백색광과 청색광 스캐너를 이용한 지대치 인상체 스캐닝의 반복재현성 비교

전진훈,성환경,민병국,황재선,김지환,김웅철 대한치과기공학회 2015 대한치과기공학회지 Vol.37 No.4

Purpose: The purpose of this study compared of reproducibility of prepared tooth impression scanning utilized with white and blue light scanners. Methods: To evaluate reproducibility with white and blue light scanners, the impression of premolar were rotated by 10°~20° and scanned. These data were compared with the first 3-D data (STL file), and the error sizes were measured (n=5). Independent t test was used to evaluation the reproducibility of impression of premolar with white versus blue light scanners through discrepancies of mean, RMS (α=0.05). Results: Discrepancies of mean with regard to reproducibility were 11.2㎛, 5.8㎛, respectively, with white and blue light scanners (p<0.047). And discrepancies of RMS with regard to reproducibility were 33.4㎛, 18.8㎛, respectively, with white and blue light scanners (p<0.045). Conclusion: Our results indicate a good reproducibility of prepared tooth impression digitized with blue light scanner more than that with white light scanner.

치과 캐드캠 ISO평가 기준에 준한 지대치 경석고 모형 및 인상체 스캐닝의 반복측정안정성 비교 평가

전진훈,황성식,김총명,김동연,김지환,김웅철 대한치과기공학회 2017 대한치과기공학회지 Vol.39 No.1

Purpose: The purpose of this in vitro study compared to evaluation of repeatability of scanning abutment tooth stone model and impression applied CAD/CAM ISO standard in dentistry. Methods: To evaluate repeatability of scanning abutment tooth stone model, were repeatedly scanned to obtain 11 data via 3D stereolithography (STL) files. 10 data (STL files) were compared with the first 3D data (STL file), and the error sizes were measured by using 3D superimposing software(n=10). Also, the repeatability of scanning abutment tooth impression was evaluated with the same procedure. Independent t test was performed to evaluate the repeatability of scanning abutment tooth stone model versus impression through root mean square(RMS) and standard deviation(SD)(α=0.05). Results: RMS±SD with regard to repeatability were 14.7±2.5㎛, 17.1±4.0㎛, respectively, with scanning abutment tooth stone model and impression(p=0.129). Conclusion: This study results showed a little different repeatability of scanning abutment tooth stone model and impression applied CAD/CAM ISO standard in dentistry, will suggest futures good studies and clinical advantages.

도재소성 시 냉각속도가 전부도재관의 색조에 미치는 영향

전진훈,민병국,황재선,김웅철 대한치과기공학회 2015 대한치과기공학회지 Vol.37 No.4

Purpose: The purpose of this in vitro study was to evaluation the effect of shade on all ceramic restoration based zirconia according to cooling rate on Firing. Methods: 10 specimens applied to the dentin porcelain were made on the zirconia. After 5 specimens of the first group were burned in the furnace, these were put out rapidly. And after 5 specimens of the second group were burned in the furnace, these were put out slowly later 15 min. All specimens were measured L, a, b using spectrophotometer, there were calculated 10 mean(SD) of descriptive statistics with SPSS program. These data were used for ∆E with color difference equation. Independent t tests were performed between 2 groups. Results: L, a, b of 2 groups was statistically significant respectively (p<0.001), ∆E was 4.55 value. Conclusion: This study showed effect of shade on all ceramic restoration based zirconia according to cooling rate on Firing.

Accuracy of 3D white light scanning of abutment teeth impressions: evaluation of trueness and precision

