근관장 측정에 있어서 디지털 영상 처리기와 주파수 의존형 측정기의 정확도

이병립,박창서,Lee Byaung-Rib,Park Chang-Seo 대한영상치의학회 1998 Imaging Science in Dentistry Vol.28 No.2

In order to achieve a successful endodontic treatment, root canals must be obturated three-dimensionally without causing any damage to apical tissues. Accurate length determination of the root canal is critical in this case. For this reason, I've used the conventional periapical radiography, Digora/sup (R)/(digital imaging system) and Root ZX/sup (R)/(the frequency dependent type apex locator) to measure the length of the canal and compare it with the true length obtained by cutting the tooth in half and measuring the length between the occlusal surface and the apical foramen. From the information obtained by these measurements, I was able to evaluate the accuracy and clinical usefulness of each systems. whether the thickness of files used in endodontic therapy has any effect on the measuring systems was also evaluated in an effort to simplify the treatment planning phase of endodontic treatment. 29 canals of 29 sound premolars were measured with #15, #20, #25 files by 3 different dentists each using the periapical radiography. Digora/sup (R)/ and Root ZX/sup (R)/. The measurements were then compared with the true length. The results were as follows: 1. In comparing mean discrepancies between measurements obtained by using periapical radiography(mean error: -0.449±0.444 mm), Digora/sup (R)/(mean error: -0.417±0.415 mm) and Root ZX/sup (R)/(mean error: 0.123±0.458 mm) with true length. periapical radiography and Digora/sup (R)/ system had statistically significant differences(p<0.05) in most cases while Root ZX/sup (R)/ showed none(p>0.05). 2. By subtracting values obtained by using periapical radiography, Digora/sup (R)/ and Root ZX/sup (R)/ from the true length and making a distribution table of their absolute values. the following analysis was possible. In the case of periapical film. 140 out of 261<53.6%) were clinically acceptable satisfying the margin of error of less than 0.5 mm. 151 out of 261 (53,6%) were acceptable in the Digora/sup (R)/ system while Root ZX/sup (R)/ had 197 out of 261(75.5%) within the limits of 0.5mm margin of error. 3. In determining whether the thickness of files has any effect on measuring methoths, no statistically significant differences were found(p>0.05). 4. In comparing data obtained from these methods in order to evaluate the difference among measuring methods, there was no statistically significant difference between periapical radiography and Digora/sup (R)/ system(p>0.05), but there was statistically significant difference between Root ZX/sup (R)/ and periapical radiography(p<0.05). Also there was statistically significant difference between Root ZX/sup (R)/ and Digora/sup (R)/ system(p<0.05). In conclusion, Root ZX/sup (R)/ was more accurate when compared with the Digora/sup (R)/ system and periapical radiography and seems to be more effective clinically in determining root canal length. But Root ZX/sup (R)/ has its limits in determining root morphology and number of roots and its accuracy becomes questionable when apical foramen is open due to unknown reasons. Therefore the combined use of Root ZX/sup (R)/ and the periapical radiography are mandatory. Digora/sup (R)/ system seems to be more effective when periapical radiographs are needed in a short period of time because of its short processing time and less exposure.

근관치료에 대한 인식도 및 의료보험에 관한 설문조사

이병립,이정석,Lee, Byeong-Rip,Lee, Jeong-Seok 대한치과보존학회 1992 Restorative Dentistry & Endodontics Vol.17 No.2

근관치료에 대한 인식도 및 의료보험에 관한 설문조사

이정석,이병립 大韓齒科保存學會 1992 Restorative Dentistry & Endodontics Vol.17 No.2

근관장 측정에 있어서 디지탈 영상 처리기와 주파수 의존형 측정기의 정확도

이병립,박창서 大韓口腔顎顔面 放射線學會 1998 Imaging Science in Dentistry Vol.28 No.2

In order to achieve a successful endodontic treatment, root canals must be obturated three dimensionally without causing any damage to apical tissues. Accurate length determination of the root canal is critical in this case. For this reason, I've used the conventional periapical radiography, Digora(digital imaging system) and Root ZX(the frequency dependent type apex locator) to measure the length of the canal and compare it with the true length obtained by cutting the tooth in half and measuring the length between the occlusal surface and the apical foramen. From the information obtained by these measurements, I was able to evaluate the accuracy and clinical usefulness of each systems, whether the thickness of files used in endodontic therapy has any effect on the measuring systems was also evaluated in an effort to simplify the treatment planning phase of endodontic treatment. 29 canals of 29 sound premolars were measured with #15, #20, #25 files by 3 different dentists each using the periapical radiography, Digora and Root ZX. The measurements were then compared with the true length. The results were as follows: 1. In comparing mean discrepancies between measurements obtained by using periapical radiography(mean error : -0.449±0.444 mm), Digora (mean error : -0.417±0.415 mm) and Root ZX(mean error : 0.123±0.458 mm) with true length, periapical radiography and Digora system had statistically significant differences(p<0.05) in most cases while Root ZX showed none(p>0.05). 2. By subtracting values obtained by using periapical radiography, Digora and Root ZX from the true length and making a distribution table of their absolute values, the following analysis was possible. In the case of periapical film, 140 out of 261(53.6%) were clinically acceptable satisfying the margin of error of less than 0.5 mm, 151 out of 261(53,6%) were acceptable in the Digora system while Root ZX had 197 out of 261(75.5%) within the limits of 0.5 mm margin of error. 3. In determining whether the thickness of files has any effect on measuring methods, no statistically significant differences were found(p>0.05). 4. In comparing data obtained from these methods in order to evaluate the difference among measuring methods, there was no statistically significant difference between periapical radiography and Digora system(p>0.05), but there was statistically significant difference between Root ZX and periapical radiography(p<0.05). Also, there was statistically significant difference between Root ZX and Digora system(p<0.05). In conclusion, Root ZX was more accurate when compared with the Digora system and periapical radiography and seems to be more effective clinically in determining root canal length. But Root ZX has its limits in determining root morphology and number of roots and its accuracy becomes questionable when apical foramen is open due to unknown reasons. Therefore the combined use of Root ZX and the periapical radiography are mandatory. Digora system seems to be more effective when periapical radiographs are needed in a short period of time because of its short processing time and less exposure.

코드-고무 복합 재료의 피로 파괴 특성 - 최소 응력의 영향 ( Fatigue Failure Criteria for Cord-Rubber Composites - Effect of Minimum Stress on Fatigue Life )

구본희,이병립,류드솅 대한기계학회 1997 대한기계학회 춘추학술대회 Vol.- No.-

CORD-RUBBER 복합 재료의 피로 파괴 특성

구본희(B.H.Ku),이병립(B.L.Lee) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.6_2

The present study describes the fatigue behavior of angle-plied cord-rubber composite laminates. Using flat coupon specimens, the dependence of fatigue lifetime of tire belt on minimum stress was examined. At a given stress range, the use of higher levels of minimum stress up to 8.9 MPa led to longer fatigue life of the composite laminate. When the minimum stress exceeded this critical level, an opposite trend of shorter fatigue life was observed with higher level of minimum stress. These two trends were attributed to non-linear stress-strain relationship and the effect of increased damage potential.<br/>