• Restorative Dentistry and Endodontics
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• 제17권2호
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• pp.399-412
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• 1992

The purpose of this study was to evaluate the root canal transportation and remaining dentin / cementum thickness after using hand and ultrasonic instrumentation in the curved mesial root canals of extracted human mandibular molars. Fourty - six clear polyether blocks were made and randomly divided into two groups: hand instrumentation group with K - Flex files and ultrasonic instrumentation group with Suprasson SP unit. All root canals were instrumented to a size corresponding to a # 30 K - Flex file 1mm short from the radiographic apex. The roots were then sectioned perpendicular to the long axis so the apical and middle third could be evaluated with the Zoom stereomicroscope. The results were as follows : 1. In the total amount of removed dentin at middle third level, there was not significant difference between the hand instrumentation and ultrasonic instrumentation (P>0.05). 2. In the total amount of removed dentin at apical third level, there was more removed by the ultrasonic instrumentation than hand instrumentation(P<0.005). 3. In the transportation width, there was not significant difference between the two groups at both sectioned levels(P>0.05). 4. It was suggested that the canal was transported distally at middle third level and mesially at apical third level by booth techniques.

• The Journal of Advanced Prosthodontics
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• 제14권1호
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• pp.45-55
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• 2022

PURPOSE. This in vitro study investigates the effect of different post-rinsing times and methods on the trueness and precision of denture base resin manufactured through stereolithography. MATERIALS AND METHODS. Ninety clear photopolymer resin specimens were fabricated and divided into nine groups (n = 10) based on rinsing times and methods. All specimens were rinsed with 99% isopropanol alcohol for 5, 10, and 15 min using three methods-automated, ultrasonic cleaning, and hand washing. The specimens were polymerized for 30 min at 40℃. For trueness, the scanned intaglio surface of each SLA denture base was superimposed on the original standard tessellation language (STL) file using best-fit alignment (n = 10). For precision, the scanned intaglio surface of the STL file in each specimen group was superimposed across each specimen (n = 45). The root mean square error (RMSE) was measured, and the data were analyzed statistically through one-way ANOVA and Tukey test (α < .05). RESULTS. The 10-min automated group exhibited the lowest RMSE. For trueness, this was significantly different from specimens in the 5-min hand-washed group (P < .05). For precision, this was significantly different from those of other groups (P < .05), except for the 15-min automated and 15-min ultrasonic groups. The color map results indicated that the 10-min automated method exhibited the most uniform distribution of the intaglio surface adaptation. CONCLUSION. The optimal postprocessing rinsing times and methods for achieving clear photopolymer resin were found to be the automated method with rinsing times of 10 and 15 min, and the ultrasonic method with a rinsing time of 15 min.

• Restorative Dentistry and Endodontics
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• 제39권2호
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• pp.104-108
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• 2014

Objectives: To evaluate the effect of passive ultrasonic agitation on the cleaning capacity of a hybrid instrumentation technique. Materials and Methods: Twenty mandibular incisors with mesiodistal-flattened root shape had their crowns sectioned at 1 mm from the cementoenamel junction. Instrumentation was initiated by catheterization with K-type files (Denstply Maillefer) #10, #15, and #20 at 3 mm from the working length. Cervical preparation was performed with Largo bur #1 (Dentsply Maillefer) followed by apical instrumentation with K-type files #15, #20 and #25, and finishing with ProTaper F2 file (Denstply Maillefer). All files were used up to the working length under irrigation with 1 mL of 2.5% sodium hypochlorite (Biodyn$\hat{a}$mica) at each instrument change. At the end of instrumentation, the roots were randomly separated into 2 groups (n = 10). All specimens received final irrigation with 1 mL of 2.5% sodium hypochlorite. The solution remained in the root canals in Group 1 for one minute; and ultrasonic agitation was performed in Group 2 for one minute using a straight tip inserted at 1 mm from working length. The specimens were processed histologically and the sections were analyzed under optic microscope (x64) to quantify debris present in the root canal. Results: The samples submitted to ultrasonic agitation (Group 2) presented significant decrease in the amount of debris in comparison with those of Group 1 (p < 0.05). Conclusions: The hybrid instrumentation technique associated with passive ultrasonic agitation promoted greater debris removal in the apical third of the root canals.

• 한국인터넷방송통신학회논문지
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• 제16권2호
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• pp.49-54
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• 2016

