본 연구의 목적은 학생들이 사용한 세 가지 Ni-Ti파일의 성형효율을 비교하고, 각 파일의 사용 경험 유무에 따른 차이를 비교하여 치과대학생을 위한 교육에 적합한 종류를 선택하는데 도움을 얻고자하는 것이다. Ni-Ti파일 사용 경험이 없는 학생 50명과 Ni-Ti파일을 사용한 근관치료 경력이 2년 이상인 경험자 10명이 세 종류의 Ni-Ti file - $ProFile^{(R)};(PF),;HeroShaper^{(R)};(HS),;K3^{TM};(K3)$ -을 사용하여 180개의 근관 모형을 성형하였다. 근관성형 시간 및 기구 변형, 근관 이형성을 조사하고 성형 전후 상을 중첩하여 근관 삭제폭, 근관변위량과 중심변위율을 1, 3. 5 mm에서 분석하였다. 1. 근관 성형시간은 HS군이 가장 빨랐으며, 총 삭제 량은 모든 지점에서 K3군이 다른 군보다 컸다 (P<0.05) . 2. 세 군 모두 1, 3 mm에서 외측 변이를 보였고, 1 mm지점에서 PF군이 가장 안정적이었다 (P<0.05). 3. 중심변위율은 1, 3 mm에서 HS, PF군이 K3군보다 작았다. 5 mm지점에서는 PF군이 가장 작았고, PF군 3 mm에서 학생은 경험자보다 유의하게 작았다 (P<0.05).
The purpose of this study was to compare the shaping ability of three Ni-Ti file systems used by dental students or the experts and consequently to aid in choosing a proper systems for educational courses of dental students and beginners. Fifty students and ten dentists who have clinical experience over two years prepared 180 simulated root canals in resin blocks with three Ni-Ti systems; $ProFile^{(R)};(PF),;HeroShaper^{(R)};(HS),;K3^{TM};(K3)$. After preparation, the Ni-Ti files were evaluated for distortion and canal preparation time was recorded. The images of pre- and post-instrumented canals were scanned and superimposed. Amounts of increased canal widths, deviation, and centering ratio were calculated at apical 1, 3 and 5 mm levels and statistical analysis was performed The results were as follows : 1. HS showed the shortest preparation time and instrumented canal width in K3 was significantly larger than other groups (P<0.05). 2. At 1 and 3mm levels, all groups had outward deviation. In student group, at the 1mm level, PF had the least deviation (P<0.05). 3. In the centering ratio, the PF had the best centering ability compared to the others at 5mm level. At 1 and 3mm levels, HS and PF had better abilities than K3. Student group had better ratio than the expert at 3mm level with PF (P<0.05). Based on the results, it is surmised that the $ProFile^{(R)}$ is the safest and most ideal instrument for students and beginners.
