OBJECTIVE: This study evaluated transportation and extruded debris during preparation using different instruments.
METHODS: Sixty resin blocks with S-shaped canals and 60 extracted teeth were separated into four groups (n = 15), which were instrumented with Reciproc Blue, XP-endo Shaper, WaveOne Gold, and Twisted File Adaptive. For evaluating transportation, pre- and post-preparation images were obtained under a stereomicroscope and superimposed with digital software. The distance between the inner and outer canal walls was measured. For the evaluation of debris extrusion, the samples were placed in Eppendorf tubes and instrumented using one of the four rotary files. The initial weight was subtracted from the post-instrumentation weight to determine the amount of extruded debris. The Kruskal-Wallis and Dunn multiple tests were performed.
RESULTS: For transportation, no significant difference was found between the XP-endo Shaper-Twisted File Adaptive systems and between Reciproc Blue-WaveOne Gold groups (P > 0.05). The XP-endo Shaper and Twisted File Adaptive techniques led to significantly less transportation compared to the other systems (P < 0.05). Regarding debris extrusion, the XP-endo Shaper system extruded significantly less debris than the other groups (P < 0.05).
CONCLUSIONS: XP-endo Shaper extruded less debris compared to other groups, while XP-endo Shaper and Twisted File Adaptive caused less transportation than other files.

UNASSIGNED: The success of root canal treatments is influenced by the shape of the access opening and the outcomes of root canal enlargement. The aim of this study was to evaluate the impact of various rotary instruments on the maintenance of the root canal\'s central alignment post shaping, considering a range of access cavity designs.
UNASSIGNED: Using digital tooth simulation, 4 sets of 12 teeth underwent traditional (TradAC) or conservative (ConsAC) access cavity preparations. Root canals were enlarged with TruNatomy or ProTaper Ultimate rotary instruments. Canal transportation and centering ratio were separately measured. Statistical analysis was performed using JMP trial 17 software.
UNASSIGNED: The analysis revealed no significant difference in buccal and lingual canal transportation among different rotary instruments or canal enlargement designs (P > 0.05). TradAC yielded higher centering ratios in MB and ML canals, while ConsAC excelled in the distal canal for the TruNatomy group. Conversely, in the ProTaper Ultimate group, ConsAC demonstrated higher ML canal ratios (P < 0.05).
UNASSIGNED: TruNatomy maintained superior canal centering with ConsAC, while ProTaper performed better with TradAC.

UNASSIGNED: Root canal therapy is the most widely accepted treatment modality for pulpally involved teeth. Rotary NiTi instruments improve the root canal preparation because of the unique properties of the alloy. Cone beam computed tomography (CBCT) permits non-destructive and metrically exact analyses of variable such as volume, surface area, cross sectional shape, and taper. Thus the present study was conducted to evaluate the effect of biomechanical preparation of root canals using different file systems on cervical dentinal thickness at coronal level; canal transportation, and surface area at coronal, middle and apical levels using CBCT.
UNASSIGNED: Forty-five single rooted premolars were randomly divided into three groups (n=15), (Protaper hand file, MtwoNiTi rotary file and NeoNiTi single file). CBCT scans were taken before and after the preparation. Dentinal thickness was measured in all four directions to assess cervical dentin thickness and canal transportation. Surface area was evaluated in Adobe Photoshop both before and after preparation.
UNASSIGNED: The data obtained was subjected to statistical analysis. The total mean change in cervical dentin thickness and total mean canal transportation at coronal and apical was found to be maximum in Group III. The maximum increase of surface area was observed in Group I at coronal level whereas in Group III at middle and apical levels.
UNASSIGNED: It was concluded that the change in cervical dentin thickness was maximum in Group III. The canal transportation at coronal level and apical level was found to be maximum in Group III; at middle level it was maximum in Group II. The maximum increase of surface area at coronal level was observed in Group I, at middle and apical levels it was seen in Group III.

