurements were carried out at "0.5" and "Apex" mark using four EALs. The file was cemented at the location of the manufacturers' instruction (Root ZX, EDU, EMF: 0.5 mark, SmarPex: Apex mark). The apical 4mm of the apex was exposed and the distance from the file tip to the major foramen was measured by Image ProPlus (× 100). The distance from the file tip to the major foramen was calculated at 0.5 and Apex mark and the consistency of 0.5 and Apex mark was compared by SD and Quartile of Box plots. In this study, Root ZX and EMF located the apical constriction accurately within ± 0.5 mm in 100%, whereas SmarPex and EDU located in 90% and in 70% respectively. For Root ZX and EMF, there was no significant difference between the consistency of 0.5 and Apex mark. However, for the EDU and SmarPex, Apex mark was more consistent than 0.5 mark. From the evaluation of the consistency in this study, for Root ZX and EMF, both 0.5 and Apex mark can be used as a standard mark. And for EDU and SmarPex, the Apex mark can be recommended to be used as a standard mark.

수종의 유기산이 법랑질 인공우식의 형성에 미치는 영향

이찬영,금기연 大韓齒科保存學會 1996 Restorative Dentistry & Endodontics Vol.21 No.2

수종의 엔진 구동형 니켈-타이타늄 합금파일의 절삭각에 따른 근관성형 효과에 관한 전자현미경적 연구

전인수,금기연,박성호,윤태철 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.6

The purpose of this in vitro study was to compare the effects of root canal debridement following rotary Ni-Ti instruments with positive versus negative rake angle. Seventy sound, extracted human anterior teeth & premolars were randomly divided into four groups. The used rotary instruments were Ni-Ti HERO642(Micro-Mega in France, 20 specimens), Ni-Ti ProFile(Maillefer, Ballaigues, Switzerland, 20 specimen), stainless steel engine reamer(Mani, Matutani Seisakusho Co.,Japan, 20 specimen) and negative control group(10 specimens) was only extirpated with barbed broach(Mani, Matsutani Seisakusho Co., Japan) Group 1 & 2 teeth were prepared to a #40 at the apex followed by 1 mm using crown-down technique. Group 3 teeth were instrumented from a #15 to a #40 in sequential order. After preparation and final irrigation, the roots split longitudinally into a bucco-lingual direction. Root halves were cross-sectioned in apical third portion again. all root specimens were prepared for SEM investigation & photographed. Separate evaluations were undertaken for smear layer on prepared walls with a five score-index for each using reference photograph in root halves. the penetration depth of smear layer into dentinal tubules was also estimated in the other halves. the following results were obtained : 1. Smear layer was observed on all the prepared walls with three experimental groups except negative control group 2. Smear layer characteristics1) HERO 642 groups showed snowy & dusty appearance & were observed only few some dentinal tubuli open on the prepared walls, and the penetration depth of it into dential tubules may be 1-2 ㎛ thick. 2) ProFile groups showed shiny & burnished appearance & complete root canal wall covered by a homogenous smear layer with no open dentinal tubuli and penetration depth of it into dentinal tubules may be 1-2㎛ thick. 3) Engine reamer groups showed obviously file's passed tracks on the prepared walls & were observed complete root canal wall covered by a homogenous smear layer with no open dintinal tubuli. The results revealed that a completely clean root canal could not be achieved regardless of positive & negative rake angle, which is in accordance with the majority of studies on root canal cleanliness In conclusion, throughout irrigation with antibacterial solutions or chelating agents is recommended to remove the smear layer on prepared canal walls.

법랑질 인공우식의 재광화에 미치는 pH의 영향에 관한 연구

김민경,금기연,이찬영 大韓齒科保存學會 1997 Restorative Dentistry & Endodontics Vol.22 No.1