• 대한치과기공학회지
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• 제39권1호
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• pp.35-42
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• 2017

Purpose: The purpose of this paper was to evaluate the occurrence of errors regarding adaptation by conducting a three-dimensional assessment comparing the bridge type dental restoration after the cutting process, which has multiple abutments, with a single type dental restoration. Methods: By using ten identical files obtained by scanning the master model, thirty designs were created consisting of ten maxillary right first premolars and ten maxillary right first molars with single crown abutments, along with ten bridge designs with the identical abutment. A 5-axis milling machine was used to produce the design file. The produced denture prostheses were scanned using a silicone replica for a STL file. An evaluation was conducted using 3D analysis software on the master model and each of the thirty data files. Results: The RMS value of the pre-molar (14) was $38.4{\pm}4{\mu}m$ for single and $54.7{\pm}6{\mu}m$ for bridge abutment; therefore, a statistically significant difference was observed for single and bridge designs although both shared the same abutment form (P<.05). Also, the RMS value of the molar (16) was $47.6{\pm}2{\mu}m$ and $56.6{\pm}5{\mu}m$ for the single and bridge designs, respectively, thereby presenting a statistically significant difference (P<.05). Conclusion: As a result, dental prosthesis fabricated using the single method presented better internal adaptation outcomes.

• Restorative Dentistry and Endodontics
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• 제37권4호
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• pp.220-227
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• 2012

Objectives: The study was to compare the shaping ability of Reciproc (VDW) and WaveOne (Dentsply Maillefer) instruments compared with ProTaper, Profile and hand instrument during the preparation of simulated root canals. Materials and Methods: Five groups (n = 5) were established. Reciproc, WaveOne, ProTaper, Profile and K file (K-flexo file) were used to prepare the resin simulated canals. A series of preoperative and postoperative images were taken by a microscope and superimposed in 2 different layers. The amount of resin removed from both the inner and the outer sides of the canal was measured to the level of 10 mm from the apical tip, with a 1 mm increment. Results: The mean of resin removal from the inner canal wall was not different from the outer canal wall for Reciproc and WaveOne groups at apical third (1 - 3 mm level). There was no difference in the change of working length and maintenance of canal curvature. NiTi instruments are superior to stainless-steel K file in their shaping ability. Conclusions: Within the limitation of this present study, Reciproc and WaveOne instruments maintained the original canal curvature in curved canals better than ProTaper and Profile, which tend to transport towards the outer canal wall of the curve in the apical part of the canal.

• Journal of Information Processing Systems
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• 제16권2호
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• pp.301-317
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• 2020

An enterprise patch-management system (PMS) typically supplies a single point of failure (SPOF) of centralization structure. However, a Blockchain system offers features of decentralization, transaction integrity, user certification, and a smart chaincode. This study proposes a Hyperledger Fabric Blockchain-based distributed patch-management system and verifies its technological feasibility through prototyping, so that all participating users can be protected from various threats. In particular, by adopting a private chain for patch file set management, it is designed as a Blockchain system that can enhance security, log management, latest status supervision and monitoring functions. In addition, it uses a Hyperledger Fabric that owns a practical Byzantine fault tolerant consensus algorithm, and implements the functions of upload patch file set, download patch file set, and audit patch file history, which are major features of PMS, as a smart contract (chaincode), and verified this operation. The distributed ledger structure of Blockchain-based PMS can be a solution for distributor and client authentication and forgery problems, SPOF problem, and distribution record reliability problem. It not only presents an alternative to dealing with central management server loads and failures, but it also provides a higher level of security and availability.

• Restorative Dentistry and Endodontics
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• 제19권1호
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• pp.97-105
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• 1994

The purpose of this study was to evaluate the smear layer removing efficiency of two root canal preparation techniques. Twelve single-rooted teeth were used in two groups of six each. Group 1 was biomechanically prepared by hand using a K-file with a high volume of normal saline irrigation. Group 2 was. prepared by using ultrasonically activated K-file with a constant high volume of normal saline irrigation. After the experimental procedures, each root was split saggitally. The removing efficiency of the preparation methods were assessed in terms of surface condition of the canal walls at three levels, those coronal, middle, and apical thirds. On the basis of remaining debris, presence of smear layer, and patency of dentinal tubules, each canal was evaluated according to a scale form 0 to 2. A statistical analysis was used to indicated any significant differences in surface condition between the two methods. There was no statistical significance between hand instrumentation and ultrasonic instrumentation at the cervical third but removing efficiency of ultrasonic instrumentation was superior. No statistically significant differences were obhserved for middle or apical third.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제6권1호
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• pp.31-42
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• 2017

