Simulated Canals (simulated + canal)

Distribution by Scientific Domains


Selected Abstracts


An evaluation of .06 tapered gutta-percha cones for filling of .06 taper prepared curved root canals

INTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2005
M. P. J. Gordon
Abstract Aim, To compare the area occupied by gutta-percha, sealer, or void in standardized .06 tapered prepared simulated curved canals and in mesio-buccal canals of extracted maxillary first molars filled with a single .06 gutta-percha point and sealer or lateral condensation of multiple .02 gutta-percha points and sealer. Methodology, Simulated canals in resin blocks with either a 30° curve and radius of 10.5 mm (n = 20) or a 58° curve and 4.7 mm radius (n = 20) and curved mesio-buccal canals of extracted maxillary first molars (n = 20) were prepared using .06 ProFiles® in a variable tip crown-down sequence to an apical size 35 at 0.5 mm from the canal terminus or apical foramen. Ten 30° and 58° curved resin canals and 10 canals in the extracted teeth group were obturated with .02 taper gutta-percha cones and AH 26 sealer using lateral condensation. The time required to obturate was recorded. The remaining canals were obturated with a single .06 taper gutta-percha cone and AH 26 sealer. Excess gutta-percha was removed from the specimens using heat and the warm mass vertically condensed. Horizontal sections were cut at 0.5, 1.5, 2.5, 4.5, 7.5 and 11.5 mm from the canal terminus or apical foramen. Colour photographs were taken using an Olympus 35 mm camera attached to a stereomicroscope set at ×40 magnification, and then digitized using a flatbed scanner. The cross-sectional area of the canal contents was analysed using Adobe PhotoShop®. The percentage of gutta-percha, sealer or voids to the total root canal area were derived and data analysed using unpaired Student's t -test and the Mann,Whitney U -test. Results, In the 30° curved canals the levels had between 94 and 100% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone techniques. In the 58° curved canals the levels had 92,99% of the area filled with gutta-percha, with the single cone technique having significantly (P < 0.05) more gutta-percha fill at the 2.5 mm level only. In the mesio-buccal canals of the teeth the levels had between 72 and 96% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone technique. The time for obturation was significantly (P < 0.05) greater for lateral condensation compared with the single cone technique in all groups. Conclusions, The .06 taper single cone technique was comparable with lateral condensation in the amount of gutta-percha occupying a prepared .06 tapered canal. The .06 single cone technique was faster than lateral condensation. [source]


Shaping ability of ProFile and K3 rotary Ni-Ti instruments when used in a variable tip sequence in simulated curved root canals

INTERNATIONAL ENDODONTIC JOURNAL, Issue 9 2004
L. R. Ayar
Abstract Aim, To compare the shaping ability of ProFile and K3 rotary Ni-Ti instruments when used in a variable tip sequence in simulated curved root canals with different curvature and radius. Methodology, ProFile or K3 .06 taper instruments were used to prepare simulated canals of 20° curvature and 5 mm radius (n = 10) and 30° curvature and 3 mm radius canals (n = 10) in resin blocks. All canals were prepared to an apical size 40 at 0.5 mm from the canal terminus using a variable tip crown-down sequence. Pre- and postinstrumentation digital images were recorded, and an assessment of the canal shape was determined using a computer image analysis program. The material removal from the inner and outer wall of the canal was measured at 28 measuring points, beginning 0.5 mm from the end-point of the canal and the data compared using the Mann,Whitney U -test. Results, In 20° and 30° canals both instruments significantly removed more (P < 0.05) material on the outer wall than the inner wall in the apical half of the canal. For ProFile files there was no significant difference in the amount of material removed on the outer canal wall between the 20° and 30° canals. However, in the K3 groups significantly more (P < 0.05) outer canal wall was removed in the apical area in 20° canals. When comparing both instruments the results showed that in 20° canals K3 instruments removed more outer and inner canal wall than ProFile instruments (P < 0.05) but that there was no significant difference (P > 0.05) between the instruments in 30° canals. Conclusion, Within the limitation of this study, both rotary nickel-titanium instruments prepared a well-shaped root canal with minimal canal transportation. [source]


Comparison of MicroSeal and System B/Obtura II obturation techniques

INTERNATIONAL ENDODONTIC JOURNAL, Issue 12 2003
P. R. Cathro
Abstract Aim, To compare the proportion of gutta-percha, sealer and voids following the filling of simulated root canals in plastic blocks using two warm gutta-percha techniques. Methodology, Ten simulated root canals in plastic blocks were prepared using System GT Rotary Files® and a .02 taper size 40 Quantec rotary nickel,titanium instrument and then filled with MicroSeal and Kerr EWT sealer. A further 10 simulated canals were prepared solely with System GT Rotary Files® and obturated with System B/Obtura II and Kerr EWT sealer. All blocks were sectioned at 1 mm intervals. The sectioned root fillings were photographed through a stereomicroscope and the resultant slides scanned. The images were analysed using adobe photoshop 6.0 to give the proportions of gutta-percha, sealer or void at each level. The data were analysed using unpaired Student's t -test and Mann,Whitney U -test. Results, The MicroSeal technique produced a dense homogeneous gutta-percha fill at the apical 1 and 2 mm levels similar to the System B/Obtura II technique, but further coronally the sealer became mixed into the MicroFlow gutta-percha producing a heterogeneous mass with significantly less (P < 0.05) solid gutta-percha in the root filling compared to System B/Obtura II. The MicroSeal technique generally had more pooling of cement than the System B technique, however, this was only significantly different (P < 0.05) at the 4 mm level. The System B/Obtura II obturation gave an average of 99.27% ± 1.09 gutta-percha fill at all levels. Conclusions, The MicroSeal technique produced a heterogeneous fill consisting of the MicroFlow Master Cone and gutta-percha from the MicroFlow Cartridge mixed with sealer. The System B/Obtura II technique produced a homogeneous fill at all levels. [source]


