INTRODUCTION: One of the goals of conventional endodontic treatment is to minimize the amount of irritants that could be present inside the root canal system. OBJECTIVES: This study was designed to evaluate irrigant delivery using two different techniques in curved canals. MATERIALS AND METHODS: The mesiobuccal canals of 20 human extracted mandibular first molars were divided into two groups (n=10); Group (I) conventional syringe with side vented needle, Group (II) sonic irrigation (EndoActivator system). Contrast medium (OptirayTM 320, Mallinckrodt Inc. Hazelwood, MO, USA) was injected before, during and after canal preparation. All canals were prepared using Revo-S rotary system till reaching file AS35 using 5.25% NaOCl as an irrigant during instrumentation. Standardized preoperative, operative and postoperative digital radiographs were taken. The distance between full working length and the point of maximum irrigant penetration was measured using image editing software (DBS Win 5.3.1 and Image J). Data were then recorded and statistically analyzed. RESULTS: Sonic irrigation showed a statistical significant difference over the conventional needle and syringe group in increasing the depth of penetration of the contrast medium. CONCLUSIONS: the use of EndoActivator in irrigation had a superior effect in increasing the depth of penetration of irrigant when compared to conventional needle and syringe.

INTRODUCTION: During root canal preparation; irrigants, dentin chips, pulp tissue and microorganisms may be extruded into the periradicular tissues which may cause postoperative pain and complications. OBJECTIVES: The aim of this study was to compare the amount of apically extruded debris in mesio-buccal canals of 30 extracted human mandibular molars instrumented with One-Shape file after preparing a proper glide path using G-files, ProGlider and K-files. MATERIALS AND METHOD: This study was conducted on the mesio-buccal roots of 30 human mandibular molars with curvature of 20 to 35 degrees. All specimens were divided into three groups according to the type of instrument used for glide path management. Group (1): manual instrumentation with K-files (#10, 15), Group (2): G-files: (G1: #0.12mm, G2: #0.17mm), and Group (3): ProGlider: single use rotary file. All teeth were instrumented using One-Shape file. Debris extruded apically from the teeth were collected into pre-weighed Eppendorf tubes. Three consecutive weights were obtained for each tube and the mean value was obtained. The weight of extruded debris was calculated as the difference between the pre and post instrumentation weights of the tubes. RESULTS: The highest amount of debris was found in the k-file group while the lowest amount with ProGlider group with significant differences between them. Moreover, significant difference was found between ProGlider and G-file while there was no significance between G-file and K-file groups. CONCLUSIONS: All techniques showed debris extrusion, although the use of NiTi rotary instruments may be rather beneficial.

INTRODUCTION:The use of motor-driven nickel-titanium (Ni-Ti) files in root canal preparation has numerous advantages. However, they might lead to dentinal crack formation which greatly affects the endodontic treatment prognosis. Therefore, new Ni-Ti files have been developed with different heat treatments to enhance file flexibility, thus reduce stress concentration during root canal preparation. AIM OF THE STUDY: To compare the incidence of dentinal defects produced by two motor-driven Ni-Ti systems; Hyflex EDM and MPro files using stereomicroscopic analysis. MATERIALS AND METHODS:This study was conducted on thirty mesio-buccal root canals of human mandibular molars. All teeth were examined under a stereomicroscope to exclude any dentinal defects before instrumentation followed by decoronation and sectioning of distal roots. The root canals were randomly divided into three equal groups according to the file system used. Group I: Hyflex EDM files with continuous rotation motion. Group II: MPro files with continuous rotation motion, ending the preparation till tip size 25 in both groups. Group III: unprepared canals (negative control). All roots were sectioned at 3, 6, and 9 mm from the apex using a precision cutter device. Stereomicroscope analysis was performed in all sections. Data were statistically analyzed. RESULTS: All groups (including the control group) showed no dentinal defects with no statistically significant differences between the test groups and the control group at all levels. CONCLUSIONS: The new generations of heat-treated rotary files could produce root canal preparation with less dentinal defects owing to their enhanced physical and mechanical properties.

INTRODUCTION:Coronal flaring is now considered as an essential preparatory step in root canal treatment sequence. OBJECTIVES: To detect crack formation after coronal flaring of root canals with Gates Glidden (GG) drills, ProTaper Universal (PT) SX, and Endoflare (Ef) flaring instruments using cone beam computed tomography (CBCT) and scanning electron microscope (SEM). MATERIALS AND METHODS: Thirty mesiobuccal canals of mandibular first molars were selected. Teeth specimens were classified into three equal groups according to the instrument used for coronal flaring. Group1: Gates Glidden drills, group 2: ProTaper Universal SX and group 3: Endoflare instruments. Preoperative and postoperative (CBCT) imaging was performed and defect formation was detected. All roots were sectioned horizontally at 2,4and 6 mm from the cementoenamel junction. The sections were inspected under SEM, and any defect formations were recorded and compared with CBCT images according to scoring system. Data were collected and then statistically analyzed at an alpha error of 0.05. P≤0.05 were considered significant. RESULTS: The Ef file produced significantly less dentinal defects compared with the GG and PT SX at the three studied sections. Significant differences were found between the 3 groups at 2 and 4 mm with values (P=0.026) & (P=0.050) respectively, while no significant difference was found at 6mm with value of (P=0.217) when using the 2 evaluation methods. There was a significant difference (P=0.049) between the two used evaluation methods. CONCLUSIONS: Although all used coronal flaring instruments caused dentinal defects, Endoflare file showed the least defects. CBCT was not able to detect the smallest defects such as craze lines while SEM showed more capabilities and was considered as a confirmatory method.

No abstract