전진훈,김혜영,김지환,김웅철 대한치과보철학회 2014 The Journal of Advanced Prosthodontics Vol.6 No.6

PURPOSE. This study aimed to evaluate the accuracy of digitizing dental impressions of abutment teeth using a white light scanner and to compare the findings among teeth types. MATERIALS AND METHODS. To assess precision, impressions of the canine, premolar, and molar prepared to receive all-ceramic crowns were repeatedly scanned to obtain five sets of 3-D data (STL files). Point clouds were compared and error sizes were measured (n=10 per type). Next, to evaluate trueness, impressions of teeth were rotated by 10°–20° and scanned. The obtained data were compared with the first set of data for precision assessment, and the error sizes were measured (n=5 per type). The Kruskal–Wallis test was performed to evaluate precision and trueness among three teeth types, and post-hoc comparisons were performed using the Mann–Whitney U test with Bonferroni correction (α=.05). RESULTS. Precision discrepancies for the canine, premolar, and molar were 3.7 μm, 3.2 μm, and 7.3 μm, respectively, indicating the poorest precision for the molar (P<.001). Trueness discrepancies for teeth types were 6.2 μm, 11.2 μm, and 21.8 μm, respectively, indicating the poorest trueness for the molar (P=.007). CONCLUSION. In respect to accuracy the molar showed the largest discrepancies compared with the canine and premolar. Digitizing of dental impressions of abutment teeth using a white light scanner was assessed to be a highly accurate method and provided discrepancy values in a clinically acceptable range. Further study is needed to improve digitizing performance of white light scanning in axial wall.

치과용 백색광 스캐너를 이용한 impression scanning의 반복 측정에 대한 안정성 평가

전진훈,이경탁,김혜영,김지환,김웅철 대한치과기공학회 2013 대한치과기공학회지 Vol.35 No.1

White light scanner-based repeatability of 3-dimensional digitizing of silicon rubber abutment teeth impressions

전진훈,이경탁,김혜영,김지환,김웅철 대한치과보철학회 2013 The Journal of Advanced Prosthodontics Vol.5 No.4

PURPOSE. The aim of this study was to evaluate the repeatability of the digitizing of silicon rubber impressions of abutment teeth by using a white light scanner and compare differences in repeatability between different abutment teeth types. MATERIALS AND METHODS. Silicon rubber impressions of a canine, premolar, and molar tooth were each digitized 8 times using a white light scanner, and 3D surface models were created using the point clouds. The size of any discrepancy between each model and the corresponding reference tooth were measured, and the distribution of these values was analyzed by an inspection software (PowerInspect 2012, Delcamplc., Birmingham, UK). Absolute values of discrepancies were analyzed by the Kruskal–allis test and multiple comparisons (α=.05). RESULTS. The discrepancy between the impressions for the canine, premolar, and molar teeth were 6.3 μm (95% confidence interval [CI], 5.4-7.2), 6.4 μm (95% CI, 5.3-7.6), and 8.9 μm (95% CI, 8.2-9.5), respectively. The discrepancy of the molar tooth impression was significantly higher than that of other tooth types. The largest variation (as mean [SD]) in discrepancies was seen in the premolar tooth impression scans: 26.7 μm (95% CI, 19.7-33.8); followed by canine and molar teeth impressions, 16.3 μm (95% CI, 15.3- 17.3), and 14.0 μm (95% CI, 12.3-15.7), respectively. CONCLUSION. The repeatability of the digitizing abutment teeth’ silicon rubber impressions by using a white light scanner was improved compared to that with a laser scanner, showing only a low mean discrepancy between 6.3 μm and 8.9 μm, which was in an clinically acceptable range. Premolar impression with a long and narrow shape showed a significantly larger discrepancy than canine and molar impressions. Further work is needed to increase the digitizing performance of the white light scanner for deep and slender impressions.

