The Experts below are selected from a list of 27090 Experts worldwide ranked by ideXlab platform
Lars Bergmans - One of the best experts on this subject based on the ideXlab platform.
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Progressive versus constant tapered Shaft Design using NiTi rotary instruments
International Endodontic Journal, 2003Co-Authors: Lars Bergmans, J. Van Cleynenbreugel, Bart Van Meerbeek, Monique Beullens, Martine Wevers, Peggy LambrechtsAbstract:AIM: To evaluate the influence of a progressive versus constant tapered Shaft Design on canal preparation by NiTi rotary techniques. METHODOLOGY: A XMCT-scanner and custom-made software were used to nondestructively analyse the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 12.5 microm. Specimens (n = 10 per group) were scanned before and after preparation using ProTaper (progressive tapered) or K3 (constant tapered) files. Numerical values for volume, curvature, dentine removal and centring ratio were obtained in addition to a visual inspection for canal aberrations. Data were analysed by (multiway factorial) anova, Wilcoxon tests and t-tests. RESULTS: The volume of total dentine removal (mean +/- SD) was 1.21 +/- 0.66 mm(3) (ProTaper) and 1.06 +/- 0.23 mm(3) (K3) (P > 0.05), and the amount of dentine removal at all separate horizontal regions examined was comparable for both groups. The mean linear dentine removal (transportation) was in the range of 8-212 microm (ProTaper) and 4-187 microm (K3). The resultant centring ratio varied from 0.01 to 0.24 (ProTaper) and from 0.01 to 0.17 (K3), whilst different straightening patterns were observed. A centre displacement towards the furcation coronally was most pronounced for the ProTaper group whereas a centre displacement towards the outer side of the curvature more apically was only observed for the K3 group. No severe canal aberrations were found. CONCLUSIONS: The progressive tapered Shaft Design of the ProTaper instrument was less influenced by the mid-root curvature than the constant tapered Design of the K3 instrument thereby providing a good centred apical preparation. However, ProTaper instruments tended to transport towards the furcation in the coronal region.
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smooth flexible versus active tapered Shaft Design using niti rotary instruments
International Endodontic Journal, 2002Co-Authors: Lars Bergmans, J. Van Cleynenbreugel, Bart Van Meerbeek, Monique Beullens, Martine Wevers, Paul LambrechtsAbstract:AIM The aim of this study was to evaluate the influence of a smooth flexible versus active tapered Shaft Design on canal preparation by NiTi rotary techniques. METHODOLOGY A XMCT-scanner (SkyScan 1072) and developed software (Bergmans et al. 2001) were used to nondestructively analyze the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 30 microm. Specimens (n = 10 per group) were scanned before (PRE) and after (POST) preparation using Lightspeed (smooth flexible) or GT-rotary (active tapered) files. Numerical values for volumes, dentine removal (net) transportation and centring ability were obtained in addition to a visual inspection on canal aberrations. Data were analyzed by Shapiro Wilk test, multiway factorial anova, Tukey-Kramer test, Wilcoxon test and t-test. RESULTS Results indicated that the active tapered Shaft removed significantly more dentine in the middle to apical portion of the root compared to the smooth flexible Design. Both groups demonstrated some straightening, but no significant differences were found with respect to instrument types. However, absolute values for net transportation and centering ratio were small and no canal aberrations could be found. CONCLUSIONS The smooth flexible Shaft Design did not improve the morphological characteristics of canal preparation by NiTi rotary instruments when compared with the active tapered Design. Therefore, system selection should be based upon other criteria.
Bjorn Birgisson - One of the best experts on this subject based on the ideXlab platform.
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calibration of load and resistance factor Design resistance factors for drilled Shaft Design
Transportation Research Record, 2002Co-Authors: Ching L Kuo, Michael Mcvay, Bjorn BirgissonAbstract:The AASHTO load and resistance factor Design specification was approved for use in 1994 with phi factors determined from fitting allowable stress Design (ASD). Unfortunately, the latter did not provide resistance factors for Shafts founded in sand, gravel, and rock or identify the influence of construction (dry, wet, and cased). Using a database of 273 Shafts, of which 185 failed (settlement equal to 5% of the diameter) and have sufficient soil information, the resistance factors were determined for a number of different AASHTO Design methods based on probability of failure. Effects of skin friction, combined skin and end bearing, and method of construction were investigated for different soils/rock. It was found that all the methods had resistance factors between 0.3 and 0.6, which correspond to a factor of safety of 2.5 to 4.5 in ASD. Current FHWA Design methods gave the highest resistance factors in soils with the cased method of construction. In the case of rock, the dry hole method of construction an...
