جستجوی مقالات مرتبط با کلیدواژه "file" در نشریات گروه "پزشکی"

The present study was undertaken to evaluate the effect of different levels of sharpness processing filter on the accuracy of endodontic file length determination using digital periapical radiography.
Forty human single-rooted permanent teeth were selected and International Organization for Standardization (ISO) #08 K-files were inserted into the root canals of the teeth. The file lengths were measured with a digital caliper as the gold standard. Digital periapical images were obtained using a phosphor storage plate as a detector. Three levels of sharpness tool of Scanora software program version 5.1 was used to produce enhanced images: Sharpen 1 (mild level), Sharpen 2 (moderate level), and Sharpen 3 (high level). Two radiologists and two endodontists measured file lengths on the original and enhanced images. The measurements were compared using repeated measures ANOVA and Bonferroni tests (α = 0.05).
There were no significant differences between the measurement accuracy of original images and that of the Sharpen 1 and Sharpen 2 enhanced images (P > 0.05). However, significant differences were found between the measurement accuracy of original and that of the Sharpen 3 enhanced images (P 0.05).
The application of mild and moderate levels of sharpness processing filter did not influence the accuracy of endodontic file length determination. However, high-level sharpness processing filter is not recommended due to its unfavorable effects on measurement accuracy.

Removal of root filling materials is one of the key steps in success of root canal retreatment. The purpose of this study was to evaluate the efficacy of H-File and ProTaper with or without chloroform in the removal of gutta-percha during retreatment of mandibular premolars. Sixty mandibular premolars with one canal, and curvatures less than 30 degrees were used in this experimental study. They were instrumented with K-files and laterally obturated with condensed gutta-percha using AH26 as the sealer and were stored in 100% humidity at 37°C for 2 weeks. The teeth were randomly divided into four groups of 15 teeth each. Removal of gutta-percha was performed with H-File and ProTaper. All techniques were used with or without chloroform. The teeth were split longitudinally and the area of remaining gutta-percha/sealer on the root canal wall was explored under stereomicroscope. Retreatment time duration was also recorded for each sample. Data were analyzed statistically by Two-way ANOVA, t-test and Tukey’s. In all groups, no significant difference was found in remaining gutta-percha and sealer with or without using chloroform, but chloroform shortened the time of retreatment. ProTaper left significantly less remaining filling materials than H-File (P<0.05). Retreatment time was significantly different between the studied groups (P<0.001). ProTaper Ni-Ti instruments proved to be more efficient and time-saving devices for removal of gutta-percha compared to H-File in canals with no or slight curvature.