3차원 중첩 기술 차이에 따른 디지털 치과용 지대치 인상체 및 경석고 모형의 스캐닝 정밀도 평가

전진훈(Jin-Hun Jeon) 한국콘텐츠학회 2018 한국콘텐츠학회논문지 Vol.18 No.12

본 연구의 목적은 3차원 중첩 기술 차이에 따른 디지털 치과용 지대치 인상체 및 경석고 모형의 스캐닝정밀도를 비교 평가하는 것이다. 상악 제1 소구치 지대치 인상체와 경석고 모형를 제작했다. 청색광 스캐너로 스캔하여 stereolithography (STL)을 얻었다. 지대치 인상체와 경석고 모형에 대하여 스캐너 테이블에서 이동하지 않은 채로 10번의 추가 스캔을 수행하였다. no control과 best-fit-alignment 기술을 사용하여 지대치 인상체와 경석고 모형 스캐닝 데이터를 중첩시킴으로써 10개의 color-difference maps과 root mean square (RMS) 데이터를 얻었다. 서로 간의 그룹 사이에 RMS data를 가지고 독립 t 검정을 수행하였다(α=0.05). 지대치 인상체 스캐닝에 있어서 no control과 best-fit-alignment의 RMS±Standard Deviation (SD) 값은 6.86±0.94, 5.04±0.24로 나타났고, 경석고 모형 스캐닝에 있어서는 4.98±1.16, 3.39±0.07로 나타났으며, 모든 그룹 간에 유의한 차이를 보였다(P<0.001). 본 연구 결과를 통해 best-fit-alignment뿐만 아니라 no control은 디지털 치과캐드캠 연구 분야 및 임상 분야에 활용될 수 있다고 생각한다. The objective of this research was to compare the precision of scanning the digital abutment impression and gypsum model according to 3-dimensional superimposing different skills. There were made with the abutment impression and gypsum model of a maxillary 1st premolar, blue light scanner scanned to obtain the stereolithography (STL) file. After the same process was performed 10 more times without moving them on the scanner table about the abutment impression and gypsum model, respectively (n=11, per types). By superimposing the date of scanning the abutment impression and gypsum model used with no control and best-fit-alignment skills, 10 color-difference maps and root mean square (RMS) data were obtained. The independent t-test was performed to compare RMS data between the each other groups (α=0.05). In the scanning abutment impressions, RMS±SD of no control, best-fit-alignment showed 6.86±0.94, 5.04±0.24. in the scanning gypsum model, 4.98±1.16, 3.39±0.07, all groups showed a significant difference (P<0.001). Trough the this study’s result, not only best-fit-alignment but no control is used with digital dental computer-aided design/computer-aided manufacturing (CAD/CAM) research and clinical part.

신생아의 간질양 뇌파 및 뇌 영상 검사 소견에 대한 연구

전진훈(Jin Hun Jeon),설인준(In Joon Seol),문수지(Soo Ji Moon) 대한소아신경학회 1999 대한소아신경학회지 Vol.7 No.1