썸네일(thumbnail)은 JPEG, GIF 등 그래픽 파일의 축소판이며 그래픽 파일을 탐색하면서 알아보기 쉽도록 만들어주어 대용량 그래픽 파일이 빠른 속도로 사용자에게 인식될 수 있도록 도와주는 역할을 수행한다. 국내 안드로이드 스마트폰의 4.4.x(Kitkat) 이후 버전에서 설치되는 갤러리 애플리케이션은 썸네일의 metadata에 그래픽 파일의 생성시각을 기록한다. 이것을 기존 원본 그래픽 파일과 함께 병행하여 분석하면 생성, 수정, 삭제 등의 사용자 행위에 대한 타임라인을 구성할 수 있다. 또한 썸네일이 썸캐시라는 단일 파일 안에 순차적으로 저장되는 특징을 활용하면 썸캐시가 삭제된다고 하더라도 썸네일을 복원할 수 있다. 본 논문에서는 안드로이드 스마트폰의 기본 갤러리 애플리케이션이 생성하는 썸네일의 특성을 분석하고 삭제된 썸네일을 복원하는 방법과 디지털 포렌식 관점에서 활용할 수 있는 방안을 제시한다.

• 대한치과의사협회지
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• 제58권5호
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• pp.276-283
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• 2020

Objectives: The aim of this study was to evaluate the efficacy of CK files as an ultrasonic instrument, and to determine most efficient file size for smear layer removal. Materials and Methods: Thirty-six extracted human mandibular premolars with single, straight root canals and mature apices were mechanically prepared and randomly divided into three groups. Group 1 (Control) underwent conventional needle irrigation, Group 2 (CKS) underwent passive ultrasonic irrigation with a #20 CK file, and Group 3 (CKL) underwent passive ultrasonic irrigation with a #30 CK file. After preparation and irrigation, all teeth were dried and split with a chisel to obtain the mesial and distal half of their roots. Each sample was evaluated using a scanning electron microscope, and data were analyzed using the Kruskal-Wallis and Mann-Whitney rank sum tests (p<0.05). Results: The CKS group showed less debris in the apical third than the other groups (p<0.05). In this section, no significant difference was observed among the other groups. And, there was no significant difference among any groups for the middle third section. Conclusion: This study showed that PUI with #20 CK file removed more smear layer compared to using #30 CK file at the apical third of the root canal.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.236-246
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• 1998

The purpose of this study was to compare the degree of micro- leakage of new glass ionomer root canal sealer, Ketac-Endo(ESPE Co., Seefeld, Germany) with that of AH-26(De Trey Co., Ltd., U.S.A.). Root canal treatment using K -file, H -file, Gate Glidden drill was conducted on 49 extracted single-rooted teeth. 45 teeth were randomly divided into 3 experimental groups(15 teeth per group) and 4 teeth were used as the control group. Group 1 was used AH -26 sealer with the lateral condensation method for canal filling, group 2 was used Ketac-Endo with the single cone method and group 3 was used Ketac-Endo with the lateral condensation method. The control group was obturated with the single cone method without sealer. The teeth were covered with two coats of nail varnish after 48 hours of obturation. The teeth were immersed in India ink for 1 week and cleaned with methyl salicylate and then the degree of dye penetration were measured with stereomicroscope. The data were analyzed statistically by one-way ANOVA. The results were as follows: 1. 7 teeth in group 1, 5 in group 2, and 3 in group 3, were showed evidence of microleakage implying appropriate canal filling. 2, The mean average of microleakage was $0.17{\pm}0.32mm$ in group 1, $0.30{\pm}0.37mm$ in group 2. $0.10{\pm}0.21mm$ in group 3, showing that canal filling using the lateral condensation canal filling method with Ketac-Endo showed the least microleakage and using the single cone method with Ketac-Endo showed the largest amount of microleakage, 3. There were no statistically significant difference in the variation of microleakage among groups. From the results above, Ketac-Endo which has the advantage of glass ionomer, whether using the single cone method or the lateral condensation method, showed similar results as AH-26, but for clinical application it is thought that were studies on the properties of Ketac-Endo should be followed.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권7호
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• pp.625-635
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• 2008