J. Van Cleynenbreugel - One of the best experts on this subject based on the ideXlab platform.
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Progressive versus constant tapered Shaft Design using NiTi rotary instruments
International Endodontic Journal, 2003Co-Authors: Lars Bergmans, J. Van Cleynenbreugel, Bart Van Meerbeek, Monique Beullens, Martine Wevers, Peggy LambrechtsAbstract:AIM: To evaluate the influence of a progressive versus constant tapered Shaft Design on canal preparation by NiTi rotary techniques. METHODOLOGY: A XMCT-scanner and custom-made software were used to nondestructively analyse the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 12.5 microm. Specimens (n = 10 per group) were scanned before and after preparation using ProTaper (progressive tapered) or K3 (constant tapered) files. Numerical values for volume, curvature, dentine removal and centring ratio were obtained in addition to a visual inspection for canal aberrations. Data were analysed by (multiway factorial) anova, Wilcoxon tests and t-tests. RESULTS: The volume of total dentine removal (mean +/- SD) was 1.21 +/- 0.66 mm(3) (ProTaper) and 1.06 +/- 0.23 mm(3) (K3) (P > 0.05), and the amount of dentine removal at all separate horizontal regions examined was comparable for both groups. The mean linear dentine removal (transportation) was in the range of 8-212 microm (ProTaper) and 4-187 microm (K3). The resultant centring ratio varied from 0.01 to 0.24 (ProTaper) and from 0.01 to 0.17 (K3), whilst different straightening patterns were observed. A centre displacement towards the furcation coronally was most pronounced for the ProTaper group whereas a centre displacement towards the outer side of the curvature more apically was only observed for the K3 group. No severe canal aberrations were found. CONCLUSIONS: The progressive tapered Shaft Design of the ProTaper instrument was less influenced by the mid-root curvature than the constant tapered Design of the K3 instrument thereby providing a good centred apical preparation. However, ProTaper instruments tended to transport towards the furcation in the coronal region.
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smooth flexible versus active tapered Shaft Design using niti rotary instruments
International Endodontic Journal, 2002Co-Authors: Lars Bergmans, J. Van Cleynenbreugel, Bart Van Meerbeek, Monique Beullens, Martine Wevers, Paul LambrechtsAbstract:AIM The aim of this study was to evaluate the influence of a smooth flexible versus active tapered Shaft Design on canal preparation by NiTi rotary techniques. METHODOLOGY A XMCT-scanner (SkyScan 1072) and developed software (Bergmans et al. 2001) were used to nondestructively analyze the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 30 microm. Specimens (n = 10 per group) were scanned before (PRE) and after (POST) preparation using Lightspeed (smooth flexible) or GT-rotary (active tapered) files. Numerical values for volumes, dentine removal (net) transportation and centring ability were obtained in addition to a visual inspection on canal aberrations. Data were analyzed by Shapiro Wilk test, multiway factorial anova, Tukey-Kramer test, Wilcoxon test and t-test. RESULTS Results indicated that the active tapered Shaft removed significantly more dentine in the middle to apical portion of the root compared to the smooth flexible Design. Both groups demonstrated some straightening, but no significant differences were found with respect to instrument types. However, absolute values for net transportation and centering ratio were small and no canal aberrations could be found. CONCLUSIONS The smooth flexible Shaft Design did not improve the morphological characteristics of canal preparation by NiTi rotary instruments when compared with the active tapered Design. Therefore, system selection should be based upon other criteria.
Bart Van Meerbeek - One of the best experts on this subject based on the ideXlab platform.
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Progressive versus constant tapered Shaft Design using NiTi rotary instruments
International Endodontic Journal, 2003Co-Authors: Lars Bergmans, J. Van Cleynenbreugel, Bart Van Meerbeek, Monique Beullens, Martine Wevers, Peggy LambrechtsAbstract:AIM: To evaluate the influence of a progressive versus constant tapered Shaft Design on canal preparation by NiTi rotary techniques. METHODOLOGY: A XMCT-scanner and custom-made software were used to nondestructively analyse the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 12.5 microm. Specimens (n = 10 per group) were scanned before and after preparation using ProTaper (progressive tapered) or K3 (constant tapered) files. Numerical values for volume, curvature, dentine removal and centring ratio were obtained in addition to a visual inspection for canal aberrations. Data were analysed by (multiway factorial) anova, Wilcoxon tests and t-tests. RESULTS: The volume of total dentine removal (mean +/- SD) was 1.21 +/- 0.66 mm(3) (ProTaper) and 1.06 +/- 0.23 mm(3) (K3) (P > 0.05), and the amount of dentine removal at all separate horizontal regions examined was comparable for both groups. The mean linear dentine removal (transportation) was in the range of 8-212 microm (ProTaper) and 4-187 microm (K3). The resultant centring ratio varied from 0.01 to 0.24 (ProTaper) and from 0.01 to 0.17 (K3), whilst different straightening patterns were observed. A centre displacement towards the furcation coronally was most pronounced for the ProTaper group whereas a centre displacement towards the outer side of the curvature more apically was only observed for the K3 group. No severe canal aberrations were found. CONCLUSIONS: The progressive tapered Shaft Design of the ProTaper instrument was less influenced by the mid-root curvature than the constant tapered Design of the K3 instrument thereby providing a good centred apical preparation. However, ProTaper instruments tended to transport towards the furcation in the coronal region.