This study aims to compare the shaping ability of three systems using micro-computed tomography (micro-CT). Moderately-curved mesial canals of 36 mandibular molars were assigned to three groups (n = 24); Protaper Next (PTN, 0.25, 0.06), WaveOne Gold (WOG, 0.25, 0.07), TruNatomy (TRN, 0.25, 0.04), and instrumentation was performed. Pre- and post-micro-CT scans were obtained. Canal volume and surface, structure model index (SMI), centroid shift, canal transportation, and untouched canal were analyzed. One-way ANOVA and Student\'s t-test were used for statistics. There was no difference in SMI, centroid shift, and centering ability between the study groups (p > .05). Removed dentin and canal surface changes were lower in TRN, while untouched dentin walls were higher (p < .05). Cross-sections became more rounded (p < .05), but not significant between groups (p > .05). Considering the removed dentin by TRN, it can be used in critical dentin thickness, such as the danger zone (DZ). PTN, WOG, and WOG kept the original canal course similarly. Untouched dentin by TRN (41%) was wider than PTN and WOG, consequently, meticulous irrigation is recommended. TRN, which provides a controlled increase in canal volume, can be used in thin dentin such as the DZ, however, its use should be supported by copious irrigation and brushing considering the rate of untouched dentin walls. RESEARCH HIGHLIGHTS: TRN presented a higher untouched dentin wall compared to PTN and WOG. Canal volume and surface changes were the lowest in the TRN group. The centering abilities were similar in PTN, WOG, and TRN.

UNASSIGNED: The anatomical configuration classified as Vertucci\'s type III is described as the second most prevalent in mandibular incisors.
UNASSIGNED: Thirty-six Vertucci\'s type III mandibular incisors were evaluated by micro-computed tomography (micro-CT) and divided into 3 groups (n = 12) according to the root canal preparation protocol (HyFlex CM [HCM], HyFlex EDM [HEDM], and Sequence Rotary File [SRF]). The teeth were scanned before and after performing 0.25 mm and 0.40 mm apical diameter preparations. The canal volume, dentin thickness, percentage of accumulated debris and untouched canal areas, transportation, and centering ability were measured. The data were statistically analyzed by ANOVA, Tukey, Kruskal-Wallis, and Dunn tests (P < 0.05).
UNASSIGNED: The volume increase was more evident in the apical third. After 0.40 mm preparation, the SRF system provided a higher reduction (P < 0.05) in dentin thickness on the buccal surface 1 mm from the apex. There was higher canal transportation in the bucco-lingual direction. The 0.40 mm apical preparation reduced the percentage of untouched canal areas. The apical third had the highest percentage of untouched canal areas. The cervical third had the lowest volume of accumulated debris.
UNASSIGNED: Increasing the apical preparation to a diameter of 0.40 mm with the HCM, HEDM, and SRF systems in Vertucci\'s type III root canals of mandibular incisors proved to be safe and effective, reducing untouched canal areas.
UNASSIGNED: Root flattening can be intense to the point of generating a root canal bifurcation. Despite the decrease in the root canal diameter, a greater enlargement of the apical region is necessary and safe.

UNASSIGNED: Using cone beam computed tomography (CBCT), this study compared three rotary file systems-XP Endoshaper, Hyflex CM, and K3 XF-for centering, canal transportation, and root canal area growth.
UNASSIGNED: The rotating file system randomly separated 60 removed human mandibular molars into three groups (n = 20). Manufacturer-recommended root canal instrumentation was done. Specialized software examined pre- and post-instrumentation CBCT scans. Centering ability was measured by canal transportation and root canal area expansion at different levels from the apex.
UNASSIGNED: The Hyflex CM file system had the best centering and the least canal transit at all levels (P < 0.05). XP Endoshaper increased the root canal area the most (P < 0.05). The K3 XF file system had average centering and canal transfer results.
UNASSIGNED: The Hyflex CM system centered well, whereas the XP Endoshaper system increased the root canal area the most. The clinical context and therapeutic goals should determine the rotating file system.

OBJECTIVE: This study assessed the outcome of shaping the mesial roots of mandibular first molars containing band-shaped isthmuses with an isthmus floor located at the apical third with Reciproc Blue and Rotate instruments in terms of canal transportation, canal aberrations and unprepared apical canals.
METHODS: Pair-matched mesial roots of mandibular first molars according to their isthmus location (distance from apical foramina) and size were constructed based on quantitative measurements (length, major and minor diameter at isthmus roof and floor) on preoperative micro-CT scanning (n = 10). The pair-matched specimens were prepared either using Reciproc Blue R25 (25.08v) or Rotate (15.04, 20.05, 25.06) instruments and then subjected to a second micro-CT scanning. Micro-CT scans were analysed to evaluate the canal transportation at the apical foramen and isthmus floor levels and the frequency of procedural errors (separated instruments, artificial canal preparation, cross shaping and unprepared apical canals). Canal transportation values were compared using Mann-Whitney U, and the distribution of procedural errors was compared with chi-square tests with a 5% significance threshold.
RESULTS: Greater transportation values were detected in the apical foramen level compared to the isthmus floor in both groups. No significant difference was detected between Rotate and Reciproc Blue groups in terms of absolute transportation values and the incidence of procedural errors (p > .05).
CONCLUSIONS: Preparation of mesial root canals containing a band-shaped isthmus at the apical portion with Reciproc Blue and Rotate instruments caused transportation of the original canal position at the isthmus floor and the apical foramen levels and resulted in procedural errors.
CONCLUSIONS: This ex vivo micro-CT study using controlled pair-matched specimens showed that presence of a band-shaped isthmus complicates canal preparation procedure irrespective of the preparation systems.