목 적 : 신생아 경련 발작은 대부분 증후성이고 그 형태가 다양하고 비정형적이며 환아들 에서 기록되는 뇌파소견 또한 신생아기 이후 환아들의 뇌파와는 다른 모양을 갖는 경우가 많다. 저자들은 신생아들에서 흔히 나타나는 간질양 뇌파의 형태, 기질적 원인의 빈도, 뇌파와 뇌 영상 검사 소견과의 연관성을 알아보고자 본 연구를 시행하였다. 방 법 : 1993년 3월부터 1997년 2월까지 만 4년 동안 한양대학병원 소아과에서 생후 7일 이내에 경련발작이 의심되어 뇌파 검사를 시행한 환아들 중 뇌파 검사상 확실한 간질양 뇌파가 기록되고 동시에 뇌초음파검사, 뇌전산화단층촬영, 뇌자기공명영상 등의 뇌 영상 검사를 시행하여 양 검사간의 상관성을 비교할 수 있는 41례를 대상으로 후향성 연구를 하였다. 결 과 : 1) 경련의 형태는 비정형적 경련이 20례(48.8%)로 가장 많았고, 전신 강직성 경련 11례(26.8%), 다국소 간대성 경련 7례(17.1%), 국소 간대성 경련 2례(4.9%), 근간대성 경련 1례(2.4%)의 순이었다. 2) 환아들에서 기록된 간질양 뇌파를 빈도순으로 보면 과도한 일과성 예파가 28례로 가장 많았고, 그 외 다초점성 극파, 다초점성 예파, 반복적 α파, 반복적 θ파 등의 순으로 관찰 되었고 출현 부위별로는 양측이 28례로 가장 많았고 우측반구 9례, 좌측반구 8례의 순이었다. 3) 뇌 영상 임상소견들은 정상이 27례로 가장 많았으며 14례에서 뇌부종, 두 개강내 출혈, 백질 연화증, 뇌 지주막하 출혈, 두혈종, 두개골 조기봉합 등이 관찰되었다. 4) 뇌 영상 검사상 이상소견이 발견된 14례중 5례에서 국소성 이상소견이 발견되었고 이들 중 3례에서 동일 부위에서 간질양 뇌파가 기록되었지만, 국소성 간질양 뇌파가 기록된 17례 중 3례에서 만 양 검사가 일치되는 소견을 보여 전반적으로 볼 때 양 검사간의 연관성이나 뇌 영상 검사상의 이상소견에 따른 특징적인 간질양 뇌파의 출현은 관찰할 수 없었다. 5) 환아들의 경과를 보면 23례에서는 항경련제 투여 없이, 13례에서는 항경련제 투여 후에 경련이 소실된 후 재발되지 않았고, 5례에서만 지속적인 항경련제 투여를 필요로 하는 양호한 경과를 보였다. 결 론 : 본 연구에서는 신생아 경련시 뇌파의 출현 부위와 뇌 영상 검사상의 병변 부위와의 연관성을 관찰할 수는 없었으나, 신생아 경련시 뇌 영상 검사는 환아의 뇌증의 정도를 알아보기 위해서 필요하리라 생각된다. Purpose : Neonatal seizures are mostly symptomatic and have variable atypical clinical features with very different EEG findings from those of post-neonatal period. This study was performed to determine the common types of epileptiform discharges and their relationship with abnormalities in imaging study in neonates with seizures. Methods : Fourty one neonates under 7 days of age who had been hospitalized at the Hanyang university hospital from June 1993 to May 1997 were studied retrospectively. Their medical records, results of EEG and brain imaging study were reviewed. Results : 1) The types of neonatal seizures were subtle, generalized tonic, multifocal clonic, focal clonic, myoclonic in order of frequency. 2) The most common epileptiform discharge was excessive sharp transients recorded in 28 cases and the rest showed multifocal spikes, sharp waves, repetitive alpha, repetitive theta in order. Epileptiform discharges appeared on the both hemisphere in 24 cases, right hemisphere in 9 cases and left hemisphere in 8 cases. 3) Imaging study showed no abnormal findings in 27 cases and abnormal findings in 14 cases such as brain edema, intracranial hemorrhage, leukomalacia, subarachnoid hemorrhage, cephalhematoma, craniosynostosis. 4) Among 14 cases with radiological abnormalities, 5 cases had localized abnormalities and 3 of them had the abnormal EEG discharges on the same area concomittantly. But in total only 3 cases of 17 cases with localized epileptiform discharges had abnormalities in imaging study on the same site and so significant relationship between two studies was not observed. 5) As for the prognosis of seizures, subsided in 23 cases without any antiepileptic drugs, 13 cases had no seizure after taking medicine for few days and 5 cases needed continuous antiepileptic drug. Conclusion : This study showed no meaningful relationship between abnormal EEG findings and localization by imaging study in neonatal seizure but we concluded that brain imaging study was needed to determine degree of encephalopathy in neonatal seizures.

소아 결절성 십이지장염의 임상적 소견과 병리학적 소견에 대한 연구

김헌상,전진훈,김용주,장세진,홍은경 대한소아청소년과학회 2000 Clinical and Experimental Pediatrics (CEP) Vol.43 No.5