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smooth flexible versus active tapered Shaft Design using niti rotary instruments
International Endodontic Journal, 2002Co-Authors: Lars Bergmans, J. Van Cleynenbreugel, Bart Van Meerbeek, Monique Beullens, Martine Wevers, Paul LambrechtsAbstract:AIM The aim of this study was to evaluate the influence of a smooth flexible versus active tapered Shaft Design on canal preparation by NiTi rotary techniques. METHODOLOGY A XMCT-scanner (SkyScan 1072) and developed software (Bergmans et al. 2001) were used to nondestructively analyze the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 30 microm. Specimens (n = 10 per group) were scanned before (PRE) and after (POST) preparation using Lightspeed (smooth flexible) or GT-rotary (active tapered) files. Numerical values for volumes, dentine removal (net) transportation and centring ability were obtained in addition to a visual inspection on canal aberrations. Data were analyzed by Shapiro Wilk test, multiway factorial anova, Tukey-Kramer test, Wilcoxon test and t-test. RESULTS Results indicated that the active tapered Shaft removed significantly more dentine in the middle to apical portion of the root compared to the smooth flexible Design. Both groups demonstrated some straightening, but no significant differences were found with respect to instrument types. However, absolute values for net transportation and centering ratio were small and no canal aberrations could be found. CONCLUSIONS The smooth flexible Shaft Design did not improve the morphological characteristics of canal preparation by NiTi rotary instruments when compared with the active tapered Design. Therefore, system selection should be based upon other criteria.
Monique Beullens - One of the best experts on this subject based on the ideXlab platform.
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Progressive versus constant tapered Shaft Design using NiTi rotary instruments
International Endodontic Journal, 2003Co-Authors: Lars Bergmans, J. Van Cleynenbreugel, Bart Van Meerbeek, Monique Beullens, Martine Wevers, Peggy LambrechtsAbstract:AIM: To evaluate the influence of a progressive versus constant tapered Shaft Design on canal preparation by NiTi rotary techniques. METHODOLOGY: A XMCT-scanner and custom-made software were used to nondestructively analyse the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 12.5 microm. Specimens (n = 10 per group) were scanned before and after preparation using ProTaper (progressive tapered) or K3 (constant tapered) files. Numerical values for volume, curvature, dentine removal and centring ratio were obtained in addition to a visual inspection for canal aberrations. Data were analysed by (multiway factorial) anova, Wilcoxon tests and t-tests. RESULTS: The volume of total dentine removal (mean +/- SD) was 1.21 +/- 0.66 mm(3) (ProTaper) and 1.06 +/- 0.23 mm(3) (K3) (P > 0.05), and the amount of dentine removal at all separate horizontal regions examined was comparable for both groups. The mean linear dentine removal (transportation) was in the range of 8-212 microm (ProTaper) and 4-187 microm (K3). The resultant centring ratio varied from 0.01 to 0.24 (ProTaper) and from 0.01 to 0.17 (K3), whilst different straightening patterns were observed. A centre displacement towards the furcation coronally was most pronounced for the ProTaper group whereas a centre displacement towards the outer side of the curvature more apically was only observed for the K3 group. No severe canal aberrations were found. CONCLUSIONS: The progressive tapered Shaft Design of the ProTaper instrument was less influenced by the mid-root curvature than the constant tapered Design of the K3 instrument thereby providing a good centred apical preparation. However, ProTaper instruments tended to transport towards the furcation in the coronal region.
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smooth flexible versus active tapered Shaft Design using niti rotary instruments
International Endodontic Journal, 2002Co-Authors: Lars Bergmans, J. Van Cleynenbreugel, Bart Van Meerbeek, Monique Beullens, Martine Wevers, Paul LambrechtsAbstract:AIM The aim of this study was to evaluate the influence of a smooth flexible versus active tapered Shaft Design on canal preparation by NiTi rotary techniques. METHODOLOGY A XMCT-scanner (SkyScan 1072) and developed software (Bergmans et al. 2001) were used to nondestructively analyze the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 30 microm. Specimens (n = 10 per group) were scanned before (PRE) and after (POST) preparation using Lightspeed (smooth flexible) or GT-rotary (active tapered) files. Numerical values for volumes, dentine removal (net) transportation and centring ability were obtained in addition to a visual inspection on canal aberrations. Data were analyzed by Shapiro Wilk test, multiway factorial anova, Tukey-Kramer test, Wilcoxon test and t-test. RESULTS Results indicated that the active tapered Shaft removed significantly more dentine in the middle to apical portion of the root compared to the smooth flexible Design. Both groups demonstrated some straightening, but no significant differences were found with respect to instrument types. However, absolute values for net transportation and centering ratio were small and no canal aberrations could be found. CONCLUSIONS The smooth flexible Shaft Design did not improve the morphological characteristics of canal preparation by NiTi rotary instruments when compared with the active tapered Design. Therefore, system selection should be based upon other criteria.
