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Article in Chinese | WPRIM | ID: wpr-881373


Objective@#This study aims to compare the incidence of dentinal microcracks produced by ProTaper Universal (PTU) and ProTaper Gold (PTG) file systems during root canal procedures in different curved canals using a dyeing technique.@*Methods@#Sixty extracted human molars were divided into 3 groups of 20 samples each in terms of root curvature (mild bending group, 10 °-19 °; moderate bending group, 20 °-29 °; severe bending group, 30 °-39 °). Ten samples of each group were then randomly allocated to the PTU and PTG file systems. After preparation, all roots were stained using a dyeing method and sectioned at the most curved plane and 2 mm below and above the most curved plane with a low-speed saw under cold water. A stereomicroscope was used to inspect dentinal microcracks at 60 × magnification, and differences between these three instrument groups were analyzed using the chi-square test.@* Results @# The PTG file system induced significantly fewer dentinal microcracks for total, incomplete and complete cracks (P < 0.05), and the effect was more obvious with increasing canal curvature.@*Conclusion @# With the limitations of this in vitro study, it can be concluded that ProTaper Gold can result in fewer dentinal microcracks than ProTaper Universal.

Article in Chinese | WPRIM | ID: wpr-751038


Objective @#To compare the shaping ability of 3 different nickel (Ni)-titanium (Ti) systems in simulated root canals in resin and to provide a reference for clinicians.@*Methods@#Forty-eight resin blocks were prepared using the F360 (Komet, Brasseler GmbH & Co., Lemgo, Germany) (Group 1), F6 SkyTaper (20/06) (Komet, Brasseler GmbH & Co., Lemgo, Germany) (Group 2), F6 SkyTaper (25/06) (Komet, Brasseler GmbH & Co., Lemgo, Germany) (Group 3) and Reciproc R25 systems (VDW, Munich, Germany) (Group 4) (n=12 canals/group). The images taken before and after preparation were superimposed and analyzed by Adobe Photoshop v7.0. The amount of resin removed by each system was measured, and the centering ability was assessed. The data were statistically analyzed using SPSS 20.0.@*Results @#At the 1 mm point, the transportation in Group 4 [(0.10 ± 0.03) mm] was significantly greater than that in Groups 2 [(0.05 ± 0.03) mm] and 3 [(0.05 ± 0.03) mm] (P < 0.05). At the 8 mm and 9 mm points, the transportation values in Group 4 [(0.12 ± 0.06) mm and (0.13 ± 0.05) mm] were significantly higher than those in Groups 2 [(0.05 ± 0.05) mm and (0.05 ± 0.05) mm] and 3 [(0.05 ± 0.04) mm and (0.06 ± 0.05) mm] (P < 0.05). At the 10 mm point, the transportation was significantly greater in Group 4 [(0.13 ± 0.06) mm] than in Group 2 [(0.06 ± 0.06) mm].@*Conclusion@#F6 SkyTaper exhibits better centering ability than Reciproc.

Article in Chinese | WPRIM | ID: wpr-465662


Objective To evaluate the root canal deviations in vitro teeth curved root with TF and Protaper instru-ments by cone beam computer tomography( CBCT) . Methods 40 teeth in vitro in the standard collection were ran-domly assigned to two groups, prepared with the crown-down method, the TF group ready to 0. 06/#25; the Pro-taper group ready to F2 . CBCT scans were taken to measure the mesial and distal thicknesses of the tube wall in vitro teeth before and after preparation. The root canal deviation and the rate of shaft center were measured with ref-erence to the formula proposed by Gambill. Results The TF group need less time in preparation and has more effi-ciency(P<0. 05) than the Protaper group; both TF and Protaper devices appeared deformation after 5 root canal preparations in average, no instruments broken. Comparing the offset of the internal and external wall of root canal in 3, 5, 7 mm from the apex, the root canal deviation prepared by the TF group was less than the Protaper group, and its rate of axis center was greater than the Protaper group, closer to 1. Conclusion TF can maintain original root canal morphology in preparing curved root canal, also has higher efficiency;under the noninvasive condition, the root canal forming ability of preparation instruments can be evaluated by CBCT.

J. appl. oral sci ; 17(5): 501-507, Sept.-Oct. 2009. ilus, tab
Article in English | LILACS | ID: lil-531404


OBJECTIVE: This study evaluated the wear in the apical third of simulate canals after preparation with ProTaper Universal Rotary System. MATERIAL AND METHODS: 24 sets of instruments were used in 24 simulated canals in transparent epoxy resin blocks with degree of curvature of either 20°or 40°. The canals were photographed preoperatively and after preparation of the apical stop with ProTaper F3, F4 and F5 instruments. The initial and final images were exported to Adobe Photoshop® software and superimposed to detect the root canal wall differences (in mm) between them, in two points located 1 (A) and 5 (B) mm from the point where the working length was established. Data were subjected to analysis of variance to verify the existence of interaction among the factors: canal curvature, instrument size and curve location. Significant level was set at 5 percent. RESULTS: Regardless of the location and the canal curvature, F4 and F5 instruments produced the greatest wear (p<0.05). CONCLUSIONS: There was a deviation from the original pathway towards the outside of the root curvature in both analyzed points. All instruments produced canal transportation, but the F4 and F5 instruments produced more than the other instruments, and should thus be used with care in curved canals.

Humans , Dental Pulp Cavity/anatomy & histology , Root Canal Preparation/instrumentation , Tooth Apex/anatomy & histology , Dental Alloys , Detergents/therapeutic use , Epoxy Resins , Equipment Design , Image Processing, Computer-Assisted , Models, Anatomic , Root Canal Irrigants/therapeutic use , Root Canal Preparation/methods , Software , Stainless Steel , Surface Properties , Sodium Dodecyl Sulfate/therapeutic use
Article in Chinese | WPRIM | ID: wpr-406075


Objective: To evaluate the treatment efficacy of reverse flaring technique applied by two rotary instruments, Hero 642 and ProTaper, on complicated molar root canal preparation. Methods: 100 molars with curved root canals (maximum curved angle ≥25 degrees) suffered from pulpitis or periapicities were randomly divided into two groups. In experimental group reverse flaring technique was applied by rotary instruments while in control group reverse flaring technique was not adopted. 50 experimental teeth with curved canals were operated with K files, Hero 642 and ProTaper in sequence. Lateral condensation obturation method was utilized in both groups. Root canal preparation and obturation efficiency were evaluated by X-ray, root canal preparation time and complication incidence (1 year follow-up rate was 95%). Results: Reverse flaring technique applied by Hero 642 and ProTaper Ni-Ti rotary instruments on complicated (curved) root canal preparation in group A demonstrated better root canal coning and smoothness, without instrument fractures, while instrument fractures occurred in control group. Significant difference was found in exact root canal obturation rate and not enough full rate, root canal smoothness and postoperative pain between two groups(P<0.05). Conclusion: Reverse flaring technique applied by Hero 642 and ProTaper NI-Ti rotary instruments indicates complementary potencies, demonstrating satisfactory root canal shape and obturation effectiveness, and lower complication incidence. Reverse flaring technique applied by Ni-Ti rotary instruments is apt for medium/severe curved root canal preparation and worthy of clinical application.