UNASSIGNED: This study aimed to compare the accuracy and agreement between cone-beam computed tomography (CBCT) and micro-computed tomography (micro-CT) in the assessment of canal transportation and centering ratio following root canal instrumentation with rotary files.
UNASSIGNED: Twenty mesiobuccal canals of mandibular molars were prepared using the 2Shape sequential rotary system. CBCT and micro-CT scans were performed before and after instrumentation, and the magnitude of transportation and centering ratio were measured. The acceptable transportation was set at ≤0.15 mm. The accuracy and agreement between CBCT and micro-CT were calculated, and the intra-class correlation coefficient (ICC) and kappa coefficient were determined to assess the agreement between the two modalities. Statistical analyses were performed using repeated measures ANOVA.
UNASSIGNED: Transportation was detected by both modalities at all distances from the apex after instrumentation. The agreement between CBCT and micro-CT in assessing canal transportation was observed in 80%, 85%, 75%, and 75% of specimens at 1-, 3-, 5-, and 7-mm from the apex, respectively. The ICC for transportation and centering ratio was much lower than 0.75, indicating poor agreement between the modalities. The kappa coefficient did not show acceptable agreement between the methods.
UNASSIGNED: CBCT and micro-CT demonstrated poor agreement in assessing canal transportation and centering ratio. Micro-CT remains the preferred modality for in vitro investigations, while CBCT should be limited to clinical settings.

UNASSIGNED: The rotary systems have found a common application in the clinical practice for the endodontic therapies. Hence, we compared three recent endodontic systems for the comparison of the dentine removal and the apical transportation particularly in the curved canals.
UNASSIGNED: Oneshape, Pro Taper Next, and Edgefile X3 were the three systems that were compared. Thirty maxillary mesio buccal canals of the human permanent teeth were compared due to its curved nature. The volume of dentin removed and apical transportation (mm) were measured using micro-computed tomographic imaging (mm). Both the coronal section and the entire canal length had their dentin removed in accordance with measurements. Total dentine removed, coronal dentine removed, and the canal transportations were compared for the three rotary file systems. The values were compared with appropriate statistical tests for evaluating the significance.
UNASSIGNED: There was no statistically significant difference between the three file systems for the dentin removed. The mean canal transportation was 0.33 ± 0.12, 0.21 ± 0.25, and 0.23 ± 0.21 mm, respectively, for Oneshape, Pro Taper Next, and Typhoon CM. In terms of statistics, there were no appreciable variations among the three rotary tools for apical transfer.
UNASSIGNED: The three rotary systems were comparable for the apical transportation and the dentine removal. Despite variations in the magnitude of apical enlargements, none of the instrumentation methods detected apical transportation.

OBJECTIVE: Apically extruded debris, canal transportation and shaping ability were compared between contracted endodontic cavities (CECs) and traditional endodontic cavities (TECs) after instrumentation with XP-endo Shaper (XPS), ProTaper Gold (PTG), ProTaper for hand-use (HPT) and Hero Shaper.
METHODS: The CECs or TECs groups were sub-divided into 24 groups according to root canal morphology and nickel-titanium (Ni-Ti) instruments. The weight of apically extruded debris was calculated using the Myers and Montgomery model. Pre- and postoperative images of teeth were scanned using micro-CT and the three-dimensional models were constructed and compared.
RESULTS: Under CECs or TECs, XPS and PTG produced less apical debris and formed less canal transportation than HPT and Hero Shaper (P < 0.05). XPS group under CECs extruded less apical debris than that under TCEs for round canals with curvature of 20°-35° (P < 0.05). The centering ratios of four tested instruments were higher under TECs than those under CECs (P < 0.05). The HPT and Hero Shaper had more transportation under CECs than that under TCEs (P < 0.05). No statistical difference was found regarding shaping ability among all the groups.
CONCLUSIONS: Under CECs, XPS preserves the original root canal anatomy, meanwhile it produces less apical debris than the other instruments.