Canal shapes produced sequentially during instrumentation with Quantec SC rotary nickel,titanium instruments: a study in simulated canals

INTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2001
I. T. Griffiths
Abstract Aim The aim of this study was to determine the shaping ability of Quantec SC nickel,titanium rotary instruments in simulated root canals. Methodology Forty simulated canals consisting of four different shapes in terms of angle and position of curvature were prepared with Quantec SC instruments. Sequential still images were taken of the canals using a video camera attached to a computer with image analysis software. Images were taken preoperatively, and then after instrument 7 (Size 25, 0.05 taper), instrument 8 (size 25, 0.06 taper), and instrument 10 (size 45, 0.02 taper) were taken to length. Each sequential postoperative image was superimposed individually over the preoperative image in order to highlight the amount and position of material removed during preparation. Results Overall, the mean preparation time to size 10 was 3.6 min with 12 mm canals taking on average less time than 8 mm canals. There was a highly significant difference between the canal types (P < 0.0001). No instruments fractured within the canal or deformed, although one instrument separated from the latch grip. All canals remained patent. Following preparation to size 10, 19 canals (48%) retained their length, eight (20%) lost length, and 13 (32%) gained length; the magnitude of the change in length was always 0.5 mm or below. Following preparation to size 7 instruments all canals showed aberrant shapes. Excess removal of material along the outer aspect of the curve between the beginning of the curve and the end-point (outer widening) was found in 26 canals (65%) after instrument 7. At the same stage of preparation six canals (15%) had zips, three (8%) had ledges and five (13%) had perforations. Following preparation to size 10, 27 (68%) canals were perforated. Conclusions Under the conditions of the study, Quantec SC instruments consistently produced aberrations when canals were enlarged to size 7 (size 25, 0.05 taper) or above. Care should be exercised when using these instruments in real teeth. [source]


Shaping ability of Hero 642 rotary nickel,titanium instruments in simulated root canals: Part 2

INTERNATIONAL ENDODONTIC JOURNAL, Issue 3 2000
S. A. Thompson
Abstract Aim To determine the shaping ability of Hero 642 nickel,titanium rotary instruments during the preparation of simulated canals. Methodology A total of 40 simulated root canals made up of four different shapes, in terms of angle and position of curvature, were prepared by Hero 642 instruments using a crown-down preparation sequence. Pre- and postoperative images of the canals were taken using a video camera attached to a computer with image analysis software. The pre- and postoperative views were superimposed to highlight the amount and position of material removed during preparation. This report describes the efficacy of the instruments in terms of prevalence of canal aberrations, the amount and direction of canal transportation and overall postoperative shape. Results Four zips and four elbows were created during preparation, all in canals with 40°, 12 mm curves. No perforations or danger zones were created. Highly significant differences (P < 0.001) were apparent between the canal shapes in total canal width at the apex and beginning of the curve, and in the amount of resin removed from the inner and outer aspects of the curve at the orifice. Canal transportation was most frequently directed toward the outer aspect of the curve at specific points along the canal, except at the orifice, where it was apparent that canals with 20° curves transported toward the inner. Overall, mean absolute transportation was always less than 0.15 mm; however, significant differences occurred between canal shapes at the end-point (P < 0.01), apex of the curve (P < 0.01) and at the orifice (P < 0.01). Conclusions Under the conditions of this study, Hero 642 rotary nickel,titanium instruments created canals with few aberrations and no perforations. The relatively high proportion of aberrations in canals with short, acute curves may indicate that instruments with increased taper should be used with caution at or near the full working distance. Further research in real teeth is necessary to elucidate the full potential of these new rotary instruments for use in root canal preparation. [source]


Engine-Driven Preparation Of Curved Root Canals: Measuring Cyclic Fatigue And Other Physical Parameters,

AUSTRALIAN ENDODONTIC JOURNAL, Issue 1 2002
Ove A. Peters Dr med dent
An increasing number of engine-driven rotary systems are marketed to shape root canals. Although these systems may improve the quality of canal preparations, the risk for instrument fracture is also increased. Unfortunately, the stresses generated in rotary instruments when shaping curved root canals have not been adequately studied. Consequently, the aim of an ongoing project was to develop a measurement platform that could more accurately detail physical parameters generated in a simulated clinical situation. Such a platform was constructed by fitting a torque-measuring device between the rotating endodontic instrument and the motor driving it. Apically directed force and instrument insertion depth were also recorded. Additional devices were constructed to assess cyclic fatigue and static fracture loads. The current pilot study evaluated GT rotary instruments during the shaping of curved canals in plastic blocks as well as "ISO 3630,1 torque to fracture" and number of rotations required for fatigue fracture. Results indicated that torques in excess of 40Nmm were generated by rotary GT-Files, a significantly higher figure than static fracture loads (less than 13Nmm for the size 20. 12 GT-File). Furthermore, the number of rotations needed to shape simulated canals with a 5 mm radius of curvature in plastic blocks was 10 times lower than the number of rotations needed to fracture instruments in a "cyclic fatigue test". Apical forces were always greater than IN, and in some specimens, scores of 8N or more were recorded. Further studies are required using extracted natural teeth, with their wide anatomical variation, in order to reduce the incidence of fracture of rotary instruments. In this way, the clinical potential of engine-driven rotary instruments to safely prepare curved canals can be fully appreciated. [source]