휴대용 멀티미디어 재생기는 기존의 멀티미디어 파일 서버와는 다른 성질들을 가지고 있다. 개인 사용자 전용, 비교적 낮은 하드웨어 성능, 사용자 기능으로 인한 순간적인 높은 부하, 그리고 짧은 개발주기 등이 이러한 성질들이다. 다양한 멀티미디어 파일 시스템은 여러 사용자의 요구는 처리하기에는 적합하지만 단일 사용자의 특수 기능을 지원하기에는 적합하지 않다. 팁과 같은 추가 정의를 응용프로그램과 과일시스템이 주고받는 방식들도 제안되었지만 프로그램의 개발주기를 증가시킬 수 있다. 본 논문에서는 파일블록배치, 버퍼-캐시, 그리고 미리 읽기를 사용하여 휴대용 재생기에서 사용자 기능을 효과적으로 지원하는 파일 시스템을 디자인하고 그 성능을 평가하였다. 힌트를 사용하는 기존의 미리읽기들과는 달리 제안된 미리읽기인 SPRA (Speed-based PRefetch Algorithm)는 힌트를 사용하지 않고 입출력 요구의 패턴을 통해서 미리 읽을 블록을 예측한다. 이는 응용프로그램이 수정되고 재컴파일 되는 과정을 제거함으로써 프로그램 개발기간을 단축시킨다. 실험결과 SPRA의 평균 반환시간은 리눅스의 추가읽기와 비교해서 $4.29%{\sim}52.63%$이며, 고속 재생 시 리눅스 추가읽기의 $1.01{\sim}3.09$배의 대역폭을 가진다.

• Restorative Dentistry and Endodontics
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• 제30권1호
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• pp.31-37
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• 2005

본 실험은 resin 시편을 이용하여 미리 제작한 근관 내 불규칙 확장부에서 근관 충전용 sealer의 적용 방법에 따른 충전 효과를 평가해 보았다. Endo-training Bloc을 절단하여 사십 개의 규격화된 resin 블록 시편을 획득하였다. 각각의 시편에 $\#20$, 08taper GT 파일을 사용하여 근관을 형성하였고 근관에 손상이 가지 않도록 시편을 양분한 후 양분된 시편의 한 쪽 근관 벽에 다양한 근관 내 확장부를 표현하는 구를 형성하였다. 양분된 시편을 결찰하고 절단 부위를 밀봉하였으며 AH26 sealer를 사용하여 단일 cone 충전법으로 근관을 충전하였다. 네 가지의 근관 충전용 sealer의 적용방법을 이용하였다: A군, $\#20$ K-file : B군, ultrasonic file : C군, lentulo spiral: D군. EZ-Fill bi-directioanl spiral. 모든 시편은 $37^{\circ}\;100\%$ 상대습도에서 1주일간 보관한 후 각 시편을 근단에서 3mm, 4mm, 5mm 부위에서 수평으로 절단하고 각각의 절단면을 위상차현미경과 디지털 카메라를 이용하여 30배율로 관찰하고 촬영하였다. 관찰된 절단면은 scoring system을 이용하여 점수를 산정하였고 각 군 간의 통계적인 유의성 유무는 Fisher's Exact Test를 이용하여 시행하였다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권2호
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• pp.91-99
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• 2023

Background: Extrusion of debris is a major factor that results in postoperative pain during root canal treatment with various instruments and instrumentation techniques. Therefore, instrumentation techniques that extrude minimal debris into the periapical area while reducing pain are desirable. This study aimed to compare the incidence of postoperative pain and intake of analgesic medication (frequency and quantity) after endodontic treatment of mandibular posterior teeth using two single files and full-sequence continuous rotary systems with different kinematic motions. Methods: Thirty-five of 105 patients were assigned equally to three groups according to the instrumentation system used: ProTaper Next (PN) X2, 25/06 (Dentsply, Maillefer, Ballaigues, Switzerland), One Shape (OS), #0.25/06 (Micro Mega, Besancon, France), and Wave One Gold (WG), Red - #0.25, 0.07 (Dentsply, Maillefer, Ballaigues, Switzerland). Five specialists were included in this study design; each professional prepared 21 teeth, and randomly selected 7 per instrument system. The VAS sheet ranging from 0 to 10 was used to record the initial and postoperative pains at 24, 48, and 72 h, and 7^th day after single visit endodontic treatment in mandibular premolars and molars with a diagnosis of asymptomatic irreversible pulpitis with or without apical periodontitis. Postoperatively, an analgesic, ibuprofen 400 mg was administered for intolerable pain at a dose of 1 tablet for 6 h. The patients were asked over the telephone regarding postoperative pain at intervals of 24, 48, and 72 h, and 7^th day using a visual analogue scale. Result: There were no statistically significant differences among the PN, OS, and WG systems (P > 0.05) with regard to the incidence of postoperative pain at any of the four time points assessed. Conclusion: The intensity of postoperative pain, frequency, and analgesic intake were similar across all three types of instrument systems; however, the reciprocating single file (WG) was associated with less postoperative pain than the full sequence continuous rotary file.