Purpose : Nodular duodenitis is defined as two or more erythematous nodules in the duodenum, with surrounding inflammation and with or without apical erosions. But the clinical features and natural history of nodular duodenitis remain largely undefined, therefore we examined clinical, endoscopic and pathologic features of nodular duodenitis in children to find about its natural history, relationship between endoscopic and pathologic findings, relationship between Helicobacter pylori and nodular duodenitis as well as clinical response to antisecretory therapy. Methods : Forty-nine children presented with chronic abdominal pain, chronic diarrhea, vomiting and indigestion showed nodular duodenitis on gastroduodenoscopic examinations at the Department of pediatrics of Hangyang University Hospital from January 1995 to August 1997. Endoscopic and pathologic findings were graded and the correlation coefficient between endoscopic and pathologic grades were analyzed. Clinical responses to therapy were compared between Helicobacter pylori(H. pylori)-associated and non H. pylori-associated children. Results : The chief most common complaint was chronic abdominal pain and this disease was most commonly developed in females and in school-aged children. In endoscopic examinations, Grade 1 was the most commonly noted, while in pathologic examinations, Grade 2 was most common. The correlation coefficient between endoscopic and pathologic findings was 0.278(P= 0.053). Clinical symptoms were improved by H2-blocker or anti-H. pylori therapy in most patients. Conclusion : There was no significant correlation between endoscopic and pathologic grades. H. pylori infection may be an etiologic factor of nodular duodenitis in some cases. 목 적 : 결절성 십이지장염은 내시경 소견상 상부 십이지장에 다발성의 발적을 보이는 결절이 관찰되고 주위로 염증 소견을 보이는 질환이다. 최근 소아 위장 내시경술의 발달과 더불어 소아에서의 결절성 십이지장염이 자주 관찰되나 이 질환에 대한 연구 보고는 국내외적으로도 드물다. 이에 저자들은 본 질환의 임상적, 병리학적 특성을 파악하기 위해 본 연구를 시행하였다.방 법 : 1995년 1월부터 1997년 8월까지 한양대학교 부속병원 소아과 외래 내원 및 입원하여 상부 위장관 내시경 검사상 결절성 십이지장염으로 진단받은 49명의 환아를 대상으로 후향적으로 연구를 시행하였다. 환아의 성별, 나이, 주증상, 내시경 소견, 조직학적 소견, 치료제에 대한 반응 정도를 조사하였다. 내시경 검사상 병변의 정도를 십이지장 점막의 결절의 크기와 그 분포에 따라 제 1도, 제 2도, 제 3도로 분류하였고 병리학적 검사상 십이지장 고유층의 염증세포의 침윤의 정도, 상피세포 및 융모의 소실 정도에 따라 정상, 제 1도, 제 2도, 제 3도 염증으로 분류하였다. 내시경적 소견의 정도와 병리학적 소견의 정도 간에 상관관계가 있는지를 알아보기 위해 SPSS를 이용하여 상관 계수와 P-value를 계산하였다.결 과 : 본 연구에서 소아 결절성 십이지장염은 여자에서 더 많았고 7-12세의 학동기 소아에 많았고 만성 복통이 가장 흔한 증상이었다. 내시경적 소견상 제1도가 가장 많았고 병리학적 소견상 제 0도의 환아는 없었고 제 2도가 가장 많았으며 두 등급간의 상관 계수는 0.278(P=0.053)이었다. H. pylori 감염자는 14명(29%)이었고 이중에서 Denol 과 amoxicillin으로 치료받은 13명중 12명에서 호전을 보였다. 1명은 호전이 없어 metronidazole, amoxicillin 2주 및 Denol 6주 투여후 호전되었다. 나머지 35명의 H. pylori 비감염자에서 H2-blocker 투여자 22명중 19명에서 호전되었고 2명은 호전이 없어 omeprazole 투여 2주후 호전되었다. 나머지 1명은 omeprazole 2주 투여후 호전되었다가 재발되어 ranitidine 2주 투여후 호전되 었다.

2종류의 버와 3종류의 버를 이용해 제작된 크라운 보철물의 정밀도 평가

김총명,전진훈,김웅철,이재준,김지환 대한치과기공학회 2016 대한치과기공학회지 Vol.38 No.2

Purpose: The purpose of this study was to assess precision of crown prostheses that were fabricated by using 2 kinds of bur or 3 kinds of bur. Methods: The crowns were fabricated by using the first molar of the right maxillary in this study. The abutments that were prepared were scanned by using a scanner and designed by using CAD software. Based on the crown design, NC data were created with CAM software. The created NC data were used while fabricating the crown prostheses by using 5-axis milling machine. Scanning was done for the internal and external surface of the completed crown prostheses and 3-dimensional measurement was conducted for precision assessment. Results: The RMS±SD value for the external surface of the crown prostheses that was fabricated by using two burs and three burs were 28.5±4.1㎛ and 19.1±2.8㎛, respectively; and the value for two burs were bigger than that for three burs with statistical significance (p<0.001). The RMS±SD value for the internal surface of the crown prostheses that was fabricated by using two burs and three burs were 14.9±1.9㎛ and 13.3±2.5㎛, respectively;and the value for two burs were bigger than that for three burs but with no statistical significance. Conclusion: Based on this study, the prostheses that were fabricated by using 3 bur presented better stability compared to those that were fabricated by using 2 bur and statistically significant difference was found only in the external surface.