본 논문에서는 아두이노 기반의 효율적인 홈 시큐리티 모니터링 시스템을 제안한다. 제안하는 홈 시큐리티 모니터링 시스템은 비교적 가격이 저렴한 메인 프로세서인 아두이노와 초음파 센서, 인체 감지 센서를 이용하여 침입여부를 판단하도록 홈 시큐리티 시스템을 구성하였고, 초음파 센서와 인체 감지 센서의 데이터는 아두이노에 연결된 이더넷 쉴드를 통해 웹 서버로 전송하도록 설계하였다. 그리고 웹 서버에서는 저장된 초음파 센서와 인체 감지 센서 데이터를 이용하여 침입여부를 확인하고, JQuery를 이용하여 연결되어 있는 웹캠으로 스냅 샷을 촬영하도록 하였으며, 촬영 된 스냅 샷은 웹 서버에 이미지 파일로 저장되며, HTML5와 CSS, Canvas를 사용하여 사용자는 웹 또는 스마트 디바이스 환경에서 모니터링이 가능하도록 설계하였다. 제안된 홈 시큐리티 모니터링 시스템을 실제 구현함으로서 효율성 검증 결과 기존 홈 시큐리티 시스템에 비해 구성이 쉬워 도면을 보고 쉽게 제작이 가능하였으며, 아두이노를 이용하여 구성과 설치비에 대한 가성비가 뛰어났고, 개인이 오류에 대한 직접적인 대처가 가능해 비용에 대한 효율성과 편리성을 입증하였으며, 신뢰도 높은 데이터를 이용하여 안정적인 시스템 운영이 가능하였다.

• Restorative Dentistry and Endodontics
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• 제46권4호
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• pp.56.1-56.11
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• 2021

Objectives: This study evaluated 2 nickel-titanium rotary systems and a complementary protocol with an ultrasonic tip and a small-diameter instrument in flattened root canals. Materials and Methods: Thirty-two human maxillary second premolars with flattened canals (buccolingual diameter ≥4 times larger than the mesiodistal diameter) at 9 mm from the radiographic apex were selected. The root canals were prepared by ProDesign Logic (PDL) 30/0.01 and 30/0.05 or Hyflex EDM (HEDM) 10/0.05 and 25/0.08 (n = 16), followed by application of the Flatsonic ultrasonic tip in the cervical and middle thirds and a PDL 25/0.03 file in the apical third (FPDL). The teeth were scanned using micro-computed tomography before and after the procedures. The percentage of volume increase, debris, and uninstrumented surface area were analyzed using the Kruskal-Wallis, Dunn, Wilcoxon, analysis of variance/Tukey, and paired and unpaired t-tests (α = 0.05). Results: No significant difference was found in the volume increase and uninstrumented surface area between PDL and HEDM (p > 0.05). PDL had a higher percentage of debris than HEDM in the middle and apical thirds (p < 0.05). The FPDL protocol resulted in less debris and uninstrumented surface area for PDL and HEDM (p < 0.05). This protocol, with HEDM, reduced debris in the middle and apical thirds and uninstrumented surface area in the apical third (p < 0.05). Conclusions: High percentages of debris and uninstrumented surface area were observed after preparation of flattened root canals. The HEDM, Flatsonic tip, and 25/0.03 instrument protocol enhanced cleaning in flattened root canals.

• Restorative Dentistry and Endodontics
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• 제15권2호
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• pp.46-57
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• 1990

초음파진동과 열을 이용하는 초음파 금관충전법의 근관페쇄효과를 연구하기 위하여 색소회복법(dye recovery method)에 기초한 분광광도계 측정법으로 근단공 누출정도를 정량적으로 측정하였다. 발거된 상하악 중절치 및 측절치에서 치관을 절제한 120개의 치근에 재래식 방법으로 근관형성을 하고 측방가압법, McSpadden 근관충전법 및 초음파 근관충전법으로 근관을 충전한 후 $37^{\circ}C$ 항온기내에서 2% methylene blue에 10일간 침지시킨 다음 색소용출을 위해 60% 질산에 용해시키고 색소회복법에 의한 분광광도계 측정을 시행한 후 검량선에 의한 누출량을 산출하여 통계학적으로 상호비교 하였다. 초음파 근관충전법의 색소침투량은 sealer 사용유무와는 관계없이 측방가압충전법과 유사하게 나타났고 McSpadden 충전법은 측방가압법보다 색소 침투량이 더 많이 나타났다. 측방가압풍전법과 초음파 근관충전법에서는 sealer를 병용시 근관폐쇄효과는 양호하였으나, McSpadden 근관충전법에서는 sealer 사용유무에 따른 근관폐쇄효파는 별 차이가 없었다.

• 대한의용생체공학회:의공학회지
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• 제19권6호
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• pp.571-575
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• 1998

초음파 영상 진단 장비의 중요한 특징 중의 하나는 실시간으로 생체내의 연부 조직에 대한 정보를 보여준다는 것이다. 심초음파도는 심장판막 및 심벽의 상태를 실시간 단면 영상으로 보여줄 수 있으므로 심장 질환 진단에 널리 이용되고 잇다. 그러나, 초음파 영상은 스펙클 잡음이나 영상 탈락 등으로 인하여 화질이 많이 열화되어 있다. 그러므로, 이러한 초음파 영상을 개선시킬 수 있는 새로운 기술을 개발하는 것이 매우 중요하다. 본 연구에서는 심초음파도의 개선된 이진 영상을 검출하기 위한 영상 처리 기술을 제안한다. 아날로그 영상인 심초음파도로부터 디지털 동영상 파일을 만들고, 이것을 다시 프레임 단위로 각각 8bit 그레이 레벨을 갖는 정지 영상으로 변환하여 저장하였다. 효율적인 영상 처리를 위해 심중격과 삼첨판을 중심으로 한 심장 부위를 관심 영역으로 두었고, 스펙클 잡음이 포함된 각각의 영상은 영상 개선 필터와 모폴러지 필터를 이용하여 처리되었다. 그 결과, 원 영상이나 문턱치에 의한 이진 영상에 비해 명확한 윤곽선을 가진 개선된 이진 영상을 얻을 수 있었다. 결론적으로, 본 논문에서 제안한 장법은 보다 최적의 초음파 이진 영상 처리 기술 개발과 심초음파 영상의 좌심실벽 운동과 같은 정량적 분석에 중요한 심벽 윤곽선 검출 등에 기여할 수 있을 것이라 생각된다.

• Restorative Dentistry and Endodontics
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• 제26권5호
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• pp.379-386
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• 2001

This study was performed to evaluate the sealing ability of various retrograde filling materials by using bacterial penetration and dye penetration test. One hundred and forty extracted human teeth with single, straight canals and mature apiece were collected and used for this study. All canals were instrumented using an engine driven Ni-Ti file (ProFile). After removing 3mm from the apex of tooth, a standardized 3mm root end cavity was prepared using an ultrasonic instrument. The 70 teeth were randomly divided into 7 groups : 6 groups for retrograde filling using Super-EBA, ZOE, Chelon-Silver, IRM, ZPC and amalgam. The 7th group was used as a negative control. Nail varnish was applied to all external root surfaces to the level of the reseated root ends to prevent lateral microleakages. The specimens were then sterilized in an ethylene oxide sterilizer for 24 hours. 2 mm of the reseated root was immersed in a culture chamber containing a Tripticase Soy Broth with a phenol red indicator. The coronal access of each specimen was inoculated every 72 hours with suspension of Proteus vulgaris. The culture media were observed every 24hours for color change indicating bacterial contamination. The specimens were observed for 4weeks. The remaining 70 teeth were submitted to a dye penetration test. The canals of all teeth were first sealed with AH26 and obturated using an Obtura II system. Root resection, root end preparation and retrograde filling was performed as above. All specimens were suspended in 2% methylene blue dye for 72 hours before being ion gitudinally split. The degree of dye penetration was then measured using a stereomicroscope at 10 magnification and evaluated. The results were as floows : 1. In the bacterial penetration, the degree of leakage was the lowest in the Super-EBA, followed by, in ascending order, ZOE, Chelon-Silver IRM and ZPC. The amalgam showed highest bacterial leakage of all(p<0.01). 2. In the dye penetration, the degree of microleakage was the lowest in the Chelon-Silver and Super-EBA, followed by, in ascending order, IRM, ZPC. The ZOE and amalgam showed the highest microleakage of all (p<0.05). These results suggested that the eugenol based cement, Super-EBA, have excellent sealing ability as a retrograde filling material.

• Restorative Dentistry and Endodontics
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• 제48권3호
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• pp.28.1-28.13
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• 2023

Objectives: This study aimed to investigate the effect of the application method of 2% chlorhexidine (CHX) and its influence on the adhesion of fiberglass posts cemented with a self-adhesive resin cement. Materials and Methods: Sixty human mandibular premolars were endodontically treated and divided into 5 groups (n = 12), according to the canal irrigant and its application method: 2 groups with conventional syringe irrigation (CSI)-2.5% sodium hypochlorite (NaOCl) (control) and 2% CHX- and 3 groups with 2% CHX irrigation/activation-by passive ultrasonic irrigation (PUI), Easy Clean file, and XP-Endo Finisher file. Two roots per group were evaluated for smear layer (SL) removal by scanning electron microscopy. For other roots, fiber posts were luted using a self-adhesive resin cement. The roots were sectioned into 6 slices for push-out bond strength (BS) (7/group) and nanoleakage (NL) (3/group). Data from SL removal were submitted to Kruskal-Wallis and Student-Newman-Keuls tests (α = 0.05). Data from BS and NL were evaluated by 2-way analysis of variance and Tukey's test (α = 0.05). Results: For SL removal and BS, the CHX irrigation/activation promoted better values than CSI with CHX (p < 0.05), but it was not significantly different from CSI with NaOCl (p > 0.05). For NL, the lowest values were obtained by the chlorhexidine irrigation/activation groups (p < 0.05). Conclusions: Active 2% CHX irrigation can be used to improve the post space cleaning and adhesion before fiber post cementation with self-adhesive resin cements.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.88-91
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• 1997

One of the most significant feature of diagnostic ultrasonic instrument is to display information on the soft tissues in the body in real time. In this paper we carried out basic study on the digital moving image processing for tracing the movement of heart valves in echocardiograms. Digital moving image file was made from analog echocardiograms and it was remade as 256 gray-level images on each frame. The ROI(Region of interest) was placed on a heart valve region to process images efficiently. Images were processed by the use of image enhancement filters and morphology filters. The result shows that the processed images were more enhanced than original images. When a moving image is reconstructed by using these enhanced images, we can trace the movement of heart valves more easily. In this study we proposed the availability of the moving image reconstruction using enhancement images.